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Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
ISSN
1640-5544
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

Volume 39 (2013): Edizione 1 (December 2013)

Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
ISSN
1640-5544
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

25 Articoli
Accesso libero

An Efficient Method of Key-Frame Extraction Based on a Cluster Algorithm

Pubblicato online: 31 Dec 2013
Pagine: 5 - 14

Astratto

Abstract

This paper proposes a novel method of key-frame extraction for use with motion capture data. This method is based on an unsupervised cluster algorithm. First, the motion sequence is clustered into two classes by the similarity distance of the adjacent frames so that the thresholds needed in the next step can be determined adaptively. Second, a dynamic cluster algorithm called ISODATA is used to cluster all the frames and the frames nearest to the center of each class are automatically extracted as key-frames of the sequence. Unlike many other clustering techniques, the present improved cluster algorithm can automatically address different motion types without any need for specified parameters from users. The proposed method is capable of summarizing motion capture data reliably and efficiently. The present work also provides a meaningful comparison between the results of the proposed key-frame extraction technique and other previous methods. These results are evaluated in terms of metrics that measure reconstructed motion and the mean absolute error value, which are derived from the reconstructed data and the original data.

Parole chiave

  • Motion Capture
  • ISODATA
  • Adaptive Threshold
Accesso libero

An Efficient Method of Key-Frame Extraction Based on a Cluster Algorithm

Pubblicato online: 31 Dec 2013
Pagine: 15 - 23

Astratto

Abstract

The purpose of the present study was to investigate the effects of different configurations of repetitions within a set of deadlifts on the mechanical variables of concentric force, concentric time under tension, impulse, work, power, and fatigue. Eleven resistance trained men (age: 21.9 ± 1.0 years; deadlift 1 repetition maximum: 183.2 ± 38.3 kg) performed four repetitions of the deadlift exercise with a load equivalent to 90% of 1 repetition maximum under three different set configurations: Traditional (continuous repetitions); Doubles cluster (repetitions 1 and 2, and 3 and 4 performed continuously with a 30 s rest inserted between repetitions 2 and 3); Singles cluster (30 s rest provided between repetitions). The order of the sessions was counterbalanced across the subjects and the mechanical variables were calculated during each repetition from the synchronized signals recorded from force platforms and a motion analysis system. Relative to the Traditional set, the insertion of rest periods in the cluster set configurations resulted in greater time under tension (p < 0.001) and therefore, greater impulse (p < 0.001) during the repetitions. Reductions in power were observed during the cluster sets compared to the Traditional set (p = 0.001). The Doubles cluster set resulted in greater fatigue scores for power compared to the Traditional set (p = 0.04). The influence of cluster sets on mechanical variables appears to be mediated by the mechanical characteristics of the exercise (i.e. stretch-shortening cycle) and the competing physiological mechanisms of fatigue and potentiation.

Parole chiave

  • interrepetition rest
  • fatigue
  • resistance exercise
Accesso libero

Digital Filtering of Three-Dimensional Lower Extremity Kinematics: an Assessment

Pubblicato online: 31 Dec 2013
Pagine: 25 - 36

Astratto

Abstract

Errors in kinematic data are referred to as noise and are an undesirable portion of any waveform. Noise is typically removed using a low-pass filter which removes the high frequency components of the signal. The selection of an optimal frequency cut-off is very important when processing kinematic information and a number of techniques exists for the determination of an optimal frequency cut-off. Despite the importance of cut-off frequency to the efficacy of kinematic analyses there is currently a paucity of research examining the influence of different cut-off frequencies on the resultant 3-D kinematic waveforms and discrete parameters. Twenty participants ran at 4.0 m•s-1 as lower extremity kinematics in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system. The data were filtered at a range of cut-off frequencies and the discrete kinematic parameters were examined using repeated measures ANOVA’s. The similarity between the raw and filtered waveforms were examined using intra-class correlations. The results show that the cut-off frequency has a significant influence on the discrete kinematic measure across displacement and derivative information in all three planes of rotation. Furthermore, it was also revealed that as the cut-off frequency decreased the attenuation of the kinematic waveforms became more pronounced, particularly in the coronal and transverse planes at the second derivative. In conclusion, this investigation provides new information regarding the influence of digital filtering on lower extremity kinematics and re-emphasizes the importance of selecting the correct cut-off frequency.

Parole chiave

  • Low pass filter
  • kinematics
  • gait analysis
Accesso libero

Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking

Pubblicato online: 31 Dec 2013
Pagine: 37 - 47

Astratto

Abstract

The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. -1.45%, p < 0.001), RF (37.5% vs. -8.33%, p < 0.001), VM (12% vs. - 12%, p < 0.018), and VL EMG activity (20% vs. -6.67%, p < 0.001) after dynamic stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching.

Parole chiave

  • Muscle activation
  • Quadriceps
  • Kicking velocity
  • Warm-up
Accesso libero

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

Pubblicato online: 31 Dec 2013
Pagine: 49 - 57

Astratto

Abstract

The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.

Parole chiave

  • Exercise
  • reflex
  • silent period
  • surface electromyography
Accesso libero

Alterations in Three-dimensional Knee Kinematics and Kinetics during Neutral, Squeeze and Outward Squat

Pubblicato online: 31 Dec 2013
Pagine: 59 - 66

Astratto

Abstract

The squat exercise was usually performed with varying feet and hip angles by different populations. The objective of this study was to compare and contrast the three-dimensional knee angles, moments, and forces during dynamic squat exercises with varying feet and hip angles. Lower extremity motions and ground reaction forces for fifteen healthy subjects (9 females and 6 males) were recorded while performing the squat with feet pointing straight ahead (neutral squat), 30º feet adduction (squeeze squat) and 30º feet abduction (outward squat). Nonparametric procedures were used to detect differences in the interested measures between the conditions. No significant difference in three-dimensional peak knee angles was observed for three squat exercises (p>0.05), however, the overall tendency of knee rotations was affected by varying feet and hip positions. During the whole cycle, the outward squat mainly displayed adduction moments, while the neutral and squeeze squat demonstrated abduction moments. Peak abduction moments were significantly affected by feet positions (p<0.05). Moreover, the tibiofemoral and patellofemoral joint forces progressively increased as knee flexed and decreased as knee extended, yet peak forces were not affected by varying feet positions (p>0.05). In conclusion, a neutral position is recommended to perform the squat exercise, while the squeeze squat and outward squat might contribute to the occurrence of joint pathologies.

Parole chiave

  • squat performance
  • foot angle
  • knee alignment
  • rehabilitation
  • osteoarthritis
Accesso libero

Kinematic Chains in Ski Jumping In-run Posture

Pubblicato online: 31 Dec 2013
Pagine: 67 - 73

Astratto

Abstract

The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper’s body’s kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper’s body at the in-run position are greater nearer the chain’s ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments’ positions in the kinematic chain of the ski jumper’s body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.

Keywords

  • 2-D videography
  • biomechanics
  • ski jumping
  • kinematic chains
Accesso libero

Electromyographic Comparison of Traditional and Suspension Push-Ups

Pubblicato online: 31 Dec 2013
Pagine: 75 - 83

Astratto

Abstract

There is very limited scientific data concerning suspension training. The purpose of this investigation was to compare the electromyographic activity of the pectoralis major, anterior deltoid, and triceps brachii between a suspension push-up and traditional push-up. Twenty-one apparently healthy men (n = 15, age = 25.93 ± 3.67 years) and women (n = 6, age = 23.5 ± 1.97 years) volunteered to participate in this study. All subjects performed four repetitions of a suspension push-up and a traditional push-up where the order of the exercises was randomized. The mean peak and normalized electromyography of the pectoralis major, anterior deltoid, and triceps brachii were compared across the two exercises. Suspension push-ups elicited the following electromyographic values: pectoralis major (3.08 ± 1.13 mV, 69.54 ± 27.6 %MVC), anterior deltoid (5.08 ± 1.55 mV, 81.13 ± 17.77 %MVC), and triceps brachii (5.11 ± 1.97 mV, 105.83 ± 18.54 %MVC). The electromyographic activities during the traditional push-up were as follows: pectoralis major (2.66 ± 1.05 mV, 63.62 ± 16.4 %MVC), anterior deltoid (4.01 ± 1.27 mV, 58.91 ± 20.3 %MVC), and triceps brachii (3.91 ± 1.36 mV, 74.32 ± 16.9 %MVC). The mean peak and normalized electromyographic values were significantly higher for all 3 muscles during the suspension push-up compared to the traditional push-up (p < 0.05). This study suggests that the suspension push-up elicited a greater activation of pectoralis major, anterior deltoid, and triceps brachii when compared to a traditional push-up. Therefore, suspension push-ups may be considered an advanced variation of a traditional push-up when a greater challenge is warranted.

