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Muscle activity during multi-step descent
Kaitlin Kremsky1, Emma R Connolly2, Mary Kallberg1
1Human Motion Laboratory, University of Scranton, Leahy Hall, 237 Jefferson Avenue, Scranton, PA 18510, USA.
Journal of Bodywork and Movement Therapies
|November 27, 2024
Summary
Muscle activity during stair descent varies by step and strategy. Step-match and step-over-step descent show distinct muscle activation patterns, challenging steady-state assumptions and informing rehabilitation for lower extremity issues.
Area of Science:
- Biomechanics
- Human Movement Analysis
- Exercise Physiology
Background:
- Previous research identified mechanical differences in stair descent across steps.
- Muscle activity variations during stair descent between different strategies and across individual steps remain underexplored.
Purpose of the Study:
- To quantify muscle activity differences during step descent.
- To compare muscle activity between step-over-step and step-match strategies.
- To examine muscle activity variations across individual steps of a staircase.
Main Methods:
- Twenty-five participants descended a seven-step staircase using self-selected pace for both step-over-step and step-match strategies.
- Muscle activity was recorded using bipolar electrodes on key lower limb muscles (tibialis anterior, peroneals, medial gastrocnemius, rectus femoris, biceps femoris).
- Two-way Repeated Measures ANOVA analyzed co-activation (ankle and knee joints) and integrated electromyography (EMG) in lead and trail limbs.
Main Results:
- Muscle activity during stair descent was significantly dependent on the step number for both step-over-step and step-match strategies.
- Distinct patterns of ankle and knee co-activation were observed between the two descent strategies, particularly in the lead limb.
- Trail limb co-activation showed similarities between strategies, with higher activity in step-over-step and for the knee in step-match.
Conclusions:
- The study challenges the assumption of a 'steady-state' during stair descent, revealing significant muscle activity variations across steps and between strategies.
- Differences in muscle activation patterns across steps and between strategies have implications for individuals with lower extremity musculoskeletal conditions.
- Tailoring rehabilitation to specific staircase lengths and acknowledging step number variability in research are recommended.
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