Volume 11 (2019): Issue 1 (February 2019)

Study aim: There are currently limited methods available to access dynamic knee range of motion (ROM) during free-living activities. This type of method would be valuable for monitoring and progressing knee rehabilitation. Therefore, the aim of this study was to evaluate the functioning of stretch sensors for the measurement of knee ROM and to assess the level of the measurement error. Material and methods: Nine healthy participants were included in the study. Three stretch sensors (StretchSense™, Auckland, NZ) were attached on the participants’ right knees by Kinesiotape®. A Cybex dynamometer was used to standardise movement speed of the knee joint. Data was recorded through the StretchSense™ BLE application. Knee angles were obtained from the video clips recorded during the testing and were analysed by MaxTraq® 2D motion analysis software. The knee angles were then synchronised with the sensor capacitance through R programme. Results: Seven out of the nine participants presented with high coefficient of determination (R2) (>0.98) and low root mean square error (RMSE) (<5°) between the sensor capacitance and knee angle. Two participants did not confirm good relationship between capacitance and knee angle as they presented high RMSE (>5°). The equations generated from these 7 participants’ data were used individually to predict knee angles. Conclusions: The stretch sensors can be used to measure knee ROM in healthy adults during a passive, non-weight-bearing movement with a clinically acceptable level of error. Further research is needed to establish the validity and reliability of the methodology under different conditions before considered within a clinical setting.

Study aim: The aims of this study were to examine the prevalence of low back pain (LBP) and explore possible factors associ­ated with LBP among Malaysian army personnel deployed in Klang Valley in the year 2018. Material and methods: A self-administered questionnaire on sociodemographic data, occupational background, occupational exposure and LBP evaluation was used in this study. A total of 330 respondents participated in this study and 321 (97%) of them completed and returned the questionnaires. Results: One hundred and fifty-seven respondents complained of LBP, giving a prevalence of 48.9%. LBP was found to be associated with smoking status, history of LBP, history of accident, military rank, category of regiment, lifting weights, push­ing weights, pulling weights and job-related physical activity. Logistic regression analysis identified four associated risk fac­tors of LBP: history of accident (OR = 4.42, 95% 2.29-8.55), history of LBP (OR=1.92, 95% 1.11-3.31), combat regiment (OR = 1.97, 95% 1.14-3.42) and high job-related physical activity (OR = 2.35, 95% 1.31-4.20). Conclusion: Almost half of Malaysian army personnel stationed in Klang Valley reported LBP symptoms. Smoking status, history of LBP, history of accident, junior non-commissioned officers (NCOs), combat regiments, manual handling of objects and moderate/high job-related physical activity are associated with LBP, but there is no evidence of a temporal relationship in the current study. Further exploration with a longitudinal study is needed to identify a cause and effect relationship between occupational exposure and LBP among Malaysian army personnel.

Study aim: The main purpose of this study was to examine the level of moral competences of 437 pre-service physical educa­tion (PE) university students. It was also designed to evaluate the level of moral competency and the correlations with factors (i.e. Parents, Religion, School education, PE teacher, Sport coach, Studies, Media and Peers) potentially influencing moral development in pre-service PE teachers. Material and methods: The study included data collected in 2017 from 216 male and 221 female students aged 21.5 ± 1.85 from the faculty of Physical Education in Poznań, Poland. The students were categorised into three levels of moral competences, after which possible correlations between the factors influencing moral development were examined. The Moral Competence Test (MCT) survey was used to measure the ability to rate arguments by their moral quality. Participants were requested to confront two moral dilemmas and agree or disagree with the statements which were presented to them. Results: The results suggest that a vast majority of students (78.7%) present a very low level of moral competences, and with regard to the factors influencing moral development, the lowest value was attributed to PE teachers. Moderate positive correla­tions were found between School education and PE teacher, and between Sport coach and PE teacher. Conclusions: The findings indicate the need for more attention to be paid to moral education in teacher training in PE.

Study aim: The purpose of this study was to examine smartphone-using university students’ musculoskeletal system pain complaints, duration of smartphone and computer usage, participation in moderate-vigorous physical activities (MVPA), and prolonged sitting time.