Parole chiave

  • EMG
  • instability devices
  • resistance training
  • TRX
Accesso libero

Validity of the ithleteTM Smart Phone Application for Determining Ultra-Short-Term Heart Rate Variability

Pubblicato online: 31 Dec 2013
Pagine: 85 - 92

Astratto

Abstract

The purpose of this investigation was to cross-validate the ithleteTM heart rate variability smart phone application with an electrocardiograph for determining ultra-short-term root mean square of successive R-R intervals. The root mean square of successive R-R intervals was simultaneously determined via electrocardiograph and ithleteTM at rest in twenty five healthy participants. There were no significant differences between the electrocardiograph and ithleteTM derived root mean square of successive R-R interval values (p > 0.05) and the correlation was near perfect (r = 0.99, p < 0.001). In addition, the ithleteTM revealed a Standard Error of the Estimate of 1.47 and Bland Altman plot showed that the limits of agreement ranged from 2.57 below to 2.63 above the constant error of -0.03. In conclusion, the ithleteTM appeared to provide a suitably accurate measure of root mean square of successive R-R intervals when compared to the electrocardiograph measures obtained in the laboratory within the current sample of healthy adult participants. The current study lays groundwork for future research determining the efficacy of ithleteTM for reflecting athletic training status over a chronic conditioning period.

Keywords

  • HRV
  • Athlete Monitoring
  • Parasympathetic
  • Mobile Device
Accesso libero

Exercise Intensity and Validity of the Ratings of Perceived Exertion (Borg and OMNI Scales) in an Indoor Cycling Session

Pubblicato online: 31 Dec 2013
Pagine: 93 - 101

Astratto

Abstract

The purpose of the study was: 1) to determine the intensity of an indoor cycling session; 2) to know the correlation between the rating of perceived exertion (RPE) scales (Borg and OMNI) and % heart rate reserve (%HRR) with categories; and 3) to evaluate the validity of RPE scales (Borg and OMNI) with respect to the heart rate (HR) and %HRR. A total of fifty-three subjects, 25 males and 28 females (ages: 28.79 ± 6.04 years; body height: 1.71 ± 0.09 m; body mass: 69.59 ± 13.69 kg) were recruited from a private fitness club. All subjects performed the same predesigned indoor cycling session with a total duration of 50 minutes. During the experimental trial, the HR was recorded every 5 s. The Borg 6-20 RPE and OMNI 0-10 scales were used to assess perceived exertion in each phase. The average HR in the cardiovascular phase was 152.24 ± 14.11 b•min-1, the %HRR was 80.62 ± 7.10; and the overall RPE (Borg and OMNI scales) was 14.94 ± 1.11 and 7.18 ± 0.79 points, respectively. The correlation between an average HR and %HRR with Borg and OMNI scales was lower than r = 0.4 (p < 0.05). The correlation value between the Borg and the OMNI RPE scales was r = 0.82 (p < 0.001). It can be concluded that indoor cycling elicits effort of high intensity which could be inappropriate for some participants. The Borg and OMNI scales showed a low validity to quantify the intensity performed in indoor cycling sessions. It indicates the necessity to control the intensity of effort with other instruments to improve efficacy and decrease the risk of overload in this activity.

Keywords

  • Spinning®
  • wellness
  • aerobic
  • effort
  • cardiovascular
  • fitness
Accesso libero

The Effects of High Intensity Interval Training in Normobaric Hypoxia on Aerobic Capacity in Basketball Players

Pubblicato online: 31 Dec 2013
Pagine: 103 - 114

Astratto

Abstract

The aim of the present study was to evaluate the efficacy of 3-week high intensity interval training in normobaric hypoxia (IHT) on aerobic capacity in basketball players. Twelve male well trained basketball players, randomly divided into a hypoxia (H) group (n=6; age: 22±1.6 years; VO2max: 52.6±3.9 ml/kg/min; body height - BH: 188.8±6.1 cm; body mass - BM: 83.9±7.2 kg; % of body fat - FAT%: 11.2±3.1%), and a control (C) group (n=6; age: 22±2.4 years; VO2max: 53.0±5.2 ml/kg/min; BH: 194.3 ± 6.6 cm; BM: 99.9±11.1 kg; FAT% 11.0±2.8 %) took part in the study. The training program applied during the study was the same for both groups, but with different environmental conditions during the selected interval training sessions. For 3 weeks, all subjects performed three high intensity interval training sessions per week. During the interval training sessions, the H group trained in a normobaric hypoxic chamber at a simulated altitude of 2500 m, while the group C performed interval training sessions under normoxia conditions also inside the chamber. Each interval running training sessions consisted of four to five 4 min bouts at 90% of VO2max velocity determined in hypoxia (vVO2max-hyp) for the H group and 90% of velocity at VO2max determined in normoxia for the group C. The statistical post-hoc analysis showed that the training in hypoxia caused a significant (p<0.001) increase (10%) in total distance during the ramp test protocol (the speed was increased linearly by 1 km/h per 1min until volitional exhaustion), as well as increased (p<0.01) absolute (4.5%) and relative (6.2%) maximal workload (WRmax). Also, the absolute and relative values of VO2max in this group increased significantly (p<0.001) by 6.5% and 7.8%. Significant, yet minor changes were also observed in the group C, where training in normoxia caused an increase (p<0.05) in relative values of WRmax by 2.8%, as well as an increase (p<0.05) in the absolute (1.3%) and relative (2.1%) values of VO2max. This data suggest that an intermittent hypoxic training protocol with high intensity intervals (4 to 5 x 4 min bouts at 90% of vVO2max-hyp) is an effective training means for improving aerobic capacity at sea level in basketball players.

Keywords

  • intermittent hypoxic training
  • aerobic capacity
  • basketball
Accesso libero

Effectiveness of Injury Prevention Programs on Developing Quadriceps and Hamstrings Strength of Young Male Professional Soccer Players

Pubblicato online: 31 Dec 2013
Pagine: 115 - 125

Astratto

Abstract

Muscular strength is an important factor which is crucial for performance and injury prevention in most sports. The purpose of this study was to evaluate the effects of the FIFA’s Medical Assessment and Research Centre 11+ and HarmoKnee injury prevention programs on knee strength of young professional male soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) were divided equally into three groups; the 11+, HarmoKnee and control groups. The programs were performed for 24 sessions. Hamstring and quadriceps strength was measured using the Biodex System 3 at 30°, 60° and 90° of knee flexion. The 11+ increased quadriceps strength in the dominant leg by 19.7% and 47.8% at 60°and 90° knee flexion, respectively, and in the non-dominant leg by 16%, 35.3% and 78.1 % at 30°, 60° and 90° knee flexion, respectively. The HarmoKnee group, however, showed increased quadriceps strength only at 90° i.e., by 85.7% in the dominant leg and 73.8% in the non-dominant leg. As for hamstring strength, only the 11+ group demonstrated an increment by 24.8% and 19.8% at 30° and 60° knee flexion in the dominant leg, and in the nondominant leg, by 28.7% and 13.7% at 30° and 60° knee flexion, respectively. In conclusion, both warm-up programs improve quadriceps strength. The 11+ demonstrated improvement in hamstring strength while the HarmoKnee program did not indicate any improvement. We suggest adding eccentric hamstring components such as Nordic hamstring exercise to the HarmoKnee program in order to enhance hamstring strength.

