EFFECT OF ELECTRICAL-STIMULATION ON LUMBAR PARASPINAL MUSCLES

Forty healthy, sedentary, premenopausal women were entered into a rand omized, single-blind, controlled study to determine the effects of cap acitively coupled electrical stimulation on the strength of the lumbar paraspinal muscles and the bone mineral in the lumbar spine. All were between 35 and 45 years of age and had normal physiologic estrogen. T he study group received electrical stimulation over the lower lumbar p araspinal muscles for 30 minutes twice a day. Isometric strength of th e lumbar paraspinal muscles was assessed with a strain-gauge dynamomet er at entry and again after 3, 6, 9, and 12 months. Bone mineral was m easured in the lumbar spine by dual-energy x-ray absorptiometry at ent ry and at 6 and 12 months. After 3 months, the median increase in isom etric strength was 8.1% in the study group and 1.6% in the control gro up (P < 0.03). This initial difference was maintained during the remai nder of the study. No further changes were seen between the two groups at 6, 9, and 12 months. It was concluded that capacitively coupled el ectrical muscle stimulation can, throughout a 1-year period, improve a nd maintain isometric strength of the lumbar paraspinal muscles indepe ndent of exercise, but it has no measurable effect on bone mass in the lumbar spine.