The paradox of muscle injuries: are peak speeds the ‘cause’ or the ‘vaccine’?
Peak speed exposure can be a ‘vaccine’ against muscle injuries. But if not managed in the right amounts, it might also be the cause of all kind of injuries.
In team-sports, like football and field hockey, the type of workload that each player has to perform is largely dependent on their playing position. These differences in playing positions influence the capacities that each player needs to have to fulfill these match demands. Based on the position-specific profiles and the physical capacities of the individual players, it is possible to determine on which factor the individual players need to improve (maximal speed, high speed running capacity, more explosive accelerations, or winning duels). Even though these factors can be improved within conditional training sessions, in this blog we will discuss how you can further improve these factors with strength training.
Before we discuss exercises that could be used to improve one of the capacities described above, it is important to know one of the strength-training models. When looking at the way the muscles produce force, it is important to know the relationship between force and velocity (see figure 1). Even if you have never seen this relationship before, you have encountered situations during which you have experienced it. Just think back to the time when you were lifting weights. With light weights to lift, you are able to perform the movement quite fast. However, as soon as you start to use heavier weights, you can’t lift it as fast as the lighter weights. This is because your muscles need to produce higher forces and, therefore, are not able to contract at the same speed. This is exactly the relationship that you see in figure 1: when the required forces are large, the speed at which you can perform the movement is relatively low; and when the needed force is small, the movement speed is high.
The purpose of strength training is to shift the force-velocity curve to the right. For untrained individuals, focusing on general strength will already shift the whole curve to the right. However, for trained individuals more specific training is needed to move a specific part of the curve to the right. Therefore, when players return from the summer break (and suffered some detraining effects), it is important to initially focus on general strength training first. When this has improved, it is advised to work towards the more specific strength exercises. For example, for a winger, it is important to train the speed-(strength) part of the curve, whereas for central defenders the focus will be on strength-(speed)/power.
Now that we have seen the relationship between the force-velocity curve and different physical capacities, the question remains which maximal effort exercises belong to the specific parts of the curve (see figure 2). For the strength related exercises, the exercise needs to be performed with maximal effort, even though this will not result in high movement speed. But if we move more towards the speed-part of the curve, the movement’s speed of the exercises becomes more important (and should thus increase).
Once you have focused on one of these aspects for an individual player, it is advisable to check whether the strength training had an effect on the performance of the player. For this, it is not only interesting to see if the player has improved on performance the exercise itself, but especially the change in on-field performance is of interest. If you have focused on speed-related capacities it is worthy to see whether a player has covered more distance at a higher speed or whether his maximal speed during a match has increased. Or if you have focused on improving strength, checking whether the player was able to increase the number of high accelerations (relative to the number of total accelerations), will give you information on whether his/her on-field performance improved. In the end, it is not the improvement in exercise performance that will make the difference, it is the on-field performance that is crucial and needs to be optimized.
Different playing position requires different physical capacities for the individual players. One of the ways to improve the physical capacity of the players in through strength training. The goal of strength training is to challenge the muscles and hence, shift the force-velocity curve to the right. For trained individuals, you need to perform exercises corresponding to the specific parts of the curve to shift these specific parts to the right. To check whether the player has improved his performance, it is essential to check whether there have been changes in the external workload (GPS data) of the players during the match.