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Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

Volume 78 (2021): Edizione 1 (March 2021)

Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

26 Articoli

Section I - Kinesiology

Accesso libero

Muscle Force Patterns in Lower Extremity Muscles for Elite Discus Throwers, Javelin Throwers and Shot-Putters – A Case Study

Pubblicato online: 31 Mar 2021
Pagine: 5 - 14

Astratto

Abstract

Optimal release variables, as well as the kinematics and kinetics of athletes, are crucial for the maximization of throwing distance in athletics. Mathematical models and simulations allow throwing techniques to be studied. However, muscle force patterns and the contribution of specific muscle groups in athletics throwing events are not well understood and require detailed research. In this study, important variables of the muscle force generated during the javelin, discus and shot put events were determined using OpenSim software. Musculoskeletal simulations were carried out based on kinematic and kinetic data collected using the Vicon system and Kistler plates with the help of nine top Polish athletes (three in each event). OpenSim software was used to calculate muscle forces and joint velocities. For each discipline, it was found that the main muscle groups involved in the throwing movement were better at distinguishing throwers than joint velocities. The contribution of right ankle plantar flexors at the beginning of the final acceleration phase as well as left hip extensors at the end of the final acceleration phase was given special attention. This work provides a better understanding of the techniques used in athletics throws. Musculoskeletal simulations of throwing styles might help coaches analyze the techniques of individual athletes, resulting in better adjustment of training programmes and injury prevention protocols.

Key words

  • athletics throws
  • musculoskeletal simulation
  • ballistic movement
  • inverse dynamics
Accesso libero

The Neuromuscular Characteristics of Gymnasts’ Jumps and Landings at Particular Stages of Sports Training

Pubblicato online: 31 Mar 2021
Pagine: 15 - 28

Astratto

Abstract

Safe and proper landings are crucial elements of gymnastics events. Long-term training leads to specific neuromuscular adaptations which are yet to be explored in terms of gymnastic landings. The aim of the study was to assess differences in landings’ neuromuscular characteristics between gymnasts at three subsequent gymnastic training stages and age-matched non-athletes. Forty-six gymnasts (G) and 58 controls (C) performed countermovement jumps on a force plate with simultaneous surface electromyography (SEMG) of lower body muscles, measured during the pre-(100 ms) and post-landing phase (0-100 and 0-200 ms). Three age groups participated in the study: 8–10 (G1, C1), 12–14 (G2, C2), 18–25 (G3, C3) years. Analysis included the normalized root mean square (NRMS) SEMG signal and ground reaction forces (GRFs). Gymnasts achieved 13% higher values (p = 0.04) of relative peak GRFs in comparison with controls. It was especially seen in 8–10-year-olds: G1 presented 33% higher (p = 0.03) results than C1 and G2. In SEMG analysis, gymnasts showed overall lower NRMS values in comparison with the controls. In the pre-landing phase, the NRMS in the rectus femoris was from 1.6 up to 3.4 times higher for C1 (p = 0.02) than for C2, G2, C3, and G3. Gymnasts across subsequent training stages exhibit different patterns of neuromuscular coordination during landings. The highest GRF observed in the youngest gymnasts may be a potential risk factor of injuries. Therefore, further injury-focused investigation is recommended to monitor landing strategies among gymnasts of different stages with particular emphasis on the beginners.

Key words

  • ground reaction forces
  • countermovement jump
  • artistic gymnastics
  • neuromuscular coordination
Accesso libero

Common Movement Patterns of the Jump Shot while Increasing the Distance from the Basket in Elite Basketball Players

Pubblicato online: 31 Mar 2021
Pagine: 29 - 39

Astratto

Abstract

The aim of this study was to examine chosen kinematic variables (duration of the shot, position of the centre of mass, position of the shooting hand, rotation of the shoulder axis) of successful shots and to describe differences in movement patterns in elite basketball players while increasing the distance from the basket during a jump shot. Our participants were three elite shooting guards who were all Slovenian national team and Euroleague players. They were shooting from three different distances (3.75 m, 5.25 m, and 6.75 m); analysis included 90 successful shots. The kinematics of the entire body was analysed using the inertial motion capture suit. The main interest was on the transverse plane (direction Y), focusing on rotational movements and movements to the left and right. The results showed that the rotation of the shoulder axis in the transverse plane, with all three participants, was greatest (p < .05) from the longest distance. Despite that graphs of individual players differed, deviation to the left was most significant while shooting from the largest distance for all participants. Also the landing from the jump shot was on the left according to the origin. For example, the average deviation to the left for player no. 2 was 11.9 ± 3.6 cm (the shortest distance), 12.6 ± 4.7 cm (the middle distance), and 23.3 ± 5.1 cm (the longest distance). Distance from the basket influenced the kinematics of the shot, especially from the longest distance. Along with the already well-known changes in the sagittal plane (direction X and Z), this research provides information on changes in the transverse plane, which are also very important, especially while shooting from longer distances.

Key words

  • transverse plane
  • duration of the shot
  • position of the centre of mass and shooting hand
  • rotation of the shoulder axis
Accesso libero

Analyses of Countermovement Jump Performance in Time and Frequency Domains

Pubblicato online: 31 Mar 2021
Pagine: 41 - 48

Astratto

Abstract

This study aimed to analyze counter-movement jump (CMJ) performance in time and frequency domains. Fortyfour Division I American football players participated in the study. Kinetic variables were collected from both dominant and non-dominant legs using two force plates. Normalized peak power, normalized net impulse, and normalized peak force significantly correlated with jump height (r = .960, r = .998, r = .725, respectively with p < .05). The mean frequency component was significantly correlated with CMJ performance (r = .355 with p < .05). The reliability of the frequency variables was higher than the time domain variables. Frequency domain variables showed weaker correlations with jump height compared with time domain variables. Frequency domain analysis provides frequency components, which represent the rate of energy transmission from the eccentric phase to the end of the push-off phase. Frequency component information may provide additional information for the analyses of CMJ performance for athletes.

Key words

  • countermovement jump
  • kinetics
  • time domain
  • frequency domain
Accesso libero

Do Expert Fencers Engage the Same Visual Perception Strategies as Beginners?

Pubblicato online: 31 Mar 2021
Pagine: 49 - 58

Astratto

Abstract

An effective visual perception strategy helps a fencer quickly react to an opponent’s actions. This study aimed to examine and compare visual perception strategies used by high-performance foil fencers (experts) and beginners. In an eye tracking experiment, we analysed to which areas beginning and expert fencers paid attention during duels. Novices paid attention to all examined areas of interest comprising the guard, foil (blade and tip), armed hand, lower torso, and upper torso of their opponents. Experts, however, paid significantly less attention to the foil, picking up information from other areas, mainly the upper torso and the armed hand. These results indicate that expert fencers indeed engage different visual perception strategies than beginners. The present findings highlight the fact that beginner fencers should be taught already in the early stages of their careers how to pick up information from various body areas of their opponents.

Key words

  • perception strategies
  • foil fencing
  • experts
  • beginners
  • eye tracking

Section II - Exercise Physiology & Sports Medicine

Accesso libero

The Second‐to‐Fourth Digit (2D:4D) Ratio of Male Combat Athletes is Associated with the Choice of Sport

Pubblicato online: 31 Mar 2021
Pagine: 59 - 66

Astratto

Abstract

The second-to-fourth-digit (2D:4D) ratio has been widely used as a putative marker of prenatal exposure to testosterone in health, behavioral and sport sciences, but it has only been used few times regarding combat athletes. This study involved 200 male elite combat athletes (Olympic wrestling, kickboxing, judo, taekwondo and karate) and 179 males not participating in any sports. The lengths of the index finger (2D) and ring (4D) finger were measured using computer-assisted image analysis (AutoMetric 2.2 software). The 2D:4D ratio of combat athletes was significantly lower than that of the controls. Moreover, a lower 2D:4D ratio was found among wrestlers, judo athletes and kickboxers than in the control group, and a higher 2D:4D ratio was found, but with borderline significance, among karate and taekwondo athletes. Moreover, multivariate analysis adjusted for age showed that judo, Olympic wrestling and kickboxing athletes combined had 2D:4D ratios significantly lower (by 0.035 on average) than those of the rest of the subjects and that karate and taekwondo athletes together had 2D:4D ratios significantly higher (by 0.014 on average) than those of the rest of the subjects. The research results and literature review indicate that knowledge about the functional meaning of the 2D:4D ratio is still too fragmentary and it is too early to use the 2D:4D ratio in the selection of sport talent; however, it may be a useful criteria when screening prospective athletes to be recruited to a team. That is why 2D:4D reference values should be defined for particular sports.

Key words

  • digit ratio (2D:4D)
  • combat sports
  • sport selection
  • aggression
  • predispositions
Accesso libero

Influence of Biological Maturity on the Muscular Strength of Young Male and Female Swimmers

Pubblicato online: 31 Mar 2021
Pagine: 67 - 77

Astratto

Abstract

The present study compared the evolution of strength and muscle mass in swimmers of both sexes across different chronological and biological ages. Seventy-six swimmers (55 males and 21 females) from 10 to 20 years of age underwent evaluations of sexual maturation using the developmental stage of the genitals (G1, G2, G3 G4 and G5) and pubic hair (P1, P2, P3, P4 and P5) (Tanner criteria), lean mass using the dual-energy X-ray absorptiometry method, and isokinetic strength of the knee extensor muscles. Boys did not present a significant difference in strength among G1, G2, and G3 (p > 0.05) nor between 10 and 13 years of age (p > 0.05), although significant differences in strength of the extensor (p = 0.038) muscles of the knee were found between G3 and G4 and between athletes of 10 and 14 years of age (extensor muscles, p = 0.033). Muscle mass was different between G3 and G4 (p = 0.003) and between 10 and 14 years of age (p = 0.020). The mean age of boys in the G4 pubertal stage was 13.7 ± 2.0 years, although from 12 to 16 years of age, boys are typically in the G4 stage. Girls showed no significant differences in strength nor muscle mass among the pubertal stages (p > 0.05). We conclude that by equating boys by chronological age, individuals with different pubertal development levels, muscle mass, and strength levels can be grouped. Therefore, the relationship between the level of pubertal deve-lopment and chronological age seems to be a useful strategy for grouping boys, while grouping girls by chronological age seems adequate for training and competition.

