Leg Power Research Articles

Promene povezane sa rastom u antropometrijskim i motoričkim sposobnostima devojčica uzrasta 10-13 godina

This study is aimed at evaluating 10-13-year-old girls' motor skills and anthropometric characteristics as well as their interrelationships during their growth. Three hundred seventy-eight girls from elementary schools underwent a standard anthropometry (body height, weight and body mass index) and motor fitness tests (sprint run for 20 meters, Bent knee push-up, sit-up test for 30 seconds, standing long jump and sit and reach). Data was stratified by age. Age-specific percentile values (i.e., P5 to P95) were generated. Significant age-related main effects for body height, body weight, and body mass indexes were observed, including running speed, abdominal strength, and muscle endurance, as well as the explosive leg power. Physical fitness was considerably affected by anthropometric parameters. Body height seemed to be positively correlated with the explosive leg power and abdominal strength and muscles endurance, and negatively with speed, strength and endurance of the upper body muscle groups. Test results for assessing strength were insufficient. Likewise, body weight appeared positively correlated with explosive leg power and negatively with speed, strength and endurance of the upper body muscle groups and flexibility. As for the body mass index, it was proven to be negatively correlated with strength and the endurance of the upper body muscle groups and flexibility.

Comparison of Gastrocnemius Muscle Strength between Basketballs and Non-basketball Player

Background : Basketball is one of the best aerobic-predominant exercises and the most important muscle used in this sport is the gastrocnemius muscle. This muscle plantar flexes the ankle when the knee is extended to maintain the balance and to stabilize the body during vigorous movements. Furthermore, the gluteus, quadriceps, hamstrings, and calves may get activated when running up and down the court and jump in the air when doing basketball training. This study was conducted to compare the gastrocnemius muscle strength in basketball and non-basketball players. Methods : This analytical study was to measure the gastrocnemius muscle strength in basketball (n=16) and non-basketball (n=16) players, using hand-held dynamometer (HHD). Gender, weight, height, Body Mass Index (BMI) and maximal gastrocnemius muscle strength were recorded and compared between groups. The study was conducted from August to October 2013 in the Faculty of Medicine, Universitas Padjadjaran. Results : The maximal gastrocnemius muscle strength showed no significant differences both in basketball and non-basketball players for females and males with p-value 0.092 and 0.711, respectively. Conclusions : There is no significant difference in gastrocnemius muscle strength between basketball and non-basketball players in males as well as in females. Presumably, there are other muscles that take parts to develop leg power by doing the right weight-training exercises.

Pattern Recognition on Anthropometric and Fitness Components Relative Birth-month Quartiles among Malaysian Boys and Girls

Biasness selection during talent identification program in sports may occurred due to the chronological age system applied nowadays. The aim of this study is to recognize pattern on anthropometric and fitness components relative birth-month quartiles among studied population. A total of 39372 boys (aged 7.36 ± 0.29 year) and 33723 girls aged (7.34 ± 0.29 year) were classified into four chronological birth-month groups which is first quartile (Q1 - Jan to March), second quartile (Q2-Apr to June), third quartile (Q3 - July to Sept) and fourth quartile (Q4 - Oct to Dec) involved in this study. Multiple analysis of variance (MANOVA) revealed significant difference of F(18, 111336), p < 0.0001, p < 0.05 and F (18, 95358), p-value < 0.0001, alpha=0.05 between four birth-month quartiles for boy and girl participants, respectively. Tukey (HSD) follow up test of analysis of variance revealed that studied population are significantly difference in body weight, standing height, explosive leg power, hand-eye coordination and speed for all the contrast with p-value < 0.0001, alpha=0.05. However, result found no significant different for flexibility within all the contrast for boys and girls. Present study also revelaed a stronger influence of RAE among boys as compared to girls. The information of evidence-based of anthropometric and fitness performance according birth-month quartile would able to reduce RAE that may cause bias and subjective decision making for talent identification in sports.

