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Summary Objective We undertook to examine growth patterns and the development of leg muscle power by socioeconomic classes among healthy Tunisian adolescents aged 13 to 19 years. Methods Five hundred and sixty Tunisian healthy adolescents (259 males and 301 females) were randomly selected. Anthropometric variables were measured and socioeconomic status was assessed according to a standard questionnaire. Jump heights and leg power were provided by an Optojump device using countermovement jump and squat jump. Results Tunisian adolescents from high socioeconomic status had significant differences (P Conclusion The socioeconomic status act on growth patterns and the development of leg muscle power in healthy Tunisian adolescents aged between 13–19 years. Tunisian adolescents from high socioeconomic status had higher mean values of leg muscle volume than those from low socioeconomic status.

Objective: The aim of this study is to find out the relationships among body composition, Yo-Yo intermittent recovery (IR) test and vertical jump test in elite young soccer players. Material and Methods: Eighteen healthy young male soccer players (Age: 16.5±0.3 years, height: 178.0±5.9 cm, body weight: 65.9±7.9kg,) voluntarily participated in the study. Total and regional body composition parameters of the soccer players were examined through a dual-energy x-ray absorptiometry (DEXA) method. Vertical jump performance tests were squat jump (SJ) and active jump (AJ), and endurance performances were determined by the Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1). Relationships among body composition, Yo-Yo intermittent recovery test and vertical jump test were analyzed with Pearson Correlation coefficient. Significance level was taken as ≤0.05. Results: A statistically significant negative correlation was found between squat jump and countermovement jump (r=-0.588, r=-0.573, p0.05). Conclusion: Changes in body composition are important issues for the physical performance level of young soccer players, as local excess body fat may cause deterioration, especially in jumping performance.

Fitzpatrick, JF, Hicks, KM, Russell, M, and Hayes, PR. The reliability of potential fatigue-monitoring measures in elite youth soccer players. J Strength Cond Res 35(12): 3448-3452, 2021-Monitoring fatigue is of vital importance to practitioners; however, logistics and concerns about reliability may impede the use of certain measures. This study aimed to quantify the reliability of potential measures of fatigue; a subjective wellness questionnaire, jump performance tests, and tri-axial accelerometer variables derived during submaximal shuttle running in elite youth soccer players. A secondary aim was to establish the minimum test duration that could be used for the submaximal shuttle run while maintaining good reliability. Seventeen male youth team players (age: 17.4 ± 0.5 years) were assessed on 2 occasions, spaced 7 days apart. Typical error, coefficient of variation (CV%), interclass correlation (ICC), and minimum detectable change were calculated for a subjective wellness questionnaire, countermovement jump (CMJ), squat jump (SJ) and drop jump contact time (DJ-CT), drop jump height (DJ-JH), and reactive strength (DJ-RSI). A novel submaximal shuttle running test was also used to assess tri-axial accelerometer data reliability. Results suggest that CMJ, SJ, DJ-CT, and DJ-RSI have good test-retest reliability (CV% = 4.5-7.7; ICC = 0.80-0.88); however DJ-JH did not show acceptable reliability (CV% = 6.0; ICC = 0.76). Good reliability was found for all tri-axial accelerometer variables during a 3-minute (2-minute analysis) submaximal shuttle run (CV% = 2.4-8.0; ICC = 0.81-0.95), except for % PlayerLoad anterior-posterior (%PLAP) (CV% = 7.2; ICC = 0.63). The subjective wellness questionnaire demonstrated poor reliability for all items (CV% = 11.2-30.0; ICC = 0.00-0.78). The findings from this study provide practitioners with valuable information about the reliability of a range of potential fatigue-monitoring measures. This can be used to help make accurate decisions about the magnitude of change in these assessments when used in practice.

Dowse, RA, Secomb, JL, Bruton, M, Parsonage, J, Ferrier, B, Waddington, G, and Nimphius, S. Ankle proprioception in male and female surfers and the implications of motor experience and lower-body strength. J Strength Cond Res XX(X): 000-000, 2021-The primary objectives were to evaluate if the active movement extent discrimination apparatus (AMEDA) condition (i.e., front foot and back foot plantarflexion, dorsiflexion, inversion, and eversion) and the level of competition explained ankle movement discrimination scores and, thereafter, examined the contribution of surf experience, physical capacity, and ability to proprioception. It was also considered important to re-evaluate the surf experience, anthropometric characteristics, physical capacities, and abilities of male and female surfers. Twenty-six male (n = 12, surf experience = 18 ± 8 years) and female surfers (n = 14, surf experience = 9 ± 6 years) completed a pre-exercise medical questionnaire, anthropometric assessment, 8 AMEDA assessments, countermovement jump, squat jump, and isometric midthigh pull assessment. The AMEDA condition and level of competition did not have a statistically significant main effect on ankle movement discrimination scores; however, the effect of the gender/sex was significant (p = 0.044). Surf experience (p = 0.029) and lower-body isometric strength (p = 0.029) had a statistically significant but small main effect on ankle movement discrimination scores. The results also confirmed that there were significant differences in surf experience, anthropometric characteristics, physical capacity, and jumping ability between male and female surfers. As surf experience and physical capacity were only able to explain a small magnitude of ankle movement discrimination scores, it is suggested that ankle proprioception in surfers may be related to both the volume and quality of the motor experience attained, which may be augmented by environmental and sociocultural factors.

Objetivos: Os objetivos do presente estudo foram descrever e comparar variáveis antropométricas e o desempenho em testes motores entre as posições de jogo, e testar a correlação entre estas variáveis em jogadores de handebol adultos. Métodos: Participaram do estudo 23 jogadores (20,78 ± 3,83 anos), sendo subdivididos por posição em armadores (n = 9), pontas (n = 9) e pivôs (n = 5). Foram realizadas duas baterias de avaliações, com 72 h de intervalo entre elas, e analisados na primeira bateria variáveis antropométricas (estatura, massa corporal, massa magra, massa gorda, e percentual de gordura), e o desempenho nos testes squat jump, counter movement jump e salto horizontal, e na segunda o desempenho nos testes sprint de 10 m e teste-T. Resultados: Os pivôs apresentaram maior massa corporal, massa gorda e percentual de gordura em comparação aos armadores e pontas, sendo pivôs e armadores os jogadores de maior estatura da equipe (p < 0,05). O desempenho no teste-T dos pivôs foi menor em comparação aos de armadores. Foram encontradas correlações entre maior massa gorda com menor desempenho em teste-T, squat jump, counter movement jump e salto horizontal, e entre maior percentual de gordura com menor desempenho em teste-T, squat jump e counter movement jump. Conclusão: As características antropométricas e o desempenho motor variam em função da posição de jogo. Além disso, foram evidenciadas correlações moderadas entre maiores índices de gordura e menor desempenho em testes de agilidade e salto vertical e horizontal.

Background Continuous relative phase (CRP) has gained popularity to assess movement performances in recent decades. Research question The application and interpretation of CRP in common movements such as running and jumping are still unclear. Methods This systematic review summarized the current applications, methodology, parameters of interest, and interpretations of CRP variables in running and jumping. Reviewed articles were found in five databases from January 1999 to December 2020, and 1613 records were obtained. After applying selection criteria and analysis of study quality to titles, abstracts, and full texts, 38 articles were identified for subsequent review. Results Twenty-eight reviewed articles relating to running were found to compare the coordination among pathological gait, footwear designs, running speed, gender, age, running level, fatigue state, and treadmill effect. In addition, ten reviewed articles relating to jumping were found to compare the coordination among different types of jump (e.g., squat jump coordination, countermovement jump, single leg jump) and insole effect. Significance The CRP and its variability (CRPv) are two common variables to describe the changes and differences of coordination patterns, respectively. These reviewed articles suggest that CRP tools are effective to assess the coordination and performances in running and jumping, as these values are related to external (environment/equipment) and internal (self-biological) changes. In the future, studying higher-order analysis of movement patterns using CRP tools can provide meaningful interpretation of movement behavior.

