Differences in anthropometric and vertical jump force-time characteristics between U16 and U18 female basketball players.

Considering the importance of body composition and lower-body strength and power for basketball players' on-court performance, as well as a lack of sports science research focused on female athletes, the purpose of the present investigation was to record the anthropometric and countermovement vertical jump (CMJ) characteristics of top-tier U16 and U18 female basketball players and examine between-group differences in the aforementioned tests. Thirty-two athletes who were a part of the national basketball academy volunteered to participate in the present investigation. Following the body composition assessment conducted via a segmental multifrequency bioimpedance analyzer, athletes performed three CMJs while standing on a force plate system sampling at 1000 Hz. Independent t-test and Mann-Whitney U-test were used to examine between-group differences. The findings reveal significant differences in body composition and lower-body neuromuscular performance characteristics between female basketball players ages 16 and 18. Although no differences were observed in muscle and body fat percentages, the U18 group had significantly greater height, overall body mass (both muscle and fat mass), as well as greater segmental fat-free mass (trunk, both legs and arms), intracellular and extracellular water, and body mass index when compared to their U16 counterparts. On the other hand, the U18 group demonstrated longer eccentric, concentric, and braking phase duration, as well as overall contraction time when compared to the U16 players. In addition, the U18 athletes exhibited higher eccentric mean force and power, concentric impulse, peak power, and mean and peak force.

Effects of the Flying Start on Estimated Short Sprint Profiles Using Timing Gates.

Short sprints are predominantly assessed using timing gates and analyzed through parameters of the mono-exponential equation, including estimated maximal sprinting speed (MSS) and relative acceleration (TAU), derived maximum acceleration (MAC), and relative propulsive maximal power (PMAX), further referred to as the No Correction model. However, the frequently recommended flying start technique introduces a bias during parameter estimation. To correct this, two additional models (Estimated TC and Estimated FD) were proposed. To estimate model precision and sensitivity to detect the change, 31 basketball players executed multiple 30 m sprints. Athlete performance was simultaneously measured by a laser gun and timing gates positioned at 5, 10, 20, and 30 m. Short sprint parameters were estimated using a laser gun, representing the criterion measure, and five different timing gate models, representing the practical measures. Only the MSS parameter demonstrated a high agreement between the laser gun and timing gate models, using the percent mean absolute difference (%MAD) estimator (%MAD < 10%). The MSS parameter also showed the highest sensitivity, using the minimum detectable change estimator (%MDC95), with an estimated %MDC95 < 17%. Interestingly, sensitivity was the highest for the No Correction model (%MDC95 < 7%). All other parameters and models demonstrated an unsatisfying level of sensitivity. Thus, sports practitioners should be cautious when using timing gates to estimate maximum acceleration indices and changes in their respective levels.

Application of a Reactive Agility Training Program Using Light-Based Stimuli to Enhance the Physical and Cognitive Performance of Car Racing Drivers: A Randomized Controlled Trial.

BACKGROUND: There is a need to develop strategies that could contribute to the physical and mental preparation of motorsport athletes. A common method used by experienced motorsport athlete physical trainers is flashing light devices to train or assess reactive agility, despite limited evidence. Therefore, in the present study, we determined the effects of a 6-week reactive agility training program using light-based stimuli on the physiological and cognitive abilities of car racing drivers. MATERIALS AND METHODS: The CONSORT guidelines for randomized controlled trial were used. In a single-blinded randomized controlled trial, 24 car racing drivers (EXP, n = 12; CON, n = 12) performed a comprehensive battery of cognitive tests marketed specifically at motorsport athletes from Vienna test system (VTS) at rest or during moderate intensity exercise on a bicycle. Physiological abilities were determined via a maximal incremental cardio-respiratory treadmill test. Baseline and post-intervention tests were performed on three consecutive days. Participants in EXP underwent a 6-week intervention consisting of 60-min training sessions twice a week using the Witty SEM light stimulus. RESULTS: Participants in EXP but not in CON performed some of the VTS cognitive tasks with higher accuracy and/or shorter reaction time after the intervention at rest and during exercise. Car racing drivers performed the STROOP word-reading condition more accurately when the task was performed during the exercise vs. rest, regardless of group. In addition, the intervention induced beneficial changes in peak heart rate (HR), HR at gas exchange threshold, ventilation, and relative maximal oxygen consumption (rVO2 max). In contrast, body mass and fat mass increased, while peak HR and rVO2 max decreased in CON. Finally, participants in EXP improved their reactive agility performance and reaction time throughout the training program. CONCLUSION: Overall, the reactive agility training program using light-based stimuli appeared to be efficient to induce beneficial effects on some physiological and cognitive performance measures; therefore, it may have the potential to contribute to car racing drivers' physical and mental performance.

Muscle activation history at different vertical jumps and its influence on vertical velocity.

In the present study we investigated displacement, time, velocity and acceleration history of center of mass (COM) and electrical activity of knee extensors to estimate the dominance of the factors influencing the vertical velocity in squat jumps (SJs), countermovement jumps (CMJs) and drop jumps (DJs) performed with small (40°) and large (80°) range of joint motion (SROM and LROM). The maximum vertical velocity (v4) was 23.4% (CMJ) and 7.8% (DJ) greater when the jumps were performed with LROM compared with SROM (p < 0.05). These differences are considerably less than it could be expected from the greater COM and knee angular displacement and duration of active state. This small difference can be attributed to the greater deceleration during eccentric phase (CMJ:32.1%, DJ:91.5%) in SROM than that in LROM. v4 was greater for SJ in LROM than for SJ in SROM indicating the significance of the longer active state and greater activation level (p < 0.001). The difference in v4 was greater between SJ and CMJ in SROM (38.6%) than in LROM (9.0%), suggesting that elastic energy storage and re-use can be a dominant factor in the enhancement of vertical velocity of CMJ and DJ compared with SJ performed with SROM.

The effects of vibration on explosive and reactive strength when applying individualized vibration frequencies.

The aim of this study was to assess the effects of 8 weeks of whole-body vibrations on explosive and reactive leg strength. Thirty-three physically active students took part in the study and were randomly assigned to an individualized-vibration group, a fixed-vibration group or a control group. The frequency of vibration was set to 30 Hz for the fixed-vibration group, whereas the frequency for the individualized-vibration group was determined by monitoring the participants' EMGrms activity. The participants in the two vibration groups were exposed three times a week for 8 weeks to a series of 10 x 1-min whole-body vibrations with a 1-min pause between series of vibrations and a 4-min pause after the first five series of vibrations. Jump height in the squat jump increased significantly in all three groups (by 11% for the individualized-vibration group, p=0.001; by 3% for the fixed-vibration group, p=0.011; and by 2% for the control group, p=0.006), but countermovement jump height was not affected. In continuous rebound jumps by the individualized-vibration group, jumping height increased by 22% (p=0.006) and power increased by 18% (p=0.002). The results of this study suggest that the use of an individualized vibration frequency produces a greater response from the neuromuscular system and is more beneficial than vibrations at a fixed pre-selected frequency.