Measuring intermittent exercise performance using shuttle running

The aim of this study was to include self-paced exercise within a modified Loughborough Intermittent Shuttle Test (LIST-P) in order to quantify key performance variables not possible with prescribed workloads. Sixteen male games players performed two trials of the LIST-P, at least 7 days apart. The LIST-P incorporates 4x15-min blocks of "prescribed-pace" activity (participants exercise in time to audible signals) followed by 2x15-min blocks of "self-paced" running (no audible signals). Distances covered and mean speeds were monitored during self-paced exercise. Total distance covered (12.54 +/- 0.45km vs. 12.64 +/- 0.32km; P=0.10) and mean speed (8.37 +/- 0.31 km center dot h(-1) vs. 8.44 +/- 0.22 km center dot h(-1); P=0.10) was similar between trials. Other indices also showed the test to be reliable (Pearson's correlation=0.89 and 0.90 (P<0.01), total distance and mean speed, respectively; intraclass correlation coefficient=0.88 and 0.88 (P<0.01); standard error of measurement=+/- 0.13km and +/- 0.09 km center dot h(-1); coefficient of variation (CV)=1.7% and 1.7%; ratio limits of agreement=1.00 */divided by 1.03 and 1.01 */divided by 1.04). Sprint time was also similar between trials (2.60 +/- 0.19s vs. 2.64 +/- 0.23s; P=0.29). Incorporating self-paced exercise within an established intermittent shuttle running test appears to be a sensitive means of quantifying key performance variables for multiple-sprint sports research.