Role of Specific Playing Position on Various Anthropometric, Body Composition and Physical Fitness Parameters of Indian Male Sepak Takraw Players

Background: Anthropometric and physiologic properties have influence on exercise performance in sepak takraw and physiological profiles of athletes differ between sports and playing positions. Objectives: Present study was aimed to determine the effect of playing position on anthropometric, body composition and physical fitness parameters in young male sepak takraw players. Methods: The cross-sectional study was conducted on three positional groups of total 44 male Indian sepak takraw players (spiker/killer, n = 14; tekong, n = 14; and feeder, n = 16) of national level. Anthropometric parameters, body composition profile, physical fitness variables including 30m flying, 6X10m shuttle run, vertical jump, sit up, endurance and anaerobic power were assessed by following standard protocols. Results: Significant differences were observed in height, weight and leg length among the positional groups. Almost all body composition parameters were significantly (P < 0.01) higher among ‘tekong’ position except fat mass. Handgrip strength, back strength, vertical jump, sit up, VO2max, explosive leg power and maximum anaerobic power were found to be significantly differed among the three positional groups of sepak takraw. Regression prediction model identified back strength (P = 0.034), peak explosive power (P < 0.001) and leg length (P < 0.001) as the significant predictor of vertical jump (R2 = 0.930 and P < 0.001). Conclusions: Players of ‘tekong’ position were better in anthropometric and body composition profiles than ‘spiker and feeder’. Whereas, ‘spiker’ position was found to have higher back strength, explosive power, vertical jump and sit up abilities. Regression model identifies back strength, peak explosive power and leg length as the significant predictors of performance in sepak takraw.

KONTRIBUSI DAYA LEDAK OTOT TUNGKAI DAN DAYA LEDAK OTOT LENGAN TERHADAP KEMAMPUAN TOLAK PELURU TEKNIK O’BREIN

The study aims to determine the contribustion of explosive power arm and leg muscles personal or groups with the ability the O’brein technique ini shot put.The research was a guantitative method using corelational research design. The population was athlete track and field UKO University Bung Hatta as much as 40 athlete. Was taken by purposive random sampling as much as 30 athlete. The instrument standing broad jump was used to measure leg muscles explosive power. The instrument medicine ball put tes was used to measure arm muscles explosive power and skil of the technique o’brain was used to measure shot put.The result empirically showed that: 1) the contribution of leg muscle explosive power of the shot put capability was 14,36% 2) the contribution of the explosive power of the arm muscles shot put athlete track and field ability was 19,18%. 3) the contribution of leg and arm muscle explosive power joinly to word o’brain technique short put was 25,70%.

EFFECTS OF A 6-WEEK TASK SPECIFIC POWER TRAINING WITH AND WITHOUT COGNITIVE TRAINING AMONG OLDER ADULTS WITH SLOW GAIT

Task-specific power training (InVEST) targets leg power and mobility skills that are beneficial for treating slow gait speed for older adults. This study investigated the efficacy of a short-term InVEST training on leg power, mobility performance, and gait characteristics and further examine whether the addition of cognitive training would augment the impact on the outcomes. Mobility limited community-dwelling older Veterans age ≥65 years were recruited. Participants were randomly assigned to either InVEST training (n=10) or InVEST+cognitive training (n=11). Training occurred 3 times per week for 6 weeks. Sessions were either 70 minutes (InVest+cognitive training) or 40 minutes (InVEST) in duration. Leg power, mobility performance (Short Physical Performance Battery), and gait characteristics (gait speed, stance time, step width, swing time, step length and their variabilities under single-task, simple and complex dual-task walking conditions) were evaluated. Twenty-one men with mean age 76±7 years completed the study and 86% were of white race. Among all participants, clinically relevant and statistically significant improvements in leg power, mobility performance, and gait characteristics (gait speed, step length, stance time under all three gait conditions) were observed. There were no statistically significant or clinically relevant group differences among any of the outcomes based on cognitive training status. Short-term InVEST training led to clinically meaningful improvements in leg power, mobility performance, and gait characteristics. These findings add to the body of evidence supporting the benefits of InVEST training on mobility and do not support the contention that mixed modes of training (cognitive and physical) may augment mobility outcomes.

