The Effect of Prosthetic Leg Length on Low Back Muscle Activity and Pain during Walking and Sit-to-Stand – UROP Summer Symposium 2021

The Effect of Prosthetic Leg Length on Low Back Muscle Activity and Pain during Walking and Sit-to-Stand

Robyn Pfeiffer

Robyn Pfeiffer

Pronouns: She/Her/Hers

UROP Fellowship: Engineering
Research Mentor(s): Deanna Gates, PhD
Research Mentor Institution/Department: School of Kinesiology, Department of Biomedical Engineering

Presentation Date: Wednesday, August 4th
Session: Session 1 (3pm-3:50pm EDT)
Breakout Room: Room 1
Presenter: 2

Event Link


People with lower limb amputation have a greater incidence of low back pain than the general population, with some estimates as high as 65%. One potential cause of pain in this population is leg length asymmetry as it can lead to altered trunk-pelvis movement, and subsequently altered low-back loading. The purpose of this study was to determine the effect of changes in prosthetic leg length on low back muscle activity and self-reported low-back pain. Ten people with transtibial amputations performed walking and sit-to-stand movements with their prescribed prosthetic leg length. A prosthetist then changed the prosthetic leg length ± 2 cm. Participants rated their pain level on a visual analog scale from 0 (“no pain”) to 100 mm (“worst pain”) after each condition. Scores were divided into four categories: no, mild, moderate and severe pain. We also collected muscle activity from bilateral electromyography (EMG) sensors placed on the gluteus medius, thoracic paraspinals, and lumbar paraspinals at 1200 Hz during all tasks. While several muscles contribute to spinal stability, we choose these as the thoracic and lumbar paraspinals cooperatively work with the gluteus medius to produce a compound movement known as lumbopelvic rhythm. For each muscle, we measured the iEMG, the integral of the envelope of the EMG signal, as a measure of total muscle activity. There was no difference in immediate low-back pain between the prescribed and short (p = 0.51) or tall (p = 0.06) conditions and all but one participant experienced only mild pain. In the future, I will compare the muscle activity between the conditions. I hope that this will provide additional insight into the extent of which leg length discrepancies contribute to the development of low back pain over time.

Authors: Robyn N. Pfeiffer, Luis A. Nolasco, and Deanna H. Gates
Research Method: Clinical Research

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