Date of Award

2015

Document Type

Scholarly Project

Degree Name

Doctor of Physical Therapy (DPT)

Department

Physical Therapy

First Advisor

Thomas Mohr

Keywords

Electromyography; Muscles -- physiology; Stair Climbing -- physiology

Abstract

Introduction: Prior to this study, little evidence exists for a quality predictive tool correlating maximum velocity contraction (MVC) strength of the hip abductor muscles to walking and stair climbing (ascending/descending, side-stepping) ability. Stair climbing is an important functional activity of daily living and as physical therapists we are involved in training clients to ascend/descend stairs safely, which can be difficult for clients with hip abductor muscle weakness. Subjects: Eleven females voluntarily agreed to participate in this study. All participants were under the age of 30 years old, nonpregnant, physical therapy students without a current musculoskeletal injury. Methods: During each of the trials, the muscle activity of each muscle was recorded. The EMG activity was recorded using a Noraxont TeleMy02400 G2 telemetry unit with a sampling rate of 1 kHz which was transmitted to a TeloMyo PC interface card connected to a laptop computer. EMG activity was recorded by placing Blue Sensor (model M-OOS) surface electrodes on the skin over each of the muscles under study. The muscles that were monitored were the: 1) tensor fascia latae, and 2) gluteus medius. A foot switch placed inside the shoe was used to measure when the subject's right foot was on or off the ground. The four activities tested were: subject ascending stairs normally with right foot leading, subjects descending stairs normally with right foot lagging, subjects ascending stairs sideways with right foot leading, and subjects descending stairs sideways with right foot lagging. The subjects performed each activity to a set metronome to 100 bpm for level walking and 80 bpm for stair climbing. Results: The tensor fascia latae produced higher muscle activity than the gluteus medius during walking. During stair climbing, side-stepping produced more muscle activity as compared to normal stair ascending. The tensor fascia latae also appeared to produce a greater muscle activity than the gluteus medius during stair side-stepping. The average gluteus medius muscle activity was equal during normal stair ascending and sidestepping ascending. Discussion: Side-step stair ascending has long been thought to activate and strengthen the gluteus medius muscles. These results show that this isn't the case, as the gluteus medius muscle averaged the similar EMG activity during both walking and stair-climbing. In comparison, side-stair ascending produced more activity in the tensor fascia latae than did normal stair ascending. Conclusions: The results indicate that using side-step stair climbing to increase strength and activity of the gluteus medius muscle doesn't appear to be justifiable. However, they do show that the tensor fascia lalae and gluteus medius are both important for stair-ascending in patients without compensation. Thus, strengthening the tensor fascia latae may be just as important as the gluteus medius for stair-climbing.

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