Key words

  • puberty
  • sexual maturity
  • isokinetic
  • lean mass
Accesso libero

Different Training Methods Cause Similar Muscle Damage in Youth Judo Athletes

Pubblicato online: 31 Mar 2021
Pagine: 79 - 87

Astratto

Abstract

It is well known that different factors can contribute to muscle damage in judo matches or training. Previous research analyzed only the effects of simulated judo combat or judo training on biochemical markers of muscle damage without determining its specific causes. Our objective was to identify possible differences in biochemical markers of muscular damage in response to different training methods in youth judo athletes. Twelve high-level male judo athletes were randomly assigned to a standing (SP, n = 6, age = 16.6 ± 1.1 years) or a groundwork (GP, n = 6, age = 17.8 ± 0.8 years) position combat practice group. Both groups had the same protocol of four 4-minute combat practice bouts separated by 1-minute rest intervals. Before and immediately after combat practice blood samples were taken to assess muscle damage markers: creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). There were significant increases in AST, LDH, and CK after the standing and groundwork training sessions compared with resting values in both groups. Additionally, no significant differences in the enzyme's activity between SP and GP groups were found. These results showed that standing and groundwork randori training (free sparring or free practice) causes similar muscle damage in adolescent judo athletes. Future research should assess the effects of the same damage mechanisms over a longer period of time

Key words

  • biochemical markers
  • adolescent, exercise testing
  • judo, training
Accesso libero

Workout Pacing Predictors of Crossfit® Open Performance: A Pilot Study

Pubblicato online: 31 Mar 2021
Pagine: 89 - 100

Astratto

Abstract

To observe workout repetition and rest interval pacing strategies and determine which best predicted performance during the 2016 CrossFit® Open, five male (34.4 ± 3.8 years, 176 ± 5 cm, 80.3 ± 9.7 kg) and six female (35.2 ± 6.3 years, 158 ± 7 cm, 75.9 ± 19.3 kg) recreational competitors were recruited for this observational, pilot study. Exercise, round, and rest time were quantified via a stopwatch for all competitors on their first attempt of each of the five workouts. Subsequently, pacing was calculated as a repetition rate (repetitions·s-1) to determine the fastest, slowest, and average rate for each exercise, round, and rest interval, as well as how these changed (i.e., slope, Δ rate / round) across each workout. Spearman’s rank correlation coefficients indicated that several pacing variables were significantly (p < 0.05) related to performance on each workout. However, stepwise regression analysis indicated that the average round rate best predicted (p < 0.001) performance on the first (R2 = 0.89), second (R2 = 0.99), and fifth (R2 = 0.94) workouts, while the competitors’ rate on their slowest round best predicted workout three performance (R2 = 0.94, p < 0.001). The wall ball completion rate (R2 = 0.89, p = 0.002) was the best predictor of workout four performance, which was improved by 9.8% with the inclusion of the deadlift completion rate. These data suggest that when CrossFit® Open workouts consist of multiple rounds, competitors should employ a fast and sustainable pace to improve performance. Otherwise, focusing on one or two key exercises may be the best approach.

Key words

  • strategy
  • competition
  • recreational athletes
  • HIFT
  • exercise
Accesso libero

Acute Effects of Resistance Training with Blood Flow Restriction on Achilles Tendon Thickness

Pubblicato online: 31 Mar 2021
Pagine: 101 - 109

Astratto

Abstract

The Achilles tendon is one of the strongest and thickest tendons of the human body. Several studies have reported an immediate decrease in Achilles tendon thickness after a single bout of resistance training. However, the effects of blood flow restriction training on Achilles tendon thickness have not been investigated. The purpose of this study was to investigate the acute effects of different regimens of resistance training on Achilles tendon thickness. Fiftytwo participants (27.3 ± 7 years; 177.6 ± 11 cm; 72.2 ± 13.7 kg) were randomly allocated into one of the three groups: low-intensity exercise without (LI, n = 13) and with blood flow restriction (LI-BFR, n = 24), and high-intensity exercise (HI, n = 15). Participants from LI and LI-BFR groups performed four sets (1 x 30 + 3 x 15 reps) at 30% 1RM, while the HI group performed four sets (1 x 30 with 30% 1RM + 3 x 10 reps with 75% 1RM). All groups performed a plantar flexion exercise. For the LI-BFR group, a blood pressure cuff was placed on the dominant calf and inflated at 30% of the individual´s occlusion pressure (47.6 ± 19.8 mmHg). Sonographic images of Achilles tendon thickness were taken at pre, immediately after, 60 min and 24 h following acute bouts of exercise. Achilles tendon thickness was significantly reduced immediately after, 60 min and 24 h post-LI-BFR exercise (pre: 4.4 ± 0.4 mm vs. IA: 3.8 ± 0.4 mm vs. 60 min: 3.7 ± 0.3 mm vs. 24 h: 4.1 ± 0.3 mm; p < 0.001), whereas Achilles tendon thickness was unchanged for HI and LI groups (p > 0.05). These results suggest that blood flow restriction training may be an effective strategy to stimulate a positive response in Achilles tendon thickness.

Key words

  • tendon morphology
  • low-load exercise
  • injury
  • ultrasonography
  • occlusion training
  • rehabilitation
Accesso libero

The Effects of High Mineral Alkaline Water Consumed over Three Consecutive Days on Reaction Time Following Anaerobic Exercise – A Randomized Placebo‐Controlled Crossover Pilot Study

Pubblicato online: 31 Mar 2021
Pagine: 111 - 119

Astratto

Abstract

Drinking alkaline water after intense anaerobic exercise may enhance both cognitive and physical performance. This study aimed to investigate the effect of high mineral alkaline water consumed over three consecutive days on reaction time after anaerobic exercise in twelve healthy young males (aged 21.1 ± 1.3 years) with a valid sports medical examination. Participants were excluded when they took any medications or performance-enhancing supplements for the period of at least four weeks before the study commenced. Participants were randomly divided into two groups in this double-blind, placebo-controlled crossover pilot study. They ingested either alkaline water (AW) or regular table water ( RTW) for three consecutive days before anaerobic exercise. The anaerobic exercise consisted of two 2-min high-intensity step-tests with a passive rest interval of 3 minutes between the two bouts of exercise. Performance in the step-test (W), reaction time for visual and auditory signals, the rate of perceived exertion (RPE), urine specific gravity, and lactate concentration were analysed. No effect of AW was found on reaction time and the other variables except anaerobic performance. An-aerobic performance was significantly higher after ingestion of AW in both step-tests (p < 0.05). The ingestion of AW for three consecutive days before anaerobic exercise seems to positively affect anaerobic performance.

Key words

  • Rate of Perceived Exertion
  • step-test
  • exercise
  • buffer system
Accesso libero

Influence of a Maximal Incremental Test Until Exhaustion on the Urinary Excretion of Steroid Hormones in Trained Cyclists

Pubblicato online: 31 Mar 2021
Pagine: 121 - 129

Astratto

Abstract

This study aimed to assess the effect of a maximum incremental stress test through urinary concentrations of steroid hormones in trained cyclists. Twenty male cyclists participated in the study (23.83 ± 2.3 years; 1.76 ± 0.03 m; 66.94 ± 3.59 kg; training volume: 20.50 ± 2.35 h/week). Athletes performed a maximum incremental test until exhaustion on a cycle ergometer and urine samples were collected at three different time points: before, immediately after, and 48 h after the test. Lactate, creatinine and urinary concentrations of testicular and adrenal androgens were obtained as well as urinary concentrations of glucocorticoid hormones. An increase in lactate was observed after the test (p < 0.01). There were decreases in the urinary excretion of androgenic hormones after the test, which were significant in testosterone, androsterone, androstenedione, total adrenal androgen and total testicular androgen (p < 0.05). The values were restored after 48 h (p < 0.05). Urinary cortisol concentrations decreased after the test (p < 0.05). A decrease was also observed in the ratio of anabolic/catabolic hormones (p < 0.05) increasing 48 h after the test (p < 0.05). Increased acute physical exercise until exhaustion causes variations in the urinary excretions of steroid hormones which were restored 48 h after exercise. Urinary excretion of steroid hormones could be a valid method of monitoring training loads.

Key words

  • exercise
  • androgens
  • glucocorticoids
  • stress
  • recovery
Accesso libero

The Effect of a Tailored Intervention on Female Soccer Players’ Hydration Status

Pubblicato online: 31 Mar 2021
Pagine: 131 - 140

Astratto

Abstract

Numerous studies have reported that athletes’ pre-training/-game hydration status is of concern. Up to now, only two cohort studies have examined the effect of an intervention aimed at improving pretraining/-game hydration status; however, without including a control group. Therefore, the aim of this quasi-experimental study was to examine whether and to what extent an individually tailored intervention focused on the benefits of being optimally hydrated before training or game would alter the hydration status of female soccer players. Two teams of young adult female soccer players were allocated to an intervention (n = 22; 19.8 ± 3.0 years) or a control group (n = 15; 22.8 ± 4.0 years). Players in the intervention group received an individually tailored intervention, based on Urine Specific Gravity (USG) measurements, which took place in between two training weeks. Before each training and match play, a urine sample was collected to determine players’ hydration status. Mixed modelling was applied to assess within and between differences in hydration status over time. The pre-training/-game hydration status of the intervention group improved significantly, with players’ mean USG-value decreasing from 1.013 ± 0.001 g/mL to 1.008 ± 0.002 g/mL (p = 0.005). In contrast, the mean USG-value in the control group increased significantly from 1.012 ± 0.002 g/mL to 1.016 ± 0.002 g/mL (p = 0.023), indicating a deterioration of their pre-training/-game hydration status. The individually tailored intervention did show a positive effect even though female soccer players in the present study were already reasonably well hydrated before the start of the intervention.