Material and methods: This study was conducted on Hitit University students (n = 387; 206 female, 181 male) in the province of Çorum. The International Physical Activity Questionnaire-Short Form (IPAQ-SF), the Physical Activity Assessment Ques­tionnaire (PAAQ) (sports/exercise activities section), and a personal information form prepared by the researchers were used as data collection tools. Descriptive statistics and the t-test were used to determine differences between groups. The Pearson chi-square test was used to examine the relationship between categorical variables.

Results: It was observed that half of the participants with musculoskeletal system pain complaints (54.5%) feel the pain in all four areas (neck, shoulder, upper and lower back). There was no statistically significant relationship between physical activity intensity and pain complaint (p > 0.05). The students with musculoskeletal pain complaints spend more time on the smartphone and computer than students who do not have pain complaints (p < 0.05). During electronic device usage, the students who are in the low-intensity physical activity category spend more time sitting down than students in the moderate/vigorous intensity physical activity category (p < 0.05).

Conclusions: In consequence, information can be provided about the importance of reducing sitting time during smartphone use and increasing the duration of moderate/vigorous-intensity physical activity (PA) so awareness can be raised on the issue among university students.

Self-myofascial release (SMR) is a well-known and popular therapy. Its growing popularity is based on high effectiveness and availability. However, there is a lack of agreement about which parameters should be used to optimize the effects of the therapy. The purpose of this review is to critically select and assess current literature and ascertain the values of the follow­ing parameters: (1) therapy duration, (2) volume of applied pressure, (3) speed and (4) frequency of roll, (5) type of roller, (6) the number of treatment applications during one session, (7) the duration of intervals between applications that yield the best results in terms of soft tissue.

The authors launched their research in May 2018. The search strategy included the electronic databases EBSCOhost and PubMed. The following inclusion criteria were assessed:

- English language, high quality manuscripts (evaluation in PEDro scale)

- at least one of the groups using the foam roller, tennis ball or the stick to fascial release

- basic parameters of therapy described.A total 55 articles met the inclusion criteria. Patients can usually withstand a maximum tolerable pressure for 30-120 seconds, repeated 1-3 times, separated by 30 seconds of rest. The intensity of a single rolling movement should be moderate, and the movement should last about 3 seconds. Keeping the roller on particularly sensitive areas is recommended to release tension and enhance blood perfusion.Currently, there is no consensus on an optimal FR programme. However, there is a tendency to use SMR tools with a physiol­ogy-based method to enhance therapeutic efficiency.

Study aim: To verify the relationship between different durations of regular practice of physical activity in aspects related to the anthropometric profile and hepatic function of patients infected by hepatitis C virus (HCV). Material and methods: 125 patients (aged 55.2 ± 10.4 years) participated in the study. Clinical data were obtained through medical records available at the Pernambuco Liver Institute. Physical activity levels were obtained through the International Physical Activity Questionnaire (IPAQ) short form to classify the patients according to the guidelines of the American College of Sports Medicine (ACSM). Results: Significant differences were found in GGT 141 (28-378 U/L) and HDL 39 (27-56 mg/dL) respectively in insuffi­ciently active and physically active groups, AST 71 (26-268 U/L), ALT 83 (36-452 U/L), GGT 78 (3-532 U/L), alkaline phos­phatase 74 (47-302 mg/dL) and total bilirubin 0.7 (0.1-2.8 mg/dL) in insufficiently active and very physically active groups. Anthropometric data showed significant differences in chest (p < 0.01), abdomen (p < 0.02) and waist measurement (p < 0.01) between insufficiently active and very physically active groups.

Conclusion: Physical activity, when practiced regularly for more than 300 minutes per week, can improve the clinical and an­thropometric profile in patients infected with HCV.

Study aim: The aim of this study was to examine whether in women over 50 years of age the rate of decline in physical fitness with age affects the self-assessment of health and quality of life.

Material and methods: The survey was conducted among 113 women, aged 50–70. The women were divided into two groups: of low and high assessment of their own health and quality of life (WHOQOL-bref). The strength of the dominant hand muscles was tested and the Senior Functional Fitness Test was performed [21]. Linear regression analysis was used in the studies.

Results: Women satisfied with their health and quality of life were characterized by alower rate of decline in physical fitness after the age of 50, in particular the strength of the dominant hand muscles, aerobic capacity, upper body flexibility, and speed and coordination, than the dissatisfied or undecided women.

