Knee strength balance ratios are not affected by aging among male runners

Abstract

Objectives This study aimed to assess thigh muscular strength, conventional and functional strength balance ratios, and muscle quality in well-trained male runners aged 20–70 yr. Methods Eighty-nine male runners were divided into five age categories: 20–29, 30–39, 40–49, 50–59, and 60–70 yr. Participants underwent an isokinetic strength test for knee flexor and extensor muscles and a body composition analysis via dual-energy X-ray absorptiometry. Results No significant difference was observed in concentric peak torque of the knee extensor muscles between the 20–29 and 40–49 age groups. However, the 50–59 age group showed significantly lower strength than the 20–29 age group (p = 0.049), and the 60–70 age group demonstrated significantly lower strength than the 40–49 group (p < 0.001). The conventional and functional balance ratios remain stable across all age groups. Conclusion Knee flexor and extensor strength in male runners decreases significantly after the age of 50, while conventional and functional strength balance ratios remain stable.