Similarity of joint kinematics and muscle demands between elliptical training and walking: implications for practice.

BACKGROUND: People with physical disabilities often face barriers to regaining walking ability and fitness after discharge from rehabilitation. Physical therapists are uniquely positioned to teach clients the knowledge and skills needed to exercise on functionally relevant equipment available in the community, such as elliptical trainers. However, therapeutic use is hindered by a lack of empirical information.
OBJECTIVE: The purpose of this study was to examine joint kinematics and muscle activation recorded during walking and elliptical training to provide evidence-based data to guide clinical decision making.
DESIGN: This was a prospective, controlled laboratory study using a repeated-measures design.
METHODS: Twenty adults free from impairments that might hinder gait participated. After familiarization procedures, subjects walked and trained on 4 elliptical devices while kinematic, electromyographic (EMG), and stride characteristic data were recorded.
RESULTS: Movement similarities between elliptical training and walking were supported by the documentation of relatively high coefficients of multiple correlation for the hip (.85-.89), thigh (.92-.94), knee (.87-.89) and, to a lesser extent, the ankle (.57-.71). Significantly greater flexion was documented at the trunk, pelvis, hip, and knee during elliptical training than during walking. One of the elliptical trainers most closely simulated sagittal-plane walking kinematics, as determined from an assessment of key variables. During elliptical training, gluteus maximus and vastus lateralis muscle activation were increased; medial hamstring, gastrocnemius, soleus, and tibialis anterior muscle activation were decreased; and gluteus medius and lateral hamstring muscle activation were relatively unchanged compared with muscle activation of those muscles in walking. On the basis of EMG findings, no elliptical trainer clearly emerged as the best for simulating gait. LIMITATIONS: To date, only 4 elliptical trainers have been studied, and the contributions of the upper extremities to movement have not been quantified.
CONCLUSIONS: Although one of the elliptical trainers best simulated sagittal-plane walking kinematics, EMG analysis failed to identify one clearly superior device. This research provides evidence-based data to help guide clinical decision making related to the use of elliptical trainers across the health care continuum and into the community.