if you are working static holds, does it matter if the weight is near max or not? I mean would a static hold of 100lbs for minutes work the muscle the same as a static hold of 300lbs for 20 seconds?
Do static holds recruit muscle fibres the same way contractions do? Are you training FT fibres with static holds by requiring straps with heavy weights?[/quote]
You can translate the weight and time held on static holds to weight and repetitions on concentric lifts. You’ll have better carry-over to 1rm deadlift by performing short duration heavy holds and better carry-over to 10rm deadlift by performing long duration sub-maximal holds.
If I were to try 20 rep deadlifts again I’d load up a weight I could hold for a good minute in snatch-grip for accessory work. Anything below 5rm would be 10seconds at most.
As for the ft twitch, well, your forearms are dominantly slow-twitch because of the constant contraction in your hands. Slow twitch always fire first, but under near maximal weight your fast twitch also fire. This of course, doesn’t mean your forearms can’t grow. It’s extremely possible with isolated work incorporated into your routine, just like calves.
Just be careful; too much isolation work and you’ll have trouble walking up a flight of stairs.