This study examined the acute potentiating effects of heavy sprint-style sled pulls on sprint performance. Twenty-two experienced resistance-trained rugby athletes performed 2 heavy sprint-style sled pull training protocols on separate occasions using a randomized, crossover, and counterbalanced design. The protocols consisted of 2-baseline 15 m sprints followed by 15 m sprints at 4, 8, and 12 minutes after completing 15 and 7.5 m heavy sled pulls with loads of 75 and 150% body mass (respectively). A significantly faster (p ≤ 0.05) 15 m sprint time was observed at 12 minutes for the 75% body mass load. Small nonsignificant improvements (effect size [ES] = 0.22–0.33) in 5, 10, and 15 m sprint times were observed at 8 and 12 minutes after the 75% body mass sled pull. No significant changes were observed for any sprint time after the 150% body mass sled pull. Significant differences in the percentage of change in sprint times between the 2 sled pull conditions were observed at 4 (ES = 0.44–0.52), 8 (ES = 0.59), and 12 minutes (ES = 0.64). It would seem that the 75% body mass sled pull can be an effective preload stimulus for improving subsequent sprint performance provided that adequate recovery (8–12 minutes) is allowed. Practitioners should be advised that prescription of training load based on decrement in sprint velocity may be the best approach to determine loading for athletes.
Available at: http://works.bepress.com/justin_keogh/96/