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Lower extremity muscle activation during horizontal and uphill running
M A Sloniger1, K J Cureton, B M Prior
1Department of Exercise Science, The University of Georgia, Athens, Georgia 30602-6554, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 14, 1998
Summary
High-intensity running to exhaustion activates most lower extremity muscles, but not maximally. Uphill running recruits more total muscle volume than horizontal running through altered activation patterns.
Area of Science:
- Exercise Physiology
- Biomechanics
- Sports Science
Background:
- Understanding muscle activation patterns is crucial for optimizing athletic performance and injury prevention.
- Previous research has provided limited insight into the extent and pattern of lower extremity muscle activation during high-intensity running.
Purpose of the Study:
- To quantify lower extremity muscle activation during high-intensity horizontal and uphill running to exhaustion.
- To compare muscle activation patterns between horizontal and uphill running conditions.
Main Methods:
- Magnetic resonance (MR) imaging was used to assess exercise-induced contrast shifts, indicating muscle activation.
- 12 young women performed high-intensity (115% of peak oxygen uptake) horizontal and uphill running to exhaustion (2.0-3.9 min).
- Activation levels of 13 individual muscles or groups in the right lower extremity were quantified.
Main Results:
- Mean lower extremity muscle activation was significantly greater during uphill running (73%) than horizontal running (67%).
- Individual muscle activation varied widely (41-90% horizontal, 44-83% uphill), with adductors, hamstrings, and gluteals highly activated in both conditions.
- Uphill running significantly increased activation in the vastus group and soleus, while decreasing activation in the rectus femoris, gracilis, and semitendinosus compared to horizontal running.
Conclusions:
- Lower extremity muscles are not maximally activated during 2-3 minutes of high-intensity running to exhaustion.
- There appears to be a limit to additional muscle mass recruitment for meeting increased force and energy demands.
- Altered muscle activation patterns, involving differential recruitment, contribute to greater overall muscle activation during exhaustive uphill running.