Key words

  • USG
  • football
  • quasi-experiment
  • athlete
  • women
  • intervention

Section III - Sports Training

Accesso libero

Post-Activation Potentiation in Strength Training: A Systematic Review of the Scientific Literature

Pubblicato online: 31 Mar 2021
Pagine: 141 - 150

Astratto

Abstract

This review aimed to determine the ideal combination of post activation potentiation (PAP) strategies for an improved strength performance. After analysing 202 articles, 15 studies met the inclusion criteria. The findings of this review suggest that a potentiation effect exists as long as a minimum intensity and enough rest are provided. Although intensities of 65% 1RM are sufficient to elicit a potentiation effect, higher effects can be achieved with 85 - 90% 1RM intensities. Similarly, we found that experienced athletes will benefit more from a higher volume bout (1-3 sets), as long as 7-8 minutes of rest are allowed to avoid fatigue.

Key words

  • PAP
  • complex training
  • performance
  • resistance training
  • strength training
Accesso libero

Does Youth Soccer Players’ Group Cooperation Improve when Pitch, Goal, and Team Size Are Reduced?

Pubblicato online: 31 Mar 2021
Pagine: 151 - 160

Astratto

Abstract

The aim of this study was to analyse the effects of the modification of the pitch size, goal size, and the number of players per team on the level of cooperation in youth soccer players (U-12). A quasi-experimental design was implemented to measure the effects of the changes in the number of players per team (8-a-side vs. 5-a-side), goal size (6 x 2 m vs. 3 x 2 m), and field size (58 x 38 m vs. 38 x 20 m) on the cooperation. Four soccer teams under-12 (n = 48 players) participated in three tournaments (standard rules; proposed rules; standard rules). The five variables of cooperation were measured using the “Sports Cooperation Questionnaire”: conditional cooperation, cooperation with the coach, disposition of unconditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play. Players presented the same level of cooperation in conditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play with both types of rules. The modification of rules involved a reduction of the cooperation with the coach and a disposition of unconditional cooperation. The causes of the reduction may be related to players’ adaptation to new tactical dispositions and game situations. Future studies are needed of player’s cooperation and different competition rules in youth sports.

Key words

  • sport
  • teamwork
  • rules modification
  • sports initiation
  • adaptation
Accesso libero

Coexistence of Distinct Performance Models in High-Level Women’s Volleyball

Pubblicato online: 31 Mar 2021
Pagine: 161 - 173

Astratto

Abstract

In performance analysis, and most notably in match analysis, generalizing game patterns in a sport or competition may result in formulating generic models and neglecting relevant variability in benefit of average or central values. Here, we aimed to understand how different game models can coexist at the same competitive level using social network analysis with degree centrality to obtain systemic mappings for six volleyball matches, one for each of the six national teams playing in the 2014 World Grand Prix Finals, guaranteeing a homogeneous game level and balanced matches. Although the sample was not recent, this was not relevant for our purposes, since we aimed to merely expose a proof of concept. A total of 56 sets and 7,176 ball possessions were analysed through Gephi Software, considering game actions as nodes and the interaction between them as edges. Results supported the coexistence of different performance models at the highest levels of practice, with each of the six teams presenting a very distinct game model. For example, important differences in eigenvector centrality in attack zones (ranging from 0 to 34) and tempos (20 to 38) were found between the six teams, as well as in defensive lines (20 to 39) and block opposition (22 to 37). This further suggests that there may be multiple pathways towards expert performance within any given sport, inviting a re-conceptualization of monolithic talent identification, detection and selection models. Future studies could benefit from standardizing the metrics in function of the number of ball possessions.

Key words

  • performance analysis
  • systemic mapping
  • performance variability
  • volleyball
Accesso libero

Effects of Plyometric, Strength and Change of Direction Training on High-School Basketball Player’s Physical Fitness

Pubblicato online: 31 Mar 2021
Pagine: 175 - 186

Astratto

Abstract

The study aim was to compare the effects of a 7-week plyometric, strength and change of direction (COD) training program on basketball-specific performance measures in high-school players. Forty male players were randomly assigned to one of the four groups: plyometric (PG, n = 10), strength (SG, n = 10), COD (CODG, n = 10), and control group training (CG, n = 10). Two training sessions were performed at weekly intervals before basketball training. Performance of the counter movement jump (CMJ), Abalakov jump (ABKJ), 10 m zig-zag sprint, 20 m in line sprint (measurements at 10 and 20 m), and sit and reach flexibility test (SRFT) was assessed before and after the intervention. A 4 (group) × 2 (time) repeated measures analysis of variances (ANOVA) was conducted for each variable. Bonferroni post-hoc tests were used when the interaction was significant. Significant (all p < 0.05) time x group interaction was noted for SRFT, CMJ, ABK, sprint, and zig-zag 10 m, in favor of the experimental groups compared to the control group. However, improvements in physical fitness were similar between the three experimental groups. In conclusion, 7 weeks of specific plyometric, strength and COD training produced similar medium to large improvements in physical fitness of high-school basketball players.

Key words

  • vertical jump
  • pubertal
  • sport conditioning
  • youth athletes
Accesso libero

Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games

Pubblicato online: 31 Mar 2021
Pagine: 187 - 196

Astratto

Abstract

The aim of this study was to compare external training loads between small-sided games (SSGs) and largesided games (LSGs) in soccer players. Twenty outfield soccer players (14.8 ± 0.6 years old) who competed in the Spanish U16 Provincial Division and belonged to the same team participated in the study. The soccer sided games were played at different individual interaction space (IIS) per player (i.e., SSG = 100 m2 and LSG = 200 m2) and were disputed in the same format (five-a-side plus goalkeepers) on two different pitch sizes (i.e., 38 x 26 vs. 53 x 37 m) defending an official soccer-goal. The sided games’ duration was 4 bouts of 6 min with 2 min rest intervals between bouts. The results of this study showed no meaningful differences in the total distance and intensity of accelerations and decelerations between SSGs and LSGs except for the lower distance covered at medium intensity (2.5 - 4 m·s-2) observed during LSGs (-10.2%; ES (effect size): -0.51). Players registered greater sprints, maximum velocity (Velmax) and body impacts at different intensities (i.e., I5-6g, I6-6.5g, I6.5-7g, I7-8g, I8-10g,) in LSGs in comparison to SSGs. These findings suggest that an increase in the pitch size (i.e., IIS per player) can induce higher external loads for soccer players.

Key words

  • soccer
  • quantification
  • external loads
  • individual interaction space
  • neuromuscular
Accesso libero

Specific and Holistic Predictors of Sprint Front Crawl Swimming Performance

Pubblicato online: 31 Mar 2021
Pagine: 197 - 207

Astratto

Abstract

The aim of the study was to examine the impact of selected water- and dry-land predictors of 50-m front crawl performance among 27 male swimmers aged 19.3 ± 2.67 years. The following water tests were performed: front crawl tethered arm stroking in a water flume (flow velocity: 0.9 m·s–1) and leg tethered flutter kicking in a swimming pool. Anaerobic tests on dry land included arm cranking and a set of 10 countermovement jumps. The maximal and average forces generated by legs in tethered swimming (Fl max and Fl ave) turned out to be the strongest predictors of sprint swimming aptitude. These values were strongly correlated with total speed (Vtotal50) (r = 0.49, p < 0.05 and r = 0.54, p < 0.01, respectively), start, turn, and finishing speed (VSTF) (r = 0.60, p < 0.01 and r = 0.67, p < 0.01, respectively). The relationship of Fl max and Fl ave with surface speed (Vsurface) was moderate (r = 0.33, non-significant and r = 0.41, p < 0.05, respectively). The maximal force generated by arms (Fa max) during flume tethered swimming significantly influenced Vsurface and Vtotal50 (0.51, p < 0.01 and 0.47, p < 0.05, respectively). Its relationship with VSTF was close to significant (0.36, p = 0.07). Upper and lower limb dry-land tests showed lower and more holistic relationships with the 50-m front crawl race, however, being a good complement to overall fitness assessment. Specific in-water evaluation, especially the newly prepared flutter kicking test, as well as dry-land tests, can be applied to regularly monitor progress in swimming training, and to identify talented swimmers.

Key words

  • strength
  • test
  • power
  • movement velocity
  • biomechanics
Accesso libero

Performing Repetitions To Failure in Lower-Limb Single-Joint Exercise does not Reduce Countermovement Jump Performance in Trained Male Adults

Pubblicato online: 31 Mar 2021
Pagine: 209 - 217

Astratto

Abstract

Performing repetitions to failure (RF) is a strategy that might acutely reduce neuromuscular performance, as well as increase the rating of perceived exertion (RPE) and the internal training load (ITL) during and after a resistance training (RT) session. Thus, this study aimed to analyze the acute effects of RF or repetitions not to failure (RNF) on countermovement jump (CMJ) performance and the ITL in trained male adults. Eleven men performed two experimental protocols in randomized order (RF vs. RNF). Under the RF condition, participants performed three sets of the leg extension exercise using 100% of the 10RM load and rest intervals of 180-s between sets. Under the RNF condition, participants were submitted to six sets of five repetitions with the same intensity and an 80-s rest interval between sets in the same exercise. The CMJ test was analyzed before and following (15-s and 30-min, respectively) each experimental session. The ITL was evaluated by multiplying the RPE and the total session time, 30-min after the protocol. No main effect or interaction time vs. condition was found for CMJ performance (p > 0.05). In contrast, the ITL showed higher values under the RF condition (p = 0.003). Therefore, even though RF-induced a greater ITL, our results suggest that adopting this strategy in one single-joint exercise for the lower limbs does not seem sufficient to reduce CMJ height.

