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In one of the earliest published studies on the effects of high-intensity electrical stimulation on the maintenance of size and strength in immobilised muscles, researchers electrically stimulated the quads and hamstrings on a daily basis for three weeks in the immobilised leg of an athlete wearing a lower-extremity cast as a result of Grade-II medial-collateral and anterior-cruciate ligament sprains in his knee.
On the day the cast was removed, the girth of the athletes thigh was increased, suggesting that muscle hypertrophy had occurred, instead of the usual cast-associated atrophy. In addition, single-leg, vertical-leap height was 92% as great in the immobilised leg following cast removal, compared with the uninjured leg, and the athlete was able to immediately return to competition. Of course, studies like these lack controls, but subsequent research has confirmed that neuromuscular electrical stimulation can be a valid therapeutic modality for injured athletes (3). Basically, several investigations have documented increases in isometric strength in muscles treated with neuromuscular electrical stimulation (NMES) when NMES-stimulated subjects are compared with unexercised controls; some of these studies have found no difference in strength between NMES-treated subjects and voluntary-exercise groups. The use of NMES to prevent muscle atrophy as a result of prolonged knee immobilisation following either injury or knee-ligament reconstructive surgery has been very intensely studied. Basically, this research has shown that NMES is effective in preventing decreases in muscle strength, muscle size, and even the oxygen-consumption capabilities of thigh muscles after knee immobilisation. In all but one of the studies in this area which have been published in scientific journals, NMES has been shown to be better in preventing negative changes in leg and knee-joint function, compared with no exercise, isometric exercise of the quadriceps-femoris muscles, and even isometric co-contractions of the quads and hamstrings. |
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