Associations of muscle force, power, cross‐sectional muscle area and bone geometry in older UK men

Abstract

BackgroundAgeing is associated with sarcopenia, osteoporosis, and increased fall risk, all of which contribute to increased fracture risk. Mechanically, bone strength adapts in response to forces created by muscle contractions. Adaptations can be through changes in bone size, geometry, and bending strength. Muscle mass is often used as a surrogate for muscle force; however, force can be increased without changes in muscle mass. Increased fall risk with ageing has been associated with a decline in muscle power—which is a measure of mobility. The aims of this study were as follows: (i) to investigate the relationship between muscle parameters in the upper and lower limbs with age in UK men and the influence of ethnicity on these relationships; (ii) to examine the relationships between jump force/grip strength/cross‐sectional muscle area (CSMA) with bone outcomes at the radius and tibia.MethodsWhite European, Black Afro‐Caribbean, and South Asian men aged 40–79 years were recruited from Manchester, UK. Cortical bone mineral content, cross‐sectional area, cortical area, cross‐sectional moment of inertia, and CSMA were measured at the diaphysis of the radius and tibia using peripheral quantitative computed tomography. Lower limb jump force and power were measured from a single two‐legged jump performed on a ground‐reaction force platform. Grip strength was measured using a dynamometer. Associations between muscle and bone outcomes was determined using linear regression with adjustments for age, height, weight, and ethnicity.ResultsThree hundred and one men were recruited. Jump force was negatively associated with age; for every 10 year increase in age, there was a 4% reduction in jump force (P < 0.0001). There was a significant age–ethnicity interaction for jump power (P = 0.039); after adjustments, this was attenuated (P = 0.088). For every 10 year increase in age, grip strength decreased by 11%. Jump force was positively associated with tibial bone outcomes: a 1 standard deviation greater jump force was associated with significantly higher cortical bone mineral content 3.1%, cross‐sectional area 4.2%, cortical area 3.4%, and cross‐sectional moment of inertia 6.8% (all P < 0.001). Cross‐sectional muscle area of the lower leg was not associated with tibial bone outcomes. Both grip strength and CSMA of the arm were positively associated, to a similar extent, with radius diaphyseal bone outcomes.ConclusionsJump force and power are negatively associated with age in UK men. In the lower limb, the measurement of jump force is more strongly related to bone outcomes than CSMA. It is important to consider jump force and power when understanding the aetiology of bone loss and mobility in ageing men.

Age-dependent effects of caloric restriction on mTOR and ubiquitin-proteasome pathways in skeletal muscles

“…One well-studied characteristic is muscle mass. Skeletal muscles decrease in size with aging (Chen et al 2015;Zengin et al 2017). Using the same research design as the present study (e.g., same ages), we found muscle mass decreased 10-20% in rats between 8 (young) and 20 months of age (middle-aged) (Chen et al 2015).…”

Muscle wasting and sarcopenia in heart failure: a brief overview of the current literature

“…The mean age of this population was 70.1 years, and the prevalence of sarcopenia was 36.5%. 23 These findings buttress the loss in muscle strength with advancing age. Tyrovolas et al used data from 18 363 people aged 65 years or older who participated in the Collaborative Research on Ageing in Europe survey that was conducted in Finland, Poland, and Spain as well as data from the World Health Organization Study on Global Ageing and Adult Health Survey conducted in China, Ghana, India, Mexico, Russia, and South Africa.…”

“…Interestingly, jump force was positively associated with tibial bone outcomes. 23 These findings buttress the loss in muscle strength with advancing age. They also serve as a basis for understanding the increased risk of falls as assessed in the STRAMBO study.…”

Bone in heart failure

“…Muscle forces cause the largest burden on bones and the largest bone strains. Skeletal unloading due to prolonged bed rest or poor exercise capacity in HF patients leads to bone loss via reductions in the mechanical forces applied to bones . The mechanism of this bone loss appears to be a consequence of a decrease in the bone formation rate and a concurrent increase in the bone resorption rate .…”