Background: Youth populations benefit from neuromuscular training; however, the extent to which training frequency, baseline fitness, and maturity status moderate the response to long-term neuromuscular training in male youth remains unclear. Hypothesis: Twice-weekly training (G2x) would induce larger improvements in movement competency and strength and power kinetics compared with once-weekly training (G1x). Maturity status and baseline fitness would also moderate the training response in strength and power kinetics. Study Design: Nonrandomized, repeated-measures design. Level of Evidence: Level 3 Methods: Ninety-five male athletes of varying maturity status (pre– or post–peak height velocity) were divided into G2x, G1x, or control (CON) groups. Training groups received G2x or G1x for 28 weeks. Back squat assessment (BSA) movement competency and isometric mid-thigh pull (IMTP), squat jump (SJ), and countermovement jump (CMJ) kinetics were measured pre- and postintervention. Results: The G2x achieved significantly greater adaptations in BSA total score, IMTP allometrically scaled peak force (PFallo), IMTP peak rate-of-force development (PRFD), SJ PFallo and PRFD compared with G1x and CON ( P < 0.05; d = 0.3-0.9). Baseline fitness, training frequency and maturity status were significant predictors of IMTP PFallo ( R2 = 27.5%) and PRFD ( R2 = 42.9%), while a combination of training frequency and baseline fitness explained a small amount of variance in SJ PFallo ( R2 = 12.2%) and SJ PRFD ( R2 = 6.5%). There were no significant predictors of CMJ kinetics. Conclusion: G2x achieved significantly larger improvements in movement competency, isometric strength and concentric jump variables compared with G1x, with the training response greater in those youth with lower baseline fitness and more advanced maturity status. Clinical Relevance: Exposure to neuromuscular training twice-weekly elicits a greater response than G1x in young male athletes. Practitioners should take maturity status, training frequency, and baseline fitness levels of young male athletes into account when interpreting testing data, as these variables appear to moderate training responsiveness.

Resistance exercises eliciting eccentric overload (EO) are considered to strongly promote muscular hypertrophy and broad neuromuscular adaptations but typically require specialized equipment. The aims of these experiments were to assess whether EO is achieved during common high-speed stretch-shortening cycle (SSC) exercises (rebound bench press throw [RBPT] and squat jump [SJ]), and to test the effect of the external load on the EO achieved. Twenty-nine under 18 handball players and fifteen physically active males (24.9 ± 3.2 years) took part in the experiments. Testing consisted of a single set of 6 repetitions with light (25%-30% 1-RM), moderate (50% 1-RM), and heavy (70%-75% 1-RM) loads. Eccentric and concentric force near the zero-velocity point (50-200 ms) as well as eccentric-concentric force ratio (EO; %) were calculated. In RBPT, higher EO values were found at 50% 1-RM than 70% 1-RM in the time interval 50 ms before and after the zero-velocity point. Higher EO values were also found at 50% 1-RM than both 30% 1-RM and 70% 1-RM 100 ms before and after the zero-velocity point. For the SJ, higher EO values were found at 50% 1-RM and 75% 1-RM than 25% 1-RM 100 ms before and after the zero-velocity point. Higher EO values were found at 50% 1-RM than 25% 1-RM 200 ms before and after the zero-velocity point. However, the higher EO values in the SJ were found far from the zero-velocity point. High-speed SSC resistance training provides similar EO to other methods and thus should promote muscle hypertrophy and other neuromuscular adaptations.

To evaluate the physical fitness of older women enrolled in physical exercises programs and their correlation with falls history rates in this population. Nineteen older adults (60.3 ± 4.2 years and 65.9 ± 10.2kgs) participated in the study. A descriptive analysis was performed to verify the following physical components: muscle power, aerobic endurance, gait speed, agility/dynamic balance, muscular endurance, flexibility, and strength. The Downton scale and the international physical activity questionnaire (IPAQ) were also applied. The sample was grouped by the history of falls as HF = 0 (history of falls equal to zero in the last year) or HF ≥ 1 (history of falls higher than 1 in the last year). Chi-square test was used to verify possible relations between IPAQ scores and history of falls. Pearson correlation coefficient was used to test the relationship between groups and each dependent variable. Also, independent sample t- tests were applied to test absolute differences between groups. According to the IPAQ, 37.5% as 18.1% were physically active from those reporting HF = 0 and HF > 1, respectively (p = 0.03). Also, the results showed that the occurrence of falls when subjects present greater body mass (p = 0.03), and lower limb muscle strength (p = 0.02), endurance (p = 0.01) and power (Countermovement jump: p = 0.04, Squat jump: p = 0.04). Thus, it is possible to conclude that physical activity levels and performance in strength tests should be monitored in the older adults’ population, while exercise programs aiming to improve these parameters are suggested as strategy to preventing falls.

This study aimed to (1) track changes in body composition, lower body force-time characteristics, and swim start performance over a competitive season, and (2) investigate the intra-individual associations between changes in body composition and lower body force-time characteristics to swim start performance in five high performance swimmers (three males, two females). Over a ∼12-month period, body composition, lower body force-time characteristics and swim start performance were assessed at three time points via DXA scan, squat jump and swim start performance test (start times to 5 and 15 m and several kinematic and kinetic outputs). Throughout a competitive season of concurrent swimming and dry-land resistance training, improvements in lower body lean mass and squat jump force-time characteristics were observed. However, changes in start times varied between athletes. Total body and lower body lean mass both displayed large negative correlations with the time spent in the entry and propulsive underwater phases ( r = –0.57 to –0.66), along with a large positive correlations with glide time ( r = 0.56–0.53). Additionally, lower body lean mass exhibited large to very large positive correlations with the flight phase ( r = 0.70–0.73). Overall, these findings provide some insight into the potential magnitude of change in body composition, lower body force-time characteristics and swim start performance in high performance swimmers within a season. The large to very large correlations between increased lower body lean mass and SJ force-time metrics to improvements in aspects of start performance may provide useful information to coaches and sports scientists.

Comprehensive information regarding neuromuscular function, as assessed through force-velocity-power (FVP) profiling, is of importance for training optimization in athletes. However, neuromuscular function is highly task-specific, potentially governed by dissimilarity of the overall orientation of forceapplication. The hip thrust (HT) exercise is thought to be of relevance for sprinting considering its antero-posterior force orientation and considerable hip-extensor recruitment, however, the association between their respective FVP profiles remains unexplored. Therefore, to address the concept of force orientation specificity within FVP profiling, the maximal theoretical neuromuscular capabilities of 41 professional male footballers (22.1 ± 4.1 years, 181.8 ± 6.4 cm, 76.4 ± 5.5 kg) were assessed during sprint acceleration, squat jumping (SJ) and the HT exercise. No significant associations were observed for maximal theoretical force or velocity between the three FVP profiling modalities, however, maximal theoretical power (Pmax) was correlated between sprinting and SJ (r = 0.73, P