Conclusions: Physical fitness of women is important in assessing one’s own health and quality of life.

Study aim: Oxygen Uptake (VO₂) is avaluable metric for the prescription of exercise intensity and the monitoring of training progress. However, VO₂ is difficult to assess in anon-laboratory setting. Recently, an artificial neural network (ANN) was used to predict VO₂ responses during aset walking protocol on the treadmill [9]. The purpose of the present study was to test the ability of an ANN to predict VO₂ responses during cycling at self-selected intensities using Heart Rate (HR), time derivative of HR, power output, cadence, and body mass data.

Material and methods: 12 moderately-active adult males (age: 21.1 ± 2.5 years) performed a50-minute bout of cycling at a variety of exercise intensities. VO₂, HR, power output, and cadence were recorded throughout the test. An ANN was trained, validated and tested using the following inputs: HR, time derivative of HR, power output, cadence, and body mass. A twelve-fold hold-out cross validation was conducted to determine the accuracy of the model.

Results: The ANN accurately predicted the experimental VO₂ values throughout the test (R₂ = 0.91 ± 0.04, SEE = 3.34 ± 1.07 mL/kg/min).

Discussion: This preliminary study demonstrates the potential for using an ANN to predict VO₂ responses during cycling at varied intensities using easily accessible inputs. The predictive accuracy is promising, especially considering the large range of intensities and long duration of exercise. Expansion of these methods could allow ageneral algorithm to be developed for a more diverse population, improving the feasibility of oxygen uptake assessment.

Study aim: Interactions between the fingers and a handle can be analyzed using a finite element finger model. Hence, the biomechanical response of a hybrid human finger model during contact with varying diameter cylindrical handles was investigated numerically in the present study using ABAQUS/CAE.

Materials and methods: The finite element index finger model consists of three segments: the proximal, middle, and distal phalanges. The finger model comprises skin, bone, subcutaneous tissue and nail. The skin and subcutaneous tissues were assumed to be non-linearly elastic and linearly visco-elastic. The FE model was applied to predict the contact interaction between the fingers and a handle with 10 N, 20 N, 40 N and 50 N grip forces for four different diameter handles (30 mm, 40 mm, 44mm and 50 mm). The model predictions projected the biomechanical response of the finger during the static gripping analysis with 200 incremental steps.

Results: The simulation results showed that the increase in contact area reduced the maximal compressive stress/strain and also the contact pressure on finger skin. It was hypothesized in this study that the diameter of the handle influences the stress/strain and contact pressure within the soft tissue during the contact interactions.

Conclusions: The present study may be useful to study the behavior of the finger model under the static gripping of hand-held power tools.

Study aim: The purpose of this study was to evaluate the effects of astudent-centered approach and alternative assessments on students’ learning domains (i.e., cognitive, affective, psychomotor) during health education learning sessions.

Material and methods: Four groups totaling 65 mixed-gender undergraduate students (ages 20–25) of physical and health education participated in this study of alternative assessments’ effects on students’ learning once per week (3 hours) in their respective classrooms for seven weeks at a central Malaysia university. Students’ knowledge on the lesson contents was gathered using a series of quizzes. Students’ self-efficacy was assessed using the modified Traits Sport-Confidence Inventory (TSCI), and students’ levels of physical activity were assessed using a mobile pedometer. Data were analyzed using descriptive statistics and t-tests to evaluate pre/post differences.

Results: The students’ perception and knowledge on health education improve across interventions with greater efficacy (7.64± 0.97) at the post-test compared to the pre-test (7.30± 1.38). Students’ recorded improvement in step counts between week two and week five. A slight reduction during weeks six and seven may be due to the end of the semester and preparation for the final examinations.

Conclusions: This study demonstrated that astudent-centered approach and alternative assessment of learning were effective to engage students with contents and developing whole learning domains within the classroom.

Study aim: Evidence supports female sex hormones have an influencing effect on amultitude of physiological and psychological systems related to exercise. Little is known, however, whether is effect persist into the recovery from exercise. Our objective was to examine aspects of muscle damage/inflammation process during recovery in healthy, exercise-trained women following endurance activity at the mid-follicular (MF; low sex hormone level) and mid-luteal (ML; elevated sex hormone levels) phases of their menstrual cycle.

