Longitudinal impact of aging on muscle quality in middle-aged men

Abstract

The present follow-up study aims at assessing the longitudinal changes in muscle quality after an interval of 9.45 years in middle-aged men. In addition, the relative contribution of muscle mass, muscle strength, and muscle power at middle age to these changes was investigated. The results showed a small, though unexpected, increase in total body and leg muscle mass (respectively 0.22 ± 0.04 and 0.29 ± 0.06 % yearly, p<0.0001), whereas basic strength (−0.71 to −0.87 % yearly, p<0.0001) and velocity-dependent strength and power (−1.19 to −1.86 % yearly, p<0.0001) declined. Consequently, muscle quality, defined as the ratio of basic strength or velocity-dependent strength and power to muscle mass decreased (−1.46 to −2.43 % yearly, p<0.0001) from baseline to follow-up. We found that baseline basic strength is a strong determinant of the decline in muscle quality basic strength with advancing age, whereas only a small part of the age-associated decline in muscle quality based on velocity-dependent strength and power could be explained. To conclude, our results indicate that muscle becomes less efficient at middle age and that baseline muscle strength is a strong predictor of this change. These findings imply that unmeasured neural factors, influencing both contraction speed and the capacity of muscle to produce strength, are possibly other involved determinants. Therefore, timely interventions including strength training and higher-velocity strength training at middle age are recommended.

Age-related decline in muscle mass and muscle function in Flemish Caucasians: a 10-year follow-up

“…However, if we only considered subjects above 46 years of age, Δ percentage/year was −0.96 ± 2.16 % in women and −0.77 ± 2.28 % in men. This is in agreement with the findings of Kennis et al (2014): they observed a decrease of 0.71 ± 0.24 % per year in isokinetic strength at 60°/s in a subsample of this study (n = 105 men, age = 46.93 ± 0.06 years.). If we considered the oldest age category (+60 years), Δ percentage/year was −1.53 ± 2.67 % in women and −1.06 ± 2.27 % in men (Table 4).…”

“…Nevertheless, results between studies are similar, pointing out losses in muscle mass of up to 12.9 and 5.3 % after a 9.7-year followup period in men and women, respectively, aged 45-75 years (Hughes et al 2001). In addition, isometric strength decreased with~0.87 % per year in men aged between 45 and 49 years, whereas declines in isokinetic strength were up to 2.56 % per year at 60°/s and 4.20 % per year at 240°/s in 62-81-year-old men and women (Frontera et al 2008;Kennis et al 2014).…”

Effects of elastic band resistance training and nutritional supplementation on muscle quality and circulating muscle growth and degradation factors of institutionalized elderly women: the Vienna Active Ageing Study (VAAS)

“…In this respect, MQ can be regarded as a marker of muscle efficiency. Kennis et al ( 2014 ) showed that although the quantity of muscle even increased in middle-aged men within a period of 9.5 years, their strength- and power-generating capacity strongly declined resulting in a loss of MQ of 1.5–2.4 % per year. Several studies reveal that strength training programmes improve MQ even in elderly (Fragala et al 2014 ; Radaelli et al 2014 ; Ring-Dimitriou et al 2009 ), but general knowledge about the association of MQ with biochemical markers of muscle growth and degradation is scarce.…”

Strength training-induced responses in older adults: attenuation of descending neural drive with age

“…In contrast, heavy resistance training (∼80 % of 1RM) is shown to effectively restore muscle strength in moderately old (60-75 years) subjects to a similar level as active young after only 3-4 months (Kosek et al 2006). Although the typical age-related alterations in muscle strength may partly be explained by changes in muscle mass, there are indications that neural properties may also play a conspicuous role (Young et al 1985;Klitgaard et al 1990;Kamen et al 1995;Jubrias et al 1997;Roos et al 1997;Morse et al 2004;Kennis et al 2014), both in the typically observed decline with age and as a part of training-induced strength adaptations. However, evidence regarding the role of the neural drive, especially involving supraspinal factors, is limited during maximal muscle contractions.…”