Post-activation potentiation: is there an optimal training volume and intensity to induce improvements in vertical jump ability in highly-trained subjects?

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nevertheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols

Influence of an Enforced Fast Start on 10-km-Running Performance

The effects of an enforced fast-start on long distance performance are controversial and seem to depend on the athlete’s capacity to delay and tolerate metabolic disruption. The aim of this study was to investigate the effects of an enforced fast-start on 10-km running performance and the influence of the some physiological and performance variables on the ability to tolerate an enforced fast-start during the running. Fifteen moderately-trained runners performed two 10-km time-trials: free-pacing (FP-TT) and fast-start (FS-TT). During FS-TT, speed during the first kilometer was 6% higher than in FP-TT. Maximal oxygen uptake (VO2max), peak velocity (PV), velocity associated with VO2max (vVO2max), ventilatory threshold, and running economy (RE) at 10 km·h-1, 12 km·h-1 and FP-TT average velocity (AV-10 km) were individually determined. There were no differences between FP-TT and FS-TT performance (45:01 ± 4:08 vs 45:11 ± 4:46 min:s, respectively, p=0.4). We observed that eight participants improved (+2.2%) their performance and were classified as positive responders (PR) and seven decreased (-3.3%) performance and were classified as negative responders (NR). Running speed was significantly higher for PR between 6 km and 9.2 km (p<0.05) during FS-TT. In addition, PR presented higher PV (p=0.02) and vVO2max (p= 0.01) than NR, suggesting the PV and vVO2max might influence the ability to tolerate a fast-start strategy. In conclusion, there was an individual response to the enforced fast-start strategy during 10-km running, and those who improved performance also presented higher vVO2max and PV, suggesting a possible association between these variables and response to the strategy adopted

The effects of training volume and repetition distance on session rating of perceived exertion and Internal load in swimmers

To assess swimmers' session rating of perceived exertion (sRPE) after standardized sets of interval swimming training performed at the same relative intensity but with different total volume and repetition distance. Thirteen moderately trained swimmers (21.1 +/- 1.1 y, 178 +/- 6 cm, 74.1 +/- 8.3 kg, 100-m freestyle 60.2 +/- 2.9 s) performed 4 standardized sets (10 x 100-m, 20 x 100-m, 10 x 200-m, and 5 x 400-m) at the same relative intensity (ie, critical speed), and 1 coach (age 31 y, 7 y coaching experience) rated their efforts. Swimmers' sRPE was assessed 30 min after the training session. Coach sRPE was collected before each training session. Internal load was calculated by multiplying sRPE by session duration. Results: When bouts with the same repetition distance and different volumes (10 x 100-m vs 20 x 100-m) are compared, sRPE and internal load are higher in 20 x 100-m bouts. When maintaining constant volume, sRPE and internal load (20 x 100-m, 10 x 200-m, and 5 x 400-m) are higher only in 5 x 400-m bouts. The coach's and swimmers' sRPE differed in 10 x 200-m and 5 x 400-m. These results indicate that sRPE in swimming is affected not only by intensity but also by volume and repetition distance. In addition, swimmers' and the coach's sRPE were different when longer repetition distances were used during training sessions. Therefore, care should be taken when prescribing swimming sessions with longer volume and/or longer repetition distances10784885