Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strength training with 3 sets of 10-12 repetitions with 2-3 minutes rest between sets. All groups were measured before and after the 12-week period with; dynamic leg press and seated-row 6-repetition maximum (6-RM) and functional capacity tests (30-second chair stands and arm curl test, Timed Up and Go), as well as whole-body skeletal muscle mass (SMM) (kg) and fat mass (FM-kg, FM%) assessed by bioelectrical impedance (BIA). Basal blood samples (in the intervention groups only) taken before and after the intervention assessed low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), blood glucose (GLU), triglycerides (TG), high-sensitive C-reactive protein (hsCRP) concentrations and total antioxidant status (TAS) after a 12 h fast. Hormone analysis included prolactin (PRL), progesterone (P) estradiol (ESTR), testosterone (T), follicle stimulating hormone (FSH), and luteinizing hormone (LH). While C showed no changes in any variable, both M and E significantly improved leg press (+ 46 ± 22% and + 21 ± 12%, respectively; p < 0.001) and seated-row (+ 48 ± 21% and + 42 ± 18%, respectively; p < 0.001) 6-RM, as well as all functional capacity outcomes (p < 0.01) due to training. M were the only group to increase muscle mass (+ 3 ± 2%, p < 0.01). Both M and E group significantly (p < 0.05) decreased GLU (-4 ± 6% and -8 ± 10%, respectively), whereas significantly greater decrease was observed in the E compared to the M group (p < 0.05). Only E group significantly decreased TG (-17 ± 25%, p < 0.01), whereas M group increased (+ 15%, p < 0.01). The difference in TG between the groups favored E compared to M group (p < 0.01). These results suggest that short-term "hypertrophic" ST alone mainly improves strength and functional capacity performance, but it influences metabolic and hormonal profile of healthy older women to a lesser extent. In this group of previously untrained older women, time-of-day did not have a major effect on outcome variables, but some evidence suggests that training in the morning may be more beneficial for muscle hypertrophy (i.e. only M significantly increased muscle mass and had larger effect size (M: g = 2 vs. E: g = 0.5).

The purpose of the study was to determine the acute responses to a jump squat protocol designed to induce postactivation potentiation on sprint running performance in experienced track and field athletes and soccer players. Twenty-five regional level athletes (12 track and field: ∼17 years; ∼177 cm; ∼73 kg and 13 soccer: ∼18 years; ∼175 cm; ∼72 kg) performed 2 test sessions assessing 40-m sprint running performance in a balanced, crossover design. Dual-beam light timing gates measured 0-20 and 20-40 m sprint times before and after either 9 minutes of sitting (control) or 2 sets of 6 repetition half-squat jump with the load eliciting maximum power (experimental) conditions. Sprint performance was significantly enhanced over both 0-20 m (3.09 ± 0.07 to 3.04 ± 0.08 seconds; Δ ∼1.5%; p ≤ 0.05) and 20-40 m (2.42 ± 0.09 to 2.39 ± 0.09 seconds; Δ ∼1%; p ≤ 0.05) in track and field athletes only. Also, the magnitude of enhanced sprint performance was related to baseline 0-20 m sprint performance (r = 0.44; p = 0.028; n = 25). It seems that using loaded half-squat jumps to enhance sprint performance could be used in training of high-level young athletes.

The purpose of this study was to evaluate differences in multiple athletic performances, and to examine associations between athletic performance and Functional Movement Screen (FMS) in young soccer players. Forty-one soccer players were tested on peak height velocity (PHV), 5-, 10-, and 30-m sprint times, 505 change of direction (505 COD), Y-reactive agility tests, countermovement jump (CMJ), and squat jump (SJ) height. Significant main effects ( P <0.01) were recorded in all tests except FMS total score whereas the U16 group outperformed U12 and U14 in almost each test. However, when the results were adjusted to the PHV 7 of 11 tests were nonsignificant. Significant associations were recorded between trunk stability push-up (TSPU) and 5 m ( P =0.04) and 505 COD (preferred) times ( P =0.01), and SJ height ( P =0.03) in the U12. In the U14, significant associations were recoded between TSPU and SJ ( P <0.01) and CMJ height ( P =0.03). In the U16, significant associations were recorded between deep overhead squat and 5-m sprint time ( P =0.02) and CMJ height ( P =0.04). Results of this study indicate that athletic performance in young soccer players is multidimensional in nature, and it is a consequence of several factors including maturation, different training strategies, and movement proficiency.