Effect of Plyometric Hurdle Hops and Tuck Jump Training on Strength and Leg Muscle Power in Martial Arts Athletes at Kostrad Company-C Malang

The purpose of this study was to analyze the effect of hurdle hops and tuck jump exercises on leg muscle strength and power, as well as the different effects of hurdle hops and tuck jump exercises on leg muscle strength and power. The research method used in this study is quantitative with quasi-experimental methods, with the design of this study using a non-randomize control group pretest and posttest design, with data analysis using ANOVA. The process of data retrieval is done by testing the leg muscle strength using a strength test tool that is a leg dynamometer and leg muscle power test with a jump md, during the pretest and posttest, then the data are analyzed using SPSS 22.0 series. The target of this study was martial arts athlete Kostrad Company-C with 30 members, divided into 3 groups with each group totaling 10 people, this research was conducted for 6 weeks. Paired sample strength test results and paired sample test of leg muscle power test that the significance level of each variable obtained sig 0,000 &lt;0.05 thus there is a significant influence or difference between the pretest and posttest of the dependent variables of leg muscle strength and power, ANOVA test results on leg muscle strength and strength, showing strength, F: 12,191, sig 0,000, Power F: 4,778, sig 0.17, so it can be concluded that there are significant differences in the results of leg muscle strength and strength in three different groups, because sig &lt;0.05. From the results of the post hoc multiple comparations (LSD) test of independent variables that have a significant influence on the increase in the dependent variable, it can be seen from the mean different results that the hurdle hops group gained 31,900 strength, power 155,367,00, meaning that the hurdle hops exercise was more influential. Based on the above analysis it can be concluded that there is an increase in leg muscle strength and power for each group, through the ANOVA test. Where hurdle hops exercises have a better effect than tuck jump exercises and the control group on leg muscle strength and power.

LIFE HABITS AND LIPID PEROXIDATION OF WOMEN OVER 40 YEARS OLD

Oxidative stress is involved in degenerative processes, aging, and diseases. Lifestyle can be change oxidative stress. One of reactive oxygen species targets is polyunsaturated fatty acid, an important cellular membrane component. The aim of this study is to analyse the contribute of lifestyle in lipid peroxidation in over fourty years old women. Were included 60 women whith age ranged between 41 and 82 years old (53.3 ± 9.1 years). Lifestyle were explored doing a food frequency questionnaire, Perceptive Stress Scale (PSS) and International Physical Activity Questionnaire (IPAQ). The functional capacity was determinate by 6-min walking test (cardiorespiratory capacity) and Squat-jump (leg strength and power). Parameters of oxidative stress were determinate from plasma during fasting, lipid peroxidation was evaluated by TBARs, and antioxidant capacity was evaluated by catalase activity and ABTS. Spearman correlation and Multiple Linear Regression model, through Stepwise method, considering TBARs as dependent variable, and age, weight, body mass index, waist circumference, stress perception, physical activity level, total antioxidant capacity, catalase activity, cardiorespiratory capacity, leg strength and power, daily caloric intake, daily fruit, vegetables, coffee/tea, vitamin E and alcohol intake, as independent variable, was performed. Negative correlations were obtained between TBARs and cardiorespiratory capacity (r= -0.35; p=0.026) and between TBARS and ABTS (r= -0.33; p=0.038). Total antioxidant capacity was the model’s first variable (F= 5.50; p = 0.013), explaining 15.3% of TBARS, then cardiorespiratory capacity (F= 5.50; p = 0.047), explaining 10.5% of TBARs The results revealed total antioxidant capacity and cardiorespiratory capacity as predictors to lipid peroxidation damage.

