Marius_Hancu said:
Absolutely, but my impression is that one needs something else too. I'm convinced e.g. Agassi benefitted a lot say in his serving in his last years from his weights program (in leg power, upper body, etc).
Then, with a better related base, he just went out and practiced serving.
This I agree with from personal experience, though the scientific literature doesn't always seem to agree. I think that often, the scientific literature, when trying to examine sports performance, either tend to choose untrained individuals so the effects can be most clearly seen, or tend to choose highly trained individuals, which many of us are not. Therefore, many adaptations which are not specific to the individual motion are still beneficial because we're not in a highly trained state, don't have the support from other core musculature, and would benefit from additional training of almost any sort.
A prime example of this would be the studies on weight training for endurance events like cycling. There is one study most often quoted by proponents (Hickson, et al, 1988) which used untrained individuals and showed marked improvements in time to exhaustion solely from weight training. Significantly more studies with elite athletes don't show these advantages, possibly because an elite athlete already has sufficient training load and is muscularly developed to the level and proportion very close to optimal for the task.
This all being said, for the average weekend athlete who might peruse this, I don't see how a method like this is going to be substantially better at helping a sports specific performance. The exact specificity still can't be there and if the idea is to simply build a better base, it seems there are going to be easier ways to accomplish nearly the same goal by traditional means.
