Attempt toward a development of aquatic exercise device for gait disorders

To develop an aquatic exercise device to facilitate locomotive motor output and achieve repetitive physiological gait patterns to improve movement dysfunctions.

A custom designed leg movement apparatus (LMA) consisted of closed 4-linkage mechanisms and one-length changeable link using a spring. Three-dimensional motions and electromyographic (EMG) activities were recorded in eight healthy subjects to evaluate the reproducibility of the physiological gait patterns using the LMA with or without a spring apparatus in water.

Using the LMA with a spring apparatus compared to walking in water, the foot trajectories and the time course of the elevation angles in each lower limb joint kinematics were preserved. The time-series of the EMG showed reciprocal modulation between agonist and antagonist muscle groups in the hip and ankle joints. However, the amplitudes of the tibialis anterior muscle in the first half and rectus femoris in the last half of the movement cycle were reduced using the LMA with a spring apparatus.

We developed a novel aquatic exercise device to reproduce physiological gait patterns. The LMA with a spring apparatus would be particularly valuable in therapy for movement dysfunctions to facilitate locomotive motor outputs. Implications for Rehabilitation The leg movement apparatus with spring for underwater use (LMA) would be effective gait training to induce the locomotor-like EMG activities. Hydrotherapy with the LMA has advantages over the partial body weight support treadmill training on land with a robotic device; (1) the LMA is electrically and mechanically safe, and (2) the LMA would require self-effort to generate the gait pattern for movement disorders, or also enable passive gait training by the physiotherapists.