Key words

  • fatigue
  • resistance training
  • perceived exertion
  • psychophysiological variables
  • acute effects
Accesso libero

Effects of Acute Caffeine Intake on Power Output and Movement Velocity During a Multiple-Set Bench Press Exercise Among Mild Caffeine Users

Pubblicato online: 31 Mar 2021
Pagine: 219 - 228

Astratto

Abstract

The main goal of this study was to evaluate the effectiveness of an acute dose of caffeine (6 mg/kg body mass (b.m.)) on power output and bar velocity during a bench press multiple-set resistance training session in participants with mild daily caffeine consumption (in the range of 1 to 3 mg/kg/b.m). Thirteen recreationally active male participants (age: 21.9 ± 1.2 years, body mass: 74.4 ± 5.3 kg, body mass index: 23.1 ± 1.6 kg/m2, bench press onerepetition maximum (1RM): 79.2 ± 14.9 kg), with daily caffeine ingestion of 1.56 ± 0.56 mg/kg/b.m., participated in the study with a randomized double-blind experimental design. Each participant performed two identical experimental sessions, 60 min after the intake of a placebo (PLAC) or 6 mg/kg/b.m. of caffeine (CAF-6). In each experimental session, participants performed 5 sets of 5 repetitions of the bench press exercise with a load equivalent to 70% 1RM. The eccentric and concentric phases of the bench press exercise were performed at maximal possible velocity in each repetition. Bar velocity was recorded with a linear position transducer and power output was calculated using velocity and load data. A two-way repeated measures ANOVA indicated no significant substance x set interaction for mean power output (MP), mean bar velocity (MV), peak power output (PP) and peak bar velocity (PV). However, there was a significant main effect of substance on MP (p < 0.01; η2 = 0.47) and MV (p < 0.01; η2 =0.45). Post hoc analysis for main effect revealed that MP and MV values in the CAF-6 group were higher than in the PLAC group in all 5 sets of the exercise (p < 0.05). In conclusion, this study demonstrated that an acute dose of caffeine before resistance exercise increased mean power output and mean bar velocity during a multiple-set bench press exercise protocol among mild caffeine users.

Key words

  • caffeine tolerance
  • ergogenic aids
  • resistance exercise
  • sport performance
  • upper limbs

Section IV - Behavioural Sciences in Sport

Accesso libero

Caffeine Produces Neutral Effects on Extraverts’ and Introverts’ Performance of Fundamental Motor Skills

Pubblicato online: 31 Mar 2021
Pagine: 229 - 237

Astratto

Abstract

Extraverts are active and talkative, while introverts are quiet and calm. This difference has been attributed to the cortical activation level (arousal), which is low in extraverts and high in introverts. Thus, to reach an optimal level of arousal, extraverts seek stimulation and introverts avoid it. As caffeine increases arousal levels, our primary aim was to investigate the effect of caffeine on the performance of extraverted and introverted university students in the execution of stability, manipulative, and locomotor tasks. Considering the above, we evaluated side effects, such as restlessness and trembling of hands, we also analyzed the individual's perception regarding caffeine intake and the placebo. Forty two volunteers were classified as 21 extraverts and 21 introverts by the Eysenck Personality Questionnaire. Participants performed three tasks on two different days, having previously ingested caffeine and a placebo in counterbalanced order. A double-blind technique was employed. The dependent variable was the execution time to perform the tasks. The analyses of variance [2 (extraversion/introversion) x 2 (caffeine x placebo)] for each task did not show significant differences. Regarding the secondary aim, the chi-square test showed that introverts had a better perception of the substance they had ingested than did extraverts. Our findings indicate that in the execution of stability, manipulative, and locomotor tasks, either caffeine or the placebo produced the same effect, regardless of the participants' extraversion score. In addition, introverts were more sensitive to perceive which substance was ingested, caffeine or the placebo, than extraverts.

Key words

  • personality
  • coffee
  • motor control
  • motor skills
Accesso libero

The Effects of Avoiding Instructions Under Pressure: An Examination of the Volleyball Serving Task

Pubblicato online: 31 Mar 2021
Pagine: 239 - 249

Astratto

Abstract

Wegner predicts that under pressure self-avoiding instructions not to perform in a certain manner will break down precisely where it is least desired that is the hypothesis of the present study. Specifically, the aim was to test the hypothesis that when instructed not to serve into a certain zone, ironic error would be more prevalent under pressure. Our sample comprised 43 female participants between the age of 13 and 16 (Mage = 14.51, SD = 1.35) who were active volleyball players (Mtraining years = 5.40, SD = 2.38). We measured the participants’ psychophysiological indications of anxiety via the heart rate, heart rate variability as well as the self-reported Mental Readiness Form-3. To measure performance, we counted the number of target and non-target serving zones under different anxiety conditions. Participants scored +5 points for serving into the target zone, scored -5 points for serving to the out or hitting the net and 1 point for serving into the court except the target zone. A 2 (anxiety) × 3 (serving zone) fully repeated measures ANOVA revealed a significant anxiety x serving zone interaction F (2, 84) = 36.52, p < .001. When instructed not to serve in a certain zone, players’ overall performance did not change across anxiety conditions t (42) = .68, p =.50. Results did not provide support for the Wegner’s theory as expected, but instead revealed evidence for the Woodman et al.’s (2015) differentiation of ironic performance error. The results demonstrate that the theory of ironic processes may account for practical instruction-based solution for reducing the susceptibility to ironic errors in the serving type of task in volleyball.

Key words

  • performance
  • anxiety
  • ironic error
  • mental control
Accesso libero

Applying the Input-Process-Outcome Model to Team Learning in Sport Sciences: An Exploratory Qualitative Study on Twenty Soccer Players

Pubblicato online: 31 Mar 2021
Pagine: 251 - 262

Astratto

Abstract

In sport science literature, referring to the Input-Process-Outcome (IPO) model, few studies demonstrated links between team training and team learning despites several calls for empirical studies. Thus, this study aimed at exploring systemically the building process of the interpersonal coordination by focusing on (1) a specific antecedent (i.e., video feedback during practice), (2) the influence of this antecedent on the team learning process, and (3) outcomes from this process as shared cognitive contents. Thus, this study was original by examining empirically the IPO model in a sport-training context. Our study showed that Input influenced the specific learning Process during practice (five processes) and video feedback sessions (five processes) and produced Outcomes (six typical shared cognitive contents). Finally, results are discussed in relation to team learning processes theoretically identified in the literature and an IPO soccer model adapted to team learning in a soccer context is proposed.

Key words

  • team learning
  • team training
  • soccer
  • video feedback
Accesso libero

The Short Grit Scale (GRIT-S) does not Relate to Acute Muscular Endurance Performance

Pubblicato online: 31 Mar 2021
Pagine: 263 - 269

Astratto

Abstract

Grit has been previously presented as a personality trait that reflects an individual’s perseverance of effort and consistency of interest for achieving their long-term goals. In resistance training this could mean that a “grittier” individual may perform more repetitions at a given intensity as they are better able to overcome metabolic and neuromuscular fatigue. Thus, the purpose of this study was to examine if grit was related to back squat muscular endurance performance. Fifty-eight resistance-trained males and females volunteered for participation (age = 23±3 yrs; body height = 172.53 ± 8.64 cm; body mass = 80.64 ± 6.49 kg). The grit of each participant was assessed via the Short Grit Scale (GRIT-S), and muscular endurance performance was tested via completion of a back squat set to volitional failure at 70% of the participant’s one-repetition maximum. Spearman rho or Pearson’s correlations, depending on normality, were used with 1000 bootstrapped replicate samples and revealed no relationship between GRIT-S scores (3.78 ± 0.52) and repetitions performed (14 ± 4) in a combined cohort of all 58 individuals (ρ = -0.051), males only (r = 0.057) or females only (ρ = -0.441). Supplementary investigation of the data also showed that the five “best” performers (i.e. the five individuals who performed the most repetitions) tended to have lower GRIT-S scores than the five “worst” performers. The results of the current study suggest that the GRIT-S has limited value in the context of muscular endurance performance. The skewed range of GRIT-S scores (2.75-5.0) observed in this investigation, also highlights the potential for social desirability to bias one’s self-perception of grit.

Key words

  • resistance training
  • strength
  • athletic performance
  • back squat
Accesso libero

Efficacy Sources that Predict Leadership Behaviors in Coaches of Athletes with Disabilities

Pubblicato online: 31 Mar 2021
Pagine: 271 - 281

Astratto

Abstract

Researchers suggest that sport participation among athletes with disabilities promotes healthier lifestyles, increases self-esteem, and enhances peer acceptance. Ideally, coaches should be confident in teaching skills, tactics, and sportsmanship, while exhibiting appropriate leadership behaviors in order to positively impact the psychosocial development of any athlete. Thus, the present research examined sources of coaching efficacy that predict leadership behaviors in coaches who work with athletes who have physical disabilities. Seventy international Paralympic coaches of female and male sport teams completed a modified version of the Coaching Success Questionnaire-2, the Coaching Efficacy Scale and the Leadership Scale for Sports. Regression models indicated that total coaching efficacy was a significant predictor of instructional and positive feedback leadership behaviors, with prior success also being a significant predictor of instructional behavior.

