Application of the Laser Linear Distance-Speed-Acceleration Measurement System and Sport Kinematic Analysis Software.

The industrial development of technology, with appropriate adaptation, enables us to discover possibilities in sport training control. Therefore, we have developed a new approach to linear running analysis. This study aims to determine the measurement possibilities using an LDM301A laser system in obtaining basic kinematic parameters. The second goal is the application of specialized computer programs based on appropriate algorithms to calculate a vast number of variables that can be used to adjust the training and the rivalry. It is a non-invasive, non-contact measurement method. We can also determine the influence of both subjective and objective external factors. In this way, we can also conduct training with real-time scientific feedback. This method is easy to use and requires very little time to set up and use. The efficiency and running economy can be calculated with various time, speed, acceleration, and length indexes. Calculating the symmetries between the left and right leg in velocity, stride lengths, support phase times, flight phase times, and step frequency are possible. Using the laser measurement method and detailed kinematic analysis may constitute a new chapter in measuring speed. However, it still has to compete with classic photocell measurement methods. This is mainly due to their high frequency of measurement used, despite some reservations about the scale of measurement errors.

Reliability of Sprint Force-Velocity-Power Profiles Obtained with KiSprint System.

This study aimed to assess the within- and between-session reliability of the KiSprint system for determining force-velocity-power (FVP) profiling during sprint running. Thirty (23 males, 7 females; 18.7 ± 2.6 years;) young high-level sprinters performed maximal effort sprints in two sessions separated by one week. Split times (5, 10, 20 and 30 m), which were recorded with a laser distance meter (a component of the KiSprint system), were used to determine the horizontal FVP profile using the Samozino's field-based method. This method assesses the FVP relationships through estimates of the step-averaged ground reaction forces in sagittal plane during sprint acceleration using only anthropometric and spatiotemporal (split times) data. We also calculated the maximal theoretical power, force and velocity capabilities and the slope of the FV relationship, the maximal ratio of horizontal-to-resultant force (RF), and the decrease in the RF (DRF). Overall, the results showed moderate or good to excellent within- and between-session reliability for all variables (ICC > 0.75; CV < 10 %), with the exception of FV slope and DRF that showed low relative reliability (ICC = 0.47-0.48 within session, 0.31-0.33 between-session) and unacceptable between-session absolute reliability values (CV = 10.9-11.1 %). Future studies are needed to optimize the protocol in order to maximize the reliability of the FVP variables, especially when practitioners are interested in the FV slope and DRF. In summary, our results question the utility of the sprint-based FVP profiling for individualized training prescription, since the reliability of the FV slope and D RF variables is highly questionable.

Are Change-of-Direction Speed and Reactive Agility Independent Skills Even When Using the Same Movement Pattern?

Coh, M, Vodicar, J, Zvan, M, Simenko, J, Stodolka, J, Rauter, S, and Mackala, K. Are change-of-direction speed and reactive agility independent skills even when using the same movement pattern? J Strength Cond Res 32(7): 1929-1936, 2018-The purpose of this investigation was to determine whether there are differences between the 2 approaches to quantifying agility (preplanned vs. unplanned response) when reacting to a stimulus in an identical spatial scenarios. The study involved 45 male and 31 female trained athletes (age 21.2 ± 1.78 and 20.6 ± 1.27 years, body height 181.6 ± 8.31 and 167.7 ± 5.03 cm, and body mass 78.9 ± 11.33 and 63.3 ± 8.65 kg, respectively). A light-based reactive training system was used to measure the time to completion in a task that assessed agility by change-of-direction speed (CODS) in a preplanned condition and reactive agility (RA) in an unplanned condition across 4 spatial configurations. Sprint performance in a 30-m sprint and lower limb reactive power in a 10-m single leg jump test was also measured. Significant differences (p ≤ 0.05) were found between men and women in all tests and between performance in the CODS and RA condition for each spatial configuration. Significant correlations were observed between 30-m starting sprint speed and CODS and RA performance measured in a semicircle (r = 0.62, r = 0.60) and lateral (r = 0.54, r = 0.58) configuration in male athletes. The present findings suggest that CODS and RA are 2 different and independent skill domains that define agility. These qualities should be diagnosed by discrete assessments and enhanced by different training methodologies.

The Relationship between 200 m Performance and Selected Anthropometric Variables and Motor Abilities in Male Sprinters.

