ABDOMINAL AND LOW BACK MUSCLE INVOLVEMENT DURING EIGHT SIT-UP VARIATIONS

Abstract

Sit-up exercises are often recommended by health and fitness experts and by members of the medical community as both a prophylactic and a treatment for low back pain. The general rationale for such prescriptions is that an increase in the resting tension levels of the abdominal muscles may help prevent or reduce excessive anteriortilt ofthe pelvis and lumbar lordosis. Although a variety of sit-up styles or variations are currently practiced, it is well-documented that at least some variations of the sit-up also exercise the hip-flexor muscles. Among the hip-flexors is the iliopsoas complex, which tends to increase lumbar lordosis when it is over-developed. Since this is undesirable in that excessive lumbar lordosis may actually contribute to the development oflow back pain, the optimal sit-up exercise is clearly one which maximizes abdominal muscle involvement while minimizing the participation of the hip flexors. For these reasons, the hook-lying sit-up, (performed with the knees in flexion), has been recommended (Williams, 1974).