A group-enhanced sprint interval training program for amateur athletes.

Sprint interval training (SIT) can elicit improvements in aerobic and anaerobic capacity. While variations in SIT protocols have been investigated, the influence of social processes cannot be overlooked. As research supports the use of groups to influence individual cognitions and behaviours, the current project assessed the effectiveness of a group-based intervention with participants conducting SIT. Specifically, 53 amateur athletes (age, 21.9 ± 2.9 years; 53% females) took part in a 4-week training program (3 sessions per week, 30-s "all-out" efforts with 4 min active recovery, repeated 4-6 times per session), and were assigned to "true group", aggregate, or individual conditions. Results indicated no significant differences between groups for the physiological measures. With regards to training improvements from baseline for all participants- regardless of condition - significant main effects for time were identified for maximal oxygen uptake (2.5-2.8 mL·kg(-1)·min(-1), p < 0.001, η(2) = 0.03), time-trial performance (14-32 s, p < 0.001, η(2) = 0.37), and anaerobic power (1.1-1.7 k·h(-1), p < 0.001, η(2) = 0.66). With regards to the psychological measures, significant main effects between groups were found for motivation (p = 0.033, η(2) = 0.13), task self-efficacy (p = 0.018, η(2) = 0.15), and scheduling self-efficacy (p = 0.003, η(2) = 0.22). The true group experienced greater improvements in motivation than the individual condition, but the aggregate and individual conditions demonstrated greater increases in task and scheduling self-efficacy. Though the SIT paradigm employed induced training improvements similar to previous work, the group intervention was not able to further these improvements.