The objective of the study was to evaluate the circulating levels of chemical elements after exercise-induced muscle damage (EIMD) followed by the repeated bout effect (RBE). Seven physically active subjects (26.5 ± 4.0 years) performed two sessions of EIMD (5 sets of 20 drop jumps), the second session 14 days after the first for RBE assessment. Blood collections, countermovement jump (CMJ), squat jump (SJ), and delayed-onset muscle soreness (DOMS) were performed before (Pre), after (Post), and 24, 48, and 72 h after the exercise session. Creatine kinase (CK) was detected by biochemical analysis and the concentration of chemical elements by total reflection X-ray fluorescence (TXRF). Differences between time points and sessions were assessed with two-way ANOVA and the effect size (ES). EIMD induced a reduction in the CMJ at 24 h (P 0.05) and an increase in DOMS at 24 h (P 0.01) and 48 h (P 0.01), and CK at 72 h (P 0.05). RBE alleviated all symptoms of EIMD in the second session (P 0.05). EIMD induced a large to very large ES for Zn reduction at 24 h (- 1.37) and 72 h (- 0.93) and Br (- 0.83) at 72 h. RBE presented large to very large ES for the increase in P at 48 h (0.92); Cl at 24 h (1.04); K at 24 h (0.91), 48 h (1.10), and 72 h (0.96); Ca at 72 h (0.92); and Fe at 24 h (0.85). RBE influenced the concentration of elements associated with fatigue (K, Ca, Cl), inflammatory response, and glucose metabolism (Zn).

The aim of this study was to determine the relationships between back squat maximal strength, maximal isometric force, jump squat and countermovement jump and whether power training improves parameters mentioned above in well-trained speed skaters. Sixteen athletes devided in two groups, performed two maximal squat strength test and two vertical jump test before and after the intervention program. Absolute strength showed a strong correlation with squat jump height (r = 0.762, p < 0.001) and countermovement jump height (r = 0.760, p < 0.001) but also between maximal isometric force and squat jump (r = 0.418, p = 0.036). Percentage change within the experiment group were significantly different from pre to post intervention for each parameter tested in the order described, respectively: 14%; 16.8%; 14.9%; 9.1%. These results suggest that jump squat training can improve several athletic performances developing high levels of lower body strength to enhance jump performance.

Taylor, L and Jakeman, JR. The impact of a repeated sprint training program on performance measures in male field hockey players. J Strength Cond Res XX(X): 000-000, 2021-Sprint interval training (SIT) has been shown to be effective at improving athletic performance in laboratory studies, but the efficacy of SIT programs incorporated into normal training schedules is poorly considered. This study aimed to investigate the impact of a running SIT intervention applied to competitive athletes within a training program and to consider whether an uphill or flat (horizontal) SIT protocol had different effects on performance changes over time. Eighteen male hockey players (mean ± SD: age, 20.7 ± 0.9 years; hockey training experience, 9.9 ± 3.0 years) completed 2 sessions of SIT per week for 8 weeks, with intensity progressively increasing from 6 sprints in week 1 to 12 sprints in week 8. Subjects were randomly allocated to a flat or uphill (6% gradient) training condition (n = 9) and completed 30-m maximal sprint efforts with a 30-second recovery. Performance measures, including squat jump, 30-m sprint speed, and repeated sprint time, all improved significantly (p ≤ 0.05). Squat jump performance improved by 3.84 (d = 0.8) and 3.55 (d = 0.7) in the flat and uphill groups, respectively. Thirty-meter sprint speed improved by 0.06 (d = -0.4) and 0.10 (d = -0.7), and repeated sprint performance also improved, with the fastest of recorded sprints after intervention being 0.06 and 0.04 faster in the flat and uphill groups, respectively. Supplementing a normal hockey training week with SIT can have a positive impact on performance measures in male university hockey players. Furthermore, using an uphill training modality had a small, nonsignificant additional positive effect to some performance adaptations.

The aim of this study was to assess the effects of plyometric training with an agility ladder on components of physical fitness in youth soccer players. A total of twenty male under-13 soccer players were randomly assigned to a plyometric training group with an agility ladder (n=10) or a control group (n=10). Before and after training intervention linear sprint test (5 m, 10 m, 20 m), vertical jump ability (squat jump, countermovement jump and countermovement jump with arms), agility test, and slalom dribble test were assessed. The plyometric training with agility ladder was applied two times per week over six weeks. Data were analyzed using linear mixed model. The plyometric training group showed significant improvements (p0.05). The between-group analysis showed significant differences in countermovement jump with arms (p=0.03), but no significant differences (p>0.05) were found in squat jump, countermovement jump, sprint, agility test, and slalom dribble test. In conclusion, the short-term plyometric training with agility ladder seems to be ineffective and not time-efficient to improve physical fitness in youth soccer players. However, the interpretation of these results must be understood within the sample size limitations.

Summary Introduction The aim of this study was to compare the acute effects of the Running Anaerobic-based Sprint Test (RAST) with different loads in physiologic and neuromuscular parameters. Summary of facts and results 12 amateur rugby union players performed the RAST, with heart rate (HR) and blood lactate concentration ([LAC]) measurements pre, post and 5 min post RAST, squat jump (SJ), countermovement jump (CMJ), 10 m (S10) and 20 m (S20) sprints pre and post RAST. These procedures were carried out during three sessions, randomly performed in different conditions: no load (NL), load with 13% (L13) or 25% (L25) of body mass. Between loads, peak power in RAST and mean power were statistically different, with lower in L25 condition. Between moments, significant differences were observed with decrease in HR, increase in [LAC] for pre, post and 5 min post, respectively, and performance decrease in CMJ and S10, without load vs moment interaction. In addition, between loads, with exception of power produced in RAST, no significant differences were observed for any variable. Conclusion Therefore, despite the differences in power production during RAST, it is concluded that RAST performed with or without loads of either 13 or 25% of body mass induces similar acute effects in both physiologic and neuromuscular parameters.

[Purpose] Blood lactate reduction helps in understanding muscle recovery. Although light exercise and stretching are known interventions to reduce its concentration, the impact of skeletal muscle mass on blood lactate clearance is unknown. This study aimed to determine the relationships between blood lactate reduction and skeletal muscle mass following exercise. [Participants and Methods] Healthy non-athletic males performed squat jumps for 1 minute and 30 seconds. Blood lactate level was measured before and immediately after the exercise and then every 2 minutes for a period of 20 minutes. The decrease in blood lactate level was estimated as the difference between the minimum and maximum values. The rate of decrease was calculated by dividing the decrease in blood lactate level by time. Blood lactate level was measured using Lactate ProTM 2, while skeletal muscle mass was assessed using InBody 430. [Results] There was a significant positive correlation between skeletal muscle mass, the amount of blood lactate level reduction, and the rate of reduction of blood lactate level. [Conclusion] Our results demonstrated that greater skeletal muscle mass enabled a greater decrease in blood lactate level, suggesting that skeletal muscle mass may be involved in the reduction of blood lactate level after a squat jump. Interventions to increase skeletal muscle mass may promote more efficient lactate metabolism and muscle fatigue recovery.