Keywords

  • knee
  • strength
  • professional soccer player
  • the 11+
  • HarmoKnee
Accesso libero

Effect of a Single Finnish Sauna Session on White Blood Cell Profile and Cortisol Levels in Athletes and Non-Athletes

Pubblicato online: 31 Dec 2013
Pagine: 127 - 135

Astratto

Abstract

The aim of the present study was to investigate the effect of Finnish sauna bathing on a white blood cell profile, cortisol levels and selected physiological indices in athletes and non-athletes. The study evaluated 9 trained middle-distance runners and 9 male non-athletes. The subjects from both groups participated in 15-minute sauna sessions until their core temperature rose by 1.2°C (mean temperature in the sauna room was 96° ± 2°C; relative humidity was 15 ± 3%) with a 2 minute cool down with water at a temperature of 19-20°C. Body mass was measured before and after the session and blood samples were taken for tests. Rectal temperature was monitored at five-minute intervals during the whole session. Serum total protein, haematological indices and cortisol levels were determined. Sauna bathing caused higher body mass loss and plasma volume in the athletes compared to the group of non-athletes. After the sauna session, an increased number of white blood cells, lymphocyte, neutrophil and basophil counts was reported in the white blood cell profile. Higher increments in leukocyte and monocyte after the sauna bathing session were recorded in the group of athletes compared to untrained subjects. The obtained results indicated that sauna bathing stimulated the immune system to a higher degree in the group of athletes compared to the untrained subjects.

Keywords

  • sauna bath
  • white blood cell profile
  • cortisol
  • immunology
Accesso libero

CKM Gene G (Ncoi-) Allele Has a Positive Effect on Maximal Oxygen Uptake in Caucasian Women Practicing Sports Requiring Aerobic and Anaerobic Exercise Metabolism

Pubblicato online: 31 Dec 2013
Pagine: 137 - 145

Astratto

Abstract

The search for genes with a positive influence on physical fitness is a difficult process. Physical fitness is a trait determined by multiple genes, and its genetic basis is then modified by numerous environmental factors. The present study examines the effects of the polymorphism of creatine kinase (CKM) gene on VO2max - a physiological index of aerobic capacity of high heritability. The study sample consisted of 154 men and 85 women, who were students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. The study revealed a positive effect of a rare G (NcoI-) allele of the CKM gene on maximal oxygen uptake in Caucasian women practicing sports requiring aerobic and anaerobic exercise metabolism. Also a tendency was noted in individuals with NcoI-/- (GG) and NcoI-/+ (GA) genotypes to reach higher VO2max levels.

Keywords

  • CKM gene
  • athletic performance
  • genetic polymorphism
  • metabolic efficiency
Accesso libero

Mechanical Analysis of the Acute Effects of a Heavy Resistance Exercise Warm-Up on Agility Performance in Court-Sport Athletes

Pubblicato online: 31 Dec 2013
Pagine: 147 - 156

Astratto

Abstract

The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

Keywords

  • change of direction
  • agility
  • warm-up
  • stride length
  • stride frequency
  • ground reaction force
Accesso libero

Does an in-Season 6-Week Combined Sprint and Jump Training Program Improve Strength-Speed Abilities and Kicking Performance in Young Soccer Players?

Pubblicato online: 31 Dec 2013
Pagine: 157 - 166

Astratto

Abstract

The aim of this study was to examine the effect of a six-week combined jump and sprint training program on strength-speed abilities in a large sample of youth competitive soccer players. It was hypothesized that the experimental training group would enhance their jumping and sprinting abilities. Enhancement of kicking performance was also hypothesized due to an expected increase in explosive strength established by a plyometric and sprinting regimen. Fiftytwo young male soccer players playing at the national level (aged 13.4 ± 1.4 years, body mass 53.4 ± 11.7 kg, body height 1.66 ± 0.11 m) took part in the study. Half of the group underwent the plyometric and sprint training program in addition to their normal soccer training, while the other half was involved in soccer training only. The plyometric training group enhanced their running (+1.7 and +3.2%) and jumping performance (+7.7%) significantly over the short period of time, while the control group did not. Furthermore, both groups increased their kicking velocity after just six weeks of training (+3.3 vs. 6.6%). The findings suggest that a short in-season 6-week sprint and jump training regimen can significantly improve explosive strength in soccer-specific skills and that these improvements can be transferred to soccer kicking performance in terms of ball speed.

Keywords

  • speed training
  • lower extremity
  • kicking
  • soccer
Accesso libero

The Acute Effect of Upper-Body Complex Training on Power Output of Martial Art Athletes as Measured by the Bench Press Throw Exercise

Pubblicato online: 31 Dec 2013
Pagine: 167 - 175

Astratto

Abstract

The purpose of this study was to examine the acute effect of upper body complex training on power output, as well as to determine the requisite preload intensity and intra-complex recovery interval needed to induce power output increases. Nine amateur-level combat/martial art athletes completed four distinct experimental protocols, which consisted of 5 bench press repetitions at either: 65% of one-repetition maximum (1RM) with a 4 min rest interval; 65% of 1RM with an 8 min rest; 85% of 1RM with a 4 min rest; or 85% of 1RM with an 8 min rest interval, performed on different days. Before (pre-conditioning) and after (post-conditioning) each experimental protocol, three bench press throws at 30% of 1RM were performed. Significant differences in power output pre-post conditioning were observed across all experimental protocols (F=26.489, partial eta2=0.768, p=0.001). Mean power output significantly increased when the preload stimulus of 65% 1RM was matched with 4 min of rest (p=0.001), and when the 85% 1RM preload stimulus was matched with 8 min of rest (p=0.001). Moreover, a statistically significant difference in power output was observed between the four conditioning protocols (F= 21.101, partial eta²=0.913, p=0.001). It was concluded that, in complex training, matching a heavy preload stimulus with a longer rest interval, and a lighter preload stimulus with a shorter rest interval is important for athletes wishing to increase their power production before training or competition.

Keywords

  • conditioning
  • Myotest
  • potentiation
  • power
Accesso libero

Effects of Resistance Exercise Order on the Number of Repetitions Performed to Failure and Perceived Exertion in Untrained Young Males

Pubblicato online: 31 Dec 2013
Pagine: 177 - 183

Astratto

Abstract

Exercise order is an essential variable of resistance training (RT) programs which is usually related to repetition performance. The purpose of this study was to investigate the acute effect of different resistance exercise order on the number of repetitions performed to failure and related ratings of perceived exertion (RPE). Thirteen male adolescents (age: 14.46 ± 1.39 years, body height: 165.31 ± 12.75 cm, body mass: 58.73 ± 12.27 kg, estimated body fat: 21.32 ± 2.84%), without previous experience in RT, performed four resistance exercises: incline leg press (ILP), dumbbell lunge (DL), bench press (BP) and lying barbell triceps extension (TE) in two sequences - Sequence A (SEQA): ILP, DL, BP and TE; sequence B (SEQB): ILP, BP, DL and TE. The exercise sequences were performed in a randomized crossover design with a rest interval of 72h between sessions. Within-subjects analysis showed significant differences in the number of repetitions performed to failure in both sequences, but not in the RPE. Post-hoc tests revealed significant decrements in the number of repetitions from the first to the remaining exercises in both sequences. However, pairwise comparisons did not indicate significant differences between the same exercises performed in different sequences. In conclusion, the results of the current study in adolescents suggest that the main exercises should be performed at the beginning of the RT session.

Keywords

  • Resistance training
  • Exercise order
  • Strength performance
  • Adolescents
Accesso libero

Wave Characteristics in Breaststroke Technique with and Without Snorkel Use

Pubblicato online: 31 Dec 2013
Pagine: 185 - 194

Astratto

Abstract

The purpose of this paper was to examine the characteristics of waves generated when swimming with and without the use of Aquatrainer® snorkels. Eight male swimmers performed two maximal bouts of 25 m breaststroke, first without the use of a snorkel (normal condition) and then using a snorkel (snorkel condition). The body landmarks, centre of the mass velocity, stroke rate, stroke length, stroke index, and Strouhal number (St) were quantified. Fourier analysis was conducted to determine the frequency, amplitude, and phase characteristics of the vertical undulations. We also determined the undulation period, the first and second harmonic wave percentage, and the contribution of these components to the power of each of the wave signals. The first wave harmonics had a frequency of 0.76 Hz (normal condition) and 0.78 Hz (snorkel condition), and the second wave harmonics had a frequency of 1.52 Hz (normal condition) and 1.56 Hz (snorkel condition). Under the normal conditions, the wave amplitude was higher on the vertex (0.72 m) and cervical (0.32 m) than that produced under snorkel conditions (0.71 m and 0.28 m, respectively). The lowest values were found in the hip (0.03 m in normal conditions, and 0.02 m in snorkel conditions) and in the trunk (0.06 m in normal conditions, and 0.04 m in snorkel conditions). It can be concluded that snorkel use seems to lead to slight changes in the biomechanical pattern in swimming velocity, as well as several stroke mechanical variables.

