The transfer of training is a major concern of most strength & conditioning coaches when it comes to exercise selection. It is very easy to improve the strength of most athletes and have them lift more weight in the gym. What is more difficult is to make sure that this improved strength results in an improved performance on the field.
When it comes to improving speed an often used training method is resisted sprint training. Many coaches use resisted sprint training in the belief that it bridges the gap between weight room activities and actual sprinting.
On the flip side, there are coaches who will stay well clear of this type of training in the fear of it confusing neural patterns.
The attempt to perform the exact same movement that is used in competition, but with added resistance, is a contentious issue in the world of sports performance training. This type of training, where the two movements look almost identical, has been termed mimicry training. The term mimicry training has negative connotations, since it is believed such techniques can negatively affect the neural patterns in the competitive movement.
So how can we make sure that we do not fall into the trap of mimicry training when using resisted sprint training methods?
A good starting point would be to take a look at some of the research out there regarding the determinants of sprinting performance.
It has been shown that maximum sprinting speed is dependant on the ability to produce a large vertical ground reaction force in a short period of ground contact (Weyand et al., 2000). This finding alone gives us a big clue as to what types of resisted sprint training should and should not be used.
If the key factor determining sprinting speed is the amount of force that can be applied to the ground, then we can rule out using ankle weights as an appropriate form of resisted sprint training. This training method will only serve to increase force production during the hip flexion that occurs during the flight phase. This is the exact opposite movement pattern to that which must be developed in order to increase the application of force to the ground.
Effective resisted sprint training methods that develop the ability to apply force during the ground contact phase include: hill sprints; weighted vest sprinting; speed chute sprinting and sled sprints. Which of these is chosen will depend upon the level of the athlete and the type of speed that is to be trained.
Some of the different types of speed include: acceleration, maximum speed and multi-directional speed. The strongest predictor of acceleration performance is horizontal force production (Hunter et al., 2005). Methods such as sled sprints and speed chute sprints emphasise the horizontal component of force production, and are therefore the most suitable tools for the development of acceleration. In contrast, weighted vest sprinting would be the most suitable method for the development of maximum speed since it emphasises vertical force production.
Hill sprinting represents a compromise between training for acceleration and training for maximum speed. The athlete is moving uphill, and so the effect of gravity means there is a greater emphasis on vertical force production. This lends itself to the development of maximum speed. However, the body angles when sprinting uphill are more suitable for the development of the acceleration phase of sprinting.
Hill sprinting is, however, a very suitable training tool for athletes in the early stages of their development. Such athletes may not yet have the strength to hold a good body position for the acceleration phase of sprinting, and so training on a steep hill may be the only way for these athletes to experience this.
By looking at the different types of resisted sprint training methods we have only scratched the surface. Hopefully I have provided some food for thought though. The next obvious consideration would be the level of resistance the athlete should be working against. This opens up a whole new can of worms.