Dowse, RA, McGuigan, MR, and Harrison, C. Effects of a resistance training intervention on strength, power, and performance in adolescent dancers. J Strength Cond Res 34(12): 3446-3453, 2020-The aim of this study was to determine whether a 9-week resistance training program could have a significant effect on maximum lower-body strength and power, dynamic balance, and dance performance in adolescent dancers. Twelve competitive adolescent female dancers trained in jazz, ballet, and contemporary were recruited from local dance schools and assigned to a resistance training group (dance experience 9.2 ± 2.4 years; age 14.2 ± 1.9 years; height 155.6 ± 9.1 cm; and mass 48.9 ± 13.8 kg). Anthropometry (height, seated height, mass, and skinfolds), subjective dancing performance, dynamic balance (eyes open [EO] and eyes closed), maximum lower-body strength (isometric midthigh pull), and power (vertical countermovement jump, squat jump, and single-leg countermovement jump) were assessed before and after the 9-week intervention period. Post-testing identified a significant improvement EO overall stability (p = 0.003; effect size [ES] = 0.88), EO anterior-posterior stability (p = 0.003; ES = 0.92), peak force (p < 0.001; ES = 0.61), peak power (p = 0.021; ES = 0.22), and subjective dancing performance (p = 0.008; ES = 0.76). These results were accompanied by a trivial but significant change in mass (p = 0.023; ES = 0.09) that was attributed to growth and no significant change in body fat or the sum of skinfolds. This study demonstrated that resistance training can have a significant effect on dynamic balance, maximum lower-body strength, and power without adversely affecting artistic or aesthetic components. The results suggest that incorporating resistance training may enhance strength and power adaptations and manage growth-related changes in adolescent dancers.

The purpose of this study was to evaluate differences in multiple athletic performances, and to examine associations between athletic performance and Functional Movement Screen (FMS) in young soccer players. Forty-one soccer players were tested on peak height velocity (PHV), 5-, 10-, and 30-m sprint times, 505 change of direction (505 COD), Y-reactive agility tests, countermovement jump (CMJ), and squat jump (SJ) height. Significant main effects (P

The transition between the different phases of triathlon affects both athletic performance and risk of injury. The aim was to determine the neuromuscular fatigue induced by 40 km cycling and the plyometric training efficacy in order to improve such fatigue and running performance. Twelve triathletes participated, 5 of them did specific plyometric training versus 7 who continued with their usual training. Different jump tests were carried out before and after 40 km cycling in order to determine the fatigue, the 5km-running pace was also recorded. Significant differences were observed in the jump height (p

La investigación se centró en evaluar el impacto de un sistema de entrenamiento combinado para desarrollar la fuerza explosiva de los miembros inferiores de los taekwondocas, viene a reforzar el enfoque del desarrollo de la capacidad mediante una lógica metodológica que parte de la creación de las condiciones morfológicas y funcionales para asegurar la potenciación de una hipertrofia sarcoplasmática, como base del desarrollo de la hipertrofia sarcomérica y finalmente favorecer la conversión a potencia y el desarrollo de la fuerza explosiva, en concordancia se transitó por un diagnóstico, elaboración y validación, utilizando convenientemente métodos y técnicas como: entrevista, encuesta, observación, la prueba, la medición, el criterios de experto, la estadística descriptiva e inferencial y el pre-experimento, este último con tres momentos (pre-test/ intervención de 16 semanas/ post-test), participaron 20 taekwondocas universitarios Categoría Sénior y dos entrenadores. Se consideró la evaluación de la fuerza máxima (1RM) de los planos musculares que intervienen directamente en las técnicas de pateo, por estar asociada con la calidad del reclutamiento de la fibras motoras; la evaluación de la fuerza explosiva se realizó mediante el test de salto vertical: Squat Jump (SJ) extraído del protocolo del test de Bosco, para ello fue necesario emplear una plataforma de contacto digital. Los datos se compararon mediante una prueba T de diferencias de medias, cuyos resultados mostraron cambios significativos (p= .000) entre el pre y post tratamiento, verificándose Hi, concluyendo que el sistema de entrenamiento combinado mejoró el desarrollo de la fuerza explosiva de los miembros inferiores de los taekwondocas. Summary: The research focused on assessing the impact of a combined training system to develop the explosive strength of the lower limbs of the taekwondoins. It wants to reinforce the approach of capacity development through a methodological logic that starts from the creation of morphological and functional conditions to ensure the enhancement of a sarcoplasmic hypertrophy, as a basis for the development of sarcomeric hypertrophy, and finally, favor the conversion to power and the development of the explosive force. At the same time, it went through a diagnosis, elaboration and data validation, using propper methods and techniques such as: interview, survey, observation, testing, measurement, expert criteria, descriptive and inferential statistics, and the pre-experiment. The last one with three stages (pre-test / 16-week intervention / post-test) Twenty senior category university taekwondoins and two coaches participated. The evaluation of the maximum force (1RM) of the muscular planes that directly influence in the kicking techniques was considered. As it was associated to the quality of motor fiber recruitment; The evaluation of the explosive force was performed using the vertical jump test: Squat Jump (SJ) extracted from the Bosco test protocol. For this, it was necessary to use a digital contact platform. The data were compared using a T-test, the results of which showed significant changes (p = .000) between the pre and post treatment, verifying Hi. Concluding that the combined training system improved the development of the explosive strength of the limbs lower of the taekwondoinst.

Aim: The study aims to conduct a kinematical analysis of blocking skill in volleyball and their relationships with the explosive force of lower limbs, for the athletes from the elite Algerian team.Methods: A total of 06 male Volleyball Players from the elite Algerian team as volunteers (Age: 25.66+3.32 yr, Length:198.00+3.68 cm, Weight: 86.66+6.62 kg). We used for kinematical analysis the software Dartfish9. For video capturing, we used three cameras (AEE Magic Cam) for record the performance during an Experimental competition, two CAMІ&П(X1m, Y, Z1.5m) were placed in the sides of volleyball Court, and CAMⅢ(X4.5m, Y1m, Z1.5m) behind the elite Algerian team. Also, two force Explosive tests were executed; Squat Jump (SJ) and Counter Movement Jump (CMJ). The data were analyzed in SPSS 22.0 program. Descriptive statistics (mean±SD) and P test for the correlations between variables studied.Results: Through the statistical analysis, there were significant correlations between values of CMJ test with both of the DHeightBCG (p

We aimed to determine key biomechanical parameters explaining age-related jumping performance differences in youth elite female soccer players. Multiple biomechanical parameters from countermovement (CMJ) squat (SJ) and drop (DJ) jump testing of elite female soccer players (n = 60) within the same national training centre were analysed across ages 9-11y, 12-14y and 15-19y. Effects of age group and jump type on jump height were found, with the older jumping higher than the younger groups in all jumps (P 0.05). For DJ, higher reactive strength index was found for older, compared to each younger group (P 0.001). For CMJ and SJ, peak power was the most decisive characteristic, with significant differences between each group for absolute peak power (P 0.0001) and body-weight-normalised peak power in CMJ (57 ± 7W/kg, 50 ± 7W/kg, 44.7 ± 5.5W/kg; P 0.05) and between the older and each younger group in SJ (56.7 ± 7.1W/kg, 48.9 ± 7.1W/kg, 44.6 ± 6W/kg; P 0.01). Age-related differences in jumping performance in youth elite female soccer players appear to be due to power production during standing jumps and by the ability to jump with shorter ground contact times during reactive jumps.

