Juupa wrote:It's pure insanity to go from "I need to work on my stability/core" to "standing on an exercise ball is probably a good way to address my issues". I understand the need to do core work and I understand the need to address stability issues. Neither of those justify standing on an exercise ball. In fact, if you're standing on a ball you're probably unable to address anything too specific.
I'd say it's a bit harsh to go from not having the same opinion to the other opinion as being insanity.
However, you're perfectly correct about addressing specific muscles. If you for example wants to improve your double leg td explosivity you should probably do squats with heavy weights on your shoulders and those kind of kettle bell swings Velaquez demonstrated in an above posted video.
However, a chain is never stronger than it's weakest link and if you neglect any joint in your exercize and that specific joint is being challenged in a motion, that will probably cause to fail the attempt.