Six weeks of balance or power training induce no generalizable improvements in balance performance in healthy young adults

BackgroundTraining programs for fall prevention often fail to induce large general effects. To improve the efficacy of fall prevention programs, it is crucial to determine which type of training is most effective in inducing generalizable effects, i.e., improvements in untrained situations. Two likely candidates are balance and resistance training. Here, we assessed whether either varied balance training or a training program aiming to increase leg power would improve performance and acquisition rate of a novel balance task.MethodsForty-two healthy recreationally active subjects (16 females, age 24 ± 3y) were assigned to a control group, a varied practice balance group or a loaded squat and plyometrics power group, training for 6 weeks (twice per week, 40 min per session). Before and after the training, we measured peak power in countermovement jumps and balance performance in two different untrained balance tasks (10 trials pre and 50 trials post-training).ResultsAfter training, the performance and the acquisition rate in the two untrained tasks were similar for all groups (no group x time interaction), i.e., no generalization of learning effect was induced by either form of training. Peak power in the countermovement jump did not change significantly in any of the groups.ConclusionsNeither a six-week power training nor a varied balance training improved performance or acquisition of an untrained balance task. This underpins the task-specificity principle of training and emphasizes the need for studies that assess the mechanisms of transfer and generalization, thus helping to find more effective intervention programs for fall prevention.

Acute effects of differential learning on football kicking performance and in countermovement jump.

The aim of this study was to identify the acute effects of a differential-learning training program on football kicking performance and countermovement jump. Twenty youth Portuguese under-15 football players participated in this study. All players were exposed to two training approaches: i) traditional, in which the players performed a total of 36 kicks in a blocked and repetitive approach; and ii) differential learning, which consisted in the 36 kicks using differential variations in each kick. Football kicking impact and velocity were assessed using a Stalker radar gun, while the kicking accuracy was assessed by aggregating the total number of points achieved during 12 kicks into a goal, which was divided into quantifiable scoring zones. Lastly, leg power was measured using a countermovement jump. Measurements were performed at baseline, post-intervention, and following a 35-minute training match. The comparisons between the baseline and post-test revealed that the differential learning approach promoted a possibly ~5% increase in the countermovement jump (small effects) and a likely ~3% increase in the average velocity (small effects) when compared with the traditional training approach. From the accuracy perspective, there was a moderate decrease from the baseline to the post-test and post-match in accurate kicks into zone 1 (centre of the goal) and a moderate decrease from the baseline to the post-match in accurate kicks into zone 5 (lateral zones at short height) in the differential intervention. In turn, a small increase in the accurate kicks into zones 4 and 6 (lateral zones of the goal and nearest to the bar, respectively) was found from the baseline to the post-match in the differential intervention. Overall, the differential learning intervention was more beneficial than a traditional training protocol with respect to acute improvements in countermovement jump performance, football kicking velocity and higher scoring zones kicking accuracy.

Key Anthropometric and Physical Determinants for Different Playing Positions During National Basketball Association Draft Combine Test.

Annual draft combine test of National Basketball Association (NBA) is a key player testing process where prospective players with extraordinary athletic abilities are evaluated and the assessment results would further inform the determination of prospective players for the league during draft day. Nonetheless, key attributes from the combine test that distinguished successful players in the draft from those unselected has yet to be investigated. The study was aimed to: (i) compare the difference between NBA drafted and undrafted players from five playing positions, considering anthropometric characteristics and physical fitness ability during draft combine test; and (ii) determine the key combine test factors that most effectively discriminate between draft groups. A total of 3,610 players participating in the 2000–2018 NBA draft combine test were included. Independent t-test was applied to compare difference between drafted and non-drafted players in variables related to anthropometrics, and strength and agility test. A descriptive discriminant analysis was subsequently used to identify which variables could best discriminate between two draft groups in each playing position. The significance level was set at p < 0.05. The drafted players from five positions outperformed the undrafted in height, wingspan, vertical jump height and reach, line agility and three-quarter sprint test (p < 0.01, ES = 0.26–0.87). The discriminant functions for each position (p < 0.001, Λ = 0.81–0.83) were emphasized by specific variables that discriminated both draft groups. The findings revealed that in addition to height and wingspan, leg power served as key determinants for being drafted as guards, as did agility and speed for power forwards and centers.

