Article

Effects of Strength Training and Detraining on Muscle Quality: Age and Gender Comparisons

University of Maryland, Baltimore, Baltimore, Maryland, United States
The Journals of Gerontology Series A Biological Sciences and Medical Sciences (Impact Factor: 5.42). 03/2000; 55(3):B152-7; discussion B158-9. DOI: 10.1093/gerona/55.3.B152
Source: PubMed

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 (1RM) strength by quadriceps muscle
volume determined by magnetic resonance imaging. All groups demonstrated significant increases in 1RM 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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    • "A atividade física em idosos promove benefícios psicológicos e fisiológicos tais como o aumento da força muscular, equilíbrio, flexibilidade e consumo máximo de oxigénio (VO2máx) (Smith, Winegard, Hicks, & McCartney, 2003; Teixeira- Salmela et al., 2005), que levam a um aumento da independência e da qualidade de vida de mulheres idosas. Embora estes benefícios ocorram, as mulheres idosas estão sujeitas a períodos de interrupção durante a prática de programas de treino (Ivey et al., 2000; Lemmer et al., 2000) que podem provocar alterações fisiológicas, levando à redução dos benefícios obtidos com o exercício físico. A magnitude destas alterações poderá depender da duração do período de destreino (Izquierdo et al., 2007; Pereira et al., 2012) e da amplitude dos benefícios obtidos pelo exercício (Williams & Thompson, 2006). "
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    ABSTRACT: A atividade física proporciona benefícios para a saúde e qualidade de vida de mulheres idosas. Ainda são escassos os estudos longitudinais em mulheres idosas com duração superior a um ano de prática de exercício físico. Assim o objetivo do estudo foi analisar os efeitos de três anos de treino multicomponente na capacidade funcional de mulheres idosas. Métodos: 51 mulheres (66.7±5.30 anos e 159±0.11cm) participaram ao longo de três anos num programa constituído por períodos de nove meses de treino multicomponente seguidos de três meses de destreino. As avaliações decorreram no início/fim de cada período de treino e destreino. Resultados: No 1º, 2º e 3º ano verificaram-se aumentos estatisticamente significativos em todos os parâmetros da capacidade funcional (p<0.05). No entanto, o 2º ano revelou ser o período de treino onde observamos os maiores aumentos nos testes T6M (7.43%), SA (383.33%), AC (40.33%), FA (13.05%) e LS (12.5%) (p<0.05). Os testes T6M, LS, FA, AC, SA melhoraram entre 4.17% a 576.60% em todos os períodos de treino e diminuíram entre 3.21% a 85.31% em todos os períodos de destreino. Conclusões: Três anos de treino multicomponente contribuíram para a melhoria da capacidade funcional em mulheres idosas, principalmente no 2º ano de intervenção.
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    • "To our knowledge, this is the first study to compare the effects of volume on MQ of elderly women during short-term ST. The mechanisms responsible for training induced improvements in MQ are still unclear; however, neural adaptations (changes in motor unit recruitment, firing frequency, and summation of motor unit action potential synchronization) as well as enhancement of contractile properties may offer substantial support for the observed increases (Ivey et al. 2000; Tracy et al. 1999). The current results reinforce our previous findings that short-term ST is an effective method to improve MQ of elderly women (Pinto et al. 2014). "
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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.
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    • "Our results are in agreement with that of a previous study, which demonstrated that relative dynamic strength following training for HI remained increased above pre-training level after detraining (Ivey et al., 2000). Previous studies (Hakkinen et al., 2000; Kubo et al., 2010) reported that the muscle strength remained preserved in task-specific exercises during detraining. "
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    ABSTRACT: We investigated the effects of 3 weeks of detraining on muscle cross-sectional area (CSA) and one-repetition maximum strength (1-RM) in young men who had previously participated in 6 weeks (3 days week−1) of bench press training [blood flow restricted low-intensity (LI-BFR; n = 10, 20% 1-RM) or high-intensity (HI; n = 7, 75% 1-RM)]. Bench press 1-RM and muscle CSA of triceps brachii (TB) and pectoralis major (PM) were evaluated before (pre) and after training period (post) as well as after detraining period (detraining). Bench press 1-RM was higher at both post and detraining than at pre for LI-BFR (P<0·01) and the HI (P<0·01). TB and PM muscle CSA were higher at both post and detraining than at pre for the HI group (P<0·01), while the LI-BFR group only increased (P<0·01) at post. Relative dynamic strength (1-RM divided by TB muscle CSA) was higher at both post and detraining than at pre for the HI group (P<0·01), while the LI-BFR group only increased (P<0·01) at detraining. In conclusion, increased muscle strength following 6 weeks of training with LI-BFR as well as HI was well preserved at 3 weeks of detraining. HI-induced muscle strength appears to be dependent upon both neural adaptations and muscle hypertrophy with training and detraining. On the other hand, LI-BFR-induced muscle strength appears to be related primarily to muscle hypertrophy with training and to neural adaptations with detraining.
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