The goal of this study was the investigation of the relationship between 200 m performance and motor abilities and anthropometric characteristics of different level of male sprinters (200 m performance 23.80 ± 2.16 s--the best results 21.40 s). The physical fitness measures included: 50 m from standing and flying start, standing long jump (SLJ) standing five jump (SFJ), double and single leg countermovement jumps CMJ), flexibility (sit and reach) and 4 kg shot put throwing (over head). The Spearman correlation coefficient was applied to verify the association. The results demonstrated strong relationships (p < 0.05) between 200 m performance and experience (age) and body mass (r = 0.85, r = -0.80 respectively) As for the motor abilities strong relationship exists between 200 m and time of 150 m, 50 m from standing and flying start and CMJ on single leg. Vertical jumping displayed stronger relationship with 200 m performance that horizontal one. From a practical point of view this is very important notice.

The Relationship between Selected Motor Ability Determinants and Anthropometric Characteristics in Adolescent Athletes from Various Sport.

The main purpose of this study was to examine the relationship between speed, lower extremities explosive power, simple, and complex responses in adolescent athletes from various disciplines. Thirty nine athletes of 16.5 years old, N = 13 sprinters and jumpers, N = 13 soccer players, and N = 13 judokas participated in the experiment. Pearson correlations, a one-way ANOVA and an independent t-test for establishing differences between those three groups of athletes was applied. Additionally the Ward method of hierarchical cluster analysis also was applied. The strong correlation occurred between complex responses and speed; 20 m from standing and 20 m flying start (r = 0.62 and r = 0.65 respectively). In other cases, no strong association was found. The substantial differences between groups occurred in the 20 m run from flying start (t = 5.92) and standing triple jump (t = 4.16). The study indicates that adolescent athletes may need to be assessed differently to a certain extent, including sport specialization.

Kinematic, Dynamic and EMG Analysis of Drop Jumps in Female Elite Triple Jump Athletes.

The purpose of the study was a biodynamic analysis of the kinematic, dynamic and EMG parameters of two types of drop jumps (heights of 25 cm and 45 cm). The sample of measured subjects included four female elite triple jump athletes, with their best results varying from 13.33 to 15.06 meters. The kinematic and dynamic parameters were calculated with the use of a bipedal tensiometric force plate, which was synchronized with nine CCD cameras. A 16-channel electromyography (BTS Pocket, Myolab) was used to analyze the EMG activation of the following muscles: m. erector spinae, m. gluteus, m. rectus femoris, m. vastus medialis, m. vastus lateralis, m. biceps femoris, m. soleus and m. gastrocnemius medialis. In the drop jump from a 25 cm height, the measured subjects achieved the following results: height of jump 43.37 ± 5.39 cm and ground reaction force 2770 ± 411 N. In comparison, results for the drop jump from a 45 cm height were: height of jump 45.22 ± 4.65 cm and ground reaction force 2947 ± 366 N. Vertical velocity of the take-off in the 25 cm drop jump was 2.77 ± 0.19 ms(-1) and in the 45 cm drop jump it was 2.86 ± 0.15 ms(-1). Observation of the EMG activation revealed the proximal to distal principle of muscle activation at work in both types of drop jumps. In the first phase of the concentric phase the most active muscles were m. gluteus maximus and m. rectus femoris. The greatest activity of m. gastrocnemius medialis and m. soleus was noticed in the last third of the take-off action. Significantly high EMG activation of m. vastus medialis and m. vastus lateralis was already shown in the flight phase prior to the feet making contact with the ground.

Differences between the elite and subelite sprinters in kinematic and dynamic determinations of countermovement jump and drop jump.

The aim of this study was to examine the relationship between selected variables of lower extremities explosive power measured via countermovement jump (CMJ) and drop jump (DJ) and sprinting ability over 60- and 100-m dash. Twelve national-level Slovenian sprinters were assigned to 2 groups: elite (n = 6) and subelite (n = 6). The grouping criterion was performance in 60 and 100 m in official competition. Biomechanical parameters of both jumps were measured with the use of bipedal force platform and a system of 9 infraspectral charge-coupled device (CCD) cameras with a 200 Hz frequency. Differences between the groups of sprinters were examined with the use of repeated-measures analysis of variance. In CMJ, the differences (p < 0.05) between the groups were revealed in take off velocity (elites = 3.23 m · s, subelites = 2.94 m·s), height of the jump, vertical velocity of body center of gravity, and the impulse of force in the concentric phase of the jump (concentric impulse: elites = 123.91 N · s; subelites = 108.06 N · s). In the DJ, elite and subelite sprinters differentiated in the realization of movement velocity in the eccentric and concentric phases (take off velocity: elites = 3.18 m · s, subelites = 2.87 m · s; eccentric velocity: elites = 3.05 m · s, subelites = 2.81 m · s). This investigation provides evidence that vertical jumps and DJs are very important tools to meet the demands of sprint training according eccentric-concentric muscular work. The DJ showed better quality than CMJ in the neuromuscular specificity.

