Effects of a Flexible Workout System on Performance Gains in Collegiate Athletes.

ABSTRACT: Walts, CT, Murphy, SM, Stearne, DJ, Rieger, RH, and Clark, KP. Effects of a flexible workout system on performance gains in collegiate athletes. J Strength Cond Res 35(5): 1187-1193, 2021-Although research on the topic of periodization is abundant, investigations into different flexible periodization strategies in collegiate athletes are limited. Furthermore, how state of readiness (SOR) and workout autonomy affect training improvements is largely unknown. Therefore, the purpose of this study was to determine if a flexible periodization (FP) program would elicit significantly greater performance gains compared with a nonflexible periodization (NP) program (significance set p ≤ 0.05). A total of 32 male and female intercollegiate lacrosse players completed performance measures of vertical jump, sprinting speed, change of direction, and strength in bench press and deadlift. After pretesting, subjects were matched and randomly assigned to either FP (n = 17, age = 19.4 ± 1.4 years, height = 1.72 ± 0.10 m, mass = 72.29 ± 13.73 kg) or NP (n = 15, age = 19.9 ± 1.5 years, height = 1.72 ± 0.08 m, mass = 71.68 ± 13.55 kg) training groups. Both groups trained 3 days per week for 8 weeks. The NP group completed all workout volume and intensity as prescribed by a certified strength and conditioning coach. However, the FP group modified workout volume and intensity based on a daily SOR questionnaire. Although appreciable pretest to posttest improvements were observed for the entire subject cohort, multivariate analysis of variance (ANOVA) and a series of ANOVA tests demonstrated no statistically significant between-group differences for pretest to posttest changes on any of the performance tests (range of p values: 0.17-0.95). Although FP does not seem to be more effective than NP for eliciting performance gains, it may provide greater opportunities for autonomy while eliciting equivalent improvement levels. Therefore, flexible periodization based on SOR may be a viable training strategy.

The longitudinal effects of resisted sprint training using weighted sleds vs. weighted vests.

The purpose of this study was to determine the longitudinal effects of weighted sled (WS) and weighted vest (WV) sprint training on maximum velocity sprint performance and kinematics. Twenty male collegiate lacrosse players were randomly assigned to a WS group (n = 7) towing 10% body mass, a WV group (n = 6) loaded with 18.5% body mass, or an unresisted (UR) active control group (n = 7). All subjects completed 13 training sessions over 7 weeks. Pre- and post-test measures of sprint time and average velocity across the distance interval of 18.3 to 54.9 m were used to assess sprint performance, whereas high-speed video (300 Hz) and motion-analysis software were used to analyze stride length, stride rate, ground contact time, and flight time. A 3 × 2 repeated measures analysis of variance was performed for each dependent variable and revealed no significant between-group differences for any of the sprint performance or kinematic stride cycle measures. Effect size statistics suggested small improvements in 18.3- to 54.9-m sprint time and average velocity for the UR group but only trivial improvements for the WS and WV groups. With regard to sprint performance, the results indicate that WS and WV training had no beneficial effect compared with UR training. In fact, for the loads used by WS and WV in this study, UR training may actually be superior for improving sprint performance in the 18.3- to 54.9-m interval.

Do sex or race differences influence strength training effects on muscle or fat?

PURPOSE: To examine the influence of sex and race on the effects of strength training (ST) on thigh muscle volume (MV), midthigh subcutaneous fat (SCF), and intermuscular fat (IMF). METHODS: One hundred eighty-one previously inactive healthy Caucasian (N = 117) and African American (N = 54) men (N = 82) and women (N = 99), aged 50-85 yr, underwent about 10 wk of unilateral knee extension ST. Ten subjects were neither Caucasian nor African American and were, therefore, not included in the race analysis. Quadriceps MV and midthigh SCF and IMF cross-sectional area were measured with computed tomography before and after ST. Sex and race comparisons were made with a 2 x 2 (sex by race) analysis of covariance. RESULTS: Training-induced increases in absolute MV were significantly greater (P < 0.001) in men than in women, though both sex groups increased MV significantly with ST (P < 0.001), and the relative (%) increases were similar. There were significant increases in MV within race groups (P < 0.001), but no significant differences between races. There were no significant changes in SCF or IMF, whether sex and racial groups were separated or combined. In addition, there was no sex by race interaction for changes in MV, SCF, or IMF with ST. CONCLUSION: Strength training does not alter subcutaneous or intermuscular fat, regardless of sex or racial differences. Although men exhibit a greater muscle hypertrophic response to strength training than do women, the difference is small. Race does not influence this response.