Material and methods: The MF and ML exercise sessions consisted of running for 90 minutes at 70% VO_2max on atreadmill in a controlled laboratory environment. Menstrual cycle phase was hormonally confirmed, diet and physical activity was control throughout the study. Outcome measures were: blood creatine kinase (CK) and interleukin-6 (IL-6) assessed at immediate-post exercise (IP), 24-hour and 72-hour into recovery. Statistics involved ANOVA procedures.

Results: At 24-hours and 72-hour into recovery CK activity was greater in MF than ML (p < 0.05) while for IL-6 at IP, 24-hour and 72-hour responses were significantly greater at MF than at ML (p < 0.05).

Conclusions: Amore robust recovery CK and IL-6 response occur in the MF of the menstrual cycle when female sex hormones are reduced. This finding suggests female sex hormone changes due to menstrual cycle phase affect the physiologic responses during the extended recovery period from intensive exercise in eumenorrheic women.

Study aim: The objective of the study was to reveal the functional limits of the motor system in women practising combat sports and team sports.

Material and methods: 102 women (mean age 25.2 years, body mass 62.2 kg, body height 168.3 cm) practising competitive ITF (International Taekwon-Do Federation) taekwon-do (n = 22), Brazilian jiu-jitsu (BJJ) (n = 15), football (n = 35) and basketball (n = 30) participated in the study. The assessment tool was the FMS test, comprising 7 movement patterns scored on a scale of 0–3.

Results: The studied female athletes earned medium scores. Women practising combat sports scored generally higher in the FMS test, although the difference was not significant (combat sports – mean value 15.57 ± 2.39, team sports – mean value 14.72 ± 1.93, difference – p = 0.07). Statistically significant differences (p < 0.05) were observed in the second (hurdle step) and the fifth pattern (active straight leg raise – ASLR). The aggregated FMS results of female taekwon-do (15.77) and BJJ athletes (15.22) were similar. Significant differences (p < 0.05) were observed in one pattern (ASLR). Women practising football (14.77) and basketball (14.67) attained a similar level of results in the test. Statistically significant differences were noted in two trials: footballers scored higher in the ASLR task (p < 0.05), and basketball players scored higher in rotary stability (p < 0.01).

Conclusion: A statistically significant result in the FMS test was obtained by martial arts athletes, which may point to a higher level of functional movement, which may be a result of more universal training.

Study aim: The purposes of this study were to analyze: the influence of physical activity level on the association between motor coordination and body fatness; the influence of body fatness on the association between motor coordination and physical activity; and how much physical activity and body fatness, separately and together, explain motor coordination in adolescent boys.

Material and methods: Fifty-one boys (n = 51), aged between 12 and 14 years, participated in the study. Motor coordination and physical activity and body fat percentage were assessed with, respectively, the Körperkoordinationstest für Kinder (KTK) and a validated self-administered questionnaire (PAQ-C). Skinfold thickness was measured to assess the participant’s body fat percentage. The Kruskal-Wallis test was performed to compare levels of motor coordination, physical activity, and body fat according to age (12, 13, 14 years). Bivariate and partial correlations were used to analyze the interrelationships among the selected variables.

Results: In the total studied group (n = 51 boys), motor coordination was positively associated with physical activity level (r = 0.300) and negatively associated with body fatness (r = –0.297). However, these associations were not statistically significant (p > 0.05) when controlled for body fatness and physical activity, respectively. Also, body fat and physical activity together explained 11% of the variance in the motor coordination level in adolescent boys.

Conclusions: These findings suggest that body fatness can influence the association between motor coordination and physical activity as well as that physical activity level can influence the association between motor coordination and body fat percentage. Also, body fat and physical activity together, but not separately, partially explained the variance in the motor coordination level. Therefore, body fat and physical activity seem to be complementarily associated with motor coordination in adolescent boys.

Study aim: The aim of the study was to investigate the relationship between attention and physical endurance (running) and anthropometric parameters of athletes.

Material and methods: The study examined 61 students aged 19 to 25 years, divided into two groups: athletes (33 participants) and non-athletes (28 participants). We employed anthropometric measurements and the Vienna System Test, including tools to measure focused attention, such as LVT (visual orientation performance test) and DAUF (test for examination of sustained attention) and the Cooper test to measure endurance.

