Uniform Homeostatic Stress Through Individualized Interval Training Facilitates Homogeneous Adaptations Across Rowers With Different Profiles

Physiological and performance adaptations to beta alanine supplementation and short sprint interval training in volleyball players

This study aimed to elucidate the impact of combining Beta-Alanine (BA) supplementation with short sprint interval training on cardiorespiratory fitness, anaerobic power, and bio-motor abilities in volleyball players. Twenty young male athletes were randomly divided into 2 equal groups and performed 8 weeks of short sprint interval training while supplementing 4.8 g daily BA or placebo (polydextrose). The players were evaluated for volleyball-specific bio-motor abilities (vertical jump, horizontal jump, spike jump, block jump, 10-m linear sprint, and T-test change of direction speed) and physiological parameters (cardiorespiratory fitness and anaerobic power) pre- and post-intervention. Both groups demonstrated significant (p ≤ 0.05) improvements in all measured variables over time. A time-regimen interaction was observed in jumping ability enhancement from pre- to post-training, wherein BA elicited more significant changes in both vertical and horizontal jumps compared to the placebo. Analyzing residuals in changes and the coefficient of variations (CV) in mean group changes demonstrated that BA supplementation results in uniformly inducing adaptive changes among individuals. Therefore, in light of these results, it is recommended that coaches and trainers take into consideration the utilization of BA as an ergogenic aid to enhance the vertical and horizontal jumps of volleyball players and increase the homogeneity in adaptive responses over the training period.

Optimal homeostatic stress to maximize the homogeneity of adaptations to interval interventions in soccer players

This study examined the uniformity of adaptations in cardiorespiratory fitness and bio-motor abilities by analyzing individual responses to measures representing the mentioned qualities. Twenty-four male well-trained soccer players (Age = 26 ± 4 years; stature = 181 ± 3.8; Weight = 84 ± 6.1) were randomized to two groups performing short sprint interval training [sSIT (3 sets of 10 × 4 s all-out sprints with 20 s of recovery between efforts and 3 min of rest intervals between sets)] or a time-matched small-sided game [SSG (3 sets of 3 v 3 efforts in a 20 × 15 m area with 3 min of relief in-between)]. Before and after the 6-week training period, aerobic fitness indices, cardiac hemodynamics, and anaerobic power were assessed through a graded exercise test utilizing a gas collection system, noninvasive impedance cardiography, and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring linear speed, change of direction, and jumping ability. Comparing inter-individual variability in the adaptive changes by analyzing residuals in individual adaptations indicated that sSIT induces more uniform changes in the first and second ventilatory threshold (VT1 & VT2), stroke volume, and peak power output across team members than SSG. SSG also yielded lower proportions of responders in V ˙ O 2 ⁡ max , VT1, VT2, peak, and average power output compared to sSIT. Additionally, the coefficient of variation in mean group changes in measures of aerobic fitness and bio-motor abilities in response to sSIT were lower than in SSG. Short sprint interval training induces more homogenized adaptations in measures of cardiorespiratory fitness and anaerobic power than small-sided games across team members.