Krčmár, M, Krčmárová, B, Bakaľár, I, and Šimonek, J. Acute performance enhancement after squats combined with elastic bands on short sprint and vertical jump height in female athletes. J Strength Cond Res 35(2): 318–324, 2021—The main purpose of this study was to compare back squats with and without elastic bands on sprint and vertical jump height. Fourteen female athletes (21.9 ± 2.3 years; 177.5 ± 6.36 cm; 66.2 ± 6.2 kg; 1 repetition maximum [1RM]/ body mass: 1.96 ± 0.14) agreed to participate. On 4 separate days, athletes walked freely for 5 minutes (CON), performed 3 sets of 4 repetitions at 85% of their 1RM with 20% or 30% (BAND20 or BAND30) of the total resistance originated from elastic bands, or performed 3 sets and 4 repetitions at 85% of their 1RM with an isoinertial load (ISO) before performance tests. Posttesting began 5 and 10 minutes after the last set of squats and included sprints over 3, 5, and 10-m, squat jump (SJ), and countermovement (CMJ) vertical jump height. The results of this study show that all postactivation performance enhancement (PAPE) protocols significantly improved 10-m sprint time (p < 0.05 to p < 0.01). Only BAND30 significantly improved 3-m and 5-m sprint times at both times of posttesting (p < 0.01). Comparison of PAPE protocols showed a significant difference when comparing BAND30 vs. ISO in SJ height in favor of BAND30 only when the best SJ height results from both posttesting times were selected (p < 0.01, g = 1.08). The results of this study suggest that all PAPE protocols were able to enhance short sprints and vertical jump height, but it seems that there is a greater trend to achieve better performance after performing the BAND30 protocol that can be seen by higher effect sizes achieved almost in all tests compared with the other PAPE protocols.

This study investigated the effects of instantaneous performance feedback during the jumpsquat exercise over a 6-week training period. Twenty-five strength-trained athletes were randomly divided into an instant feedback (n = 13, half-squat 3-RM/body weight = 2.38 ± 0.19) or a non-feedback (n = 12, half-squat 3-RM/body weight = 2.03 ± 0.44) group. Both groups performed the same training program (3×week), consisting of 4 sets of 8 repetitions (weeks 1-3) and 8 sets of 4 repetitions (weeks 4-6) using a barbell with a load that maximized the average concentric power output (Pmax) of each athlete. Subjects in the instant feedback group were given real-time data after each repetition. Pre-, mid-, and post-training testing consisted of maximum 20m, 30m and 50m running speed, 3-RM back half-squat load, Pmax and the load that maximized average concentric power output (Pmax load), countermovement (CMJ) and squat jump (SJ) height. Results revealed that the feedback group significantly improved all selected tests versus non-feedback (time×group interaction, p<0.01). Significant improvements post-training for 20m, 30m, 50m, 3-RM load, Pmax load, CMJ and SJ were observed in the feedback group only (p<0.01). Training without instant feedback did not lead to significant performance improvements, this group actually demonstrated significant decreases in SJ and Pmax (W) and Pmax load (p<0.05). The results of this study indicate that the use of instant feedback during jump-squat training in athletes was beneficial for improving multiple performance tasks over 6-weeks of training. Instant feedback is an important element of power training to maximize adaptations when training strength-trained athletes.