Originally Posted by
OBoile
I would be careful with KB swings. You're generating a lot of force when you decelerate these which, coupled with fatigue from doing high reps, could make it easy for your form to break down. Not saying don't do them, or that they are a bad idea, but don't think there is no injury risk either.
In general, high reps can be fairly risky due to the large amounts of fatigue involved near the end of the set. Also, it's far easier for one's concentration to lapse over a 20 rep set than over a 5 rep set.
One other thing to consider: while a 20 rep set may have the same potential for hypertrophy as a heavy 5 rep set, it's far easier to do multiple heavy sets of 5 than multiple sets of 20 with a lighter weight. There's a reason sets of 20 squats are called "widow maker". If you're doing them heavy enough, your day is pretty much done after one of these. The cost/benefit just isn't there in most cases.
Back when I used to do sets of 30, I did about 7 exercises, circuit style. That worked well. Downside of high reps is that they're time-consuming, why I stopped doing them. You're right on about the exhaustion thing. OTOH, getting really tired and then resting makes you really strong, not just hypertrophy but resilient. When I did high rep sets, I did them all with the same weight, calibrated not to fail until late in the 3rd set. Felt light in that first set.