I have a question about the isometric strength involved in sprinting. My coach told me before that isometrics were useless because they only increased strength within about 15 degrees of the joint angles at which they were performed. If I do yielding isometrics with a pause at the bottom of an RDL then how would it help my isometric strength when my leg touches down during running?
Also, if I do incorporate yielding isometric exercises, are they best done at the beginning or end of my weights session?
rj has the studies, he'll give you a better answer..
it's 15-30 degrees, and that mostly applies to overcoming isometrics if I am not mistaken.. performing yielding isos nearest the weakest joint angle will strengthen the entire ROM. A yielding iso is basically a series of eccentric contractions, so strengthening the muscle in this lengthened position is much different than an overcoming iso..
think about it in terms of deep squatting or bench pressing.. a very effective tool to strengthen squat & bench is pause squats and pause bench. if you can increase the amount of force at the bottom, then the natural joint angle-strength curve will kick in.
i've personally implemented pause bench very successful on the few occasions i've used it... pausing at the bottom for 5 seconds & blasting up..
imagine you could only hold a deep lunge iso with 185 for 7 seconds... now imagine you can hold 285 for 7 seconds... there will be some pretty extreme transfer over to other movements that use that musculature.
well, if you went max effort on the yielding isos, then of course do them as the main section of your workout.. if you are only doing them as assistance, do them towards the end.
peace