Search Results

Purpose: The present intervention study examined the effects of intensity-matched velocity-based strength training with a 10% velocity loss (VL10) versus traditional 1-repetition maximum (1RM) based resistance training to failure (TRF) on 1RM and maximal oxygen uptake ( $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}$ ) in a concurrent training setting. Methods: Using the minimization method, 21 highly trained rowers (4 females and 17 males; 19.6 [2.1] y, 1.83 [0.07] m, 74.6 [8.8] kg, $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}:64.9[8.5]\mathrm{mL}·{\mathrm{kg}}^{-1}·{\text{min}}^{-1}$ ) were either assigned to VL10 or TRF. In addition to rowing endurance training (about 75 min·d ⁻¹), both groups performed strength training (5 exercises, 80% 1RM, 4 sets, 2–3 min interset recovery, 2 times/week) over 8 weeks. Squat, deadlift, bench row, and bench press 1RM and $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}$ rowing-ergometer ramp tests were completed. Overall recovery and overall stress were monitored every evening using the Short Recovery and Stress Scale. Results: Large and significant group × time interactions (P < .03, ${\mathit{\eta }}_{\mathrm{p}}^2>.23$ , standard mean differences [SMD] > 0.65) in favor of VL10 (averaged +18.0% [11.3%]) were observed for squat, bench row, and bench press 1RM compared with TRF (averaged +8.0% [2.9%]). $\dot{\mathrm{V}}{\mathrm{O}}_2\text{max}$ revealed no interaction effects (P = .55, ${\mathit{\eta }}_{\mathrm{p}}^2=.01$ , standard mean difference < .23) but large time effects (P < .05, ${\mathit{\eta }}_{\mathrm{p}}^2>.27$ ). Significant group × time interactions (P = .001, ${\mathit{\eta }}_{\mathrm{p}}^2>.54$ , SMD > |0.525|) in favor of VL10 were also observed for overall recovery and overall stress 24 and 48 hours after strength training. Conclusions: VL10 serves as a promising means to improve strength capacity at lower repetitions and stress levels in highly trained athletes. Future research should investigate the interference effects of VL10 in strength endurance sports and its effects when increasing weekly VL10 sessions within one macrocycle.

Purpose: To assess the short-term reliability of measurement instruments to quantify the acute psychophysiological response to load in adolescent soccer players in relation to biological maturity. Methods : Data were collected from 108 U12 to U17 soccer players on 2 consecutive weeks (pre, n = 32; at, n = 34; and post, n = 42 estimated peak height velocity). Measurements consisted of the Short Recovery and Stress Scale, a countermovement jump, assessment of leg stiffness, and a submaximal run to assess exercise heart rate and heart rate recovery. Test–retest reliability was assessed with the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Results : Items of the Short Recovery and Stress Scale showed poor reliability across maturity groups (CV = 7.0%–53.5%; ICC = .28 to .79). Only few countermovement jump variables (jump height, concentric impulse, and concentric velocity) possessed good reliability. For most variables of the countermovement jump, reliability was better for the post peak height velocity group followed by at-peak height velocity and prepeak height velocity. Very high levels of reliability across maturity groups were observed for exercise heart rate (CV < 1.8%; ICC > .94), while heart rate recovery was more variable (CV < 16.5%; ICC > .48). Conclusion : Results suggest that the majority of investigated variables have poor reliability, questioning their ability to detect small, yet meaningful changes in acute responses to load in adolescent soccer players.

Purpose: Cold-water immersion is increasingly used by athletes to support performance recovery. Recently, however, indications have emerged suggesting that the regular use of cold-water immersion might be detrimental to strength training adaptation. Methods: In a randomized crossover design, 11 participants performed two 8-week training periods including 3 leg training sessions per week, separated by an 8-week “wash out” period. After each session, participants performed 10 minutes of either whole-body cold-water immersion (cooling) or passive sitting (control). Leg press 1-repetition maximum and countermovement jump performance were determined before (pre), after (post) and 3 weeks after (follow-up) both training periods. Before and after training periods, leg circumference and muscle thickness (vastus medialis) were measured. Results: No significant effects were found for strength or jump performance. Comparing training adaptations (pre vs post), small and negligible negative effects of cooling were found for 1-repetition maximum (g = 0.42; 95% confidence interval [CI], −0.42 to 1.26) and countermovement jump (g = 0.02; 95% CI, −0.82 to 0.86). Comparing pre versus follow-up, moderate negative effects of cooling were found for 1-repetition maximum (g = 0.71; 95% CI, −0.30 to 1.72) and countermovement jump (g = 0.64; 95% CI, −0.36 to 1.64). A significant condition × time effect (P = .01, F = 10.00) and a large negative effect of cooling (g = 1.20; 95% CI, −0.65 to 1.20) were observed for muscle thickness. Conclusions: The present investigation suggests small negative effects of regular cooling on strength training adaptations.