Bouguezzi, R, Chaabene, H, Negra, Y, Ramirez-Campillo, R, Jlalia, Z, Mkaouer, B, and Hachana, Y. Effects of different plyometric training frequencies on measures of athletic performance in prepuberal male soccer players. J Strength Cond Res 34(6): 1609-1617, 2020-This study aimed to compare the effects of 1 vs. 2 sessions of equal-weekly volume plyometric training (PT) across 8 weeks on measures of athletic performance (i.e., sprint time, change of direction [CoD], jumping ability, and muscle strength) in prepuberal male soccer players. Thirty participants were randomly assigned either to 1 session PT group (1SPT [n = 15]) or 2 sessions PT group (2SPT [n = 15]). Plyometric training was integrated into their regular soccer training routine. Pretraining and posttraining tests for the assessment of sprint time (e.g., 5, 10, 20, and 30-m), CoD (e.g., T-test and modified Illinois change of direction test [MICODT]), jumping ability (e.g., standing long jump [SLJ], countermovement jump [CMJ], and squat jump [SJ]), muscle strength (reactive strength index [RSI]), and kicking distance were conducted. Results showed a main effect of time for 5-m sprint-time performance (F(1,56) = 4.00, effect size [ES] = 0.53 [medium], p = 0.05), T-test (F(1,56) = 23.19, ES = 1.28 [large], p0.001), MICODT (F(1,56) = 5.72, ES = 0.94 [large], p = 0.02), SLJ (F(1,56) = 16.63, ES = 1.09 [large], p0.001), CMJ (F(1,56) = 15.43, ES = 1.04 [large], p0.001), SJ (F(1,56) = 20.27, ES = 1.20 [large], p0.001), RSI (F(1,56) = 26.26, ES = 1.36 [large], p0.001), and kicking distance (F(1,56) = 47.19, ES = 1.83 [large], p0.001). There were no training group × time interactions in all the measured outcomes. In conclusion, when an equated moderate volume of jumps is performed, higher PT frequency across 8 weeks has no extra effects on prepuberal male soccer players' measures of athletic performance. The present findings may help optimizing PT interventions dedicated to prepuberal male soccer players.

El taekwondo (TKD) es caracterizado como un deporte intermitente y de alta-intensidad donde predominan la ejecución de movimientos rápidos y explosivos, con desplazamientos continuos y cambios de dirección (COD). Objetivo. El propósito de este estudio fue examinar la asociación entre la prueba TSAT y la fuerza explosiva y la velocidad lineal en 5-M en competidores de TKD de nivel nacional de ambos sexos. Material y métodos. A través de un diseño correlacional 14 competidores de ambos sexos que compiten habitualmente en torneos de nivel regional y nacional, (edad 19 ± 3 años; talla 164 ± 10 cm; peso corporal 62 ± 10 kg; experiencia 7.2 ± 2.9 años) participaron en este estudio. Como indicadores de fuerza explosiva se evaluó squat jump (SJ) y countermovement jump (CMJ), además de la velocidad lineal en 5-m (5-M) y la prueba de agilidad específica en taekwondo (TSAT) Resultados. Entre los principales hallazgos de este estudio se documentó una relación directa (r = .70) entre 5-M y TSAT; una relación inversa (r = -.63) entre SJ; CMJ (r = -.53) y TSAT respectivamente. Conclusiones. Nuestros datos muestran que la prueba de TSAT se relaciona con la velocidad lineal en 5-m y la fuerza explosiva. Los entrenadores deberían considerar el entrenamiento de estas cualidades, utilizando ejercicios similares para desarrollar la agilidad en competidores de TKD. Abstract. Taekwondo (TKD) is characterized as an intermittent and high-intensity sport in which predominates the execution of fast and explosive movements, with continuous movements and changes of direction (COD). Objective. The purpose of this study was to examine the association between the TSAT test, explosive strength, and 5-M line speed in national level TKD competitors of both sexes. Material and method. Through a correlational design, 14 competitors of both sexes who regularly compete in regional and national tournaments (age 19 ± 3 years; size 164 ± 10 cm; body weight 62 ± 10 kg; experience 7.2 ± 2.9 years), participated in this study. As indicators of explosive strength, squat jump (SJ) and countermovement jump (CMJ) were evaluated, as well as the 5-m linear speed (5-M) and the taekwondo-specific agility test (TSAT). Results. Among the main findings of this study, a direct relationship (r = .70) between 5-M and TSAT and an inverse relationship (r = -.63) between SJ, CMJ (r = -.53), and TSAT were documented, respectively. Conclusions. Our data shows that the TSAT test is related to 5-m linear velocity and explosive force. Coaches should consider training these qualities, using similar exercises to develop agility in TKD competitors.

Purpose The purpose of this study was to investigate if endurance athletes, sustaining their normal endurance training, experience attenuated adaptations to strength training compared to untrained individuals. Methods Eleven non-strength-trained female endurance athletes (E + S) added 11 weeks of strength training to their normal endurance training (5.1 ± 1.1 h per week), and 10 untrained women (S) performed the same strength training without any endurance training. The strength training consisted of four leg exercises [3 × 4 − 10 repetition maximum (RM)], performed twice a week for 11 weeks. Results E + S and S displayed similar increases in 1RM one-legged leg press (E + S 39 ± 19%, S 42 ± 17%, p E + S 12 ± 11%, S 8 ± 10%, p E + S 3 ± 4%, S 3 ± 3%, p S displayed superior increases in peak torque in knee extension at an angular velocity of 240° sec−1 (E + S 8 ± 5%, S 15 ± 7%, p E + S 8 ± 6%, S 14 ± 7%, p Conclusions In this study, concurrent training did not impair the adaptations in the ability to develop force at low contraction velocities or muscle hypertrophy. However, concurrent training attenuated strength training-associated changes in the ability to develop force at higher muscular contraction velocities.

Nunes, RFH, Cidral-Filho, FJ, Flores, LJF, Nakamura, FY, Rodriguez, HFM, Bobinski, F, De Sousa, A, Petronilho, F, Danielski, LG, Martins, MM, Martins, DF, and Guglielmo, LGA. Effects of far-infrared emitting ceramic materials on recovery during 2-week preseason of elite futsal players. J Strength Cond Res 34(1): 235-248, 2020-We investigated the effects of far-infrared emitting ceramic materials (cFIR) during overnight sleep on neuromuscular, biochemical and perceptual markers in futsal players. Twenty athletes performed a 2-week preseason training program and during sleep wore bioceramic (BIO; n = 10) or placebo pants (PL; n = 10). Performance (countermovement jump [CMJ]; squat jump [SJ]; sprints 5, 10, and 15-m) and biochemical markers (tumor necrosis factor alpha-TNF-α, interleukin 10-IL-10, thiobarbituric acid-reactive species [TBARS], carbonyl, superoxide dismutase [SOD], catalase [CAT]) were obtained at baseline and after the 1st and 2nd week of training. Delayed-onset muscle soreness (DOMS) and training strain were monitored throughout. Changes in ΔCMJ and ΔSJ were possibly (60/36/4 [week-1]) and likely (76/22/2 [week-2]) higher in BIO. Both groups were faster in 5-m sprint in week 2 compared with baseline (p = 0.015), furthermore, BIO was likely faster in 10-m sprint (3/25/72 [week 1]). Significant group × time interaction in %ΔTNF-α were observed (p = 0.024 [week-1]; p = 0.021 [week-2]) with values possibly (53/44/3 [week 1]) and likely (80/19/1 [week 2]) higher in BIO. The %ΔIL-10 decreased across weeks compared with baseline (p = 0.019 [week-1]; p = 0.026 [week-2]), showing values likely higher in BIO (81/16/3 [week-1]; 80/17/3 [week-2]). Significant weekly increases in %ΔTBARS (p = 0.001 [week-1]; p = 0.011 [week-2]) and %ΔCarbonyl (p = 0.002 [week-1]; p < 0.001 [week-2]) were observed compared with baseline, showing likely (91/5/4 [week-1]) and possibly (68/30/2 [week-2]) higher changes in BIO. Significant weekly decreases in %ΔSOD were observed compared with baseline (p = 0.046 [week 1]; p = 0.011 [week-2]), and between week 2 and week 1 (p = 0.021), in addition to significant decreases in %ΔCAT compared with baseline (p = 0.070 [week 1]; p = 0.012 [week 2]). Training strain (p = 0.021; very -likely [0/2/98]; week 1) and DOMS was lower in BIO (likely; 7 sessions) with differences over time (p = 0.001). The results suggest that the daily use of cFIR clothing could facilitate recovery, especially on perceptual markers during the early phases of an intensive training period.