Key words

  • coaching efficacy
  • disability sport
  • paralympic
26 Articoli

Section I - Kinesiology

Accesso libero

Muscle Force Patterns in Lower Extremity Muscles for Elite Discus Throwers, Javelin Throwers and Shot-Putters – A Case Study

Pubblicato online: 31 Mar 2021
Pagine: 5 - 14

Astratto

Abstract

Optimal release variables, as well as the kinematics and kinetics of athletes, are crucial for the maximization of throwing distance in athletics. Mathematical models and simulations allow throwing techniques to be studied. However, muscle force patterns and the contribution of specific muscle groups in athletics throwing events are not well understood and require detailed research. In this study, important variables of the muscle force generated during the javelin, discus and shot put events were determined using OpenSim software. Musculoskeletal simulations were carried out based on kinematic and kinetic data collected using the Vicon system and Kistler plates with the help of nine top Polish athletes (three in each event). OpenSim software was used to calculate muscle forces and joint velocities. For each discipline, it was found that the main muscle groups involved in the throwing movement were better at distinguishing throwers than joint velocities. The contribution of right ankle plantar flexors at the beginning of the final acceleration phase as well as left hip extensors at the end of the final acceleration phase was given special attention. This work provides a better understanding of the techniques used in athletics throws. Musculoskeletal simulations of throwing styles might help coaches analyze the techniques of individual athletes, resulting in better adjustment of training programmes and injury prevention protocols.

Key words

  • athletics throws
  • musculoskeletal simulation
  • ballistic movement
  • inverse dynamics
Accesso libero

The Neuromuscular Characteristics of Gymnasts’ Jumps and Landings at Particular Stages of Sports Training

Pubblicato online: 31 Mar 2021
Pagine: 15 - 28

Astratto

Abstract

Safe and proper landings are crucial elements of gymnastics events. Long-term training leads to specific neuromuscular adaptations which are yet to be explored in terms of gymnastic landings. The aim of the study was to assess differences in landings’ neuromuscular characteristics between gymnasts at three subsequent gymnastic training stages and age-matched non-athletes. Forty-six gymnasts (G) and 58 controls (C) performed countermovement jumps on a force plate with simultaneous surface electromyography (SEMG) of lower body muscles, measured during the pre-(100 ms) and post-landing phase (0-100 and 0-200 ms). Three age groups participated in the study: 8–10 (G1, C1), 12–14 (G2, C2), 18–25 (G3, C3) years. Analysis included the normalized root mean square (NRMS) SEMG signal and ground reaction forces (GRFs). Gymnasts achieved 13% higher values (p = 0.04) of relative peak GRFs in comparison with controls. It was especially seen in 8–10-year-olds: G1 presented 33% higher (p = 0.03) results than C1 and G2. In SEMG analysis, gymnasts showed overall lower NRMS values in comparison with the controls. In the pre-landing phase, the NRMS in the rectus femoris was from 1.6 up to 3.4 times higher for C1 (p = 0.02) than for C2, G2, C3, and G3. Gymnasts across subsequent training stages exhibit different patterns of neuromuscular coordination during landings. The highest GRF observed in the youngest gymnasts may be a potential risk factor of injuries. Therefore, further injury-focused investigation is recommended to monitor landing strategies among gymnasts of different stages with particular emphasis on the beginners.

Key words

  • ground reaction forces
  • countermovement jump
  • artistic gymnastics
  • neuromuscular coordination
Accesso libero

Common Movement Patterns of the Jump Shot while Increasing the Distance from the Basket in Elite Basketball Players

Pubblicato online: 31 Mar 2021
Pagine: 29 - 39

Astratto

Abstract

The aim of this study was to examine chosen kinematic variables (duration of the shot, position of the centre of mass, position of the shooting hand, rotation of the shoulder axis) of successful shots and to describe differences in movement patterns in elite basketball players while increasing the distance from the basket during a jump shot. Our participants were three elite shooting guards who were all Slovenian national team and Euroleague players. They were shooting from three different distances (3.75 m, 5.25 m, and 6.75 m); analysis included 90 successful shots. The kinematics of the entire body was analysed using the inertial motion capture suit. The main interest was on the transverse plane (direction Y), focusing on rotational movements and movements to the left and right. The results showed that the rotation of the shoulder axis in the transverse plane, with all three participants, was greatest (p < .05) from the longest distance. Despite that graphs of individual players differed, deviation to the left was most significant while shooting from the largest distance for all participants. Also the landing from the jump shot was on the left according to the origin. For example, the average deviation to the left for player no. 2 was 11.9 ± 3.6 cm (the shortest distance), 12.6 ± 4.7 cm (the middle distance), and 23.3 ± 5.1 cm (the longest distance). Distance from the basket influenced the kinematics of the shot, especially from the longest distance. Along with the already well-known changes in the sagittal plane (direction X and Z), this research provides information on changes in the transverse plane, which are also very important, especially while shooting from longer distances.

Key words

  • transverse plane
  • duration of the shot
  • position of the centre of mass and shooting hand
  • rotation of the shoulder axis
Accesso libero

Analyses of Countermovement Jump Performance in Time and Frequency Domains

Pubblicato online: 31 Mar 2021
Pagine: 41 - 48

Astratto

Abstract

This study aimed to analyze counter-movement jump (CMJ) performance in time and frequency domains. Fortyfour Division I American football players participated in the study. Kinetic variables were collected from both dominant and non-dominant legs using two force plates. Normalized peak power, normalized net impulse, and normalized peak force significantly correlated with jump height (r = .960, r = .998, r = .725, respectively with p < .05). The mean frequency component was significantly correlated with CMJ performance (r = .355 with p < .05). The reliability of the frequency variables was higher than the time domain variables. Frequency domain variables showed weaker correlations with jump height compared with time domain variables. Frequency domain analysis provides frequency components, which represent the rate of energy transmission from the eccentric phase to the end of the push-off phase. Frequency component information may provide additional information for the analyses of CMJ performance for athletes.

Key words

  • countermovement jump
  • kinetics
  • time domain
  • frequency domain
Accesso libero

Do Expert Fencers Engage the Same Visual Perception Strategies as Beginners?

Pubblicato online: 31 Mar 2021
Pagine: 49 - 58

Astratto

Abstract

An effective visual perception strategy helps a fencer quickly react to an opponent’s actions. This study aimed to examine and compare visual perception strategies used by high-performance foil fencers (experts) and beginners. In an eye tracking experiment, we analysed to which areas beginning and expert fencers paid attention during duels. Novices paid attention to all examined areas of interest comprising the guard, foil (blade and tip), armed hand, lower torso, and upper torso of their opponents. Experts, however, paid significantly less attention to the foil, picking up information from other areas, mainly the upper torso and the armed hand. These results indicate that expert fencers indeed engage different visual perception strategies than beginners. The present findings highlight the fact that beginner fencers should be taught already in the early stages of their careers how to pick up information from various body areas of their opponents.

Key words

  • perception strategies
  • foil fencing
  • experts
  • beginners
  • eye tracking

Section II - Exercise Physiology & Sports Medicine

Accesso libero

The Second‐to‐Fourth Digit (2D:4D) Ratio of Male Combat Athletes is Associated with the Choice of Sport

Pubblicato online: 31 Mar 2021
Pagine: 59 - 66

Astratto

Abstract

The second-to-fourth-digit (2D:4D) ratio has been widely used as a putative marker of prenatal exposure to testosterone in health, behavioral and sport sciences, but it has only been used few times regarding combat athletes. This study involved 200 male elite combat athletes (Olympic wrestling, kickboxing, judo, taekwondo and karate) and 179 males not participating in any sports. The lengths of the index finger (2D) and ring (4D) finger were measured using computer-assisted image analysis (AutoMetric 2.2 software). The 2D:4D ratio of combat athletes was significantly lower than that of the controls. Moreover, a lower 2D:4D ratio was found among wrestlers, judo athletes and kickboxers than in the control group, and a higher 2D:4D ratio was found, but with borderline significance, among karate and taekwondo athletes. Moreover, multivariate analysis adjusted for age showed that judo, Olympic wrestling and kickboxing athletes combined had 2D:4D ratios significantly lower (by 0.035 on average) than those of the rest of the subjects and that karate and taekwondo athletes together had 2D:4D ratios significantly higher (by 0.014 on average) than those of the rest of the subjects. The research results and literature review indicate that knowledge about the functional meaning of the 2D:4D ratio is still too fragmentary and it is too early to use the 2D:4D ratio in the selection of sport talent; however, it may be a useful criteria when screening prospective athletes to be recruited to a team. That is why 2D:4D reference values should be defined for particular sports.

Key words

  • digit ratio (2D:4D)
  • combat sports
  • sport selection
  • aggression
  • predispositions
Accesso libero

Influence of Biological Maturity on the Muscular Strength of Young Male and Female Swimmers

Pubblicato online: 31 Mar 2021
Pagine: 67 - 77

Astratto

Abstract

The present study compared the evolution of strength and muscle mass in swimmers of both sexes across different chronological and biological ages. Seventy-six swimmers (55 males and 21 females) from 10 to 20 years of age underwent evaluations of sexual maturation using the developmental stage of the genitals (G1, G2, G3 G4 and G5) and pubic hair (P1, P2, P3, P4 and P5) (Tanner criteria), lean mass using the dual-energy X-ray absorptiometry method, and isokinetic strength of the knee extensor muscles. Boys did not present a significant difference in strength among G1, G2, and G3 (p > 0.05) nor between 10 and 13 years of age (p > 0.05), although significant differences in strength of the extensor (p = 0.038) muscles of the knee were found between G3 and G4 and between athletes of 10 and 14 years of age (extensor muscles, p = 0.033). Muscle mass was different between G3 and G4 (p = 0.003) and between 10 and 14 years of age (p = 0.020). The mean age of boys in the G4 pubertal stage was 13.7 ± 2.0 years, although from 12 to 16 years of age, boys are typically in the G4 stage. Girls showed no significant differences in strength nor muscle mass among the pubertal stages (p > 0.05). We conclude that by equating boys by chronological age, individuals with different pubertal development levels, muscle mass, and strength levels can be grouped. Therefore, the relationship between the level of pubertal deve-lopment and chronological age seems to be a useful strategy for grouping boys, while grouping girls by chronological age seems adequate for training and competition.

