Is Resisted Sprint Training Effective?

Coaches in sports requiring  high acceleration and all-out sprint speed have increasingly endorsed sprint training resisted by a variety of means including weighted vests, towed weighted sleds, long elastic cords, or straps for towing another individual. Yet there have been few studies examining the effectiveness of such training. A recent study by Clark et al. in the Journal of Strength and Conditioning Research evaluated the effectiveness of two types of resisted sprint training.

Experimental Procedure
There were 3 groups of  collegiate lacrosse players that trained twice a week for 7 weeks as follows:

• Weighted Sled: 7 of the subjects trained while towing 10% of their bodyweight in a sled
• Weighted Vest: 6 of the subjects wore vests containing 18.5% of their bodyweight
• Unresisted: 7 of the subjects did not use any resistance device during their training

For all groups, each training session consisted of 7-10 sprint intervals of 20-60 yards (18.3-54.9 m) separated by rest intervals of 3-4 minutes. Both before and after training, all subjects were tested as to their sprint-speed over 40 yards (36.6 m) after a 20-yard (18.3 m) running start.

Results
For the subjects as a whole, there was significant reduction (-1.1%) in the time taken to sprint 40-yards. However, there was no significant difference in improvement between any of the training groups. However, the percentage of improvement of the unresisted training group (-2.0%) was greater than for the weighted sled group (-0.1%) or the weighted vest group (-1.2%).

Bottom Line
The fact that the number of subjects in each group was relatively low made it difficult to obtain statistically significant differences in improvement between groups. However, it does appear that the resisted training was no more effective than unresisted training for improving 40-yard sprint speed following a running start. Because the timed portion of the sprints followed a running start in this study, the results do not address the effectiveness of resisted sprint training for improving the initial acceleration phase of a sprint.