The accumulated effects of exercise-induced stress in male athletes during a national Ultimate Frisbee competition across four days

Introduction: Ultimate Frisbee (UF) is a field-based team-sport, involving high intensity activities such as jumping, sprinting, acceleration, deceleration and change-of-direction with short recovery periods. Whilst a number of studies have reported the physical demands of an UF match, the level of exercise-induced stress following a match is yet to be determined, particularly during a competition. Understanding the level of stress induced by an UF match may improve recovery strategies and optimise athlete preparedness during an UF competition involving multiple matches across days. Thus, the purpose of this study was to examine the accumulated effects of exercise-induced stress during a national UF competition across four days in male athletes. Methods Twelve elite male UF players (age 29 ± 2 years; height 179.6 ± 5.1 cm; and body mass 80.0 ± 6.0 kg) who competed in the Australian Men's National UF competition in 2019 volunteered for this study. The competition was held across four consecutive days (D1, D2, D3 and D4), with athletes undertaking 1-3 matches per day. Every morning (08:00-12:00), within the hour prior to the first match, the following assessments were undertaken for each athlete: delayed onset of muscle soreness (DOMS) using a 1-5 Likert scale (‘no soreness’ to ‘very sore’), leg power during a drop-jump from a 30 cm box, and speed during a 10m sprint. During the drop-jump protocol, athletes jumped on a force plate with a dowel on their shoulder that hosted an accelerometer. Peak velocity and muscular power was derived from the accelerometer, whilst jump height, contact time and reactive strength index (RSI: flight time/contact time) were quantified from the force plate. Results: When compared to D1, the level of DOMS was significantly increased on D2, D3 and D4. Conversely, peak jump velocity and jump height were significantly decreased on D2 and D4 while RSI and muscular power were significantly decreased on D3 and D4. No significant differences were identified across days for contact time and 10m sprint time. Discussion: In the current study, multiple UF matches performed in a single day induced stress sufficient for DOMS and impair neuromuscular performance during a drop jump task on subsequent days. In addition, an accumulation of exercise-induced stress throughout the UF competition was observed with DOMS peaking and the majority of drop-jump performance measures impaired during the last day. Thus, appropriate recovery strategies should be implemented to minimise carry-over effects of exercise-induced stress across days of an UF competition.

The effectiveness of thigh lift exercises using rubber on the ability of acceleration on sprint runs

Many forms of exercise to improve the quality of leg muscles, both strength and power. One of them is the practice of detainees using rubber assistive devices. Based on these exposures, the author wants to try to apply the form of exercise that is applied to the children who participate in athletic clubs in school age, especially running numbers. the purpose of this study is to find out the effectiveness of thigh lift exercises using rubber with the ability to accelerate sprint running. In this study, the authors used experimental research methods. The population used was all children participating in the athletic club with a total of 40 people. The author uses population research, with the reason the writer wants to examine all children who are elements of the population. To get objective data, the author uses a measuring instrument in the form of a 30 meter acceleration test. Based on the results of research and statistical calculations on the data obtained in this study, the authors can conclude that: Thigh lifting exercises using rubber have a significant effect on the ability of sprint acceleration.

Time of day effect in postural control in young soccer players: Field dynamic assessment

ABSTRACT This study aimed to examine the reliability and the time-of-day variability on standing long jump (SLJ), three hop test (THT) speed (5-m, and 20-m sprint), and balance (Y balance test [Y-BT]) in prepuberal male soccer players. Data were gathered from two phases, using 105 soccer players. Reliability was investigated in phase 1. Time of day effect on SLJ, THT, 5-m, and 20-m speed and Y-BT tests was investigated in phase 2. Phase 1 showed non-significant bias between the two applications of the SLJ, THT, 5-m, and 20-m speed, and Y-BT tests . The SLJ, THT, 5-m, and 20-m speed, and Y-BT scores showed high relative and absolute reliability. The usefulness analysis showed that the SLJ, THT, 5-m and 20-m speed, and Y-BT tests could detect small changes in performance (SEM < SWC for all tests). Phase 2 showed that leg power, speed, and postural control are affected by time of day. A significantly better (p< 0.05) leg power, speed, and postural control were observed at the end of the afternoon than at morning hours. Time-of-day may be considered as a factor in designing leg power, speed, and postural control training programmes and intervention studies for prepuberal male soccer players.