Key words

  • puberty
  • sexual maturity
  • isokinetic
  • lean mass
Accesso libero

Different Training Methods Cause Similar Muscle Damage in Youth Judo Athletes

Pubblicato online: 31 Mar 2021
Pagine: 79 - 87

Astratto

Abstract

It is well known that different factors can contribute to muscle damage in judo matches or training. Previous research analyzed only the effects of simulated judo combat or judo training on biochemical markers of muscle damage without determining its specific causes. Our objective was to identify possible differences in biochemical markers of muscular damage in response to different training methods in youth judo athletes. Twelve high-level male judo athletes were randomly assigned to a standing (SP, n = 6, age = 16.6 ± 1.1 years) or a groundwork (GP, n = 6, age = 17.8 ± 0.8 years) position combat practice group. Both groups had the same protocol of four 4-minute combat practice bouts separated by 1-minute rest intervals. Before and immediately after combat practice blood samples were taken to assess muscle damage markers: creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). There were significant increases in AST, LDH, and CK after the standing and groundwork training sessions compared with resting values in both groups. Additionally, no significant differences in the enzyme's activity between SP and GP groups were found. These results showed that standing and groundwork randori training (free sparring or free practice) causes similar muscle damage in adolescent judo athletes. Future research should assess the effects of the same damage mechanisms over a longer period of time

Key words

  • biochemical markers
  • adolescent, exercise testing
  • judo, training
Accesso libero

Workout Pacing Predictors of Crossfit® Open Performance: A Pilot Study

Pubblicato online: 31 Mar 2021
Pagine: 89 - 100

Astratto

Abstract

To observe workout repetition and rest interval pacing strategies and determine which best predicted performance during the 2016 CrossFit® Open, five male (34.4 ± 3.8 years, 176 ± 5 cm, 80.3 ± 9.7 kg) and six female (35.2 ± 6.3 years, 158 ± 7 cm, 75.9 ± 19.3 kg) recreational competitors were recruited for this observational, pilot study. Exercise, round, and rest time were quantified via a stopwatch for all competitors on their first attempt of each of the five workouts. Subsequently, pacing was calculated as a repetition rate (repetitions·s-1) to determine the fastest, slowest, and average rate for each exercise, round, and rest interval, as well as how these changed (i.e., slope, Δ rate / round) across each workout. Spearman’s rank correlation coefficients indicated that several pacing variables were significantly (p < 0.05) related to performance on each workout. However, stepwise regression analysis indicated that the average round rate best predicted (p < 0.001) performance on the first (R2 = 0.89), second (R2 = 0.99), and fifth (R2 = 0.94) workouts, while the competitors’ rate on their slowest round best predicted workout three performance (R2 = 0.94, p < 0.001). The wall ball completion rate (R2 = 0.89, p = 0.002) was the best predictor of workout four performance, which was improved by 9.8% with the inclusion of the deadlift completion rate. These data suggest that when CrossFit® Open workouts consist of multiple rounds, competitors should employ a fast and sustainable pace to improve performance. Otherwise, focusing on one or two key exercises may be the best approach.

Key words

  • strategy
  • competition
  • recreational athletes
  • HIFT
  • exercise
Accesso libero

Acute Effects of Resistance Training with Blood Flow Restriction on Achilles Tendon Thickness

Pubblicato online: 31 Mar 2021
Pagine: 101 - 109

Astratto

Abstract

The Achilles tendon is one of the strongest and thickest tendons of the human body. Several studies have reported an immediate decrease in Achilles tendon thickness after a single bout of resistance training. However, the effects of blood flow restriction training on Achilles tendon thickness have not been investigated. The purpose of this study was to investigate the acute effects of different regimens of resistance training on Achilles tendon thickness. Fiftytwo participants (27.3 ± 7 years; 177.6 ± 11 cm; 72.2 ± 13.7 kg) were randomly allocated into one of the three groups: low-intensity exercise without (LI, n = 13) and with blood flow restriction (LI-BFR, n = 24), and high-intensity exercise (HI, n = 15). Participants from LI and LI-BFR groups performed four sets (1 x 30 + 3 x 15 reps) at 30% 1RM, while the HI group performed four sets (1 x 30 with 30% 1RM + 3 x 10 reps with 75% 1RM). All groups performed a plantar flexion exercise. For the LI-BFR group, a blood pressure cuff was placed on the dominant calf and inflated at 30% of the individual´s occlusion pressure (47.6 ± 19.8 mmHg). Sonographic images of Achilles tendon thickness were taken at pre, immediately after, 60 min and 24 h following acute bouts of exercise. Achilles tendon thickness was significantly reduced immediately after, 60 min and 24 h post-LI-BFR exercise (pre: 4.4 ± 0.4 mm vs. IA: 3.8 ± 0.4 mm vs. 60 min: 3.7 ± 0.3 mm vs. 24 h: 4.1 ± 0.3 mm; p < 0.001), whereas Achilles tendon thickness was unchanged for HI and LI groups (p > 0.05). These results suggest that blood flow restriction training may be an effective strategy to stimulate a positive response in Achilles tendon thickness.

Key words

  • tendon morphology
  • low-load exercise
  • injury
  • ultrasonography
  • occlusion training
  • rehabilitation
Accesso libero

The Effects of High Mineral Alkaline Water Consumed over Three Consecutive Days on Reaction Time Following Anaerobic Exercise – A Randomized Placebo‐Controlled Crossover Pilot Study

Pubblicato online: 31 Mar 2021
Pagine: 111 - 119

Astratto

Abstract

Drinking alkaline water after intense anaerobic exercise may enhance both cognitive and physical performance. This study aimed to investigate the effect of high mineral alkaline water consumed over three consecutive days on reaction time after anaerobic exercise in twelve healthy young males (aged 21.1 ± 1.3 years) with a valid sports medical examination. Participants were excluded when they took any medications or performance-enhancing supplements for the period of at least four weeks before the study commenced. Participants were randomly divided into two groups in this double-blind, placebo-controlled crossover pilot study. They ingested either alkaline water (AW) or regular table water ( RTW) for three consecutive days before anaerobic exercise. The anaerobic exercise consisted of two 2-min high-intensity step-tests with a passive rest interval of 3 minutes between the two bouts of exercise. Performance in the step-test (W), reaction time for visual and auditory signals, the rate of perceived exertion (RPE), urine specific gravity, and lactate concentration were analysed. No effect of AW was found on reaction time and the other variables except anaerobic performance. An-aerobic performance was significantly higher after ingestion of AW in both step-tests (p < 0.05). The ingestion of AW for three consecutive days before anaerobic exercise seems to positively affect anaerobic performance.

Key words

  • Rate of Perceived Exertion
  • step-test
  • exercise
  • buffer system
Accesso libero

Influence of a Maximal Incremental Test Until Exhaustion on the Urinary Excretion of Steroid Hormones in Trained Cyclists

Pubblicato online: 31 Mar 2021
Pagine: 121 - 129

Astratto

Abstract

This study aimed to assess the effect of a maximum incremental stress test through urinary concentrations of steroid hormones in trained cyclists. Twenty male cyclists participated in the study (23.83 ± 2.3 years; 1.76 ± 0.03 m; 66.94 ± 3.59 kg; training volume: 20.50 ± 2.35 h/week). Athletes performed a maximum incremental test until exhaustion on a cycle ergometer and urine samples were collected at three different time points: before, immediately after, and 48 h after the test. Lactate, creatinine and urinary concentrations of testicular and adrenal androgens were obtained as well as urinary concentrations of glucocorticoid hormones. An increase in lactate was observed after the test (p < 0.01). There were decreases in the urinary excretion of androgenic hormones after the test, which were significant in testosterone, androsterone, androstenedione, total adrenal androgen and total testicular androgen (p < 0.05). The values were restored after 48 h (p < 0.05). Urinary cortisol concentrations decreased after the test (p < 0.05). A decrease was also observed in the ratio of anabolic/catabolic hormones (p < 0.05) increasing 48 h after the test (p < 0.05). Increased acute physical exercise until exhaustion causes variations in the urinary excretions of steroid hormones which were restored 48 h after exercise. Urinary excretion of steroid hormones could be a valid method of monitoring training loads.

Key words

  • exercise
  • androgens
  • glucocorticoids
  • stress
  • recovery
Accesso libero

The Effect of a Tailored Intervention on Female Soccer Players’ Hydration Status

Pubblicato online: 31 Mar 2021
Pagine: 131 - 140

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Abstract

Numerous studies have reported that athletes’ pre-training/-game hydration status is of concern. Up to now, only two cohort studies have examined the effect of an intervention aimed at improving pretraining/-game hydration status; however, without including a control group. Therefore, the aim of this quasi-experimental study was to examine whether and to what extent an individually tailored intervention focused on the benefits of being optimally hydrated before training or game would alter the hydration status of female soccer players. Two teams of young adult female soccer players were allocated to an intervention (n = 22; 19.8 ± 3.0 years) or a control group (n = 15; 22.8 ± 4.0 years). Players in the intervention group received an individually tailored intervention, based on Urine Specific Gravity (USG) measurements, which took place in between two training weeks. Before each training and match play, a urine sample was collected to determine players’ hydration status. Mixed modelling was applied to assess within and between differences in hydration status over time. The pre-training/-game hydration status of the intervention group improved significantly, with players’ mean USG-value decreasing from 1.013 ± 0.001 g/mL to 1.008 ± 0.002 g/mL (p = 0.005). In contrast, the mean USG-value in the control group increased significantly from 1.012 ± 0.002 g/mL to 1.016 ± 0.002 g/mL (p = 0.023), indicating a deterioration of their pre-training/-game hydration status. The individually tailored intervention did show a positive effect even though female soccer players in the present study were already reasonably well hydrated before the start of the intervention.

