Comparing individual muscle size and strength responses in younger and older adults after prolonged resistance training
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Several weeks of systematic resistance exercise, termed resistance training (RT), increases muscle size and strength in both younger and older adults and is recognized as a key measure towards combatting age-related neuromuscular decline. Considerable inter-individual variation exists, however, in the adaptations to RT. Whether this inter-individual variation differs between younger and older adults has not been extensively studied. Further, whether baseline characteristics such as pre-training muscle size and strength can predict individual responses to RT is not definitively known. The purpose of this study was to determine the magnitude of inter-individual variability in responses to prolonged RT, whether it differs between younger and older adults, and whether pre-training characteristics are related to an individual’s response to RT. Data from three previous studies in untrained younger men and/or older men and women who performed 6-12 months of supervised, progressive, whole-body RT were pooled for this retrospective analysis. Participants (n = 156) were divided into a younger group (YOUNG, n = 65, 31.6 ± 7.0 years) and an older group (OLD, n = 91, 69.2 ± 2.7 years). Measurements of muscle size – vastus lateralis cross-sectional area (VLCSA) via ultrasound – and strength – quadriceps maximal voluntary contraction (QMVC) by isometric dynamometer – were completed pre- and post-intervention. Relative changes in VLCSA (ΔVLCSA) were greater in YOUNG (12.8 ± 9.3 %, range: -6.0 to +40.7 %) compared to OLD (5.3 ± 13.0 %, range: -19.5 to +49.9 %) (p < 0.001). Ten YOUNG participants (15 %) were classified as muscle size non-responders (post-testing score below the smallest worthwhile change of the measurement) compared to 58 OLD participants (64 %). There was a significant difference in the variability of muscle size changes between YOUNG and OLD (p = 0.014). Relative change in QMVC (ΔQMVC) did not differ between YOUNG (6.4 ± 17.3 %, range: -22.8 to +57.2 %) and OLD (9.2 ± 17.2 %, range: -43.0 to +67.8 %) (p = 0.321). Twenty-seven YOUNG participants (42 %) were classified as muscle strength non- responders compared to 26 OLD participants (29 %). The variability in muscle strength changes did not differ between YOUNG and OLD (p = 0.802). Smaller pre-training VLCSA was related to greater ΔVLCSA in YOUNG (r = -0.308, p = 0.012) but not OLD (r = -0.044, p = 0.679). Lower pre-training QMVC was related to greater ΔQMVC in both YOUNG (r = -0.353, p = 0.004) and OLD (r = -0.283, p = 0.007). This investigation shows the considerable heterogeneity that exists in the muscle size and strength adaptations to RT. Older adults appear to exhibit diminished and more variable muscle size but not strength responses to RT compared to younger adults. This indicates that RT prescriptions aimed at maximizing muscle growth may need to be differentiated for older populations. Additionally, pre-training values are only weakly correlated to the RT-induced changes in muscle size and strength indicating that many other factors contribute to the inter- individual variability in muscle size and strength responses to RT. ...
MetadataShow full item record
- Pro gradu -tutkielmat 
Showing items with similar title or keywords.
Acute neuromuscular and hormonal responses and long-term adaptations to hypertrophic resistance training : with special reference to constant versus variable resistance Walker, Simon (University of Jyväskylä, 2012)
Aging and strength training influence knee extensor intermuscular coherence during low- and high-force isometric contractions Walker, Simon; Avela, Janne; Wikgren, Jan; Meeusen, Romain; Piitulainen, Harri; Baker, Stuart; Parviainen, Tiina (Frontiers Research Foundation, 2019)Aging is associated with reduced maximum force production and force steadiness during low-force tasks, but both can be improved by training. Intermuscular coherence measures coupling between two peripheral surface ...
High Responders to Hypertrophic Strength Training Also Tend to Lose More Muscle Mass and Strength During Detraining Than Low Responders Räntilä, Aapo; Ahtiainen, Juha P.; Avela, Janne; Restuccia, Joel; Kidgell, Dawson; Häkkinen, Keijo (Lippincott Williams & Wilkins, 2021)This study investigated differences in individual responses to muscle hypertrophy during strength training and detraining. Ten weeks of resistance training was followed by 6 weeks of detraining in men (n 5 24). Bilateral ...
Effects of eccentric and concentric isokinetic bench press training on dynamic strength, isometric force production and triceps brachii cross-sectional area Wanttaja, Ryan (2020)Background. Engaging in resistance training programmes is an integral part of the physical preparation process for athletes. The neural and morphological mechanisms underpinning eccentric contractions are notably different ...
Effects of resistance training frequency on muscle strength, activity and mass during a 24-week intervention in the elderly Alonso Serrano, Javier (2016)Elderly populations are increasingly affected by sarcopenia, dynapenia and osteoporosis. They all increase frailty and decrease quality of life and life-expectancy. Resistance training (RT) has been reported extensively ...