Results: Analysis of the results demonstrated a relationship between attention and physical endurance with median time from LVT (r = –0.552). A relationship was also found between the Cooper test results and the mean time to incorrect answer (r = –0.900).

Conclusions: The analysis demonstrated a relationship between attention, physical endurance and anthropometric parameters of athletes.

Study aim: The aim of the present study was to compare the physiological responses of female soccer players recorded during the Beep Test and Yo-Yo Test.

Material and methods: Twenty-three high-level women’s soccer players underwent aerobic fitness testing. Modification of the Beep Test consisted of: lengthening the distance between turns to 40 m, extending the time between the increase in speed, and including a rest period between exercise stages. During the running efforts the length of the distance run in both tests was measured as well as circulatory and respiratory variables. For statistical analyses only data obtained at maximum loads in both tests were accepted.

Results: Analyzed variables showed that all values recorded in both tests reached maximum values and did not differ statistically significantly.

Conclusion: The results show that both applied tests loaded the soccer players to a similar maximum degree and the tests are suitable for assessing the aerobic physical performance.

Study aim: The aim of the current study is to reveal the characteristics of punch techniques applied in taekwon-do.

Material and methods: The skill quantification was performed on 10 taekwon-do ITF competitors. During the test, they were asked to perform straight punches using both the preferred and the non-preferred fist into the air (i.e. without a physical target) in the lateral position employing both traditional and sport style. Applying reflective markers on fists, the punching kinematic data were collected in the HML (Human Motion Lab). For data analyses, the average and standard deviation of duration, velocity and acceleration were used. The Mann-Whitney U test was applied to determine possible differences (p < 0.05) between the dominant fist and non-dominant fist as well as between the traditional and sport punch.

Results: The results revealed that the sport punch is notably faster (shorter punch duration) with a higher acceleration than the traditional one. There is no significant difference between the preferred and non-preferred fist. The results could suggest that the left and right straight punches during taekwon-do training sessions are equally developed. However, the different goals of the punch techniques, i.e. the traditional punch for generating power and the sport punch for quickness, cause significant differences (p < 0.01) in action time.

Conclusion: The results imply that a trade-off strategy may play a role in a match, namely a powerful punch for a possible final win or a quick punch for point collection.

Study aim: The purpose of this study was twofold: (i) to compare total attacks, points in the defense phase and attack efficiency between playing positions; and (ii) to identify the main predictors of overall volleyball teams’ success related to points made during the game.

Material and methods: 282 sets with a total of 33 174 actions and 8 231 points were analyzed. The study included 14 teams participating in the male First Division Portuguese Championship (53 games from the 2016/2017 season and 27 from the first phase of the 2017/2018 season, for a total of 80 matches).

Results: The most important parameters for the overall performance are efficacy of points in defense phase, aces, block points, and attack efficiency. Overall team performance variables statistically significantly predicted the total points of the team, F_16,1091 = 39.375, p < 0.001, R² = 0.366. Considering the comparisons between players’ performances, it was found that the setter had the lowest number of points in the defense phase and total attacks. Opposites had more total attacks and points in the defense phase than the other players (at a small-to-moderate magnitude).

Conclusion: The results revealed the importance of the efficacy of points in the defense phase, namely regarding the service action, block point, and attack efficiency, to improve the possibilities of winning.

Study aim: To assess the effects of fatigue on agility and responsiveness in boxing.

Material and methods: Agroup of 20 amateur boxers aged 14–45 years participated in the study. Ditrich’s test and acomputer test, both measuring the speed of reaction to avisual stimulus, as well as agility run and 4 × 10 m shuttle run with carrying blocks, both measuring agility, were performed. Running agility and reaction speed were measured at 3levels of fatigue expressed by the heart rates. The capacity to maintain the highest possible level of measured variables was assessed by applying the performance index (PI) (mean value of three or four (in the case of Ditrich’s test) repetitions to the maximum one). Student’s t-test for dependent data and Pearson’s correlation coefficients were used in data analysis, the level p ≤ 0.05 being considered significant.

Results: Both running agility and responsiveness markedly decreased with mounting fatigue, e.g. running speed from 1.73 ± 0.12 m/s to 1.55 ± 0.11 m/s.

