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Studying the Neural Basis of Adaptive Locomotor Behavior in Insects
Published on: April 13, 2011
How muscles define maximum running performance in lizards: an analysis using swing- and stance-phase muscles
Timothy E Higham1, Paul G Korchari, Lance D McBrayer
1Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA. thigham@clemson.edu
The Journal of Experimental Biology
|April 29, 2011
Summary
Stance-phase muscles, like the gastrocnemius (GA), limit maximum locomotor performance in lizards, not swing-phase muscles. Muscle fiber properties in the GA correlate with running speed and acceleration on both level and vertical surfaces.
Area of Science:
- Zoology
- Biomechanics
- Vertebrate Physiology
Background:
- Maximum locomotor performance is vital for survival behaviors like hunting and predator evasion in vertebrates.
- Understanding the physiological determinants of maximum locomotor capacity, particularly muscle function, is crucial.
- While swing-phase muscles are often studied, stance-phase muscles, which generate propulsive force, may be more critical performance limiters.
Purpose of the Study:
- To investigate the relationship between hindlimb muscle properties and maximum locomotor performance in lizards.
- To compare the roles of stance-phase (gastrocnemius) and swing-phase (iliofibularis) muscles in determining running speed and acceleration.
- To identify which muscle group's characteristics are most predictive of locomotor capacity in a semi-arboreal lizard species.
Main Methods:
- Utilized level and vertical trackways to measure maximum running speed and acceleration in Sceloporus woodi.
- Employed high-speed videography (250 frames s⁻¹) for detailed kinematic analysis.
- Conducted histochemical analysis of gastrocnemius (stance) and iliofibularis (swing) muscles to quantify fiber types, diameters, and cross-sectional areas.
Main Results:
- Properties of the gastrocnemius (GA), a stance-phase muscle, were positively correlated with locomotor performance.
- No significant correlations were found between the iliofibularis (IF) muscle properties and performance.
- Specific GA muscle attributes correlated with performance on level tracks, while others correlated with vertical locomotion.
Conclusions:
- Stance-phase muscles, specifically the gastrocnemius, appear to be the primary limiters of maximum locomotor performance in this lizard species.
- The findings underscore the importance of considering stance-phase muscle physiology when studying locomotor capacity.
- Future research should integrate stance-phase muscle properties and diverse, ecologically relevant behaviors to better understand locomotor performance.
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