One of the commonly debated topics of sports performance training is whether or not athletes should use resisted sprint training, such as sled pulls, in their training programs. Today we’ll look at a study that compared the effects of resisted and non-resisted acceleration sprint training in Rugby players. First we will go over the study and then talk a bit about the implications for us as athletes. If after this you’d like to learn more about resisted sprint training, I’d suggest you take a look at my video on this topic from a couple years ago.
In this study titled The Effects of Sprint vs. Resisted Sled-Based Training; an 8-Week in-Season Randomized Control Intervention in Elite Rugby League Players by Johnathan Sinclair, Christopher Edmundson, John Matcalfe, Lindsay Bottoms, Stephen Atkins, and Ian Bentley, the athletes were split up into two groups, one that used sleds in their sprinting and one that sprinted without resistance. The sled load used decreased 10m sprint times by 20%, which was based on the authors’ previous work titled “Effect of velocity-based loading on acceleration kinetics and kinematics during sled towing.”
The athletes sprinted twice per week at the beginning of their gym training sessions, performing 4x submaximal warm up sprints, 2x maximal warm up sprints, and then 2 sets of 4 sprints with 2 minutes rest between sprints, and 3 minutes rest between sets. The rest of the training the athletes performed was the same, such as their strength training and sport technique related sessions.
After the first four week block, sled loads were reassessed to make sure they still caused a 20% decrement in 10 meter sprint time. In the first block of training the sled loads equated to around 25% +/- 3.4% bodyweight, and 26.9% +/- 4.6% body mass in the second block of training.
After 8 weeks of training, the study authors looked at how sprints at 5m, 10m, and 20m were affected, as well as the athletes’ countermovement jump and 5-0-5 shuttle times.
Both resisted and unresisted sprint training groups show significant improvement in their 5m, 10m, and 20m sprint times, but there was no significant difference between the two groups in their outcomes. There appeared to be a trend toward faster times in the resisted sprint training group, such as 0.99 vs 0.97 to 5m, 1.74 vs 1.70 to 10m, and 2.99 vs 2.94 to 20m, but this was not statistically significant.
Interestingly, there were statistically significant differences between groups in the countermovement jump and 5-0-5 agility tests, with the resisted sprint training groups showing greater improvements in countermovement jump and agility testing as compared to the unresisted sprint training group. The resisted sprint training group showed an average improvement in CMJ of 3.58cm, whereas the unresisted sprint training group only improved their CMJ by an average of 0.31cm, which is essentially one tenth of the improvement of the resisted sprint training group. In the agility test, the resisted group showed an improvement of 0.06 seconds, with the unresisted group improving by an average of 0.03 seconds.
While the differences between groups were non-significant as it relates to the improvements in sprinting performance, the fact that the resisted sprint training group improved in all tests goes to show that resisted sprint training is a useful training method for athletes who want to improve overall athletic performance and not just sprinting performance.
Because of the force and power demands of resisted sprinting, athletes can use sled sprints or other resisted sprinting methods to target both sprint specific performance and more general qualities like vertical jumping or agility. Considering that training time and the energy available for training are limited, we should do our best to use training methods that are both effective and efficient with their use of time and energy. If we can make the same or better improvements in acceleration with resisted sprint training, while at the same time positively impacting our general force and power outputs, it would make sense to use resisted sprint training in our programs.
One thing to consider here is that the results of the study were determined by tests performed at 4 and 8 weeks, which may not coincide with the time points at which the athletes would have seen their performance peak. If you train for 8 weeks and your body is fatigued from the training load, it is possible that you would perform better if given a week or two to deload before testing the athletes in a less fatigued state. The authors suggest that research should be done to look at results between groups at different time points so that performance changes can be tested both during and after periods of high training load.
How Can You Benefit From This Information?
For us as athletes, I think this research offers some evidence that sprinting with a sled or some other form of resistance is worth trying, seeing as the resisted sled group did not perform any worse than the unresisted group, their sprint performances trended toward faster times albeit in a non-statistically significant manner, and because sled training appears to positively affect more than just your ability to sprint.
It may be possible that, when using sleds, we can spend less time on weight room exercises dedicated toward power and high velocity strength. Because resisted sprinting with a sled combines a sprinting stimulus with a power output stimulus, we can hit two birds with one stone and have a more efficient training program with regards to energy and fatigue management.
You should consider using resisted sled training in your program, either on its own or in combination with unresisted sprints, and see how your body responds. At the very least it should not hurt your acceleration, will probably help it, and it might also help your overall athletic abilities including countermovement jump height and agility performance. Even though as sprints we do not jump or exhibit agility in our competitions, we definitely should aim to be the best athletes we can be overall. If you play other sports, such as football or rugby, then this overall improvement in athleticism is even more important due to the nature of these sports.