Disclosures: Sonia R. Shah, MD: No financial relationships or conflicts of interest

Objective: Motor-assisted ellipticals are used for locomotor training following severe injury or illness. Movement variability is often encouraged during locomotor training, yet little is known about the impact of different motor-assisted elliptical training conditions on movement variability. This research explored the influence of different motor-assisted elliptical conditions on movement variability and compared findings to treadmill walking.

Design: Prospective repeated measures design.Setting : Biomechanics laboratory.Participants : 10 adults without known disabilities.

Interventions: Lower extremity kinematics were recorded as participants completed three motor-assisted elliptical conditions [motor providing Active Assistance (AA), overriding the motor’s Active Assistance (AA+), and training against Resistance (R)] and walked at a self-selected comfortable speed on a treadmill (TM).

Main Outcome Measures: 4×1 ANOVAs with repeated measures compared maximum Sample Entropy (SE) and Lyapunov Exponent (LyE) values for hip, thigh, knee, and ankle joints across AA, AA+, R, and TM conditions performed in the forward direction. If normality assumptions were violated, then Friedman’s ANOVA was performed on ranks.

Results: SE varied significantly (p < 0.001) across conditions for hip (TM, R > AA+ > AA), thigh (TM, Res > AA), knee (TM > AA+, AA; R > AA), and ankle (R > AA+ > AA; TM > AA). In contrast, maximum LyE values varied significantly only at the ankle (AA+, R > TM, AA; p < 0.001).Conclusions: Although not always statistically significant, device conditions requiring greater participant effort (i.e., R and AA+) led to movement variability levels that more closely approximated treadmill walking levels compared to AA. SE appeared more sensitive at discerning differences within joints than LyE. The ability to constrain or promote task complexity through selection of specific motor-assisted elliptical device training parameters appears promising. However, future research is needed to determine the impact of integrating select training parameters on movement variability of participants with impairments.

Level of Evidence: Level III

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/comparison-of-lower-extremity-joint-movement-variability-during-motor-assisted-elliptical-exercise-and-treadmill-walking/