Key words

  • USG
  • football
  • quasi-experiment
  • athlete
  • women
  • intervention

Section III - Sports Training

Accesso libero

Post-Activation Potentiation in Strength Training: A Systematic Review of the Scientific Literature

Pubblicato online: 31 Mar 2021
Pagine: 141 - 150

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Abstract

This review aimed to determine the ideal combination of post activation potentiation (PAP) strategies for an improved strength performance. After analysing 202 articles, 15 studies met the inclusion criteria. The findings of this review suggest that a potentiation effect exists as long as a minimum intensity and enough rest are provided. Although intensities of 65% 1RM are sufficient to elicit a potentiation effect, higher effects can be achieved with 85 - 90% 1RM intensities. Similarly, we found that experienced athletes will benefit more from a higher volume bout (1-3 sets), as long as 7-8 minutes of rest are allowed to avoid fatigue.

Key words

  • PAP
  • complex training
  • performance
  • resistance training
  • strength training
Accesso libero

Does Youth Soccer Players’ Group Cooperation Improve when Pitch, Goal, and Team Size Are Reduced?

Pubblicato online: 31 Mar 2021
Pagine: 151 - 160

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Abstract

The aim of this study was to analyse the effects of the modification of the pitch size, goal size, and the number of players per team on the level of cooperation in youth soccer players (U-12). A quasi-experimental design was implemented to measure the effects of the changes in the number of players per team (8-a-side vs. 5-a-side), goal size (6 x 2 m vs. 3 x 2 m), and field size (58 x 38 m vs. 38 x 20 m) on the cooperation. Four soccer teams under-12 (n = 48 players) participated in three tournaments (standard rules; proposed rules; standard rules). The five variables of cooperation were measured using the “Sports Cooperation Questionnaire”: conditional cooperation, cooperation with the coach, disposition of unconditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play. Players presented the same level of cooperation in conditional cooperation, situational cooperation with teammates, and situational cooperation outside the field of play with both types of rules. The modification of rules involved a reduction of the cooperation with the coach and a disposition of unconditional cooperation. The causes of the reduction may be related to players’ adaptation to new tactical dispositions and game situations. Future studies are needed of player’s cooperation and different competition rules in youth sports.

Key words

  • sport
  • teamwork
  • rules modification
  • sports initiation
  • adaptation
Accesso libero

Coexistence of Distinct Performance Models in High-Level Women’s Volleyball

Pubblicato online: 31 Mar 2021
Pagine: 161 - 173

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Abstract

In performance analysis, and most notably in match analysis, generalizing game patterns in a sport or competition may result in formulating generic models and neglecting relevant variability in benefit of average or central values. Here, we aimed to understand how different game models can coexist at the same competitive level using social network analysis with degree centrality to obtain systemic mappings for six volleyball matches, one for each of the six national teams playing in the 2014 World Grand Prix Finals, guaranteeing a homogeneous game level and balanced matches. Although the sample was not recent, this was not relevant for our purposes, since we aimed to merely expose a proof of concept. A total of 56 sets and 7,176 ball possessions were analysed through Gephi Software, considering game actions as nodes and the interaction between them as edges. Results supported the coexistence of different performance models at the highest levels of practice, with each of the six teams presenting a very distinct game model. For example, important differences in eigenvector centrality in attack zones (ranging from 0 to 34) and tempos (20 to 38) were found between the six teams, as well as in defensive lines (20 to 39) and block opposition (22 to 37). This further suggests that there may be multiple pathways towards expert performance within any given sport, inviting a re-conceptualization of monolithic talent identification, detection and selection models. Future studies could benefit from standardizing the metrics in function of the number of ball possessions.

Key words

  • performance analysis
  • systemic mapping
  • performance variability
  • volleyball
Accesso libero

Effects of Plyometric, Strength and Change of Direction Training on High-School Basketball Player’s Physical Fitness

Pubblicato online: 31 Mar 2021
Pagine: 175 - 186

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Abstract

The study aim was to compare the effects of a 7-week plyometric, strength and change of direction (COD) training program on basketball-specific performance measures in high-school players. Forty male players were randomly assigned to one of the four groups: plyometric (PG, n = 10), strength (SG, n = 10), COD (CODG, n = 10), and control group training (CG, n = 10). Two training sessions were performed at weekly intervals before basketball training. Performance of the counter movement jump (CMJ), Abalakov jump (ABKJ), 10 m zig-zag sprint, 20 m in line sprint (measurements at 10 and 20 m), and sit and reach flexibility test (SRFT) was assessed before and after the intervention. A 4 (group) × 2 (time) repeated measures analysis of variances (ANOVA) was conducted for each variable. Bonferroni post-hoc tests were used when the interaction was significant. Significant (all p < 0.05) time x group interaction was noted for SRFT, CMJ, ABK, sprint, and zig-zag 10 m, in favor of the experimental groups compared to the control group. However, improvements in physical fitness were similar between the three experimental groups. In conclusion, 7 weeks of specific plyometric, strength and COD training produced similar medium to large improvements in physical fitness of high-school basketball players.

Key words

  • vertical jump
  • pubertal
  • sport conditioning
  • youth athletes
Accesso libero

Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games

Pubblicato online: 31 Mar 2021
Pagine: 187 - 196

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Abstract

The aim of this study was to compare external training loads between small-sided games (SSGs) and largesided games (LSGs) in soccer players. Twenty outfield soccer players (14.8 ± 0.6 years old) who competed in the Spanish U16 Provincial Division and belonged to the same team participated in the study. The soccer sided games were played at different individual interaction space (IIS) per player (i.e., SSG = 100 m2 and LSG = 200 m2) and were disputed in the same format (five-a-side plus goalkeepers) on two different pitch sizes (i.e., 38 x 26 vs. 53 x 37 m) defending an official soccer-goal. The sided games’ duration was 4 bouts of 6 min with 2 min rest intervals between bouts. The results of this study showed no meaningful differences in the total distance and intensity of accelerations and decelerations between SSGs and LSGs except for the lower distance covered at medium intensity (2.5 - 4 m·s-2) observed during LSGs (-10.2%; ES (effect size): -0.51). Players registered greater sprints, maximum velocity (Velmax) and body impacts at different intensities (i.e., I5-6g, I6-6.5g, I6.5-7g, I7-8g, I8-10g,) in LSGs in comparison to SSGs. These findings suggest that an increase in the pitch size (i.e., IIS per player) can induce higher external loads for soccer players.

Key words

  • soccer
  • quantification
  • external loads
  • individual interaction space
  • neuromuscular
Accesso libero

Specific and Holistic Predictors of Sprint Front Crawl Swimming Performance

Pubblicato online: 31 Mar 2021
Pagine: 197 - 207

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Abstract

The aim of the study was to examine the impact of selected water- and dry-land predictors of 50-m front crawl performance among 27 male swimmers aged 19.3 ± 2.67 years. The following water tests were performed: front crawl tethered arm stroking in a water flume (flow velocity: 0.9 m·s–1) and leg tethered flutter kicking in a swimming pool. Anaerobic tests on dry land included arm cranking and a set of 10 countermovement jumps. The maximal and average forces generated by legs in tethered swimming (Fl max and Fl ave) turned out to be the strongest predictors of sprint swimming aptitude. These values were strongly correlated with total speed (Vtotal50) (r = 0.49, p < 0.05 and r = 0.54, p < 0.01, respectively), start, turn, and finishing speed (VSTF) (r = 0.60, p < 0.01 and r = 0.67, p < 0.01, respectively). The relationship of Fl max and Fl ave with surface speed (Vsurface) was moderate (r = 0.33, non-significant and r = 0.41, p < 0.05, respectively). The maximal force generated by arms (Fa max) during flume tethered swimming significantly influenced Vsurface and Vtotal50 (0.51, p < 0.01 and 0.47, p < 0.05, respectively). Its relationship with VSTF was close to significant (0.36, p = 0.07). Upper and lower limb dry-land tests showed lower and more holistic relationships with the 50-m front crawl race, however, being a good complement to overall fitness assessment. Specific in-water evaluation, especially the newly prepared flutter kicking test, as well as dry-land tests, can be applied to regularly monitor progress in swimming training, and to identify talented swimmers.

Key words

  • strength
  • test
  • power
  • movement velocity
  • biomechanics
Accesso libero

Performing Repetitions To Failure in Lower-Limb Single-Joint Exercise does not Reduce Countermovement Jump Performance in Trained Male Adults

Pubblicato online: 31 Mar 2021
Pagine: 209 - 217

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Abstract

Performing repetitions to failure (RF) is a strategy that might acutely reduce neuromuscular performance, as well as increase the rating of perceived exertion (RPE) and the internal training load (ITL) during and after a resistance training (RT) session. Thus, this study aimed to analyze the acute effects of RF or repetitions not to failure (RNF) on countermovement jump (CMJ) performance and the ITL in trained male adults. Eleven men performed two experimental protocols in randomized order (RF vs. RNF). Under the RF condition, participants performed three sets of the leg extension exercise using 100% of the 10RM load and rest intervals of 180-s between sets. Under the RNF condition, participants were submitted to six sets of five repetitions with the same intensity and an 80-s rest interval between sets in the same exercise. The CMJ test was analyzed before and following (15-s and 30-min, respectively) each experimental session. The ITL was evaluated by multiplying the RPE and the total session time, 30-min after the protocol. No main effect or interaction time vs. condition was found for CMJ performance (p > 0.05). In contrast, the ITL showed higher values under the RF condition (p = 0.003). Therefore, even though RF-induced a greater ITL, our results suggest that adopting this strategy in one single-joint exercise for the lower limbs does not seem sufficient to reduce CMJ height.