Influence of between-limb asymmetry in muscle mass, strength, and power on functional capacity in healthy older adults.

Numerous daily tasks such as walking and rising from a chair involve bilateral lower limb movements. During such tasks, lower extremity function (LEF) may be compromised among older adults. LEF may be further impaired due to high degrees of between-limb asymmetry. The present study investigated the prevalence of between-limb asymmetry in muscle mass, strength, and power in a cohort of healthy older adults and examined the influence of between-limb asymmetry on LEF. Two hundred and eight healthy older adults (mean age 70.2±3.9years) were tested for LEF (400m walking and 30-seconds chair stand). Furthermore, maximal isometric and dynamic knee extensor strength, leg extensor power, and lower limb lean tissue mass (LTM) were obtained unilaterally. Mean between-limb asymmetry in maximal muscle strength and power ranged between 10% and 13%, whereas LTM asymmetry was 3±2.3%. Asymmetry in dynamic knee extensor strength was larger for women compared with men (15.0±11.8% vs 11.1±9.5%; P=.005) Leg strength and power were positively correlated with LEF (r2 =.43-.46, P<.001). The weakest leg was not a stronger predictor of LEF than the strongest leg. Between-limb asymmetry in LTM and isometric strength was negatively associated with LEF (LTM; r2 =.12, P=.005, isometric peak torque; r2 =0.40, P=.03.) but dynamic strength and power were not. The present study supports the notion that in order to improve or maintain LEF, healthy older adults should participate in training interventions that increase muscle strength and power, whereas the effects of reducing between-limb asymmetry in these parameters might be of less importance.

MOTOR SKILLS IN FOURTH GRADE PRIMARY SCHOOL STUDENTS

The authors of this paper, which is a part of a more extensive research, provide an overview of anthropometric characteristics and motor skills in fourth-grade primary school students in Vranje and differences in these between boys and girls. The anthropometric characteristics included in the measurements were body height (Tv) and body weight (Tt), while the motor skills measured were the explosive leg power, explosive torso and shoulder power, speed, static (isometric) arm and shoulder strength, and flexibility (mobility).Body height was measured by a height meter, body weight by a weight scale, explosive leg power by a standing long jump (Sudm), explosive torso and shoulder power was measured by throwing a 2 kg medicine ball (Bm), speed was measured by a 30 m run from a high start (Tvs), static (isometric) arm and shoulder strength with pull-up endurance up to 120 seconds (Iuz) and flexibility (mobility) with standing hamstring stretch (Dpk). This research included 500 participants, fourth-grade primary school students in Vranje, both boys and girls. Statistical analysis provided us with descriptive data as well as with the differences between boys and girls in anthropometric and motor skill variables which were calculated using the t-test. The research results tell us that all the statistically significant differences are in favour of the boys. The same results that this research has provided can serve as a basis for further diagnostics efforts and planning of physical education lessons. These findings have also shown us that it is necessary to identify reliable measuring instruments for monitoring and tracking the state and changes in the anthropometric characteristics of younger school age children.

Effect of heat loss on performance of thin film thermoelectric; a mathematical model

To produce a higher electrical power in thin film thermoelectric legs, one way is to conduct the heat flow in-plane parallel to the surface of thin films. One important advantage of using the thermoelectric element in-plane is that, due to high thermal resistance of the thermoelectric leg, there is no need for an efficient heat sink at cold side. A comprehensive mathematical model for analyzing performance of a ZnSb based thermoelectric thin film is proposed based on one dimensional (1D) steady state analysis. Finite element method is employed to solve governing equations, and effects of temperature dependency of thermoelectric material are considered in the model. The modeling study is carried out by a comparison between the ideal case, where there is no heat loss from the thin film, and the case that the heat loss accrues from lateral surfaces of the thin film to the ambient. By taking side surface heat transfer into account for both vertical and horizontal placement of the thin film, two different nonlinear temperature distributions along the thin film length are obtained, and variation of matched power output versus different thermal boundary conditions is shown. The results show that convective heat transfer to the ambient reduces thermoelectric power output, especially at higher temperature difference between the hot and cold sides of the leg. Furthermore, different parameters such as Seebeck coefficient, temperature, generated Seebeck voltage, heat loss, thermoelectric voltage and current at peak power point are evaluated for vertical and horizontal thin film configurations.

