Repeated sprint training: The effects of session volume on acute physiological, neuromuscular, perceptual and performance outcomes in athletes

We examined the effects of repeated sprint training (RST) session volume on acute physiological, neuromuscular, perceptual and performance outcomes. In a randomised, counterbalanced, and crossover design, 14 healthy and trained male and female athletes (age: 23 ± 3 years) completed two sets of 10 × 40 m (10 × 40), 5 × 40 m (5 × 40), 10 × 20 m (10 × 20) and 5 × 20 m (5 × 20) sprints with 30 s rest between repetitions and 3 min rest between sets for all protocols. Average and peak heart rate, average oxygen consumption (VO₂), time >90% of maximal oxygen consumption (VO_2max), differential ratings of perceived exertion (RPE), session-RPE training load (sRPE-TL), percentage sprint decrement (S_dec), acceleration load and distance >90% of maximal sprint speed were recorded during each session. Neuromuscular performance (i.e. countermovement jump, lower-limb stiffness and isometric hamstring strength) were measured post-session, 24 h, and 48 h and compared to pre-session. A univariate analysis of variance was used to compare within- and between-protocol differences. To aid data interpretation, all effects were expressed as an effect size and accompanied by probability values (p_MET). The 10 × 40 protocol induced the greatest training load compared to all other protocols (p_MET < 0.05), including moderate to very large differences in breathlessness RPE, large differences in S_dec and time >90% VO_2max and very large differences in sRPE-TL. The 5 × 20 protocol induced the lowest training load compared to all other protocols (p_MET < 0.05), including moderate to large differences in sRPE-TL and leg muscle RPE. Heart rate, VO₂, sRPE-TL, leg muscle RPE and S_dec were similar between 5 × 40 and 10 × 20 (p_MET < 0.05), but the acceleration load was greater for 10 × 20 when compared to 5 × 40 (p_MET < 0.001), and this difference was large. Changes in neuromuscular performance across all timepoints and all protocols were unclear. Larger session volumes increase the demands of RST and by manipulating volume, sprint distance and the number of repetitions, practitioners can alter the internal and external training load.