Resisted Sprint TrainingKey Points: Resisted sprint training (RST) can be effective for improving certain sprinting qualities, mainly acceleration over shorter distances. (10% reduction in sprinting speed) is that the mechanics of the sprint may be changed too much leading to alterations in sprint technique when the athlete goes back to sprinting un-weighted. In general on one side you have sprint or track coaches who fear this will be the case, while on the other hand you have strength and conditioning coaches who view heavy sled dragging or pushing as an excellent way to develop strength in the muscles important for sprinting in a semi specific way, which when combined with regular sprint training will deliver a nice transfer effect. This method is essentially turning resisted sprint training into using heavy sled dragging as a developmental strength exercise. Track coaches and sprint coaches will probably argue about this for a long time, especially until more research with elite athletes is released. For now the best we can do is look at the evidence there is to date.

Kawamori et al (2013) investigated the effects of an 8 week training programme on club level players which implemented two sessions per week. One group sprinted with a sled that reduced sprint velocity by 30% (heavy group) while another group sprinted with a load that reduced sprint velocity by 10% (light group). The average weight on the sled was 33kg and 11kg respectively. After 8 weeks of training the heavy group reduced 0-5m time by an average of 5.7% and 0-10m time by 5.0%. The light group only significantly improved in the 0-10m time, by 3%. The heavy group also increased stride length by 8.1%, whereas no significant change was seen in the light group. Interestingly the heavy group showed a significantly larger decrease in vertical and resultant impulse, while neither group had a significant change in horizontal impulse. This is contrary to the popular belief that sled dragging would be an effective way to increase horizontal GRF during acceleration. The authors in this study suggest that learning how to apply force in a more horizontal direction, than actually applying more horizontal force was the critical ingredient for the favourable changes seen in the heavy group, and that this could make the heavy sled dragging as much technique work as it is strength work. While the results of this study look promising, it is the first paper to examine a sled load of this magnitude and its effect on acceleration so more research is needed before a conclusion can be drawn.

Follow up & Practical Applications:

Resisted sprint training combined with regular sprint training may provide an advantage compared to sprint training alone for athletes trying to improve acceleration. This is useful particularly for field or court sport athletes who generally sprint short (0-30m) distances during a game play. In my opinion this type of training adaptation may also be useful for athletes who have to break tackles. If the increase in acceleration speed is due to more powerful hip, knee and ankle extension I think a case can be made that athlete will be harder to stop during game play. 100m sprinters who struggle out of the blocks may also find this method useful for improving the first 30m. It must be noted however that just because professional rugby players saw an increase in performance that the same results may not be seen in track sprinters. A study using a similar procedure to West (2013) but using high level track sprinters would certainly be interesting and I am sure it will be done in the future. (If somebody reading this knows of one please let me know in the comments section below).

Maximum velocity running is technically and physiologically different to acceleration and is worthy of a separate article which may be written in the future. Maximum velocity and acceleration training require different training strategies. While resisted sprint training has been shown by certain studies to be effective for improving acceleration, regular sprint training has been shown to increase performance over slightly longer distances after the initial acceleration phase is completed. (20m-40m, Zafeiridis 2005). This was also shown in to be the case in Alcaraz et al (2012), the resisted sprint group improved acceleration, while the regular sprint training group improved during the maximum velocity phase. No combined groups were used in either of the latter two studies.

In conclusion resisted sprint training combined with regular sprint training is likely an excellent way to improve acceleration, while regular sprint training seems to have more potential for increasing maximal velocity. There is however plenty of scope for further research in this area including more combined resisted & regular sprint groups, more studies with elite athletes, and also using track athletes as opposed to field sport athletes.

References:

Alcaraz, P. E., Elvira, J. L. L. and Palao, J. M. (2012), Kinematic, strength, and stiffness adaptations after a short-term sled towing training in athletes. Scandinavian Journal of Medicine & Science in Sports. doi:10.1111/j.1600-0838.2012.01488.x

Hyrsomallis, C. (2010) The effectiveness of resisted movement training on sprinting and jumping performance, Journal of Strength and Conditioning Research, 26(1), 299-306.

Kawamori, N., Newton, R.U., Hori, N., Nosaka, K. (2014) Effects of weighted sled towing with heavy versus light load on sprint acceleration ability Journal of Strength and Conditioning Research, Published ahead of print.

Lockie, RG, Murphy, AJ, and Spinks, CD. (2003) Effects of resisted sled towing on sprint kinematics in field-sport athletes, Journal of Strength and Conditioning Research 17(4), 760767, 2003.

Spinks, C.D, Murphy, A.J, Spinks, W.L, and Lockie, R.G (2007) The effects of resisted sprint training on acceleration performance and kinematics in soccer, rugby union, and Australian football players, Journal of Strength and Conditioning Research, 21(1), 77-85.

West, D.J, Cunningham, D.J, Bracken, R.M, Bevan, H.R, Crewther, B.T, Cook, C.J, and Kilduff, L.P (2013) Efects of resisted sprint training on acceleration in professional rugby union players, Journal of Strength and Conditioning Research, 27(4), 1014-1018.

Zafeiridis, A, Saraslanidis, P, Manou, V, Ioakimidis, P, Dipla, K, and Kellis, S. (2005) The effects of resisted sled-pulling sprint training on acceleration and maximum speed performance, Journal of Sports Medicine and Physical Fitness, 45, 284290, 2005.