Alterations in Muscle Attenuation following Detraining and Retraining in Resistance-Trained Older Adults

Abstract

Background: Aging skeletal muscle is characterized not only by a reduction in size (sarcopenia) and strength but also by an increase in fatty infiltration (myosteatosis). An effective countermeasure to sarcopenia is resistance exercise; however, its effect on fatty infiltration is less clear. Objective: To examine in resistance-trained older persons whether muscle attenuation, a noninvasive measure of muscle density reflecting intramuscular lipid content, is altered with training status. Methods: Thirteen healthy community-dwelling men and women aged 65–83 years (body mass index 27.0 ± 1.2, mean ± SE) had computed-tomography scans of the mid-thigh performed following 24 weeks of training, 24 weeks of detraining, and 12 weeks of retraining. Training and retraining were undertaken twice weekly for several upper- and lower-body muscle groups. Skeletal muscle attenuation in Hounsfield units (HU) as well as mid-thigh muscle volume was obtained for the quadriceps and hamstrings. Muscle strength was assessed by 1-repetition maximum and physical function by a battery of tests. Results: The average change in muscle strength following training, detraining and retraining was 48.8 ± 2.9%, –17.6 ± 1.3%, and 19.8 ± 2.0%, respectively. Strength changes were accompanied by significant alterations in muscle density (p < 0.001), with the quadriceps HU decreasing by 7.7 ± 1.0% following detraining and increasing by 5.4 ± 0.5% with retraining. For the hamstrings HU measure, detraining and retraining resulted in an 11.9 ± 1.4% loss and a 5.5 ± 1.8% gain, respectively. There was no significant change in muscle volume. Conclusion: Cessation of resistance exercise in trained older persons increases the fatty infiltration of muscle, while resumption of exercise decreases it. Monitoring changes in both muscle size and fat infiltration may enable a more comprehensive assessment of exercise in combating age-related muscular changes.

The wasting continuum in heart failure: from sarcopenia to cachexia

“…Overend et al (41) described more than 20 years ago that, even though total thigh cross-sectional area is not different between young and elderly men, older men have 13 % lower total muscle plus bone area, 26 % lower quadriceps and 18 % lower hamstring area. Using computed tomography imaging, Taaffe et al (42) recently described that cessation of resistance exercise in trained older persons increases the fatty infiltration of muscle, while resumption of exercise decreases it. This effect adds to the development of mitochondrial dysfunction that is evident in the elderly and possibly a consequence of oxidative damage by reactive oxygen species (29,43) ; reduced energy production may also play a role in the development of myocyte apoptosis discussed later (44) .…”

Associação entre sarcopenia, obesidade sarcopênica e força muscular com variáveis relacionadas de qualidade de vida em idosas

“…This low FFM and high FM condition has been termed sarcopenic obesity. A study reported that sarcopenic obesity was associated with worse physical function than obesity or sarcopenia alone 16 , and thus it has been identified as an important cause of frailty among the elderly [17][18][19] . Thus, it may influence quality of life, although further study is required.…”

Effects of Exercise Interventions in Older Adults with Knee Osteoarthritis

“…Hence, changing thigh muscle and fat mass may decrease knee joint loading. Taafee et al [8] showed that high-intensity strength training significantly decreases fatty infiltration of the quadriceps in 65-to 83-year-old adults. We suggest that high-intensity strength training can impact the mechanical disease pathway to knee osteoarthritis by increasing thigh muscle function and decreasing thigh fat depots, resulting in long-term improvement in pain and function and possibly attenuate disease progression.…”