Key words

  • fatigue
  • resistance training
  • perceived exertion
  • psychophysiological variables
  • acute effects
Accesso libero

Effects of Acute Caffeine Intake on Power Output and Movement Velocity During a Multiple-Set Bench Press Exercise Among Mild Caffeine Users

Pubblicato online: 31 Mar 2021
Pagine: 219 - 228

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Abstract

The main goal of this study was to evaluate the effectiveness of an acute dose of caffeine (6 mg/kg body mass (b.m.)) on power output and bar velocity during a bench press multiple-set resistance training session in participants with mild daily caffeine consumption (in the range of 1 to 3 mg/kg/b.m). Thirteen recreationally active male participants (age: 21.9 ± 1.2 years, body mass: 74.4 ± 5.3 kg, body mass index: 23.1 ± 1.6 kg/m2, bench press onerepetition maximum (1RM): 79.2 ± 14.9 kg), with daily caffeine ingestion of 1.56 ± 0.56 mg/kg/b.m., participated in the study with a randomized double-blind experimental design. Each participant performed two identical experimental sessions, 60 min after the intake of a placebo (PLAC) or 6 mg/kg/b.m. of caffeine (CAF-6). In each experimental session, participants performed 5 sets of 5 repetitions of the bench press exercise with a load equivalent to 70% 1RM. The eccentric and concentric phases of the bench press exercise were performed at maximal possible velocity in each repetition. Bar velocity was recorded with a linear position transducer and power output was calculated using velocity and load data. A two-way repeated measures ANOVA indicated no significant substance x set interaction for mean power output (MP), mean bar velocity (MV), peak power output (PP) and peak bar velocity (PV). However, there was a significant main effect of substance on MP (p < 0.01; η2 = 0.47) and MV (p < 0.01; η2 =0.45). Post hoc analysis for main effect revealed that MP and MV values in the CAF-6 group were higher than in the PLAC group in all 5 sets of the exercise (p < 0.05). In conclusion, this study demonstrated that an acute dose of caffeine before resistance exercise increased mean power output and mean bar velocity during a multiple-set bench press exercise protocol among mild caffeine users.

Key words

  • caffeine tolerance
  • ergogenic aids
  • resistance exercise
  • sport performance
  • upper limbs

Section IV - Behavioural Sciences in Sport

Accesso libero

Caffeine Produces Neutral Effects on Extraverts’ and Introverts’ Performance of Fundamental Motor Skills

Pubblicato online: 31 Mar 2021
Pagine: 229 - 237

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Abstract

Extraverts are active and talkative, while introverts are quiet and calm. This difference has been attributed to the cortical activation level (arousal), which is low in extraverts and high in introverts. Thus, to reach an optimal level of arousal, extraverts seek stimulation and introverts avoid it. As caffeine increases arousal levels, our primary aim was to investigate the effect of caffeine on the performance of extraverted and introverted university students in the execution of stability, manipulative, and locomotor tasks. Considering the above, we evaluated side effects, such as restlessness and trembling of hands, we also analyzed the individual's perception regarding caffeine intake and the placebo. Forty two volunteers were classified as 21 extraverts and 21 introverts by the Eysenck Personality Questionnaire. Participants performed three tasks on two different days, having previously ingested caffeine and a placebo in counterbalanced order. A double-blind technique was employed. The dependent variable was the execution time to perform the tasks. The analyses of variance [2 (extraversion/introversion) x 2 (caffeine x placebo)] for each task did not show significant differences. Regarding the secondary aim, the chi-square test showed that introverts had a better perception of the substance they had ingested than did extraverts. Our findings indicate that in the execution of stability, manipulative, and locomotor tasks, either caffeine or the placebo produced the same effect, regardless of the participants' extraversion score. In addition, introverts were more sensitive to perceive which substance was ingested, caffeine or the placebo, than extraverts.

Key words

  • personality
  • coffee
  • motor control
  • motor skills
Accesso libero

The Effects of Avoiding Instructions Under Pressure: An Examination of the Volleyball Serving Task

Pubblicato online: 31 Mar 2021
Pagine: 239 - 249

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Abstract

Wegner predicts that under pressure self-avoiding instructions not to perform in a certain manner will break down precisely where it is least desired that is the hypothesis of the present study. Specifically, the aim was to test the hypothesis that when instructed not to serve into a certain zone, ironic error would be more prevalent under pressure. Our sample comprised 43 female participants between the age of 13 and 16 (Mage = 14.51, SD = 1.35) who were active volleyball players (Mtraining years = 5.40, SD = 2.38). We measured the participants’ psychophysiological indications of anxiety via the heart rate, heart rate variability as well as the self-reported Mental Readiness Form-3. To measure performance, we counted the number of target and non-target serving zones under different anxiety conditions. Participants scored +5 points for serving into the target zone, scored -5 points for serving to the out or hitting the net and 1 point for serving into the court except the target zone. A 2 (anxiety) × 3 (serving zone) fully repeated measures ANOVA revealed a significant anxiety x serving zone interaction F (2, 84) = 36.52, p < .001. When instructed not to serve in a certain zone, players’ overall performance did not change across anxiety conditions t (42) = .68, p =.50. Results did not provide support for the Wegner’s theory as expected, but instead revealed evidence for the Woodman et al.’s (2015) differentiation of ironic performance error. The results demonstrate that the theory of ironic processes may account for practical instruction-based solution for reducing the susceptibility to ironic errors in the serving type of task in volleyball.

Key words

  • performance
  • anxiety
  • ironic error
  • mental control
Accesso libero

Applying the Input-Process-Outcome Model to Team Learning in Sport Sciences: An Exploratory Qualitative Study on Twenty Soccer Players

Pubblicato online: 31 Mar 2021
Pagine: 251 - 262

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Abstract

In sport science literature, referring to the Input-Process-Outcome (IPO) model, few studies demonstrated links between team training and team learning despites several calls for empirical studies. Thus, this study aimed at exploring systemically the building process of the interpersonal coordination by focusing on (1) a specific antecedent (i.e., video feedback during practice), (2) the influence of this antecedent on the team learning process, and (3) outcomes from this process as shared cognitive contents. Thus, this study was original by examining empirically the IPO model in a sport-training context. Our study showed that Input influenced the specific learning Process during practice (five processes) and video feedback sessions (five processes) and produced Outcomes (six typical shared cognitive contents). Finally, results are discussed in relation to team learning processes theoretically identified in the literature and an IPO soccer model adapted to team learning in a soccer context is proposed.

Key words

  • team learning
  • team training
  • soccer
  • video feedback
Accesso libero

The Short Grit Scale (GRIT-S) does not Relate to Acute Muscular Endurance Performance

Pubblicato online: 31 Mar 2021
Pagine: 263 - 269

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Abstract

Grit has been previously presented as a personality trait that reflects an individual’s perseverance of effort and consistency of interest for achieving their long-term goals. In resistance training this could mean that a “grittier” individual may perform more repetitions at a given intensity as they are better able to overcome metabolic and neuromuscular fatigue. Thus, the purpose of this study was to examine if grit was related to back squat muscular endurance performance. Fifty-eight resistance-trained males and females volunteered for participation (age = 23±3 yrs; body height = 172.53 ± 8.64 cm; body mass = 80.64 ± 6.49 kg). The grit of each participant was assessed via the Short Grit Scale (GRIT-S), and muscular endurance performance was tested via completion of a back squat set to volitional failure at 70% of the participant’s one-repetition maximum. Spearman rho or Pearson’s correlations, depending on normality, were used with 1000 bootstrapped replicate samples and revealed no relationship between GRIT-S scores (3.78 ± 0.52) and repetitions performed (14 ± 4) in a combined cohort of all 58 individuals (ρ = -0.051), males only (r = 0.057) or females only (ρ = -0.441). Supplementary investigation of the data also showed that the five “best” performers (i.e. the five individuals who performed the most repetitions) tended to have lower GRIT-S scores than the five “worst” performers. The results of the current study suggest that the GRIT-S has limited value in the context of muscular endurance performance. The skewed range of GRIT-S scores (2.75-5.0) observed in this investigation, also highlights the potential for social desirability to bias one’s self-perception of grit.

Key words

  • resistance training
  • strength
  • athletic performance
  • back squat
Accesso libero

Efficacy Sources that Predict Leadership Behaviors in Coaches of Athletes with Disabilities

Pubblicato online: 31 Mar 2021
Pagine: 271 - 281

Astratto

Abstract

Researchers suggest that sport participation among athletes with disabilities promotes healthier lifestyles, increases self-esteem, and enhances peer acceptance. Ideally, coaches should be confident in teaching skills, tactics, and sportsmanship, while exhibiting appropriate leadership behaviors in order to positively impact the psychosocial development of any athlete. Thus, the present research examined sources of coaching efficacy that predict leadership behaviors in coaches who work with athletes who have physical disabilities. Seventy international Paralympic coaches of female and male sport teams completed a modified version of the Coaching Success Questionnaire-2, the Coaching Efficacy Scale and the Leadership Scale for Sports. Regression models indicated that total coaching efficacy was a significant predictor of instructional and positive feedback leadership behaviors, with prior success also being a significant predictor of instructional behavior.

Key words

  • coaching efficacy
  • disability sport
  • paralympic

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