Abstract
Older adults are encouraged to engage in multicomponent physical activity, which includes aerobic and muscle-strengthening activities. The current work is an extension of the Vitality, Independence, and Vigor in the Elderly 2 (VIVE2) study - a 6-month multicenter, randomized, placebo-controlled trial of physical activity and nutritional supplementation in community dwelling 70-year-old seniors. Here, we examined whether the magnitude of changes in muscle size and quality differed between major lower-extremity muscle groups and related these changes to functional outcomes. We also examined whether daily vitamin-D-enriched protein supplementation could augment the response to structured physical activity. Forty-nine men and women (77±5yrs) performed brisk walking, muscle-strengthening exercises for the lower limbs, and balance training 3 times weekly for 6months. Participants were randomized to daily intake of a nutritional supplement (20g whey protein+800IU vitamin D), or a placebo. Muscle cross-sectional area (CSA) and radiological attenuation (RA) were assessed in 8 different muscle groups using single-slice CT scans of the hip, thigh, and calf at baseline and after the intervention. Walking speed and performance in the Short Physical Performance Battery (SPPB) were also measured. For both CSA and RA, there were muscle group × time interactions (P<0.01). Significant increases in CSA were observed in 2 of the 8 muscles studied, namely the knee extensors (1.9%) and the hip adductors (2.8%). For RA, increases were observed in 4 of 8 muscle groups, namely the hip flexors (1.1HU), hip adductors (0.9HU), knee extensors (1.2HU), and ankle dorsiflexors (0.8HU). No additive effect of nutritional supplementation was observed. While walking speed (13%) and SPPB performance (38%) improved markedly, multivariate analysis showed that these changes were not associated with the changes in muscle CSA and RA after the intervention. We conclude that this type of multicomponent physical activity program results in significant improvements in physical function despite relatively small changes in muscle size and quality of some, but not all, of the measured lower extremity muscles involved in locomotion.
Highlights
Age-related loss of muscle mass, physical- and muscular function (i. e., sarcopenia), is associated with hospitalization, morbidity, loss of independence and increased mortality, and carries a financial burden to society (Baumgartner et al, 1998; Janssen et al, 2004; Cruz-Jentoft et al, 2019; Bhasin et al, 2020)
The current study examined the effects of a structured multicom ponent physical activity program combined with nutritional supple mentation on muscle size and density of several major locomotor muscles of the hip, thigh, and calf in community-dwelling older in dividuals with low vitamin D levels
By examining the response of 8 different muscle groups covering the major joints involved in locomotion, this substudy extends the findings of our previous report on the entire VIVE2 cohort (United States and Sweden) (Englund et al, 2017) and other studies that typically report on the quadriceps muscle group
Summary
Age-related loss of muscle mass, physical- and muscular function (i. e., sarcopenia), is associated with hospitalization, morbidity, loss of independence and increased mortality, and carries a financial burden to society (Baumgartner et al, 1998; Janssen et al, 2004; Cruz-Jentoft et al, 2019; Bhasin et al, 2020). As resistance exercise is the best known strategy to increase or maintain muscle mass and function, current physical activity guidelines recommend that older people undertake at least two sessions per week of muscle-strengthening activities, in addi tion to aerobic exercise and balance training (Piercy et al, 2018; Bull et al, 2020) Against this background, we previously carried out the Vitality, Independence, and Vigor in the elderly 2 Study (VIVE2) study – a 6-month multicenter, randomized, placebo-controlled trial of 70year-old community dwelling seniors (Kirn et al, 2015). Given the non-standardized muscle involve ment in the various exercises used in multicomponent physical activity, we hypothesized that the magnitude of muscle hypertrophy and strength gains would vary between key locomotor muscles This is not necessarily a problem as improvements in physical function can occur independently of morphological adaptations. There is evidence that muscle mass and function follow different trajectories (Clark and Manini, 2012), and several changes within muscle fibers during aging, such as reduced calcium signaling, myosin concentration and mitochondrial function, could compromise muscle function without affecting muscle size (D'Antona et al, 2003; Tieland et al, 2018)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
