[quote author="Jeremy Richmond" date="1260208806]I use 70kg at the moment but want to increase to 85kg by Feb. It’s probably 50-60% of 1RM but I don’t care about RM. My target is 85kg. With any higher weight at the moment I feel my technique (ideal recruitment pattern) would deteriorate. The higher the weight the more quads I would use instead of hip extensors and calves.
Block start takes .2s.
How long does your jump squat take?
By your own argument against me, the movement would be far too slow. Yet, somehow you are reaping the benefits with the added resistance. You are training a movement with load at a slower recruitment pattern.
Post a vid of your ‘jump’ squats and we will see how much eccentric benefit you receive at the ankle joint.[/quote]
With the weight you mentioned previously (10-15lbs) I see more relevance to plyometrics with your jump squats and therefore more benefit to sprinting. In fact I do almost exactly the same except 10-15kg in a double bound movement (focussing on hip extension as opposed to knee extension).
RE: block contact time, it is usually around 330-360ms (Mero 1988, Mero et al. 1983, Coh et al. 1998 to name a few). Therefore my weighted (and trackspeedboy’s) jump squat version is probably quite relevant to the block start. Just at the moment I feel that using 65-70kg’s is a little too much and hinders my hip extension speed. The goal of my quick jump squats (and probably trackspeed boy’s -please confirm) is to reduce the time on the blocks but achieve the same force output and block velocity. If you could reduce block contact time by 0.03s that would represent a decent saving. Over the festive season break (coming up soon) I’ll try to get biomechanical analysis of both the quick jump squat and block contact time of the technique developed thereof. Crude as it were, multiple camera footage showed almost 100ms (0.1s) saved but it has been deleted since. Might even get biomechanical analysis of a 5-10kg weighted jump squat as well as a 10-15kg quick double bound.