Is PPARα intron 7 G/C polymorphism associated with muscle strength characteristics in nonathletic young men?

Peroxisome proliferator-activated receptor alpha (PPAR), a ligand-dependent transcription factor, regulates fatty acid metabolism in heart and skeletal muscle. The intron 7 G/C polymorphism (rs4253778) has been associated with athletic performance. The rare C-allele was predominant in power athletes, whereas the G-allele was more frequent in endurance athletes. In the present study, we investigated the association between this polymorphism and strength characteristics in nonathletic, healthy young adults (n=500; age 24.2 +/- 4.4 years). Knee torque was measured during concentric knee flexion and extension movements at 60 degrees/s, 120 degrees/s, and 240 degrees/s during 3, 25, and 5 repetitions, respectively. Also, resistance to muscle fatigue (i.e. work last 20% repetitions/work first 20% repetitions *100) was calculated. Differences in knee strength phenotypes between GG homozygous individuals and C-allele carriers were analyzed. The polymorphism did not influence the ability to produce isometric or dynamic knee flexor or extensor peak torque during static or dynamic conditions in this population (0.23 <0.95). Similar results were found for the endurance ratio, a measure for resistance to muscle fatigue. In conclusion, the PPAR intron 7 G/C polymorphism does not seem to influence strength characteristics in a nonathletic population.