Keywords

  • competitive swimming
  • stroke rate
  • stroke length
  • swimming snorkel
  • wave motion
  • Fourier analysis
Accesso libero

Attention, Visual Perception and their Relationship to Sport Performance in Fencing

Pubblicato online: 31 Dec 2013
Pagine: 195 - 201

Astratto

Abstract

Attention and visual perception are important in fencing, as they affect the levels of performance and achievement in fencers. This study identifies the levels of attention and visual perception among male and female fencers and the relationship between attention and visual perception dimensions and the sport performance in fencing. The researcher employed a descriptive method in a sample of 16 fencers during the 2010/2011 season. The sample was comprised of eight males and eight females who participated in the 11-year stage of the Cairo Championships. The Test of Attentional and Interpersonal Style, which was designed by Nideffer and translated by Allawi (1998) was applied. The test consisted of 59 statements that measured seven dimensions. The Test of Visual Perception Skills designed by Alsmadune (2005), which includes seven dimensions was also used. Among females, a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual-Spatial Relationships, Visual Sequential Memory, Narrow Attentional Focus and Information Processing was observed, while among males, there was a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional Focus and Information Processing. For both males and females, a positive and statistically significant correlation between achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional, Narrow Attentional Focus and Information Processing was found. There were statistically significant differences between males and females in Visual Discrimination and Visual-Form Constancy.

Parole chiave

  • Fencing
  • Visual Discrimination
  • Visual-Form Constancy
  • Visual Sequential Memory
  • Broad External Attentional
  • Information Processing
Accesso libero

The Influence of Anthropometric, Kinematic and Energetic Variables and Gender on Swimming Performance in Youth Athletes

Pubblicato online: 31 Dec 2013
Pagine: 203 - 211

Astratto

Abstract

The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance, anthropometrics, kinematics and energetics between boys and girls; (ii) swimmers with best performance are taller, have higher surface areas and better stroke mechanics; (iii) there are non-significant interactions between sports level and gender for anthropometrics, kinematics and energetics.

Keywords

  • swimming
  • performance
  • skill
  • cohort comparison
Accesso libero

Anthropometry of World-Class Elite Handball Players According to the Playing Position: Reports From Men's Handball World Championship 2013

Pubblicato online: 31 Dec 2013
Pagine: 213 - 220

Astratto

Abstract

Identifying the anthropometric measures of successful and less successful handball players may be helpful in developing a talent identification and development model, allowing for the determination of key physical capacities required for elite performance. The purpose of the study was to describe the anthropometric characteristics, including age, standing stature, body mass and body mass index (BMI) in handball players who participated in the 2013 Men's Handball World Championships. Secondly, the objective was to identify the possible differences in these parameters in terms of individual playing positions (goalkeeper, back, center back, wing, line player). Rosters with handball player's age, standing stature, and body mass were obtained from the International Handball Federation website. The research material included 409 handball players (24 teams). National teams were organized by their ranks and sub-grouped using their continents and playing positions. The results of the analyses of variance demonstrated significant differences in age (F=2.30; p=0.044; Partial ŋ2=0.028), standing stature (F=14.02; p=0.0001; Partial ŋ2=0.148), and body mass (F=5.88; p=0.0001; Partial ŋ2=0.068) among the groups (G1-G6). Players in G1 had the highest standing stature and body mass, while players in G6 had the lowest age and body mass values. The backs and line players were the tallest. In addition, the measurement of body mass showed that the line players had the highest body mass and BMI values. In conclusion, this study presented anthropometric data that differentiated levels of success in male handball teams playing in the 2013 world championships. This information should serve as a reference for the average standing stature, body mass, and BMI of handball players for particular positions at the professional level.

Keywords

  • Body Mass
  • Handball
  • Standing Stature
  • Body Mass Index
  • Talent Identification
Accesso libero

Analysis of Cohesion and Collective Efficacy Profiles for the Performance of Soccer Players

Pubblicato online: 31 Dec 2013
Pagine: 221 - 229

Astratto

Abstract

The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The results of the study proved the existence of four cohesion and efficacy profiles that presented significant differences in expectations of success, playing time, and performance. Furthermore, significant differences were found in the distribution of players in the teams as a function of performance. The main conclusion of this study is that soccer players with higher cohesion and collective efficacy levels belonged to teams that completed the season at the top-level classification. In contrast, athletes with low cohesion and collective efficacy usually played in unsuccessful teams. Coaches and sports psychologists are encouraged to promote both social and task cohesion and collective efficacy to enhance team performance.

Keywords

  • Profiles
  • cohesion
  • efficacy
  • performance
  • soccer
Accesso libero

The Athlete's Perception of Coaches’ Behavior Towards Competitors with a Different Sports Level

Pubblicato online: 31 Dec 2013
Pagine: 231 - 242

Astratto

Abstract

The study was designed to examine how active and former athletes across a different sports level perceived coaching behavior. Eighty competitive athletes (44 males and 36 females; 21.89 ±1.48 years of age; 8.35 ± 3.65 years of competitive experience) from the University School of Physical Education in Cracow, Poland, participated in the study. They represented both individual (n = 50) and team sports (n = 30). Seventeen participants were internationally renowned and 63 were recognized for competitive excellence at a national level. The participants responded to a demographic survey and the Coaches’ Behaviors Survey. The qualitative analysis procedures were employed to extract themes from open-ended questions. It was confirmed that coaches who perceived their athletes as more skilled, also treated them differently. Female athletes as compared with male athletes, more frequently pointed at the leniency in coach’s behavior towards highly skilled athletes, and perceived it as a factor inhibiting athletic development. Additionally, women often found individualization of the training process as a behavior reinforcing development. Less accomplished athletes more often pointed out to “a post-training session interest in the athlete” as directed only towards more accomplished counterparts; however, they indicated “leniency and favoring” less often than the athletes with international achievements. They also listed “excessive criticism” as a type of behavior hindering development, but they indicated coaches’ “authoritarianism and distance” less frequently than the more accomplished counterparts. The study added data to the discussion of the Pygmalion effect and the phenomenon of the self-fulfilling prophecy both in general (Rosenthal and Jacobson, 1968; Harris and Rosenthal, 1985; Jussim, 1989) and sport psychology (Harris and Rosenthal, 1985; Horn et al., 1998; Solomon and Kosmitzki, 1996; Solomon et al., 1998; Solomon, 2001).

Keywords

  • the Pygmalion effect in sport
  • self-fulfilling prophecy
  • perception of coaches’ behaviors
Accesso libero

Practical Skills of Rhythmic Gymnastics Judges

Pubblicato online: 31 Dec 2013
Pagine: 243 - 249

Astratto

Abstract

The aim of this study was to analyze the practical skills of rhythmic gymnastics judges and to identify how their degree and experience influence the assessment of these skills. Sixty one rhythmic gymnastics judges participated in the study. A questionnaire was used for data collection. This tool was composed of 28 questions and divided into six categories: identification, experience, initial training, continuing education, skills and training needs. The results suggest that the most valued skills are those related to the sport´s technical parameters and the ability to adapt to any level of competition with self-confidence and self-assuredness. Significant differences were found regarding the variables for: the ability to communicate (p = 0.002) and for the ability to observe, identify and register performance (p = 0.005). The results showed that experience was not a decisive factor in assessing skills. This study thus presents evidence that rhythmic gymnastics judges must implement and optimise a set of skills that contribute to the effectiveness of the assessment process. These findings might help in the design of programs and training models that contribute to effective professional development.