Biomechanical analysis of squat jump and countermovement jump from varying starting positions.

The purpose of this study was to investigate the effect of 2 strategies, defined by foot placement during the initiation of the take-off on performance in vertical jumps. The additional area of interest in this experiment was whether technique of the take-off phase might be an exploratory factor that has different electromyogram (EMG) muscle activity during squat jump (SJ) and countermovement jump (CMJ) performed starting from the standard position, with parallel foot placement, and from the experimental one, with straddle foot placement. Six well-experienced male 100-400 m sprinters, who were members of the Polish youth and senior national team (mean values: age 21.6 years, best performance: 100 m in 10.54 seconds and 400 m in 45.54 seconds), performed vertical SJ and vertical CMJ from 2 initial positions with different foot placement. To collect all selected kinematic and kinetic data, the video recording system BTS Vixta was used in conjunction with force platforms (Kistler model 9286B). The latest system for 3D motion analysis, BTS SMART, based on the passive IR reflective markers was also applied. Electromyograms of 6 lower limb muscles were collected using a Noraxon EMG device. The CMJ was on average 7 cm higher than the SJ (CMJ, 85 cm and SJ, 78 cm), which amounts to 8.97%. This was not because of the increase of center of gravity (COG) velocity at take-off because velocities of center of gravity (COG) projection were almost equal (SJ, 2.93 m·scompared with CMJ, 2.99 m·s). No significant differences of both magnitude and rate of development of the muscle torques and powers between jumps were found, but when we analyzed the problem with division into single legs (right and left) and with division into different jumps (SJ and CMJ), the differences were evident. The profiles of EMG activity of selected muscles showed some differences between SJ and CMJ. The vertical SJ and CMJ performance measurement may be of value to coaches and conditioning specialists who wish to develop or assess the power ability of lower extremities either unilaterally (single leg) or bilaterally (sum of both legs).

Biomechanical analysis of standing long jump from varying starting positions.

The purpose of this study was (a) to investigate the effect of the different foot movement (placement) during take-off and the initial knee joint angle used in standing long jump by the ground reaction forces analysis and 3-dimensional motion analysis (BTS SMART motion) and (b) investigate how the jump performances of different foot placement is related to the electromyography (EMG) activity (Noraxon) of 3 selected muscle groups (m. gastrocnemius, m. gluteus maximus, m. rectus femoris, m. tibialis anterior, m. biceps femoris, and m. vastus medialis). Six high caliber sprinters (100 m: 10.87 ± 0.38 seconds and 400 m: 46.75 ± 1.05 seconds) performed a series of jumps from parallel and straddle foot placement at take-off on a 2 force platform (Kistler model 9286B) to determine if a different pattern of take-off improves jumping distance. Using kinematic and kinetic data, the knee joint angle, the trajectories of center of mass (COM), magnitude of take-off peak force, and impulse during take-off phase were calculated. Average standing long jump performances with straddle foot placement were 13.58 cm (5.18%) above that from parallel feet placement. The take-off velocity with 90° knee initial angle initiation of take-off was not different (1.18 and 1.17 m·s, respectively) between the 2 jumps. The take-off angles on the COM trajectory also showed differences (69.87 and 66.8°, respectively) between each other. The contribution (EMG activation) made by the 6 muscles were almost the same during all phases for the 2 jumps; however, some differences can be found, in either unilateral (single leg) or sums of both legs (bilateral) measurements. A recommendation can be formulated that the contribution of straddle foot placement during take-off can significantly increase the value of power measurement especially when the evaluation requires a complex movement structure with the division on the left and right legs, for example, sprint start from block.

Multicomponent Velocity Measurement for Linear Sprinting: Usain Bolt's 100 m World-Record Analysis.

