Is postural stability during standing and dynamic tasks altered in young adults with flatfoot: A comparison study.

BACKGROUND

People with flatfoot were reported to exhibit poorer standing postural stability than those with normal foot posture (NF). However, whether postural stability is altered during dynamic tasks including sit-to-stand transition, step-up/down, and walking along a line in people with flatfoot is not clarified.

OBJECTIVES

To compare postural stability during static standing and dynamic tasks between young adults with flatfoot and NF.

DESIGN

A case-control study.

METHOD: Twenty-five people with flexible flatfoot and twenty-five people with NF were included. Postural stability was assessed using the NeuroCom Balance Master. Sway velocity values (deg/sec) during bipedal and unipedal standing with eyes-open and eyes-closed were obtained. The weight transfer time (sec), rising index (% body weight), and sway velocity (deg/sec) parameters of the sit-to-stand test, the speed (cm/sec) and end sway (deg/sec) parameters of the tandem walk test, and the lift-up index (% body weight), movement time (sec), and impact index (% body weight) parameters of the step-up-over test were obtained.

RESULTS

Standing postural stability was poorer in the flatfoot group with a moderate effect size (p < 0.05, Cohen's d = 0.66). The speed during tandem walking and left and right lift-up forces were lower in the flatfoot group with large effect sizes (p < 0.05, Cohen's d = 1.33, 1.01, and 0.97, respectively).

CONCLUSIONS

The flatfoot group exhibited poorer static and dynamic postural stability, with larger effects observed in dynamic conditions. Possible lower concentric muscle strength of the lower extremity warrants further investigation.