Problems with the principle of specificity in sports-specific training

jimmclennan-roger-federer-1Last week, I read an article that focused on training tennis players, especially in relation to injury prevention. Beyond the science and statistics, the article suggested some exercises to help prevent the common injuries, especially shoulder injuries. The article focused on the core, as does seemingly everything these days. However, the first exercises listed by the article were seated exercises, like the bicycle sit-up.

Is the bicycle sit-up wrong for tennis? I am not an expert on tennis, so I am not going to say that a tennis player should never do a bicycle sit-up. However, the explanation, I believe, was flawed.

The bicycle sit-up is an example of something that on the surface looks appropriate or even meaningful, but in reality, the exercise’s meaning is lost. In basketball, I call these fake fundamentals.

The explanation for incorporating the bicycle sit-up for a tennis player is the rotational movement. Whereas the article did not say it directly, it evoked the principle of specificity. The principle of specificity essentially says that to improve a specific skill, you must practice that skill. In this case, the article alluded to the rotational nature of a tennis stroke as evidence for the inclusion of a bicycle sit-up, which also has a rotational component.

The problem is force. A bicycle is a low velocity movement through a limited range of motion. A tennis stoke is a high velocity movement through a larger range of movement. Furthermore, the rotation in a tennis stroke does not start in extension and finish with the right arm moving down toward the left knee; in fact, the rotation is almost the complete opposite of the bicycle sit-up.

This is one issue with the way that many see the core (when using the core to talk primarily about the torso). The core does not drive the movement or produce the force in a tennis stroke. The legs create the force and the core transmits the force to the upper body (before someone else corrects me, the core initiates movement in the sense that the core braces prior to the leg generating force – however, my point is that the force is generated from the ground up, not by twisting one’s midsection).

Look at the two exercises below. Which is more powerful? Why? They are used by many to train the same muscles, but do they train the same movement? Are they interchangeable? When talking or writing about injuries in sports, are they due to lack of strength (muscular) or inefficient or poor quality movements?

Sitting

Standing

Again, if the purpose of the exercise is to reduce injuries, especially to the shoulders, which exercise is most appropriate? To prepare for a high velocity sport like tennis, I would argue that the standing medicine ball throw is the only three of the exercises that would meet the principle of specificity.

The other exercises may be appropriate during a period of rehab, but I don’t see the value of the bicycle sit-up for a tennis player because of the lack of velocity and the biomechanical differences, not to mention the lack of connection between the shoulders and core. Rotational movement in the tennis stroke is accompanied by hip extension, not contralateral hip flexion, as in the bicycle sit-up, and culminates with the high velocity arm swing.

To me, this is a lot like basketball training programs that use leg extension machines to strengthen the knees even though knee issues often are caused by issues with hip stability instead of a lack of strength in the quadriceps. Strengthening the quads seems like a good idea for basketball players, but if the goal is to prevent a knee injury (ACL), learning to control knee movement (varus/valgus) with the feet on the ground is more important.

Most exercises have a time and place (some are absurd). However, as an athlete (or coach/trainer), you must know if the exercise provides the correct training stimulus for the desired adaptation. Whereas I would not do a bicycle sit-up or prescribe them to an athlete, that does not mean they are wrong. However, as a means of injury prevention for a tennis player, there are better choices that better approximate the velocity, force, and coordination of tennis strokes.

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