The purpose of this report is to provide additional analysis and commentary on the men's 100 m world record of 9.58 s, set by Usain Bolt in the 2009 Berlin World Championships in Athletics. In addition, the entire race underwent a unique kinematic analysis, particularly emphasizing the maximum running velocity and its related factors. It was possible due the application of the new Stuhec software. The data were provided by LAVEG'S advanced laser measurement technology based on positional data with a high spatiotemporal resolution. The maximum velocity phase is the most critical determinant of the final race time. Bolt completed two phases in this world-record 100 m sprint: acceleration and top velocity. The borderline between these phases reached the highest velocity of 12.32 m/s on a 52 m run. He could keep the maximum velocity in five 10 m sections (50-100 m). The occurrence of functional asymmetry-the difference in step length between the left and right legs-was also noticed. Longer steps were taken with the left leg, almost over 80 m. From a practical point of view, new technologies (e.g., software) allow coaches and athletes to analyze the kinematic parameters of sprinting even more precisely and in detail. They must take into account precise changes in the course of maximum speed and the parameters determining it which are step length and frequency. Based on such an analysis, it is possible to modify the training process aimed at increasing the potential, both maximum speed and the supporting factors of strength and power. This must be conditioned by the appropriate selection of training measures shaping the abovementioned motor skills and parameters describing the optimal sprinting technique.

Correction: Mackala et al. Evaluation of the Pre-Planned and Non-Planed Agility Performance: Comparison between Individual and Team Sports. Int. J. Environ. Res. Public Health 2020, 17, 975.

Jozef Simenko was not included as an author in the original publication [...].

Temporal and Spatial Characteristics of Pacing Strategy in Elite Women's 400 Meters Hurdles Athletes.

The main objective of the study was to assess the pacing strategy of running 400 m hurdles of the world-level female athletes over the past 40 years based on the functional asymmetry -temporal and spatial characteristics. The data were collected from 1983 to 2019 using the review of scientific literature. Over the 35 years of the study, 37 top-level competitions with 283 finalists-competitors were included. The analysis of the 400 m hurdle covered mainly spatial and temporal factors of the run, related to those technical skills, the level of motor skills, and somatic structure. In addition to the basic statistics, the ANOVA analysis of variance, regression analysis, Pearson correlation, the principal component analysis (PCA), and Kaiser's criterion was used for the multivariate analysis. The final result in the 400 mH run is determined not by the simple sum of the individual temporal and/or spatial characteristics of the run (the number of steps, the type of attacking leg, but their interaction in the area of functional asymmetry. The decisive factor in the 400 mH run strategy is the second curve, where the emphasis is on the optimal setting of the stride pattern in the context of minimizing the loss of running speed. Additionally, the application of multidimensional statistical methods is a valuable tool that allows to significantly deepen the interpretation of the obtained results, and thus optimize a strategy for a 400 mH run.

Effects of Combined Plyometric and Shooting Training on the Biomechanical Characteristics during the Made Jump Shot in Young Male Basketball Players.

(1) Background: Shooting performance is one of the most important determinants of basketball success and is strongly influenced by vertical jump performance. A lot of research attention has been paid to training programs that may improve the vertical jump. However, the literature regarding the improvement of accuracy during the jump shot is limited. The aim of this study was to determine the effects of the combination of two training programs on explosive power of the lower extremities during the made jump shot. (2) Methods: A total of 61 male basketball players were assigned into training group (T, n = 31, age 15.32 ± 0.65) which was conducting a specific, i.e., experimental training program, and control group (C, n = 30, age 16.3 ± 0.71 years) involved in a regular training program. The experimental training program included specific plyometric training with shooting training which lasted for 10 weeks. The obtained data were processed by nonparametric statistics to determine the differences in the vertical jump outcomes, as well as to determine the level of impact of the experimental training program. Wilcoxon and Kruskal-Wallis tests were used. (3) Results: A significant improvement (p ≤ 0.05) was noticed in the T group, in every vertical jump variable (flight time, height of the jump, power, and speed of the jump during a jump shot for two and three points), while there was no improvement within the C group. (4) Conclusions: The combination of plyometric and shooting training has a positive impact on the explosive power of the lower extremities during the jump shot.

Gender-Related Differences in Mechanics of the Sprint Start and Sprint Acceleration of Top National-Level Sprinters.

