<div> (faz @ Sep. 06 2007,16:03)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">here is a point if we are talking about creating a stimulus in the right now,would that mean isos would be better than compounds,ie biceps dont get direct work from pull-ups but they do from curls so wouldnt curls create a better stimulus for the bicep muscle. lat-raises delts,flyes pecs,etc.</div> I don't buy all the 'direct work' malarkey. If your muscle is working then it's working. The range over which it works may be different and the load may vary differently over the range of motion for a particular exercise, but whether it's a compound or an iso it's down to the loads being used and the effective TUT with that load. What would make a difference is if you are unable to produce the same amount of strain on the muscle tissue in, say, the biceps when chinning as you can with a biceps bb curl. Is that likely? There's always a load for each exercise where the strain produced on a particular muscle will be equal between a compound or an iso exercise (although the time under that strain will likely differ). However, it may be that for certain compounds the mechanical advantage could be particularly high and so in order to stress a specific muscle, like the biceps during a chin, you might need to use a significantly higher load in order to transfer enough strain onto the biceps; that's exactly what we normally do. I haven't done the maths to show an example of this yet. It would be interesting to know how the tension on the biceps varies during a typical chinning movement. Perhaps someone knows a web link to a force/strain study on muscles for various exercises? Nice simulation project for someone to do in Wolfram's Mathematica.