Keywords

  • Practical knowledge
  • sport judges
  • rhythmic gymnastics
25 Articoli
Accesso libero

An Efficient Method of Key-Frame Extraction Based on a Cluster Algorithm

Pubblicato online: 31 Dec 2013
Pagine: 5 - 14

Astratto

Abstract

This paper proposes a novel method of key-frame extraction for use with motion capture data. This method is based on an unsupervised cluster algorithm. First, the motion sequence is clustered into two classes by the similarity distance of the adjacent frames so that the thresholds needed in the next step can be determined adaptively. Second, a dynamic cluster algorithm called ISODATA is used to cluster all the frames and the frames nearest to the center of each class are automatically extracted as key-frames of the sequence. Unlike many other clustering techniques, the present improved cluster algorithm can automatically address different motion types without any need for specified parameters from users. The proposed method is capable of summarizing motion capture data reliably and efficiently. The present work also provides a meaningful comparison between the results of the proposed key-frame extraction technique and other previous methods. These results are evaluated in terms of metrics that measure reconstructed motion and the mean absolute error value, which are derived from the reconstructed data and the original data.

Parole chiave

  • Motion Capture
  • ISODATA
  • Adaptive Threshold
Accesso libero

An Efficient Method of Key-Frame Extraction Based on a Cluster Algorithm

Pubblicato online: 31 Dec 2013
Pagine: 15 - 23

Astratto

Abstract

The purpose of the present study was to investigate the effects of different configurations of repetitions within a set of deadlifts on the mechanical variables of concentric force, concentric time under tension, impulse, work, power, and fatigue. Eleven resistance trained men (age: 21.9 ± 1.0 years; deadlift 1 repetition maximum: 183.2 ± 38.3 kg) performed four repetitions of the deadlift exercise with a load equivalent to 90% of 1 repetition maximum under three different set configurations: Traditional (continuous repetitions); Doubles cluster (repetitions 1 and 2, and 3 and 4 performed continuously with a 30 s rest inserted between repetitions 2 and 3); Singles cluster (30 s rest provided between repetitions). The order of the sessions was counterbalanced across the subjects and the mechanical variables were calculated during each repetition from the synchronized signals recorded from force platforms and a motion analysis system. Relative to the Traditional set, the insertion of rest periods in the cluster set configurations resulted in greater time under tension (p < 0.001) and therefore, greater impulse (p < 0.001) during the repetitions. Reductions in power were observed during the cluster sets compared to the Traditional set (p = 0.001). The Doubles cluster set resulted in greater fatigue scores for power compared to the Traditional set (p = 0.04). The influence of cluster sets on mechanical variables appears to be mediated by the mechanical characteristics of the exercise (i.e. stretch-shortening cycle) and the competing physiological mechanisms of fatigue and potentiation.

Parole chiave

  • interrepetition rest
  • fatigue
  • resistance exercise
Accesso libero

Digital Filtering of Three-Dimensional Lower Extremity Kinematics: an Assessment

Pubblicato online: 31 Dec 2013
Pagine: 25 - 36

Astratto

Abstract

Errors in kinematic data are referred to as noise and are an undesirable portion of any waveform. Noise is typically removed using a low-pass filter which removes the high frequency components of the signal. The selection of an optimal frequency cut-off is very important when processing kinematic information and a number of techniques exists for the determination of an optimal frequency cut-off. Despite the importance of cut-off frequency to the efficacy of kinematic analyses there is currently a paucity of research examining the influence of different cut-off frequencies on the resultant 3-D kinematic waveforms and discrete parameters. Twenty participants ran at 4.0 m•s-1 as lower extremity kinematics in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system. The data were filtered at a range of cut-off frequencies and the discrete kinematic parameters were examined using repeated measures ANOVA’s. The similarity between the raw and filtered waveforms were examined using intra-class correlations. The results show that the cut-off frequency has a significant influence on the discrete kinematic measure across displacement and derivative information in all three planes of rotation. Furthermore, it was also revealed that as the cut-off frequency decreased the attenuation of the kinematic waveforms became more pronounced, particularly in the coronal and transverse planes at the second derivative. In conclusion, this investigation provides new information regarding the influence of digital filtering on lower extremity kinematics and re-emphasizes the importance of selecting the correct cut-off frequency.

Parole chiave

  • Low pass filter
  • kinematics
  • gait analysis
Accesso libero

Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking

Pubblicato online: 31 Dec 2013
Pagine: 37 - 47

Astratto

Abstract

The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. -1.45%, p < 0.001), RF (37.5% vs. -8.33%, p < 0.001), VM (12% vs. - 12%, p < 0.018), and VL EMG activity (20% vs. -6.67%, p < 0.001) after dynamic stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching.

Parole chiave

  • Muscle activation
  • Quadriceps
  • Kicking velocity
  • Warm-up
Accesso libero

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

Pubblicato online: 31 Dec 2013
Pagine: 49 - 57

Astratto

Abstract

The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.

Parole chiave

  • Exercise
  • reflex
  • silent period
  • surface electromyography
Accesso libero

Alterations in Three-dimensional Knee Kinematics and Kinetics during Neutral, Squeeze and Outward Squat

Pubblicato online: 31 Dec 2013
Pagine: 59 - 66

Astratto

Abstract

The squat exercise was usually performed with varying feet and hip angles by different populations. The objective of this study was to compare and contrast the three-dimensional knee angles, moments, and forces during dynamic squat exercises with varying feet and hip angles. Lower extremity motions and ground reaction forces for fifteen healthy subjects (9 females and 6 males) were recorded while performing the squat with feet pointing straight ahead (neutral squat), 30º feet adduction (squeeze squat) and 30º feet abduction (outward squat). Nonparametric procedures were used to detect differences in the interested measures between the conditions. No significant difference in three-dimensional peak knee angles was observed for three squat exercises (p>0.05), however, the overall tendency of knee rotations was affected by varying feet and hip positions. During the whole cycle, the outward squat mainly displayed adduction moments, while the neutral and squeeze squat demonstrated abduction moments. Peak abduction moments were significantly affected by feet positions (p<0.05). Moreover, the tibiofemoral and patellofemoral joint forces progressively increased as knee flexed and decreased as knee extended, yet peak forces were not affected by varying feet positions (p>0.05). In conclusion, a neutral position is recommended to perform the squat exercise, while the squeeze squat and outward squat might contribute to the occurrence of joint pathologies.

Parole chiave

  • squat performance
  • foot angle
  • knee alignment
  • rehabilitation
  • osteoarthritis
Accesso libero

Kinematic Chains in Ski Jumping In-run Posture

Pubblicato online: 31 Dec 2013
Pagine: 67 - 73

Astratto

Abstract

The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper’s body’s kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper’s body at the in-run position are greater nearer the chain’s ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments’ positions in the kinematic chain of the ski jumper’s body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.

Keywords

  • 2-D videography
  • biomechanics
  • ski jumping
  • kinematic chains
Accesso libero

Electromyographic Comparison of Traditional and Suspension Push-Ups

Pubblicato online: 31 Dec 2013
Pagine: 75 - 83

Astratto

Abstract

There is very limited scientific data concerning suspension training. The purpose of this investigation was to compare the electromyographic activity of the pectoralis major, anterior deltoid, and triceps brachii between a suspension push-up and traditional push-up. Twenty-one apparently healthy men (n = 15, age = 25.93 ± 3.67 years) and women (n = 6, age = 23.5 ± 1.97 years) volunteered to participate in this study. All subjects performed four repetitions of a suspension push-up and a traditional push-up where the order of the exercises was randomized. The mean peak and normalized electromyography of the pectoralis major, anterior deltoid, and triceps brachii were compared across the two exercises. Suspension push-ups elicited the following electromyographic values: pectoralis major (3.08 ± 1.13 mV, 69.54 ± 27.6 %MVC), anterior deltoid (5.08 ± 1.55 mV, 81.13 ± 17.77 %MVC), and triceps brachii (5.11 ± 1.97 mV, 105.83 ± 18.54 %MVC). The electromyographic activities during the traditional push-up were as follows: pectoralis major (2.66 ± 1.05 mV, 63.62 ± 16.4 %MVC), anterior deltoid (4.01 ± 1.27 mV, 58.91 ± 20.3 %MVC), and triceps brachii (3.91 ± 1.36 mV, 74.32 ± 16.9 %MVC). The mean peak and normalized electromyographic values were significantly higher for all 3 muscles during the suspension push-up compared to the traditional push-up (p < 0.05). This study suggests that the suspension push-up elicited a greater activation of pectoralis major, anterior deltoid, and triceps brachii when compared to a traditional push-up. Therefore, suspension push-ups may be considered an advanced variation of a traditional push-up when a greater challenge is warranted.