(1) Background: Within the current study we aimed at exploring gender-related differences and the relationship between sprint start block kinematics and kinetics and sprint acceleration force-velocity (F-v) relationship parameters (maximal force [F0], maximal velocity [v0], maximal power [Pmax] and slope) in top national-level sprinters. (2) Methods: Twenty-eight sprinters (6 females) performed 10 maximal 30-m sprints. Start block and acceleration kinematics and kinetics were collected with an instrumented sprint start block and a laser distance sensor (KiSprint system). Displacement-time data were used to determine the F-v relationship through Samozino's method. (3) Results: Start block rear foot maximal force (effect size [ES] = 1.08), rate of force development (ES = 0.90-1.33), F0 (ES = 1.38), v0 (ES = 1.83) and Pmax (ES = 1.95) were higher in males than in females (p ≤ 0.05). There were no differences in the slope, and ratio of horizontal-to-resultant force. F0, v0, and Pmax generally presented higher correlations with the start block kinetics (median r [range] = 0.49 [0.28, 0.78]) than with the kinematics (median r [range] = -0.27 [-0.52, 0.28]). (4) Conclusions: We confirmed that sprint block phase and sprint acceleration mechanics should be mutually assessed when analyzing sprinting performance. KiSprint system could provide more accurate information regarding mechanical pattern and technique during sprint initiation and acceleration, and potentially help create a more personalized and effective training program.

The Effect of Height on Drop Jumps in Relation to Somatic Parameters and Landing Kinetics.

The aim of this study was to assess the effect of drop height and selected somatic parameters on the landing kinetics of rebound jumps in force and power production, performed by male and female student athletes. Twenty female and forty male students with a sports background participated in the experiment (mean and standard deviation (± SD): age 20.28 ± 1.31 years, height 166.78 ± 5.29 cm, mass 62.23 ± 7.21 kg and 21.18 ± 1.29, 182.18 ± 6.43, 78.65 ± 7.09). Each participant performed three maximal jumps on two independent and synchronized force platforms (Bilateral Tensiometric Platform S2P) at each of the two assigned drop-jump heights (20-, and 40-, cm for female and 30-, and 60-, cm for the male special platform). Significant between-sex differences were observed in all variables of selected somatics, with men outperforming women. Statistically significant differences were noted in four parameters, between men and women, in both DJs from 20/40 and 30/60 cm. The height of the jump was 6 cm and 4 cm higher for men. A slightly higher statistical significance (p = 0.011) was demonstrated by the relative strength (% BW) generated by the left limb in both men and women. Only women showed a significant relationship between body mass, body height, and five parameters, dropping off of a 20 cm box. In men, only the left leg-relative maximal F (p =-0.45)-showed a relationship with body mass. There were no relationships between the above-mentioned dependencies in both groups, in jumps from a higher height: 40 cm and 60 cm. From a practical application, the DJ with lower 20/30 cm or higher 40/60 cm (women/men) respectively emphasizes either the force or power output via an increase in the velocity component of the rebound action or increased height of the DJ jump.

Evaluation of the Pre-Planned and Non-Planed Agility Performance: Comparison between Individual and Team Sports.

This study assessed differences in agility performance between athletes of team and individual sports by assessing change-of-direction speed (CODS) as pre-planned agility and reactive agility (RA) as non-planed in different spatial configurations. The study involved 36 individual (sprint, hurdles, jumping, tennis, and judo) and 34 team (soccer, basketball, and handball) athletes. CODS and RA were measured with a light-based reactive training system in a frontal (FR), universal (UN), semicircular (SC), and lateral (LA) design. Lower limb power and sprint performance were also measured in a 10 m single leg jump test and 15 m sprint. Individual athletes showed significantly better performance in three of the eight agility tests: LA-RA, UN-RA, and SC-CODS (p < 0.008, p < 0.036, and p < 0.027, respectively) and were found to present stronger correlations (p < 0.01) between jump test performance and the CODS condition. Team athletes showed stronger associations between sprint performance and the CODS condition. In the RA condition both jump and sprint performance showed stronger correlations in the group of individual athletes. Agility performance as measured by CODS and RA should improve with enhanced of motor proficiency. Finally, the tests applied in this experiment seem to be multidimensional, but require spatio-temporal adjustment for their implementation, so that they meet the requirements of the particular sport.

Can infrared thermography be used to monitor fatigue during exercise? A case study.

BACKGROUND: Infrared thermographic imaging (IRTG) is a safe and reliable technology used to monitor skin temperature. The main aim of our study was to evaluate the relationship between skin temperature changes and muscle fatigue in order to answer the main research question if IRTG can be used to monitor muscle fatigue. METHODS: This was a case study performed on a 23-year-old trained middle distance runner. After warm-up the subject was exercising on the dynamometer for 7.5 min at 120°/s performing only concentric contractions of quadriceps. At the same time IRTG recording of both (exercising and non-exercising) quadriceps was performed. RESULTS: A correlational analysis that was performed in order to quantify the relationship between power and temperature change over time has shown that there is a significant negative correlation between skin temperature increase and power decrease (r = -0.543, p = 0.036) of exercising quadriceps. In linear regression model the exercising quadriceps power could be predicted from skin temperature. No such relationships were noted for the non-exercising limb that served as a control. CONCLUSION: We believe that correlation between skin temperature change and muscle power output as described in this case study deserves further analysis on the larger sample including subjects of the different ages, health status, and physical abilities in order to create a new tool for monitoring the muscle fatigue.

