Short- or long-rest intervals during repeatedsprint training in soccer?

Abstract The present study compared the effects of two repeated-sprint training (RST) programs, differing in duration of the between-sprint rest intervals, on various soccer-related exercise performances. For 5 weeks during the competitive season, twenty-nine young trained male soccer players either replaced two of their habitual fitness conditioning sessions with RST characterized by short (5\u201315; n = 9) or long (5\u201330; n = 10) rest intervals, or served as control (n = 10). The 5\u201315 and 5\u201330 protocols consisted of 6 repetitions of 30-m (~5 s) straight-line sprints interspersed with 15 s or 30 s of passive recovery, respectively. 5\u201315 improved 200- m sprint time (2.0\ub11.5%; p<0.05) and had a likely positive impact on 20-m sprint performance, whereas 5\u201330 lowered the 20-m sprint time (2.7\ub11.6%; p<0.05) but was only possibly effective for enhancing the 200-m sprint performance. The distance covered during the Yo-Yo Intermittent Recovery Test Level 2 increased following 5\u201315 (11.4\ub15.0%; p<0.05), which was possibly better than the non-significant 6.5% enhancement observed in 5\u201330. Improvements in the total time of a repeated-sprint ability test were possibly greater following 5\u201330 (3.6\ub10.9%; p<0.05) compared to 5\u201315 (2.6\ub11.1%; p<0.05). Both RST interventions led to similar beneficial (p