Keep on your toes: gait initiation from toe-standing.

Gait initiation from toe-standing is common in patients with upper motor neurone (UMN) pathology as well as in able-bodied subjects during certain dance and athletic situations. It is unclear whether balance problems in patients who toe-walk are due to the underlying pathology, or due to initiating gait from toe-standing. The aim of this study was to compare the biomechanics of gait initiation from toe-standing to that from heel-toe standing in healthy able-bodied subjects. Data were collected for three seconds prior to, and three seconds after, a visual signal to initiate gait. Ground reaction force and centre of pressure (COP) data were collected with an AMTI force platform, and electromyographic and kinematic data were collected from each limb with a Vicon motion analysis system. When initiating gait from toe-standing, there was a smaller backward displacement of the COP compared to heel-toe standing. In addition, greater forward momentum was generated, and there was an increase in gastrocnemius, rectus femoris and biceps femoris muscle activity. There were no differences in COP displacement or momentum generated in the mediolateral direction for the two conditions. Thus, initiating gait from toe-standing allows one to generate greater amounts of forward momentum but not at the expense of generating excessive stance-side momentum. This may be an advantageous method of initiating movement for dancers and athletes in certain situations. This work also suggests that balance problems in patients with UMN pathology are likely due to the underlying pathology and are not due to initiating gait from toe-standing.