Abstract

This paper evaluates several abdominal exercises, and highlights factors which are important for their safe prescription and effective use. The function of the abdominal muscles and hip flexors is considered, and the importance of the infra-umbilical portion of the rectus abdominis is emphasized. The effects of flexion on the lumbar spine are outlined. The trunk curl, sit-up, and straight leg raise are analysed, together with modifications of these exercises. The effect of foot fixation and hip flexion during the performance of the sit-up is discussed. The sit-up performed with foot fixation, and the bilateral straight leg raise can compound hip muscle imbalance, and both hyperextend and hyperflex the lumbar spine and are therefore not recommended. The importance of muscular control of pelvic tilt is considered with reference to muscle imbalance around the pelvis. It is recommended that a musculoskeletal assessment should be performed before prescribing abdominal exercises. Exercise therapy to re-educate control of pelvic tilt is described. Intra-abdominal pressure, and the effects of abdominal exercise on this mechanism, and lumbar stabilization are examined. The importance of training specificity is stressed.