Effects of strength training and detraining on muscle quality: age and gender comparisons.
ABSTRACT Maximal force production per unit of muscle mass (muscle quality, or MQ) has been used to describe the relative contribution of non-muscle-mass components to the changes in strength with age and strength training (ST). To compare the influence of age and gender on MQ response to ST and detraining, 11 young men (20-30 years), nine young women (20-30 years), 11 older men (65-75 years), and 11 older women (65-75 years), were assessed for quadriceps MQ at baseline, after 9 weeks of ST, and after 31 weeks of detraining. MQ was calculated by dividing quadriceps one repetition maximum (IRM) strength by quadriceps muscle volume determined by magnetic resonance imaging. All groups demonstrated significant increases in IRM strength and muscle volume after training (all p < .05). All groups also increased their MQ with training (all p < .01), but the gain in MQ was significantly greater in young women than in the other three groups (p < .05). After 31 weeks of detraining, MQ values remained significantly elevated above baseline levels in all groups (p < .05), except the older women. These results indicate that factors other than muscle mass contribute to strength gains with ST in young and older men and women, but those other factors may account for a higher portion of the strength gains in young women. These factors continue to maintain strength levels above baseline for up to 31 weeks after cessation of training in young men and women, and in older men.
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ABSTRACT: The purpose of this study was to examine the effects of nine weeks of unilateral high volume, heavy resistance strength training (HRST) and 31 weeks of detraining on the three regions (proximal, middle, distal) of the quadriceps in young (25 yrs) and older (69 yrs) men and women. Quadriceps CSA was assessed as a difference of the trained leg minus the untrained leg (T-UT). A multi-way ANOVA with repeated measures revealed that after HRST, young men had significantly higher CSA (T-UT) compared to young women in all three regions (6.7 ± 1.4, 9.3 ± 1.4, 7.8 ± 1.2 versus 2.3 ± 1.5, 3.4 ± 1.5, 1.7 ± 1.3 cm 2). Older men displayed significantly higher CSA (T-UT) in the proximal region compared to older women after HRST (6.4 ± 1.3 versus 2.4 ± 1.3 cm 2). Both age groups had similar CSA (T-UT) values after HRST and after 31 weeks of detraining. Thus, age did not influence the magnitude of the increase in regional CSA (T-UT) after HRST nor did it influence the degree of loss after 31 weeks of detraining.
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ABSTRACT: The strength training has been shown to be effective for attenuating the age-related physiological decline. However, the adequate volume of strength training volume adequate to promote improvements, mainly during the initial period of training, still remains controversial. Thus, the purpose of this study was to compare the effects of a short-term strength training program with single or multiple sets in elderly women. Maximal dynamic (1-RM) and isometric strength, muscle activation, muscle thickness (MT), and muscle quality (MQ = 1-RM and MT quadriceps quotient) of the knee extensors were assessed. Subjects were randomly assigned into one of two groups: single set (SS; n = 14) that performed one set per exercise or multiple sets (MS; n = 13) that performed three-sets per exercise, twice weekly for 6 weeks. Following training, there were significant increases (p ≤ 0.05) in knee extension 1-RM (16.1 ± 12 % for SS group and 21.7 ± 7.7 % for MS group), in all MT (p ≤ 0.05; vastus lateralis, rectus femoris, vastus medialis, and vastus intermedius), and in MQ (p ≤ 0.05); 15.0 ± 12.2 % for SS group and 12.6 ± 7.2 % for MS group), with no differences between groups. These results suggest that during the initial stages of strength training, single- and multiple-set training demonstrate similar capacity for increasing dynamic strength, MT, and MQ of the knee extensors in elderly women.Age 12/2014; 36(6):9720. DOI:10.1007/s11357-014-9720-6 · 3.45 Impact Factor
Article: MUSCLE AGING AND INFLAMMATION[Show abstract] [Hide abstract]
ABSTRACT: Human ageing is associated with a significant decline in neuromuscular function and performance (Doherty et al, 1993a, Ross et al, 1997 and Vandervoort, 2002). The term sarcopenia was first used by Rosenberg (Rosenberg, 1989), to describe age associated loss of skeletal muscle mass. Sarcopenia is now generally used to describe age-associated changes that occur within skeletal muscle and thus include the effects of altered central and peripheral nervous system innervation, altered hormonal status, altered caloric and protein intake and inflammatory effects. All these contribute to sarcopenia and to the characteristic skeletal muscle atrophy and weakness, which are considered major contributing factors to the loss of functional mobility, independence and frailty present in many elderly (Roubenoff and Hughes, 2000; Roubenoff et al. 2001). Because our society is an ageing one, understanding the underlying mechanisms of sarcopenia is essential for the development of effective interventions to prevent disability and optimize quality of life in older people. This review will focus on the potential role of inflammatory factors in sarcopenia and on the effects of exercise interventions.