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Related Experiment Video

Updated: Jun 8, 2026

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Published on: November 1, 2012

ACTN3 genotype does not influence muscle power.

E D Hanson¹, A T Ludlow, A K Sheaff

¹University of Maryland, Department of Kinesiology, School of Public Health, College Park, MD 20742, United States.

International Journal of Sports Medicine

|September 11, 2010

Summary

This summary is machine-generated.

The ACTN3 R577X gene variant does not impact muscle power in recreationally active individuals. This suggests the ACTN3 R577X polymorphism is likely only relevant for elite athletes, not the general population.

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Area of Science:

Exercise Physiology
Human Genetics
Sports Science

Background:

The ACTN3 R577X polymorphism is linked to athletic performance, but its influence on specific muscle power traits is unclear.
Existing research shows inconsistencies regarding the ACTN3 R577X genotype's effects on strength and power phenotypes.

Purpose of the Study:

To investigate the association between the ACTN3 R577X genotype and muscle power phenotypes in recreationally active adults.
To clarify the role of the ACTN3 R577X polymorphism in determining muscle performance characteristics.

Main Methods:

Recruited 57 recreationally active men and women.
Assessed muscle performance using an isokinetic fatigue protocol (180°/s and 250°/s) and a 30-second Wingate test.
Analyzed isokinetic torque, Wingate power, and fatigue index in relation to ACTN3 genotype groups.

Main Results:

No significant differences in isokinetic peak torque, Wingate peak power, or fatigue index were found among ACTN3 genotype groups.
The rate of decline in isokinetic torque and Wingate power during fatigue protocols did not differ between genotype groups.
Muscle performance phenotypes were not associated with the ACTN3 R577X polymorphism in this cohort.

Conclusions:

The ACTN3 R577X polymorphism does not appear to influence muscle power phenotypes in recreationally active individuals.
These findings support the notion that the R577X variant's significance may be limited to elite athletic performance.
Genetic screening using the ACTN3 R577X polymorphism in the general population is not scientifically supported by this study's results.