Author(s): Bryce Black, Lee J. Hinkle
Mentor(s): A. Wayne Johnson
Institution BYU
Greater muscle mass in old age prevents injury and compresses morbidity. Muscle mass begins to decline, however, 3-8% per year around the age of 30. PURPOSE: We aim to quantify the specific impact of age on eccentric hamstring strength in older adults for each sex. METHODS: Participants in Huntsman World Senior Games (HWSG) over age 50 (n=151) completed a demographic survey including the International Physical Activity Questionnaire (IPAQ) and performed an eccentric hamstring strength test on Nordbord to measure eccentric hamstring force production. For each sex we performed a simple linear regression looking at age as a predictor of total force production. RESULTS: For females (n=75; height: 166 ± 8.87 cm; weight: 65.7 ± 10.3 kg; total force: 310 ± 105 N), the model predicting total force by age alone found adj-R2 = 0.027, f-statistic = 3.018, degrees of freedom = 73, p = 0.087. For males (n=76; height: 178 ± 9.23 cm; weight: 82.2 ± 10.8 kg; total force: 461 ± 138 N) the model predicting total force by age alone found adj-R2 = 0.209, f-statistic = 7.584, degrees of freedom = 72, p = 0.00018. CONCLUSION: Less than 3% of female force production was explained by age; nearly 21% was explained by age in males. Age may not be an accurate predictor for decreased hamstring strength in females. This data questions whether hamstring muscle mass declines at a rate of 3-8% annually for females over the age of 50. There is a much stronger relationship between age and hamstring strength decline in males.