Foot hyperpronation alters lumbopelvic muscle function during the stance phase of gait.

BACKGROUND: Although altered muscular control of the lumbopelvic region is one of the main risk factors for the development of low back pain and dysfunction, the influence of abnormal foot posture on lumbopelvic muscular function has not been investigated.

RESEARCH QUESTION: To determine possible functional changes due to hyperpronation in the main muscles that control the lumbopelvic segment.

METHODS: Kinematic and kinetic data were collected from 15 persons with hyperpronated feet and compared to a control group of 15 persons with normally aligned feet during the stance phase of gait. A generic OpenSim musculoskeletal model was scaled for each participant. A computed muscle control approach was used to produce a forward dynamic simulation of walking to determine muscle function.

RESULTS: In the hyperpronation group significantly greater peak forces were observed in the erector spinae, iliopsoas and abdominals compared to controls. The former group showed peak latencies for abdominal muscles during early stance, and for erector spinae muscles during both early and late stance. No significant between-group differences were found in gluteus maximus muscle activation in the stance phase of gait.

SIGNIFICANCE: Abnormal foot pronation can change the timing and intensity of lumbopelvic muscle activation. These changes may predispose people to develop secondary dysfunctions.