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Obtaining Quality Extended Field-of-View Ultrasound Images of Skeletal Muscle to Measure Muscle Fascicle Length
Published on: December 14, 2020
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Skeletal muscle architectural adaptations to marathon run training
Kevin Murach1, Cory Greever, Nicholas D Luden
1Human Performance Laboratory, James Madison University, Harrisonburg, VA 22807, USA.
Summary
Marathon training altered skeletal muscle architecture in recreational runners. The lateral gastrocnemius muscle showed decreased fascicle length and increased pennation angle, suggesting training-induced adaptations.
Area of Science:
- Exercise physiology
- Skeletal muscle biology
- Biomechanics
Background:
- Marathon running involves repetitive, high-volume training.
- Skeletal muscle architecture, including fascicle length and pennation angle, influences muscle function.
- Previous research has not extensively documented training-induced changes in specific lower limb muscles like the lateral gastrocnemius and vastus lateralis.
Purpose of the Study:
- To investigate the effects of 12 weeks of marathon training on the skeletal muscle architecture of the lateral gastrocnemius (LG) and vastus lateralis (VL) in recreational runners.
- To explore potential correlations between changes in muscle architecture and physiological markers like blood lactate levels.
Main Methods:
- Ultrasound imaging was used to measure fascicle length and pennation angle of the LG and VL muscles.
- Measurements were taken before and after a 12-week marathon training program in 16 recreational runners.
- Blood lactate levels were assessed and correlated with observed architectural changes.
Main Results:
- The lateral gastrocnemius (LG) exhibited significant changes: fascicle length decreased by 10% and pennation angle increased by 17% (p < 0.05).
- A strong positive correlation (r = 0.90) was found between reduced blood lactate levels and the change in LG pennation angle.
- No significant architectural changes were observed in the vastus lateralis (VL) muscle.
Conclusions:
- This study provides the first evidence that marathon running training can induce specific architectural adaptations in the human skeletal muscle.
- The observed changes in the lateral gastrocnemius suggest a muscle's ability to modify its structure in response to endurance training demands.
- The correlation with lactate levels hints at potential links between metabolic adaptations and muscle architecture modifications during training.
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