Parole chiave

  • EMG
  • instability devices
  • resistance training
  • TRX
Accesso libero

Validity of the ithleteTM Smart Phone Application for Determining Ultra-Short-Term Heart Rate Variability

Pubblicato online: 31 Dec 2013
Pagine: 85 - 92

Astratto

Abstract

The purpose of this investigation was to cross-validate the ithleteTM heart rate variability smart phone application with an electrocardiograph for determining ultra-short-term root mean square of successive R-R intervals. The root mean square of successive R-R intervals was simultaneously determined via electrocardiograph and ithleteTM at rest in twenty five healthy participants. There were no significant differences between the electrocardiograph and ithleteTM derived root mean square of successive R-R interval values (p > 0.05) and the correlation was near perfect (r = 0.99, p < 0.001). In addition, the ithleteTM revealed a Standard Error of the Estimate of 1.47 and Bland Altman plot showed that the limits of agreement ranged from 2.57 below to 2.63 above the constant error of -0.03. In conclusion, the ithleteTM appeared to provide a suitably accurate measure of root mean square of successive R-R intervals when compared to the electrocardiograph measures obtained in the laboratory within the current sample of healthy adult participants. The current study lays groundwork for future research determining the efficacy of ithleteTM for reflecting athletic training status over a chronic conditioning period.

Keywords

  • HRV
  • Athlete Monitoring
  • Parasympathetic
  • Mobile Device
Accesso libero

Exercise Intensity and Validity of the Ratings of Perceived Exertion (Borg and OMNI Scales) in an Indoor Cycling Session

Pubblicato online: 31 Dec 2013
Pagine: 93 - 101

Astratto

Abstract

The purpose of the study was: 1) to determine the intensity of an indoor cycling session; 2) to know the correlation between the rating of perceived exertion (RPE) scales (Borg and OMNI) and % heart rate reserve (%HRR) with categories; and 3) to evaluate the validity of RPE scales (Borg and OMNI) with respect to the heart rate (HR) and %HRR. A total of fifty-three subjects, 25 males and 28 females (ages: 28.79 ± 6.04 years; body height: 1.71 ± 0.09 m; body mass: 69.59 ± 13.69 kg) were recruited from a private fitness club. All subjects performed the same predesigned indoor cycling session with a total duration of 50 minutes. During the experimental trial, the HR was recorded every 5 s. The Borg 6-20 RPE and OMNI 0-10 scales were used to assess perceived exertion in each phase. The average HR in the cardiovascular phase was 152.24 ± 14.11 b•min-1, the %HRR was 80.62 ± 7.10; and the overall RPE (Borg and OMNI scales) was 14.94 ± 1.11 and 7.18 ± 0.79 points, respectively. The correlation between an average HR and %HRR with Borg and OMNI scales was lower than r = 0.4 (p < 0.05). The correlation value between the Borg and the OMNI RPE scales was r = 0.82 (p < 0.001). It can be concluded that indoor cycling elicits effort of high intensity which could be inappropriate for some participants. The Borg and OMNI scales showed a low validity to quantify the intensity performed in indoor cycling sessions. It indicates the necessity to control the intensity of effort with other instruments to improve efficacy and decrease the risk of overload in this activity.

Keywords

  • Spinning®
  • wellness
  • aerobic
  • effort
  • cardiovascular
  • fitness
Accesso libero

The Effects of High Intensity Interval Training in Normobaric Hypoxia on Aerobic Capacity in Basketball Players

Pubblicato online: 31 Dec 2013
Pagine: 103 - 114

Astratto

Abstract

The aim of the present study was to evaluate the efficacy of 3-week high intensity interval training in normobaric hypoxia (IHT) on aerobic capacity in basketball players. Twelve male well trained basketball players, randomly divided into a hypoxia (H) group (n=6; age: 22±1.6 years; VO2max: 52.6±3.9 ml/kg/min; body height - BH: 188.8±6.1 cm; body mass - BM: 83.9±7.2 kg; % of body fat - FAT%: 11.2±3.1%), and a control (C) group (n=6; age: 22±2.4 years; VO2max: 53.0±5.2 ml/kg/min; BH: 194.3 ± 6.6 cm; BM: 99.9±11.1 kg; FAT% 11.0±2.8 %) took part in the study. The training program applied during the study was the same for both groups, but with different environmental conditions during the selected interval training sessions. For 3 weeks, all subjects performed three high intensity interval training sessions per week. During the interval training sessions, the H group trained in a normobaric hypoxic chamber at a simulated altitude of 2500 m, while the group C performed interval training sessions under normoxia conditions also inside the chamber. Each interval running training sessions consisted of four to five 4 min bouts at 90% of VO2max velocity determined in hypoxia (vVO2max-hyp) for the H group and 90% of velocity at VO2max determined in normoxia for the group C. The statistical post-hoc analysis showed that the training in hypoxia caused a significant (p<0.001) increase (10%) in total distance during the ramp test protocol (the speed was increased linearly by 1 km/h per 1min until volitional exhaustion), as well as increased (p<0.01) absolute (4.5%) and relative (6.2%) maximal workload (WRmax). Also, the absolute and relative values of VO2max in this group increased significantly (p<0.001) by 6.5% and 7.8%. Significant, yet minor changes were also observed in the group C, where training in normoxia caused an increase (p<0.05) in relative values of WRmax by 2.8%, as well as an increase (p<0.05) in the absolute (1.3%) and relative (2.1%) values of VO2max. This data suggest that an intermittent hypoxic training protocol with high intensity intervals (4 to 5 x 4 min bouts at 90% of vVO2max-hyp) is an effective training means for improving aerobic capacity at sea level in basketball players.

Keywords

  • intermittent hypoxic training
  • aerobic capacity
  • basketball
Accesso libero

Effectiveness of Injury Prevention Programs on Developing Quadriceps and Hamstrings Strength of Young Male Professional Soccer Players

Pubblicato online: 31 Dec 2013
Pagine: 115 - 125

Astratto

Abstract

Muscular strength is an important factor which is crucial for performance and injury prevention in most sports. The purpose of this study was to evaluate the effects of the FIFA’s Medical Assessment and Research Centre 11+ and HarmoKnee injury prevention programs on knee strength of young professional male soccer players. Thirty-six soccer players (age: 18.9 ± 1.4 years) were divided equally into three groups; the 11+, HarmoKnee and control groups. The programs were performed for 24 sessions. Hamstring and quadriceps strength was measured using the Biodex System 3 at 30°, 60° and 90° of knee flexion. The 11+ increased quadriceps strength in the dominant leg by 19.7% and 47.8% at 60°and 90° knee flexion, respectively, and in the non-dominant leg by 16%, 35.3% and 78.1 % at 30°, 60° and 90° knee flexion, respectively. The HarmoKnee group, however, showed increased quadriceps strength only at 90° i.e., by 85.7% in the dominant leg and 73.8% in the non-dominant leg. As for hamstring strength, only the 11+ group demonstrated an increment by 24.8% and 19.8% at 30° and 60° knee flexion in the dominant leg, and in the nondominant leg, by 28.7% and 13.7% at 30° and 60° knee flexion, respectively. In conclusion, both warm-up programs improve quadriceps strength. The 11+ demonstrated improvement in hamstring strength while the HarmoKnee program did not indicate any improvement. We suggest adding eccentric hamstring components such as Nordic hamstring exercise to the HarmoKnee program in order to enhance hamstring strength.

