Altering Work to Rest Ratios Differentially Influences Fatigue Indices during Repeated Sprint Ability Testing

La Monica, MB, Fukuda, DH, Beyer, KS, Hoffman, MW, Miramonti, AA, Riffe, JJ, Baker, KM, Fragala, MS, Hoffman, JR, and Stout, JR. Altering work to rest ratios differentially influences fatigue indices during repeated sprint ability testing. J Strength Cond Res 30(2): 400-406, 2016-This study examined the influence of recovery time on fatigue indices, performance (total work [TW], peak power [PP], and mean power [MP]), and oxygen consumption during repeated sprint ability (RSA) on a cycle ergometer. Eight recreationally-Trained men performed 3 RSA protocols consisting of 10 × 6 s sprints with 12 s, 18 s, and 24 s rest intervals between each sprint. Fatigue indices were determined as percent decrement (%Dec) and rate of decline using either a log transform method or standard slope approach for TW, PP, and MP during respective RSA protocols. The maximal Vo 2 value in response to given sprint intervals and the minimal Vo 2 value in response to given rest periods (Vo 2 work and Vo 2 rest, respectively) were recorded. A repeated measures analysis of variance was used to analyze all variables. Average Vo 2 work was not different among rest interval trials. Average Vo 2 rest with 12 s rest was greater than 18 s and 24 s (2.16 ± 0.17 L·min-1, 1.91 ± 0.18 L·min-1, 1.72 ± 0.15 L·min-1, respectively), while 18 s was greater than 24 s. Average TW and MP were greater with 24 s rest than 12 s (4,604.44 ± 915.98 J vs. 4,305.46 ± 727.17 J, respectively), with no differences between RSA protocols for PP. No differences in %Dec were observed. Both methods of calculating rates of decline per sprint for PP and TW were greater during 12 s than 18 s or 24 s. Since changes were only noted between the 12 s and 24 s protocols, a 6 s differential in rest intervals may not be enough to elicit alterations in TW, PP, MP, or %Dec in RSA performance. Rate of decline may be a more sensitive measure of fatigue than %Dec.