Made available in DSpace on 2022-04-28T19:50:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-01 BACKGROUND: This study aimed to quantify internal training load and changes in vertical jumping ability and endurance capacity of professional volleyball players during the preseason, and to explore relationships between players' physical qualities at the beginning of the preseason with internal training load accumulated during the first two weeks of training. METHODS: Sixteen male professional volleyball players from a team participating in the Brazilian National Super League took part in the study. Before and after a 10-week preseason, their vertical jumping ability and endurance capacity were assessed by squat jump, countermovement jump without and with arm swing, and YoYo endurance test, level 1. The internal training load was quantified by the session rating of perceived exertion method. Results were analyzed using analysis of variance, magnitude-based inference and Pearson's correlation. RESULTS: The internal training load varied between 1388±111 arbitrary units (a.u.) and 3852±149 a.u., and performance in all the tests was positively changed (small to moderate effect sizes) at end of preseason training. Significant (P

This study examined the effects of 8-week stretch-shortening cycle-based (SSC-based) versus non-SSC-based jump exercises on physical fitness in prepubertal male soccer players. Twenty-six participants were randomly assigned to either a SSC-based using countermovement jump (CMJG; n = 13) or a non-SSC-based jump group using squat jump (SJG; n = 13). Pre- and post-training, tests were conducted to assess measures of muscle power (countermovement jump, reactive strength index), speed (5 m, 20 m), change of direction (CoD), and sport-specific performance (maximal kicking distance). To establish the effect of the interventions on the dependent variables, a 2 (group: CMJG and SJG) × 2 (time: pre, post) ANOVA with repeated measures was determined for each parameter. Findings demonstrated a main effect of time for countermovement jump, reactive strength index, and maximal kicking distance (p 0.05; ES = 0.05). Overall, jump exercises which utilize the SSC seem to be more effective in improving measures of speed and muscle power performance in young athletes. However, jump exercises that do not involve the SSC appear to negatively affect CoD performance in young athletes.

Purpose: To analyze the effects of a 9-week plyometric training program on the sprint times (5, 10, 20, and 30 m), change-of-direction speed (modified T test and modified Illinois test), jumping (squat jump, countermovement jump, countermovement jump with arms, and horizontal 5-jump test), upper-body strength (right and left handgrip, back extensor strength, and medicine ball throw), and balance (Y and stork balance tests) of female handball players. Methods: Athletes were randomly divided into experimental (n = 21; age = 13.5 [0.3] y) and control (n = 20; age = 13.3 [0.3] y) groups. Training exercises and matches were performed together, but the experimental group replaced a part of their normal regimen by biweekly upper- and lower-limb plyometric training. Results: Both groups improved performance, but to a greater extent in the experimental group compared with controls for 20- and 30-m sprint times (Δ% = 9.6, P d = 0.557 and Δ% = 20.9, P d = 1.07, respectively), change of direction (T test: P d = 0.993 and Illinois test: P d = 0.769), vertical and horizontal jumping (P P P d = 1.07). Conclusions: A plyometric training program allows female junior handball players to improve important components of their physical performance.

Impaired balance and lower body weakness are the main causes of falls, which are considered to be the major cause of fractures and head injuries in the elderly and are recognised as a serious health problem. The aim of this study is to observe the effect of eccentric training, introducing new technologies (gliding discs), on body composition, lower body strength, balance and quality of life. A quasi-experimental study was carried out with 56 healthy participants who were divided into an experimental group (n = 31) who underwent the protocol consisting of 12 training sessions and a control group (n = 25) who did not undergo the training. Before and after the intervention, all participants underwent a measurement of body composition, the SJ jump, balance with accelerometry and quality of life with the Short Form 12 Health Survey. In the experimental group, statistically significant improvements were found in the variables balance and lower body strength. The application of this training protocol improves lower body strength and the ability to control balance in the adult population.

This study investigated the effect of 4 weeks of high-intensity interval training (HIIT) with specific techniques (TS-G) vs. repeated sprints (RS-G) and analyzed the inter-individual variability [classified into responders (Rs) and non-responders (NRs)] on sport-related fitness in taekwondo (TKD) athletes. Athletes of both genders (n = 12) were randomly assigned into TS-G and RS-G groups. Both groups trained 3 days/week for 4 weeks [two blocks of three rounds of 2 min of activity (4-s of all-out efforts with 28-s dynamical pauses) with 1 min of recovery in between and 5 min between blocks] during their regular training. The related sport fitness assessments included squat jump (SJ), countermovement jump (CMJ), multiple frequency speed of kick test (FSKTMULT), specifically total kicks and Kick Decrement Index (KDI), and 20-m shuttle run (20MSR). Relevant results indicate a significant effect of the time factor in both groups for SJ performance and a significant decrease for KDI in RS-G. In addition, an improvement in performance according to the effect size analysis in the TS-G in total kicks, KDI, and 20MSR. Complementarily, a higher proportion of athlete Rs was reported in TS-G vs. RS-G for SJ (50% vs. 30.3%, respectively), CMJ, and total kicks (16.6% vs. 0%). In conclusion, the addition to the regular training of a HIIT with specific-techniques and repeated-sprints associated with intervals and similar structure of the combat during 4 weeks of training can improve the concentric characteristics of lower limb performance, although they were not the sufficient stimuli in the other components of TKD-related fitness.

The difference between squat jump (SJ) and countermovement jump (CMJ), termed eccentric utilization ratio (EUR), is frequently suggested as an outcome that can be used in athletic training design. Unlike performance in SJ and CMJ, which is associated with sports performance, the association between EUR and sports performance is almost unexplored. This study aimed to investigate whether EUR is associated with performance in approach jump, linear sprint and change of direction (CoD) tasks in volleyball players. Forty-five male volleyball players performed SJ, CMJ, 25 m linear sprint, approach jump and two CoD tasks (505 test and modified T-test). EUR was calculated based on jump height, peak power, peak force and average power. SJ and CMJ variables showed moderate to high correlation with approach jump performance (r = 0.42–0.70), small correlation with modified T-test (r = 0.33–0.40) and small to moderate correlation with sprint time (r = 0.35–0.49). EUR showed only small associations with performance variables (r = 0.31–0.34). In all linear regression models with performance outcomes as dependent variables, the CMJ height was always the only statistically significant predictor. Our results support the recent arguments that the EUR offers limited insight into the neuromuscular capabilities of athletes.

Purpose The aim of this study is to determine and to compare the effect of sex differences in percentage of body fat on the strength and power performances of the legs and arms during short maximal exercise. Methods 72 male and 64 female students aged 20 to 23 years were enrolled in this study. After assessing their morphological characteristics (body mass, height and percentage of fat mass), a squat jump test (SJ), a 5 successive jump test (5JT), a hand gripping (HG) and back strength (BS) tests have been conducted for each subject. Male students were re-tested after being weighed down with a weight equivalent to the mean differences in body fat recorded between the two sexes in the form of a loaded worn vest. Results Male are 15.7% heavier and 7.4% taller and presented a percentage of fat mass (17.2 ± 1.8%) significantly (p Conclusion During short and maximal exercise, male performed better with their hands, back and legs than female students. Excess fat for female students has a disadvantageous effect on vertical and horizontal jumps performances. The persistence of sex differences after weighting of male students indicates that body fat is responsible for 30 to 70% of the observed differences between sexes performances and power outcomes during jump tests.