Conclusion: Developing anaerobic endurance would markedly improve agility skills and speed of reaction to external stimuli. Measuring the performance index (PI) from short, maximal, repeated exertions spaced with constant intermissions may be a valuable tool in directing training activities towards development of selected elements of boxers’ physical fitness.

Study aim: The aim of the study was to investigate the changes in gross motor skills in children participating and not participating in a project of extracurricular physical education classes in primary schools called “From fun to sport”.

Material and methods: Thirty-one children in the first grade of primary school participated in the study (16 boys and 15 girls). A pedagogical quasi-experiment was applied. Children from the experimental group participated in an additional 45-minute lesson. To assess gross motor skills the TGMD-2 (Test of Gross Motor Development-2) was used.

Results: Statistically significant differences were observed in the level of gross motor skills between children attending extracurricular physical education classes and those who did not participate in such activities (GMDQ: Δ boys = 11.86, p = 0.032; Δ girls = 13.1, p = 0.036).

Conclusion: The experiment revealed large effects of additional activities of the project on increase of children’s motor skills level. Additional time should be included in physical education for the development of gross motor skills in physical education classes at the initial stage of school education.

Study aim: Increased muscle tone, a common consequence of stroke, has neural and non-neural components. Spasticity is related to the neural component. Non-neural resistance arises from passive stiffness. This study was designed to assess the feasibility of using isokinetic dynamometry to evaluate wrist flexor muscle spasticity in stroke patients.

Materials and methods: Twenty-six patients with hemiplegia in the subacute phase of stroke participated in this study. An isokinetic dynamometer was used to stretch wrist flexor muscles at four velocities of 5, 60, 120 and 180°/s on both the paretic and non-paretic sides. Peak torque at the lowest speed (5°/s) and reflex torque at the three higher speeds were quantified. Peak torque at the lowest speed was attributed to the non-neural component of muscle tone, and was subtracted from the torque response at higher velocities to estimate reflex torque (spasticity). Data from the two sides were compared.

Results: There was no significant difference in peak torque between the paretic (2.47 ± 0.22 N·m) and non-paretic side (2.41 ± 0.28 N·m) at the lowest velocity of 5°/s (p=0.408). However, compared to the non-paretic side, the paretic side showed higher reflex torque (p<0001), and reflex torque increased rapidly with increasing velocity (p < 0.05).

Conclusion: The isokinetic dynamometer distinguished spasticity from the non-neural component and showed higher reflex torque on the paretic side compared to the non-paretic side. This instrument is potentially useful to assess the efficacy of therapeutic interventions aimed at modifying spasticity.

Study aim: The purpose of this study was to examine the effects of arepeated sprint exercise protocol on muscle damage indicators, serum IGF-Iand cortisol levels.

Material and methods: Nine trained male subjects (age 23.3 ± 3.6 years) completed arepeated sprint protocol consisting of two sets of 10 × 30-m maximal sprints with 30 s of active recovery between sprints and 5 min of passive recovery between sets. The isometric strength and flexibility were measured before, immediately after and 24 hours after exercise. 30-m maximal sprint time was measured before and 24 hours after exercise. Blood samples were taken before, immediately after and 24 hours after exercise.

Results: Isometric strength and flexibility were significantly decreased after exercise and 24 hours after exercise (p < 0.05). 30-m sprint time was significantly increased 24 hours after exercise (p < 0.05). Asignificant increase in serum lactate dehydrogenase, IGF-Iand cortisol were found after exercise (p < 0.05). Serum creatine kinase increased significantly immediately after and 24 hours after exercise compared to pre-exercise values (p < 0.05).

Conclusion: Our data show that due to increased serum IGF-Ilevel, repeated sprint exercise may have anabolic effects as well as traumatic effects on the muscles.

Study aim: The aim of this study to determine whether creatine ethyl ester (CEE) supplementation combined with resistance training (RT) is effective for improving hormonal changes, body composition and muscle strength in underweight non-athlete men.

Materials and methods: Sixteen underweight non-athlete men participated in this double-blind study and were randomly assigned to one of two groups: RT with placebo (RT + PL, n = 8) and RT with CEE supplementation (RT + CEE, n = 8). The participants performed 6 weeks of RT (60–80% 1RM) combined with CEE or PL. 48 hours before and after the training period, muscle strength (1RM for leg press and bench press), body composition (percentage of body fat, circumference measurements of the arm and thigh), serum levels of testosterone, cortisol, and growth hormone (GH) of the participant were measurements.

