A lot of bodybuilders do partial movements for almost all their bodyparts, neglecting the full range of motion. In the late ’40s and early ’50s we disparagingly called partial movements muscle spinning.
Human beings have a built-in range of movement for each muscle. Deliberately not training the full range of an exercise can be dangerous. For example, if you stop your squats short, or high, the tendons don’t work in the fully extended position, and they don’t develop as much strength as the quadriceps do. People who consistently do only partial squats’as most do’find they lack the strength to do a full squat with anything approaching the weight they use on parallel or above-parallel squats.
A few weeks ago I was training at Gold’s Gym in Pacific Beach, California, and there was a fellow in fairly good shape doing behind-the-neck presses on a Smith machine. He lowered the weight to a point just above his head, and as he pressed the weight up from that point, he arched his back under the bar. With a considerable herky-jerky motion, he locked out the weight overhead. After his last rep I walked over and said, ‘You should lighten the weight. Do several sets with something you can handle correctly for about 12. As you get blood in the area and become warmed up, increase the weight’but never at the expense of correct form.’
He was obviously uncomfortable with my comments. ‘My personal trainer told me to do them this way,’ he said sheepishly. ‘He said that if I went all the way down behind my head, I’d stretch out the tendons and make my shoulders susceptible to injury.’
‘If God hadn’t intended for you to use your full range of motion, he wouldn’t have given it to you,’ I replied. ‘As for full range of motion causing injury, just the opposite is true.’
When you work an exercise through its full range, you strengthen the joints, tendons and ligaments at both ends of the working muscle. In the case of the ligaments, which are not attached to the muscle as tendons are, partial movements deprive them of nearly all stimulation.
Is there a place for partial movements? Yes, but not an important place. Lifters can use partials more advantageously than bodybuilders, but even lifters should only use them after they’ve been training correctly for years. Proper training over a long period of time ensures that the muscle and its tendons and ligaments are proportionately strong, so there’s no imbalance.
I’ve used partials on the three powerlifts with great success, but I never used partials exclusively. If you do partials, do them only after you’ve done a basic full-range exercise first. IM