Background: Vertical jump height and body height are almost universally recognised as determinant factors in elite volleyball performance. Objective: The purpose of this study was to assess the correlation between basic anthropometric parameters (body height and body weight) and jumping performance in a group of 16 female volleyball players (age 19.14 ± 5.52 years, height 1.80 ± 0.06 m, weight 69.81 ± 6.85 kg) and in a control group of 15 female university students (age 22.90 ± 0.83 years, height 1.70 ± 0.05 m, weight 61.70 ± 8.23 kg). Methods: The Quattro Jump 9290BA force platform system (Kistler, Winterthur, Switzerland) was used to test jumping performance in single vertical jumps (squat jump, countermovement jump) and 45-s continuous jumps. In single jumps, jump height was analysed and during the 45-s continuous jumps the maximal and mean jump height, the average contact time and the fatigue index were evaluated. The efficiency of the conversion of mechanical work into mechanical energy at the moment of take-off was calculated. Results: No significant influence of body height and body weight was found in the jumping performance in the squat jump and countermovement jump. In continuous jumps, a significant correlation was found between body height and fatigue index in the volleyball players. In the control group, in most of the tests moderate correlation between body height and jump height was observed. In the volleyball players, rather low values of efficiency of take-off (23.67 ± 2.64%) were calculated. The values in the control group were even lower. Conclusions: Nowadays, many volleyball coaches choose individuals mainly according to body height, but it is important that the talent identification process should also consider jumping abilities in the simple jumps and in continuous jumps. All these parameters should help coaches choose the right players for the appropriate position and role in the team.

Body composition and power are impactful variables of athletic performance. However, few studies have assessed power and body composition changes from pre-, to mid-, to end-of-season in American Football linebackers. The purpose of this study was to determine how power and body composition respond to a competitive season in Division I Football Championship Series (FCS) American football linebackers. Participants (n=9; Age=19.7 ± 1.5 years; Weight=101.5±11.6 kg; Height=183.3±5.2 cm; [Body Fat percent (BF %) =21.31 ± 6.02%)] performed a Dual-Energy X-ray Absorptiometry (DXA) scan, and power was assessed via three vertical jumps and squat jumps at 40, 60, 80, and 100 kg at three time points: a) 1 week prior to their regular season, b) 2 days after the bye week in the middle of the season, and c) 1 week prior to the completion of the season. An Analysis of Variance (ANOVA) revealed no significant differences (p ≤ 0.05) in power or body composition. These results support past research, indicating power and body composition can be maintained throughout a competitive season. However, more research is needed to determine the optimal programming methods to maintain or improve athletic performance via optimization of body composition and power during a competitive season.

Una óptima selección deportiva está formada por la valoración del genotipo (dermatoglifía) y el fenotipo (somatotipo, composición corporal y capacidades físicas). El propósito del estudio fue determinar la relación entre la dermatoglifía y el perfil morfo-funcional en deportistas profesionales de futbol sala en la ciudad de Bogotá. La muestra estuvo conformada por 12 hombres, quienes fueron evaluados antropométricamente, con porcentaje graso de 18,4 ± 5,9; masa músculo-esquelética de 32,4 ± 4,4 kg y un somatotipo endo-mesomórfico. Por medio de la dermatoglifía se determinó predominancia en los diseños dactilares presilla (69,2±23,1), D10 (11,3±3,6), SQTL (140,7±95,1). Por último, se valoró la fuerza explosiva con la prueba de Squat Jump, en la cual la posición de poste logró mayor altura. En conclusión, existe una predisposición hacia las capacidades físicas de velocidad, potencia, coordinación y resistencia, además la fuerza explosiva es mayor en deportistas con menor valor en el componente endomórfico y en el porcentaje de masa grasa. An optimal sports selection is formed by assessment of genotype (dermatoglyph) and phenotype (somatotype, body composition and physical abilities). The purpose of the study was to determine relationship between dermatoglyphics and morpho-functional profile in professional futsal athletes in the city Bogotá. The sample consisted of 12 men, who were anthropometrically evaluated, with a fat % of 18,4 ± 5,9; a musculoskeletal mass of 32,4 ± 4,4 kg and endo-mesomorphic somatotype. Through of dermatoglyphics, predominance was determined in the fingerprint designs L (69,2 ± 23,1), D10 (11,3 ± 3,6), SQTL (140,7 ± 95,1). Finally, explosive force was assessed with the Squat Jump test, in which the post position achieved the greatest height. In conclusion, there is a predisposition towards the physical capacities of speed, power, coordination and resistance, in addition the explosive force is greater in athletes with a lower value in endomorphic component and in percentage of fat mass.

This study investigated the effects of flywheel inertia training (FIT) vs traditional resistance training (TRT) over four weeks in academy male rugby union (RU) players. Sixteen elite male academy RU players (age = 18.0 ± 1.0 years, body mass = 93.0 ± 13.1 kg) were allocated into either FIT (n = 8) or TRT (n = 8) groups. Pre and post measures of countermovement jump (CMJ), squat jump (SJ) and drop jump (DJ) were completed. Relative peak force (PF), relative peak power (PP) and jump height (H) were measured for CMJ and SJ with reactive strength index measured for the DJ. Both groups showed improvements in all measures, except for SJ peak power, following TRT. Within-group analysis showed significant increases following TRT in CMJ-H (2.79 cm, 90% CI = -0.70, 4.89 cm; p = 0.002; ES = 0.51) and SJ-H (3.68 cm, 90% CI = 1.25, 6.11 cm; p = 0.002; ES = 0.88) with a significant improvement following FIT for CMJ-PP (1.96Wkg-1, 90% CI = -0.89, 4.80 Wkg-1; p = 0.022; ES = 0.55). No significant between-group differences (p > 0.05) were evident. These findings suggest both FIT and TRT are effective for developing lower-body strength and power qualities in male academy RU players.

Traditionally, a larger difference between countermovement (CMJ) and squat jump (SJ) was seen as beneficial, as it reflects the ability to utilize the stretch-shortening cycle. However, strong arguments have been made that this might not always be the case, as larger differences between the jumps could also suggest higher muscle-tendon slack, or poor capability to take this slack up quickly. The purpose of this study was to explore SJ and CMJ, as well as the CMJ to SJ difference (CMJSJDiff) in 9 groups of young athletes. In total, 712 athletes from various disciplines (mean age range: 15.7–36.3 years) and 58 physical education students (mean age: 19.6 years) participated in the study. The major finding of this study was that the groups that showed better SJ and CMJ performance did not show the larger CMJSJDiff. For instance, SJ and CMJ heights were highest in short-distance runners and lowest in long-distance runners, while the largest and smallest CMJSJDiffwas shown in physical education students and speed skaters, respectively. Male athletes had a higher CMJSJDiffthan female athletes, but the difference was very small. While a larger CMJSJDiffhas been traditionally associated viewed as positive, our results could indicate both superior ability to utilize the stretch-shortening cycle, as well as poor ability of rapid force development and excessive muscle slack. Further studies are needed to directly investigate the associations between CMJSJDiffand indicators of athletic performance.