Results: Significant increases were observed for weight, muscle strength and muscle mass, serum levels of testosterone and GH between pre and post-test in the RT + CEE group (p < 0.05). In addition, cortisol level was significantly decreased in the post-test in the RT+CEE group. The decrease in fat percent was greater in the RT + PL group than in the RT + CEE group (%change = –6.78 vs. –0.76, respectively). Weight and leg strength changes in the RT + CEE group were significant compared to the RT + PL group (p < 0.001, p = 0.05, p = 0.001; respectively). However, in other variables, despite the increase of GH and testosterone levels and lower levels of cortisol in the RT + CEE group, no significant differences were observed between the two groups (p < 0.05).

Conclusion: It seems that the consumption of CEE combined with RT can have significant effects on body weight and leg strength in underweight non-athlete men. This supplement may provide a potential nutritional intervention to promote body weight in underweight men.

Study aim: The purpose of this study was to evaluate neuromuscular adaptations in conscripts with different fitness levels (VO_2max) during 8 weeks of military basic training (BT).

Material and methods: Twenty-four male conscripts (18–21 years) were divided into two groups (Good Fitness [GF] and Low fitness [LF]) based on their VO_2max at the beginning of BT. Body mass (BM), fat free mass (FFM) and Fat% were measured after 2, 4, and 7 weeks of training. VO_2max, maximal isometric leg press force (MVC), H-reflex (H_max/M_max) at rest and V-wave (V/M_max) during maximal isometric plantarflexion were measured from the soleus muscle at the beginning, after 5, and after 8 weeks of training.

Results: FFM decreased significantly in LF after 7 weeks of training (–3.0 ± 1.7%, p < 0.001), which was not observed in GF. Both GF (6.9 ± 4.6%, p < 0.01) and LF (5.7 ± 4.6%, p < 0.01) showed improved VO_2max after 5 weeks, with no changes during the last 3 weeks. A main effect of training was observed in decreased leg press MVC (–7.3 ± 9.3%, F = 4.899, p < 0.05), with no between-group differences. V-wave was significantly lower in LF during 5 (–37.9%, p < 0.05) and 8 (–44.9%, p < 0.05) weeks.

Conclusion: Poor development of the neuromuscular system during BT suggests that explosive and/or maximal strength training should be added to the BT protocol for all conscripts regardless of fitness level. In addition, individualized training periodization should be considered to optimize the training load.

Study aim: External focus of attention is considered as a critical factor in the OPTIMAL theory of motor learning. This theory proposes that external focus of attention facilitates motor performance and learning because it promotes focusing on the task goal. However, the effects of external focus of attention on focusing on the task goal are not well understood. The aim of this study was, therefore, to investigate the effects of an external focus of attention versus an internal focus of attention on motor learning and promoting focus of the learner on the task goal.

Material and methods: Thirty-six right-handed male students (mean age 21.16 ± 1.85 years old) with no prior experiences with the motor task were randomly assigned to three groups: external focus, internal focus, and control groups. Participants were asked to throw darts at a target during an acquisition phase (10 blocks of six trials each) and during subsequent retention and transfer tests. Throwing accuracy and focus on the task goal were measured as dependent variables. Analysis of variance (ANOVA) with repeated measures as well as a one-way ANOVA was used to analyze the differences in accuracy scores between groups during the acquisition phase as well as retention and transfer tests, respectively. The significance level was set at p < .05. The author supervised all phases of the experiment.

Results: The results showed that adopting an external focus promoted a focus on the task goal and resulted in significantly better motor learning than adopting an internal focus and control conditions (p < 0.05).

Conclusions: The findings of the present study provided support for the propositions of the OPTIMAL theory and showed that adopting an external focus of attention promotes focus of the learner on the task goal. The results are discussed in terms of benefits of external focus instructions for facilitating motor learning and goal-action coupling.

Study aim: The aim of the present study was to examine a single movement of dynamic stretching (SMDS) of the shooting arm as a pre-shot routine for free throw performance (FTP).

