HIT and fast twitch muscles

Hey guys, I use Mentzer's Heavy Duty 2 routine and just wondering if training with the 4/2/4 cadence has any positive effects on fast twitch muscles? It seems obvious it stimulates slow twitch muscles.

Using the cadence that you stated you will reach the fast twitch fibers toward the last few that are closest to last impossible rep and that is based on recruitment patterns and that the weight is heavy enough. If the weight is to light and the reps exceed 12 in most cases you run the risk that the slow twitch have recuperated and are put back into the the recruitment pattern which will cause a longer wait before the fast twitch come to bat.

If you want the fast twitch to come into play much quicker then I believe that a 4 second positive is to slow but a 1 second is to fast so I would say an under control 2 second positive will give you far better results so it would look more like a 2-0-4 (positive-contraction-negative) or a 2-4-4 on movement that have resistance in the contracted position for all other movement then it is 2-0-4.

Hope this helps

Daron