Introduction: Among the main challenges faced by coaches of team sports are to create an environment and conditions that will enable players to reach their optimal level of physical performance at the start of the competitive season, and to maintain this level throughout the season. Objective: The purpose of this study was to assess the effects of six weeks of additional training with 3-against-3 (3v3) small-sided games (SSG) on the physical performance of elite nonstarter basketball players. Methods: Eleven professional basketball players (five starters and six nonstarters) performed the same training program throughout the regular season, with the only difference that after each game, the starters (S) performed low intensity shooting drills while the nonstarters (NS) performed half-court 3v3 SSG. At the start and end of the six-week period, the athletes were assessed for muscle power, speed, agility and aerobic power. Two-way analysis of variance and effect sizes were used. Magnitude-based inferential analyses were used to complement the parametric tests. Results: After the six weeks, the S and NS showed improvement (p

BACKGROUND there is a paradox between the development of strength-power abilities and the high volume of technical/tactical training in elite soccer players during the pre-season. This concurrent effect between aerobic and neuromuscular training regimes induce impairment in power performance. METHODS this study aimed to investigate the effect of an equalized program of strength-power training (4-5 sessions/week) and soccer training (4-6 sessions/week) in power and aerobic performance during 8-weeks of pre-season in elite women soccer players. Vertical jumps [squat jump (SJ); countermovement jump (CMJ)] and Yo-Yo intermittent recovery level 1 test (YOYO-R1) were assessed pre- and post pre-season. A paired sample t-test was used to compare differences between pre and post pre-season (Δ%). The level of significance was established at p ≤ 0.05. RESULTS the women soccer players improved the SJ (p

Purpose: To analyze sex and age group differences in strength, jump, speed, flexibility, and endurance performances of TeamGym athletes.Methods: A total of 91 Swedish elite gymnasts (junior female, n = 26, age = 15.4 y; senior female, n = 23, age = 20.0 y; junior male, n = 19, age = 15.6 y; senior male, n = 23, age = 20.6 y) participated in three testing sessions on three separate days. These were: (1) a series of flexibility tests for the lower- and upper-body; (2) strength tests for the lower- and upper-body; and (3) various types of jumps, a 20-m sprint-run, and a 3,000-m run test.Results: Males were 24% stronger in the back squat one-repetition maximum (relative to body mass) compared to females (P < 0.001, Hg = 1.35). In the pull-ups and dips, 2.4 and 2.3 times more repetitions were completed by the males compared to the females (both P < 0.001, 0.70 ≤ R ≤ 0.77). However, females were similarly strong as males in the hanging sit-ups test (P = 0.724). The males jumped 29, 34, 33, and 17% higher in the squat jump (SJ), countermovement jump (CMJ), countermovement jump with arm swing (CMJa), and drop jump (DJ), respectively, compared to the females (all P ≤ 0.002, 0.14 ≤ ηp2 ≤ 0.60). In the 20-m sprint run, males were 4% faster than females (P < 0.001, R = 0.40). Moreover, the females had significantly better flexibility than the males in the trunk forward bending, front split, and side split tests (all P < 0.001, 0.24 ≤ ηp2 ≤ 0.54). In the 3,000-m run test, males were 11% faster than females (P < 0.001, ηp2 ≤ 0.54). Compared to junior athletes, seniors performed better in the pull-ups, dips, SJ, CMJ, CMJa, and 20-m sprint-run tests (all P ≤ 0.012, 0.31 ≤ R ≤ 0.56, 0.16 ≤ ηp2 ≤ 0.25), with separate within-sex age-group differences (i.e., juniors vs. seniors) that were significant for the males but not for the females in the SJ, CMJ, CMJa, and 20-m sprint-run tests (males: all P < 0.001, 0.67 ≤ R ≤ 0.69, 1.37 ≤ Hg ≤ 2.01; females: all P = 0.298–732).Conclusions: Large sex and age-group differences were observed for most physical performance metrics with specific within-sex age-group differences only observed for male athletes, with male seniors performing better than juniors in the SJ, CMJ, CMJa, and 20-m sprint-run tests.

Post‐activation potentiation (PAP) has been defined as a major enhancement of muscular performance following a preload stimulus. The eccentric actions seem to cause a potentiating effect on subsequent explosive exercises. The aim of this study was to determine whether a protocol of squat exercise using an inertial flywheel could have a potentiating effect on jump performance. Sixteen physically active volunteers participated in the study (age: 21.8 ± 2.7 years; body mass index: 23.6 ± 3). All participants completed two different protocols on separate days: a Traditional Protocol (using a half squat with a guided barbell) and an Inertial Flywheel Protocol (using a half squat with an inertial flywheel). Both protocols were similar and consisted of 3 x 6 reps at the load that maximized power, with a 3‐minute rest interval between sets. The squat jump (SJ) was measured by a contact platform at baseline, and four, eight and twelve minutes after the PAP stimulus. A two‐way ANOVA with repeated measures was performed to analyze significant differences over time. There were significant increases of SJ height (p = 0.004, d = 0.665), velocity (p = 0.003, d = 0.688) and power (p = 0.004, d = 0.682) from baseline after the inertial flywheel protocol. A significant interaction effect (time x protocol) was observed, showing that the inertial flywheel protocol had a potentiating effect on the jump performance compared to the traditional protocol, more specifically at 4 and 8 minutes after the PAP stimulus. In conclusion, the inertial flywheel protocol showed a potentiating effect on the squat jump performance, thus this pre‐ conditioning activity could be useful during the warm‐up before the competition.

Muscle strength and maximal speed are factors determining athlete’s results during competition. Their association with ACTN3 gene activity has been documented. The purpose of this study was the analysis of ACTN3 gene expression during a 2 month training cycle of soccer players and its correlation with the countermovement jump (CMJ) and squat jump (SJ). The study group consisted of 22 soccer players (aged 17‐18). The study material included peripheral blood lymphocytes. The relative expression (RQ) of the ACTN3 gene was analyzed by qPCR and performed before and after the two‐month training cycle. Before the training cycle low expression levels of ACTN3 (median RQ = 0.95) were observed, yet after the training cycle they were elevated (median RQ = 1.98) ( p = 0.003). There was an increase in performance of both jumps: SJ (p = 0.020) and CMJ (p = 0.012) at the end of the training cycle. A simultaneous increase in the ACTN3 gene expression level and height in both jump tests was observed in 73% of athletes (p > 0.05). There were no significant relationships between the ACTN3 gene expression level and the results of the CMJ and SJ. However, explosive strength is a complex feature shaped by many different factors and it could be the reason why we did not observe correlations between these variables.

The goal of this study was to assess the effects of a supervised slackline training program in a group of soccer players. Thirty-four male division I under-19 players (16.64 ± 0.81 years) agreed to participate in the study. They were randomly divided into an experimental group (EG) and a control group (CG). The first group (EG) followed a 6-week supervised slackline training program (3 sessions/week; 5-9 min/session), while the CG performed only regular soccer training. Several variables were assessed in all participants: acceleration (20-m sprint test), agility (90º turns test), jump performance (squat jump, countermovement jump), and postural control (Center of Pressure ( CoP) testing: length, area, speed, Xmean, Ymean, Xspeed, Yspeed, Xdeviation, Ydeviation). Ratings of perceived exertion and local muscle ratings of perceived exertions were also recorded after each slackline training session. At post-tests, there was a significant increase only in the EG in acceleration, agility, squat jump and countermovement jump performance, as well as several CoP variables: area in the bipedal support on a firm surface, and length, area and speed in the left leg on a firm surface. The program was rated as “somewhat hard” by the players, while quadriceps, gastrocnemius and tibialis anterior were the most exerted muscles while slacklining. In conclusion, slackline training can be an effective training tool for young, high-level soccer players.