The Effect of Respiratory Muscle Training on the Pulmonary Function, Lung Ventilation, and Endurance Performance of Young Soccer Players.

This study investigated whether the addition of eight weeks of inspiratory muscle training (IMT) to a regular preseason soccer training program, including incremental endurance training (IET), would change pulmonary function, lung ventilation, and aerobic performance in young soccer players. Sixteen club-level competitive junior soccer players (mean age 17.63 ± 0.48 years, height 182 ± 0.05 cm, body mass 68.88 ± 4.48 kg) participated in the study. Participants were randomly assigned into two groups: experimental (n = 8) and control (n = 8). Both groups performed regular preseason soccer training, including endurance workouts as IET. In addition to this training, the experimental group performed additional IMT for eigght weeks with a commercially available respiratory muscle trainer (Threshold IMT), with a total of 80 inhalations (twice per day, five days per week). Pre- and post-intervention tests of pulmonary function, maximal inspiratory pressure, and the Cooper test were implemented. Eight weeks of IMT had a positive impact on expiratory muscle strength (p = 0.001); however, there was no significant effect on respiratory function parameters. The results also indicate increased efficiency of the inspiratory muscles, contributing to an improvement in aerobic endurance, measured by VO2max estimated from running distance in the cardiorespiratory Cooper test (p < 0.005).

Comparative biomechanical analysis of the rotational shot put technique.

The study aimed to establish the modalities of the rotational shot put technique of two elite shot putters with substantially different constitutional characteristics. A biomechanical analysis of the technique was carried out using the APAS 3-D kinematic system, whereby a 15-segment model of shot putters was defined by 18 reference points. To enable the calculation of the kinematic and dynamic parameters, independent routines were programmed by the Matlab software. Anthropometric characteristics were established on the basis of 15 variables measured by the International Biological Programme (IBP) procedure. The results of the study revealed some differences between the athletes in terms of their mesomorphic constitutional component, body mass index, circular measures of the lower and upper extremities and the muscular, fat and bone mass. The technique models of both shot putters differ mostly in terms of the following kinematic and dynamic parameters: absolute release velocity, height of release, maximum angular velocity of the elbow of the throwing arm, trajectory of the centre of gravity of the body and the shot, torsional rotation of the shoulder axis relative to the hip axis, maximum force applied to the shot, kinetic energy and the kinetic energy differential of the shot.

Gender-related differences in maximum mechanical power output in short-term activities in children and adolescents.

The study was designed to examine the gender-related differences in maximum mechanical power output in various short-burst activities during growth. The subject sample consisted of four subgroups: 9 boys (14.11 +/- 0.6 yr), 9 boys (10.67 +/- 0.71 yr), 7 girls (14.29 +/- 0.49 yr), 7 girls (10.57 +/- 0.54 yr). We measured peak power (PP), mean power (MP), fatigue index (FI) during 30-s WAnT, squat jump height (SJH) and power (SJP), and counter movement jump height (CMJH) and power (CMJP), maximum speed over 20-metre distance (S20). Lactation concentration was measured in the 3rd and 5th minutes after the WAnT Ratio normalisation and ANCOVA were used to remove the influence of the differences in muscle (MM) and body mass (BM). Male adolescents had higher absolute values of PP (P < 0.05), MP (P < 0.05) than female. Ratio normalisation showed that boys had higher PP/BM (P < 0.05), PP/MM (P < 0.05), MP/BM (P < 0.05), MP/MM (P < 0.06) than girls. The ANCOVA adjustment for MM showed differences between genders in PP (P < 0.001), MP (P < 0.001), SJH (P < 0.05), SJP (P < 0.05) and CMJP (P < 0.001), whereas the ANCOVA adjustment for BM showed differences only in PP (P < 0.001), MP (P < 0.001). Prepubertal boys had higher absolute values only in SJP (P < 0.05). We concluded that variations in body composition could not be the only key to gender-related differences in power output in short-burst activities.