Material and methods: The sample consisted of 60 junior and senior basketball players from the youth league of Bosnia and Herzegovina (B&H), and the national level – the First Division of B&H. The authors found that some players during a game and training sessions apply an SMDS of the shooting arm as a pre-shot routine for FTP. Since previous literature suggests that length of the routine and pre-performance behaviors are quite different among players of all levels, the sample was divided based on the number of training hours per week (lower/higher number of training hours) and basketball experience (experienced/less experienced). The procedure involves every player performing five free throws (FTs) without prior stretching, five FTs immediately after SMDS of the triceps muscle and five FTs after SMDS of the m. flexor carpi radialis.

Results: After the first SMDS (m. triceps brachii) the percentage of FT slightly decreased in the first following attempt. After the second stretching (m. flexor carpi radialis), a significant FT percentage drop was noted in the first following FT for the whole sample. Players with more experience and more training hours per week had poorer results after the stretching.

Conclusions: The SMDS routine did not enhance the FTP and it had a rather harmful effect on FTP, especially SMDS of the flexor carpi radialis muscle, and the authors do not recommend SMDS before the FTP.

Study aim: The purpose of this study was to compare the effects of cold-water immersion (CWI) vs. active recovery performed after each individual strength and endurance training session over a 10-week period of high-intensity combined strength and endurance training.

Materials and methods: Seventeen healthy men completed 10 weeks of high-intensity combined strength and endurance training. One group (AR, n = 10) completed active recovery that included 15 minutes of running at 30–40% VO_2max after every strength training session while the other group (CWI, n = 7) completed 5 minutes of active recovery (at the same intensity as the AR group) followed by 10 minutes of cold-water (12 ± 1°C) immersion. During CWI, the subjects were seated passively during the 10 minutes of cold-water immersion and the water level remained just below the pectoral muscles. Muscle strength and power were measured by isometric bilateral, 1 repetition maximum, leg press (ISOM LP) and countermovement jump (CMJ) height. Endurance performance was measured by a 3000 m running time trial. Serum testosterone, cortisol, and IGF-1 were assessed from venous blood samples.

Results: ISOM LP and CMJ increased significantly over the training period, but 3000 m running time increased only marginally. Serum testosterone, cortisol, and IGF-1 remained unchanged over the intervention period. No differences between the groups were observed.

Conclusions: AR and CWI were equally effective during 10 weeks of high-intensity combined strength and endurance training. Thus, physically active individuals participating in high-intensity combined strength and endurance training should use the recovery method they prefer.

Study aim: Taekwondo is known for its very dynamic sports fighting, in which the athletes perform strikes mainly with their lower limbs. The aim of the study was to compare the differences between the impact force of strikes performed with the dominant and non-dominant limbs and its correlation with anthropometric indicators.

Material and methods: Six elite Olympic taekwondo players took part in the research (20.0 ± 3.2 years, 185.0 ± 8.5 cm, 75.3 ± 10.9 kg). Body composition including body mass, percent of body fat (FATP), fat mass (FATM), fat-free mass (FFM) and muscle mass (MM) was determined by bioelectric impedance analysis. Maximal strike impact force (F_max) and F_max relative to FFM (F_max · FFM⁻¹) of roundhouse kick (dollyo chagi) and side kick (yop chagi) were measured using a dynamometric punching bag with an embedded accelerometer.

Results: We found significant differences between the dominant limb (DL) and non-dominant limb (NL) in anthropometric analysis: FATP was 10.52 ± 5.38 % and 11.32 ± 4.83 %, FFM was 11.87 ± 0.97 kg and 11.43 ± 1.09 kg, MM was 11.25 ± 0.92 kg and 10.82 ± 1.02 kg for DL and NL respectively. In dollyo chagi F_max and Fmax · FFM⁻¹ were higher for DL than NL and were 2733 ± 748 N and 2206 ± 778 N, 41.34 ± 8.16 N · kg⁻¹ and 33.29 ± 9.02 N · kg–1 respectively. Yop chagi has a lower impact force compared to dollyo chagi. F_max and F_max · FFM⁻¹ for DL and NL were 1763 ± 303 N and 1779 ± 372 N, 26.76 ± 3.07 N · kg⁻¹ and 26.9 ± 3.57 N · kg–1 respectively. We found a significant correlation between F_max in yop chagi and FFM (R = 0.83, p < 0.05).

Conclusions: Athletes should fight using a stance where the dominant limb is moved further away from the target in order to strike with maximum force.