Sit-to-stand transfer mechanics in healthy older adults: a comprehensive investigation of a portable lifting-seat device

Abstract

Purpose: To evaluate lower extremity mechanics and muscle activation associated with the sit-to-stand transfer using a portable lifting-seat device and to compare these data to an unassisted transfer in healthy young and older adults. Methods: Bilateral lower extremity and low back musculature electromyography, three-dimensional leg and trunk motion, and ground reaction forces were recorded from 10 young (mean age = 25) and 10 older (mean age = 69) adults during five trials of (i) no assist and (ii) assisted transfers. Data were time normalized to represent the period of seat-off to standing. Peak sagittal plane joint angles, moments, and muscle activity profiles were calculated. Analysis of variance models was used to test for main effects and interactions (α = 0.05). Results: Trunk, hip, and knee angles were significantly reduced and dorsiflexion increased with assisted transfer (p < 0.05). Peak hip and ankle joint moments were reduced (p < 0.05) and no change found in knee moments (p > 0.05). Peak muscle activity was lower during the assisted transfer (p < 0.05). Seat device effects were similar between age groups. Older adults used higher relative muscle activation. Conclusion: Variables indicative of sit-to-stand functional demand were reduced with lifting-seat device use. Data provide a framework for future recommendations on product prescription, use, and research pertaining to the advancement of adaptive seating.

Implications for Rehabilitation

• Hip and trunk mechanical demands, and muscle activation were reduced with portable lifting seat device use.

• Greater ankle dorsiflexion was found with portable lifting seat device use, suggesting this range of motion should be considered when prescribing this device.

• Healthy older and younger adults used similar knee and trunk joint mechanics yet older adults completed the sit-to-stand trials with greater lower extremity and low back muscle activation.

• Electromyography
• lift-seat device
• lower extremity
• mechanics
• older adults
• sit-to-stand
• rehabilitation

Acknowledgements

The authors would like to thank the individuals of the Dynamics of Human Movement Laboratory, Dalhousie University for their support in data acquisition. They would also like to thank Uplift Technologies for providing the seat devices for the study.

Declaration of interest

The authors acknowledge that there are no conflicts of interest pertaining to this manuscript. All authors contributed to study inception, data collection, analysis and writing. All authors have agreed upon the typeset. This work was supported by a National Sciences and Engineering Research Counsel of Canada (NSERC) Engage Grant (#EGP/418922-2011).