|Mix of muscle types. Likely sprinter.|
|(C;C)||2.2||Better performing muscles. Likely sprinter.|
|(C;T)||2.1||Mix of muscle types. Likely sprinter.|
|(T;T)||2.2||Impaired muscle performance. Likely endurance athlete.|
Normal for white people. One working and one defective copy of the gene for alpha-actinin-3 in fast-twitch muscle fibres. This genotype may indicate somewhat impaired muscles,[PMID 18043716] however many sprinters and some endurance athletes have this.