Effects Of Age, Gender, And Myostatin Genotype On The Hypertrophic Response To Heavy Resistance Strength Training

By Ty Sevin, Sep 01, 2021

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Ivey FM, Roth SM, Ferrell RE, Tracy BL, Lemmer JT, Hurlbut DE, Martel GF, Siegel EL, Fozard JL, Jeffrey Metter E, Fleg JL, Hurley BF. Department of Kinesiology, College of Health and Human Performance, University of Maryland College Park 20742, USA.

Objectives

The primary purpose of this study was to compare muscle mass responses of young and older men and women to the same relative strength training (ST) and detraining protocols. A second aim was to assess the possible role of myostatin genotype on muscle mass response to ST. Twenty two young men and women (age 21-29 years), and 23 older men and women (age 65-75 years), had both quadriceps muscle volumes measured using magnetic resonance imaging (MRI) before and after ST and detraining. Training consisted of knee extension exercises of the dominant leg three times per week for 9 weeks. The non-dominate leg was left untrained throughout the ST program. Subjects then underwent 31 weeks of detraining during which no regular exercise was performed. Myostatin genotype was determined in a subgroup of two subjects, of which five female subjects were carriers of a myostatin gene variant.

Results

Muscle volume increased significantly in the trained leg of all groups. A significantly greater absolute increase in muscle volume was observed in men than in women (204 +/-20 vs 101 +/- 13 cm3, p < .01), but there was no significant difference in muscle volume response to ST between young and older individuals. The gender effect remained after adjusting for baseline muscle volume. In addition, there was a significantly greater loss of absolute muscle volume after 31 weeks of detraining in men than in women (151 +/- 13 vs 88 +/- 7 cm3, p < .05), but no significant difference between young and older individuals. Myostatin genotype did not explain the hypertrophic response to ST when all 32 subjects were assessed. However, when only women were analyzed, those with the less common myostatin allele exhibited a 68% larger increase in muscle volume in response to ST.

Conclusion

This study shows that aging does not affect the muscle mass response to either ST or detraining when comparing young and older individuals in the same study using the same training protocol, whereas gender does. Men increased their muscle volume about twice as much in response to ST as women did, and experienced larger losses in response to detraining than women. Myostatin genotype may play a role in the hypertrophy response to strength training for women, but future studies are needed with larger subject numbers in each genotype group to confirm this observation. This study makes it clear that aging skeletal muscle retains the capacity to fully adapt to a strength training stimulus.

Published in the Journal of Gerontology A Biol Sci Med Sci 2000 Nov;55(11):M641-8

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About the author

Ty Sevin

Director of Human Performance, Education and Research

Articles by Ty Sevin >

With over 25 years of coaching experience at both the collegiate and Olympic levels, Ty Sevin is one of the most influential track and field coaches in the country. Ty has worked for the United States Olympic Committee, serving as the Director of the Track and Field Residency Program at the USOC Olympic Training Center in Chula Vista, CA. He has also served as an assistant coach for Team USA on three separate occasions, for both the men’s and women’s teams. Ty himself was a four-time U.S. Olympics Trials qualifier in javelin. Ty most recently spent four years as the Associate Head Coach at the University of Texas at Austin for both the men’s and women’s track and field teams. Prior to that, he led the men’s and women’s track and cross-country teams at the University of New Orleans and McNeese State.

Currently, Ty applies his vast industry experience to the role of Director of Human Performance, Research and Education for Keiser Corporation, where he consults with college and professional sports teams regarding the utilization of Keiser strength equipment. He is also responsible for creating educational curriculum relating to human performance and overseeing Keiser research projects