Keywords

  • knee
  • strength
  • professional soccer player
  • the 11+
  • HarmoKnee
Accesso libero

Effect of a Single Finnish Sauna Session on White Blood Cell Profile and Cortisol Levels in Athletes and Non-Athletes

Pubblicato online: 31 Dec 2013
Pagine: 127 - 135

Astratto

Abstract

The aim of the present study was to investigate the effect of Finnish sauna bathing on a white blood cell profile, cortisol levels and selected physiological indices in athletes and non-athletes. The study evaluated 9 trained middle-distance runners and 9 male non-athletes. The subjects from both groups participated in 15-minute sauna sessions until their core temperature rose by 1.2°C (mean temperature in the sauna room was 96° ± 2°C; relative humidity was 15 ± 3%) with a 2 minute cool down with water at a temperature of 19-20°C. Body mass was measured before and after the session and blood samples were taken for tests. Rectal temperature was monitored at five-minute intervals during the whole session. Serum total protein, haematological indices and cortisol levels were determined. Sauna bathing caused higher body mass loss and plasma volume in the athletes compared to the group of non-athletes. After the sauna session, an increased number of white blood cells, lymphocyte, neutrophil and basophil counts was reported in the white blood cell profile. Higher increments in leukocyte and monocyte after the sauna bathing session were recorded in the group of athletes compared to untrained subjects. The obtained results indicated that sauna bathing stimulated the immune system to a higher degree in the group of athletes compared to the untrained subjects.

Keywords

  • sauna bath
  • white blood cell profile
  • cortisol
  • immunology
Accesso libero

CKM Gene G (Ncoi-) Allele Has a Positive Effect on Maximal Oxygen Uptake in Caucasian Women Practicing Sports Requiring Aerobic and Anaerobic Exercise Metabolism

Pubblicato online: 31 Dec 2013
Pagine: 137 - 145

Astratto

Abstract

The search for genes with a positive influence on physical fitness is a difficult process. Physical fitness is a trait determined by multiple genes, and its genetic basis is then modified by numerous environmental factors. The present study examines the effects of the polymorphism of creatine kinase (CKM) gene on VO2max - a physiological index of aerobic capacity of high heritability. The study sample consisted of 154 men and 85 women, who were students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. The study revealed a positive effect of a rare G (NcoI-) allele of the CKM gene on maximal oxygen uptake in Caucasian women practicing sports requiring aerobic and anaerobic exercise metabolism. Also a tendency was noted in individuals with NcoI-/- (GG) and NcoI-/+ (GA) genotypes to reach higher VO2max levels.

Keywords

  • CKM gene
  • athletic performance
  • genetic polymorphism
  • metabolic efficiency
Accesso libero

Mechanical Analysis of the Acute Effects of a Heavy Resistance Exercise Warm-Up on Agility Performance in Court-Sport Athletes

Pubblicato online: 31 Dec 2013
Pagine: 147 - 156

Astratto

Abstract

The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.

Keywords

  • change of direction
  • agility
  • warm-up
  • stride length
  • stride frequency
  • ground reaction force
Accesso libero

Does an in-Season 6-Week Combined Sprint and Jump Training Program Improve Strength-Speed Abilities and Kicking Performance in Young Soccer Players?

Pubblicato online: 31 Dec 2013
Pagine: 157 - 166

Astratto

Abstract

The aim of this study was to examine the effect of a six-week combined jump and sprint training program on strength-speed abilities in a large sample of youth competitive soccer players. It was hypothesized that the experimental training group would enhance their jumping and sprinting abilities. Enhancement of kicking performance was also hypothesized due to an expected increase in explosive strength established by a plyometric and sprinting regimen. Fiftytwo young male soccer players playing at the national level (aged 13.4 ± 1.4 years, body mass 53.4 ± 11.7 kg, body height 1.66 ± 0.11 m) took part in the study. Half of the group underwent the plyometric and sprint training program in addition to their normal soccer training, while the other half was involved in soccer training only. The plyometric training group enhanced their running (+1.7 and +3.2%) and jumping performance (+7.7%) significantly over the short period of time, while the control group did not. Furthermore, both groups increased their kicking velocity after just six weeks of training (+3.3 vs. 6.6%). The findings suggest that a short in-season 6-week sprint and jump training regimen can significantly improve explosive strength in soccer-specific skills and that these improvements can be transferred to soccer kicking performance in terms of ball speed.

Keywords

  • speed training
  • lower extremity
  • kicking
  • soccer
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The Acute Effect of Upper-Body Complex Training on Power Output of Martial Art Athletes as Measured by the Bench Press Throw Exercise

Pubblicato online: 31 Dec 2013
Pagine: 167 - 175

Astratto

Abstract

The purpose of this study was to examine the acute effect of upper body complex training on power output, as well as to determine the requisite preload intensity and intra-complex recovery interval needed to induce power output increases. Nine amateur-level combat/martial art athletes completed four distinct experimental protocols, which consisted of 5 bench press repetitions at either: 65% of one-repetition maximum (1RM) with a 4 min rest interval; 65% of 1RM with an 8 min rest; 85% of 1RM with a 4 min rest; or 85% of 1RM with an 8 min rest interval, performed on different days. Before (pre-conditioning) and after (post-conditioning) each experimental protocol, three bench press throws at 30% of 1RM were performed. Significant differences in power output pre-post conditioning were observed across all experimental protocols (F=26.489, partial eta2=0.768, p=0.001). Mean power output significantly increased when the preload stimulus of 65% 1RM was matched with 4 min of rest (p=0.001), and when the 85% 1RM preload stimulus was matched with 8 min of rest (p=0.001). Moreover, a statistically significant difference in power output was observed between the four conditioning protocols (F= 21.101, partial eta²=0.913, p=0.001). It was concluded that, in complex training, matching a heavy preload stimulus with a longer rest interval, and a lighter preload stimulus with a shorter rest interval is important for athletes wishing to increase their power production before training or competition.

Keywords

  • conditioning
  • Myotest
  • potentiation
  • power
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Effects of Resistance Exercise Order on the Number of Repetitions Performed to Failure and Perceived Exertion in Untrained Young Males

Pubblicato online: 31 Dec 2013
Pagine: 177 - 183

Astratto

Abstract

Exercise order is an essential variable of resistance training (RT) programs which is usually related to repetition performance. The purpose of this study was to investigate the acute effect of different resistance exercise order on the number of repetitions performed to failure and related ratings of perceived exertion (RPE). Thirteen male adolescents (age: 14.46 ± 1.39 years, body height: 165.31 ± 12.75 cm, body mass: 58.73 ± 12.27 kg, estimated body fat: 21.32 ± 2.84%), without previous experience in RT, performed four resistance exercises: incline leg press (ILP), dumbbell lunge (DL), bench press (BP) and lying barbell triceps extension (TE) in two sequences - Sequence A (SEQA): ILP, DL, BP and TE; sequence B (SEQB): ILP, BP, DL and TE. The exercise sequences were performed in a randomized crossover design with a rest interval of 72h between sessions. Within-subjects analysis showed significant differences in the number of repetitions performed to failure in both sequences, but not in the RPE. Post-hoc tests revealed significant decrements in the number of repetitions from the first to the remaining exercises in both sequences. However, pairwise comparisons did not indicate significant differences between the same exercises performed in different sequences. In conclusion, the results of the current study in adolescents suggest that the main exercises should be performed at the beginning of the RT session.

Keywords

  • Resistance training
  • Exercise order
  • Strength performance
  • Adolescents
Accesso libero

Wave Characteristics in Breaststroke Technique with and Without Snorkel Use

Pubblicato online: 31 Dec 2013
Pagine: 185 - 194

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Abstract

The purpose of this paper was to examine the characteristics of waves generated when swimming with and without the use of Aquatrainer® snorkels. Eight male swimmers performed two maximal bouts of 25 m breaststroke, first without the use of a snorkel (normal condition) and then using a snorkel (snorkel condition). The body landmarks, centre of the mass velocity, stroke rate, stroke length, stroke index, and Strouhal number (St) were quantified. Fourier analysis was conducted to determine the frequency, amplitude, and phase characteristics of the vertical undulations. We also determined the undulation period, the first and second harmonic wave percentage, and the contribution of these components to the power of each of the wave signals. The first wave harmonics had a frequency of 0.76 Hz (normal condition) and 0.78 Hz (snorkel condition), and the second wave harmonics had a frequency of 1.52 Hz (normal condition) and 1.56 Hz (snorkel condition). Under the normal conditions, the wave amplitude was higher on the vertex (0.72 m) and cervical (0.32 m) than that produced under snorkel conditions (0.71 m and 0.28 m, respectively). The lowest values were found in the hip (0.03 m in normal conditions, and 0.02 m in snorkel conditions) and in the trunk (0.06 m in normal conditions, and 0.04 m in snorkel conditions). It can be concluded that snorkel use seems to lead to slight changes in the biomechanical pattern in swimming velocity, as well as several stroke mechanical variables.

