Original Editor - Wendy Walker Show
Top Contributors - Wendy Walker, Lucinda hampton, Andeela Hafeez, Kim Jackson, Vidya Acharya, Uchechukwu Chukwuemeka, Tony Lowe, Tarina van der Stockt, WikiSysop, Simisola Ajeyalemi, Claire Knott, Rucha Gadgil, Amrita Patro, Lauren Lopez, Admin, Evan Thomas and Lizzie Cotton Aging effects all body organs and systems is the skeletal muscle. As we age our muscles undergo progressive changes, primarily involving loss of muscle mass and strength.
[3] Sarcopenia - consequences[edit | edit source]Sarcopenia is not a disease but rather refers specifically to the universal, involuntary decline in lean body mass that occurs with age, primarily due to the loss of skeletal muscle. Systematic review and meta-analyses among Japanese community-dwelling older adults suggest the prevalence of sarcopenia (9.9% overall: 9.8% among men, and 10.1% among women), providing valuable information in addressing sarcopenia prevention in the older community[4]. A narrative review published in International Journal of Molecular Sciences (2020) provides new evidence regarding the mechanisms, evaluation and detection methods, and spinal sarcopenia treatment modalities[5]. Sarcopenia has important consequences.
A systematic review and meta-analysis suggest a higher prevalence of Sarcopenia in individuals with Cardiovascular disease (CVD), dementia, diabetes mellitus, and respiratory disease[9]. [edit | edit source]With increasing age, we lose muscle mass: lean muscle mass contributes up to 50% of total body weight in young adults, but this decreases to 25% by 75 to 80 years[10]. Typical muscle changes with age: Reduction in lower limb muscle cross-sectional area have been observed to begin in early adulthood and accelerate beyond 50 years of age.This reduction in muscle cross-sectional area associated with decreases in contractile structures accompanied by increases in non contractile structures such as fat and connective tissue.[11] A cross-sectional study[12] suggested that the older inpatient showed an increase in the intramuscular quadricep muscle adipose tissue approx 1.7 times that of the healthy older individuals. Also, the study observed increased intramuscular adipose tissue with older inpatients who were unable to walk independently as compared to older inpatients who were able to walk freely. Reduced muscle strength[edit | edit source]The total number of muscle fibers is significantly reduced with age, beginning at about 25 years and progressing at an accelerated rate thereafter The decline in muscle cross-sectional area is most likely due to decreases in total fiber number, especially type II fast-twitch glycolytic fibers. This results in reduced muscle power.[11] A study examining 1-year changes in the physical functioning of older people using the ICF framework showed a significant decrease in muscle strength (both hip abductors and knee extensors) walking capacity, speed, mobility, sit-to-stand performance, upper extremity function, and balance performance at the end of 1 year[13]. Muscle Fibre changes:[edit | edit source]
Elderly individuals often fall because of poor muscle strength and reduced balancing ability related to muscle aging. Types IIA and IIB muscle fibers decrease with age in the area percentage, fiber number percentage, and mean fiber area, whereas Type I fibers increase in area and number but not in size. Morphologically, Type II fibers appeared smaller and flatter. Investigations suggest deterioration in muscle quality and balancing coordination in elderly patients. A research done provided data to help determine treatments for reversing muscle fiber changes and reducing the number of falls and related fractures in patients.[14]The reduction in number of muscle fibers contributes more to the decrease of whole muscle cross-sectional area than does the reduction in area of individual fibers. The individual fast-twitch type II fibers decrease in cross-sectional area suggest that the relative contribution of fast-twitch type II fibers to force generation is less in the older adult. 2. Motor Unit Number and Size In the aged motor unit there are decreased in the number of functional motor units associated with enlargement of the cross sectional area of the remaining units. This motor unit remodelling is achieved by selective denervation of muscle fibers, (especially type 2 b fibres) followed by re-ennervation by axonal spouting from juxtaposed innervation units.
Effects of Endocrine Changes on Muscle[edit | edit source]With increased age, the following changes in endocrine function result in sarcopenia: Conditions Associated with Impairment of Skeletal Function[edit | edit source]Physiotherapy Interventions to Minimise or Reverse Sarcopenia[edit | edit source]Outcomes Measure: SARC-F: A Simple Questionnaire to Rapidly Diagnose Sarcopenia Resistance exercise training: The effects of resisted exercise on ageing muscles are the same as for young muscles:
Evidence: Population studies Resistance or weight training has been demonstrated to produce increases in muscle strength and power, and also mobility function, in older people living in the following settings: A Systematic Review of Randomized Controlled Trials suggested that a low dose of creatine monohydrate along with resisted exercises may improve upper and lower extremities strength in healthy older adults[27]. A randomized control trial in 72 prefrail adults (65 yrs and above) with mild-to-moderate fall risk found significant improvement in fall risk, proprioception, muscle strength, reaction time, postural sway and health-related quality of life with the Multi-system Physical Exercise (MPE) which consisted of proprioceptive, muscle strengthening, reaction time, and balance training exercises[28]. Gender differences[edit | edit source]Increased muscle quality from resistance training is a common finding in older adults, and in men there appears to be no difference in young versus old[29], but there is a study that suggests that older women have a blunted response relative to younger women[30]. Frequency of resistance training[edit | edit source]Studies have demonstrated that resistance training regimes performed once, twice or even three times a week all result in strength improvements[22]. Length of training programme[edit | edit source]There are many studies which clearly demonstrate that older people who participate in resistance training programs lasting at least 6 to 12 weeks will show increase in both strength and mobility function[31][32][33]. Cochrane Review[edit | edit source]The authors collated the results from 121 RCTs examining the effects of resistance strength training exercises, and came to the following conclusions: "This review provides evidence that PRT (Progressive resistance strength training) is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported."[34] Dietary Advice[edit | edit source]The Society for Sarcopenia, Cachexia, and Wasting convened an expert panel to develop nutritional recommendations for sarcopenia prevention and management.This panel concluded that for preventing and treating this condition key components are
The greatest effects are observed when resistance training and high protein diets are combined and appear to act synergistically.
Is there a role for supplements?[edit | edit source]There is some evidence suggesting that additional supplementation with the amino acid Leucine (or its metabolite HMB) could potentially increase the effects of resistance training to combat sarcopenia[36][37]. A randomised double-blind study has found that supplementation with l-leucine can be used in the treatment of sarcopenia in older individuals[38]. Resources[edit | edit source]References[edit | edit source]
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