[cbloom]

[ QUOTE ]
Duration of the exercise is one variable that is being neglected in those studies. The duration of the effort (time under tension?) is probably quite a bit longer in the slow rep group than in the fast rep group. I imagine that extra effort (it's not work but it's still extra effort) is similar to adding a couple reps, and that those who expended more effort regardless of speed would gain more than those who didn't.

[/ QUOTE ]

Yeah, this is just one of the problems with the studies. They don't have direct comparisons where various parameters are held as constants. In fact it's hard to say exactly what you should control for so really you should have way more people in the study so that you can cross-correlate various variables to see what the real determining factors are. You ideally want a lot of people in the study over a long period.

So, eg. to test slow vs. fast reps you would want to have people people doing the same moves, but then have groups doing the same set & rep counts, groups doing the same total workout time, groups doing the same time under tension, etc. etc.

For example, someone does 10 reps of super slow. Someone else does 10 explosive reps, then decreases the weight a bit and does a superset of 10 more explosive reps, so the total time taken is about the same. How would those compare? etc. etc.

IMHO slow reps have a very valuable place in the gym, which is testing your form with low weight. It can also really help you concentrate and feel the muscles that should be working at various parts of the movement, and it can get you out of the bad habit of jerking through the movement.

Slow reps may also be superior for injury rehabilitation.