Keywords

  • competitive swimming
  • stroke rate
  • stroke length
  • swimming snorkel
  • wave motion
  • Fourier analysis
Accesso libero

Attention, Visual Perception and their Relationship to Sport Performance in Fencing

Pubblicato online: 31 Dec 2013
Pagine: 195 - 201

Astratto

Abstract

Attention and visual perception are important in fencing, as they affect the levels of performance and achievement in fencers. This study identifies the levels of attention and visual perception among male and female fencers and the relationship between attention and visual perception dimensions and the sport performance in fencing. The researcher employed a descriptive method in a sample of 16 fencers during the 2010/2011 season. The sample was comprised of eight males and eight females who participated in the 11-year stage of the Cairo Championships. The Test of Attentional and Interpersonal Style, which was designed by Nideffer and translated by Allawi (1998) was applied. The test consisted of 59 statements that measured seven dimensions. The Test of Visual Perception Skills designed by Alsmadune (2005), which includes seven dimensions was also used. Among females, a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual-Spatial Relationships, Visual Sequential Memory, Narrow Attentional Focus and Information Processing was observed, while among males, there was a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional Focus and Information Processing. For both males and females, a positive and statistically significant correlation between achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional, Narrow Attentional Focus and Information Processing was found. There were statistically significant differences between males and females in Visual Discrimination and Visual-Form Constancy.

Parole chiave

  • Fencing
  • Visual Discrimination
  • Visual-Form Constancy
  • Visual Sequential Memory
  • Broad External Attentional
  • Information Processing
Accesso libero

The Influence of Anthropometric, Kinematic and Energetic Variables and Gender on Swimming Performance in Youth Athletes

Pubblicato online: 31 Dec 2013
Pagine: 203 - 211

Astratto

Abstract

The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance, anthropometrics, kinematics and energetics between boys and girls; (ii) swimmers with best performance are taller, have higher surface areas and better stroke mechanics; (iii) there are non-significant interactions between sports level and gender for anthropometrics, kinematics and energetics.

Keywords

  • swimming
  • performance
  • skill
  • cohort comparison
Accesso libero

Anthropometry of World-Class Elite Handball Players According to the Playing Position: Reports From Men's Handball World Championship 2013

Pubblicato online: 31 Dec 2013
Pagine: 213 - 220

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Abstract

Identifying the anthropometric measures of successful and less successful handball players may be helpful in developing a talent identification and development model, allowing for the determination of key physical capacities required for elite performance. The purpose of the study was to describe the anthropometric characteristics, including age, standing stature, body mass and body mass index (BMI) in handball players who participated in the 2013 Men's Handball World Championships. Secondly, the objective was to identify the possible differences in these parameters in terms of individual playing positions (goalkeeper, back, center back, wing, line player). Rosters with handball player's age, standing stature, and body mass were obtained from the International Handball Federation website. The research material included 409 handball players (24 teams). National teams were organized by their ranks and sub-grouped using their continents and playing positions. The results of the analyses of variance demonstrated significant differences in age (F=2.30; p=0.044; Partial ŋ2=0.028), standing stature (F=14.02; p=0.0001; Partial ŋ2=0.148), and body mass (F=5.88; p=0.0001; Partial ŋ2=0.068) among the groups (G1-G6). Players in G1 had the highest standing stature and body mass, while players in G6 had the lowest age and body mass values. The backs and line players were the tallest. In addition, the measurement of body mass showed that the line players had the highest body mass and BMI values. In conclusion, this study presented anthropometric data that differentiated levels of success in male handball teams playing in the 2013 world championships. This information should serve as a reference for the average standing stature, body mass, and BMI of handball players for particular positions at the professional level.

Keywords

  • Body Mass
  • Handball
  • Standing Stature
  • Body Mass Index
  • Talent Identification
Accesso libero

Analysis of Cohesion and Collective Efficacy Profiles for the Performance of Soccer Players

Pubblicato online: 31 Dec 2013
Pagine: 221 - 229

Astratto

Abstract

The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The results of the study proved the existence of four cohesion and efficacy profiles that presented significant differences in expectations of success, playing time, and performance. Furthermore, significant differences were found in the distribution of players in the teams as a function of performance. The main conclusion of this study is that soccer players with higher cohesion and collective efficacy levels belonged to teams that completed the season at the top-level classification. In contrast, athletes with low cohesion and collective efficacy usually played in unsuccessful teams. Coaches and sports psychologists are encouraged to promote both social and task cohesion and collective efficacy to enhance team performance.

Keywords

  • Profiles
  • cohesion
  • efficacy
  • performance
  • soccer
Accesso libero

The Athlete's Perception of Coaches’ Behavior Towards Competitors with a Different Sports Level

Pubblicato online: 31 Dec 2013
Pagine: 231 - 242

Astratto

Abstract

The study was designed to examine how active and former athletes across a different sports level perceived coaching behavior. Eighty competitive athletes (44 males and 36 females; 21.89 ±1.48 years of age; 8.35 ± 3.65 years of competitive experience) from the University School of Physical Education in Cracow, Poland, participated in the study. They represented both individual (n = 50) and team sports (n = 30). Seventeen participants were internationally renowned and 63 were recognized for competitive excellence at a national level. The participants responded to a demographic survey and the Coaches’ Behaviors Survey. The qualitative analysis procedures were employed to extract themes from open-ended questions. It was confirmed that coaches who perceived their athletes as more skilled, also treated them differently. Female athletes as compared with male athletes, more frequently pointed at the leniency in coach’s behavior towards highly skilled athletes, and perceived it as a factor inhibiting athletic development. Additionally, women often found individualization of the training process as a behavior reinforcing development. Less accomplished athletes more often pointed out to “a post-training session interest in the athlete” as directed only towards more accomplished counterparts; however, they indicated “leniency and favoring” less often than the athletes with international achievements. They also listed “excessive criticism” as a type of behavior hindering development, but they indicated coaches’ “authoritarianism and distance” less frequently than the more accomplished counterparts. The study added data to the discussion of the Pygmalion effect and the phenomenon of the self-fulfilling prophecy both in general (Rosenthal and Jacobson, 1968; Harris and Rosenthal, 1985; Jussim, 1989) and sport psychology (Harris and Rosenthal, 1985; Horn et al., 1998; Solomon and Kosmitzki, 1996; Solomon et al., 1998; Solomon, 2001).

Keywords

  • the Pygmalion effect in sport
  • self-fulfilling prophecy
  • perception of coaches’ behaviors
Accesso libero

Practical Skills of Rhythmic Gymnastics Judges

Pubblicato online: 31 Dec 2013
Pagine: 243 - 249

Astratto

Abstract

The aim of this study was to analyze the practical skills of rhythmic gymnastics judges and to identify how their degree and experience influence the assessment of these skills. Sixty one rhythmic gymnastics judges participated in the study. A questionnaire was used for data collection. This tool was composed of 28 questions and divided into six categories: identification, experience, initial training, continuing education, skills and training needs. The results suggest that the most valued skills are those related to the sport´s technical parameters and the ability to adapt to any level of competition with self-confidence and self-assuredness. Significant differences were found regarding the variables for: the ability to communicate (p = 0.002) and for the ability to observe, identify and register performance (p = 0.005). The results showed that experience was not a decisive factor in assessing skills. This study thus presents evidence that rhythmic gymnastics judges must implement and optimise a set of skills that contribute to the effectiveness of the assessment process. These findings might help in the design of programs and training models that contribute to effective professional development.

Keywords

  • Practical knowledge
  • sport judges
  • rhythmic gymnastics

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