In-season in-field variable resistance training: effects on strength, power, and anthropometry of junior soccer players.

Soccer players' leg muscular strength and power have been shown to be significant due to their association with soccer-specific performance including jumps, sprints, tackles and kicks. The aim of this study, therefore, was to examine the effects of an in-season in-field variable resistance training (VRT) program on strength, power, and anthropometry of junior soccer players. A team of male soccer players were randomly assigned into Experimental (N.=10) and Control groups (N.=10). The Control group performed 8 weeks of soccer training alone. The Experimental group performed squat VRT using chains in addition to soccer training. Measures before and after training included squat strength, countermovement jump, and anthropometric estimation of thigh muscle cross sectional area (CSA). The VRT induced large improvements in absolute (34.45%; P=0.001; Cohen's d=1.78) and relative strength to thigh muscle CSA (21.53%; P=0.002; Cohen's d=1.04). Similarly, there were large (18.07%, P=0.007; Cohen's d=1.5) increases in jump height and medium gains in absolute peak power output (16.13%; P=0.009; Cohen's d=0.34) and relative peak power output to thigh muscle CSA (9.6%; P=0.002; Cohen's d=0.31). Further, there was a medium increase (5.9%, P=0.03; Cohen's d=0.36) in thigh muscle CSA. No significant changes were observed in the Control group. In-season in-field biweekly squat VRT enhanced strength and power measures in junior soccer players.

The Stair Climb Power Test as an Efficacy Outcome in Randomized Trials of Function Promoting Therapies in Older Men.

Standardization of performance-based physical function measures that are reliable and responsive to intervention is necessary for efficacy trials of function promoting anabolic therapies (FPTs). Herein, we describe a standardized method of measuring stair climbing power (SCP) and evaluate its ability to assess improvements in physical function in response to an FPT (testosterone) compared to gait speed. We used a 12-step SCP test with and without carrying a load (loaded, LSCP or unloaded, USCP) in two testosterone trials in older men. SCP was determined from mass, total step-rise, and time of ascent measured with an electronic timing system. Associations between SCP and leg press performance (strength and power), testosterone levels, and gait speed were assessed. Test-retest reliability was evaluated using interclass correlation and Bland-Altman analyses. Baseline SCP was negatively associated with age and positively with leg strength and power and gait speed. Both tests of SCP were safe and showed excellent reliability (intra-class correlation 0.91-0.97 in both cohorts). Changes in testosterone concentrations were associated with changes in USCP and LSCP, but not gait speed in mobility-limited men. Changes in leg press performance were associated with SCP in both trials. Both USCP and LSCP are safe and have high test-retest reliability. Compared to gait speed, SCP is associated more robustly with leg press performance and is sensitive to testosterone therapy. The LSCP might be a more responsive outcome than gait speed to evaluate the efficacy of FPT in randomized trials.

Squat Jump Exercise Increased Spike Jump and Block Jump Reach of Junior Volleyball Athletes

Spike jump and block jump were characteristic movements of volleyball. These movement were determined by explosive power of leg, strength of musculoskeletal, length of lower limb and length of arm. Explosive power could be enhanced by plyometric exercise, like squat jump. The aims of study to analyse the role of squat jump exercise program on spike jump reach and block jump reach of junior volleyball athletes. Twenty-three junior athletes (male 11 and female 12) participated in pre and post-test experiment study. The squat jump exercise program was conducted three time a week, for along 7 weeks. The squat jump exercise involved squat jump, squat jumpwithbox,forearmpassingwhilesquatjumpandsquatjumpwithrunningtakeoff. The data were analysed by paired t-test to compare pre and post-test. The experiment resultedincreasingofspikejumpbothmen(p&lt;0.001)andwomen(p&lt;0.001).Increasing of block jump in men (p&lt;0.001) and women (p=009). We concluded that squat jump exercise regularly effective to increase the spike jump and block jump reach junior volleyball athletes.