Repeated-sprint performance, locomotor profile and muscle oxygen uptake recovery: effect of training background.

The aim of the present study was to examine the respective importance of locomotor profile and muscle oxygen uptake (mV(˙)O₂) recovery on repeated-sprint ability (RSA) and overall repeated-sprint performance. 11 sprint- (STR) and 10 middle-distance-trained (MDTR) athletes (20.8±4.0 yr) performed an incremental test and a 40-to-50-m sprint to estimate their maximal aerobic (MAS) and sprinting (MSS) speeds. They also performed 6×30-m sprints, departing every 30 s, where mean (RS(mean)) sprint time was calculated. Muscle oxygenation (Near-infrared spectroscopy, NIRS, [Hb(diff)]) was measured for ~ 4 min post test. The mean response time of [Hb(diff)]-mV(˙)O₂ recovery (monoexponential curve fitting, MRT[Hb(diff)]-mV(˙)O₂) was calculated. Compared with MDTR, STR presented faster MSS (+11.4±6.7%, with 99% chances to observe a substantially greater value) and RS(mean) (-3.7±5.4%, 78%), but slower MAS (-15.8±8.0%, 100%) and MRT[Hb(diff)]-mV(˙)O₂ (+46.2±31.7%, 96%). RS(mean) was largely correlated with MSS [r=-0.83 (90%CL, -0.92;-0.67)], but neither with MAS [r=-0.12 (-0.47;0.25)] nor MRT[Hb(diff)]-mV(˙)O₂ [r=-0.27(-0.58;0.11)]. RS(mean) adjusted for MSS (which indirectly reflects RSA) was largely correlated with both MAS [r=0.51(0.18;0.74)] and MRT[Hb(diff)]-mV(˙)O₂ [r=0.53(0.20;0.75)]. While a fast mV(˙)O₂ recovery is associated with an improved RSA, MSS remains of primary importance for overall repeated-sprint performance (i.e., RS(mean)).