I am currently investigating skeletal muscle ageing for my PhD.
Sarcopenia is attributed to a loss in independence, how can exercise ensure healthy ageing?
What is sarcopenia? The age-related loss of muscle mass and function has been extensively studied, but the term sarcopenia was first coined by Rosenberg in 1989 which means in literal terms loss of flesh. It is expected that by 2045 the number of adults aged 65 – 100 years with sarcopenia will rise by 72.4%..
How does sarcopenia affect my muscles? As we all age, our muscle volume, mass and the speed at which they contract declines. As there is less lean tissue we are con subsequently unable to produce as much force or power making everyday living difficult and thus reduce our quality of life. It is thought that this process affects males to a greater extent than females, at least until the menopause in women.
What about my ability to move? As a direct result of reduced force and power production, we are as a consequence less mobile. Moreover, older adults are at much greater risk of falls as a result of muscle wasting. The combination of the two leads to reduced physical activity levels thus creating a negative cycle of activity leading to further functional loss.
What can I do to prevent this from happening to me? Unfortunately like all good things in life, they must eventually come to a gradual end and this is no different for our muscles. However, engaging in regular physical activity can reduce the speed of the decline in muscle function, as found in a study comparing older males who completed lifelong football training to age-matched sedentary counterparts. Even if you have not engaged in physical activity all your life then all is not lost. Men aged 83-94 years old completing 12 weeks of resistance training 3 times a week resulted in a significant increase in muscle size and a staggering 91% increase in one-repetition max!
To ensure maintenance of muscle function with age exercise really is the best medicine.
Abstract: The present study investigated whether elderly subjects exposed to lifelong football training have better rapid muscle force characteristics, body composition and postural stability in comparison with untrained elderly. Ten elderly men exposed to lifelong football training (FTE; 69.6 +/- 1.4 years) and eight age-matched untrained elderly men (UE; 70.5 +/- 1.0 years) were studied and 49 untrained young men (UY; 32.4 +/- 0.9 years) served as a reference group. FTE showed an elevated rate of force development (RFD) and impulse at 0-30, 100 and 200 ms (relative RFD at 1/6 MVC: 567 +/- 39 vs 353 +/- 42% MVC/s), higher total lean body mass (56.9 +/- 0.8 vs 52.7 +/- 2.2 kg) and better postural stability (Flamingo test: 15 +/- 1 vs 33 +/- 2 falls) compared with UE (P<0.05), with no difference between FTE and UY. The proportion of type IIA fibers was higher and the area percentage of type IIX fibers was lower in FTE than in UE (P<0.05). Rapid muscle force characteristics and postural stability were consistently higher in elderly subjects exposed to lifelong football training, providing an enhanced ability to counteract unexpected perturbations in postural balance. The superior RFD and balance in elderly footballers were of such a magnitude that no deficit could be observed when compared with young untrained individuals.
Pub.: 10 Mar '10, Pinned: 14 Apr '17
Abstract: Sarcopenia is a major public health issue. To convince health policy makers of the emergency to invest in the sarcopenia field, it is of critical importance to produce reliable figures of the expected burden of sarcopenia in the coming years. Age- and gender-specific population projections were retrieved until 2045 from the Eurostat online database (28 European countries). Age- and gender-specific prevalences of sarcopenia were interpolated from a study that compared prevalence estimates according to the different diagnostic cutoffs of the EWGSOP proposed definition. The reported prevalence estimates were interpolated between 65 and 100 years. Interpolated age- and gender-specific estimates of sarcopenia prevalence were then applied to population projections until 2045. Using the definition providing the lowest prevalence estimates, the number of individuals with sarcopenia would rise in Europe from 10,869,527 in 2016 to 18,735,173 in 2045 (a 72.4% increase). This corresponds to an overall prevalence of sarcopenia in the elderly rising from 11.1% in 2016 to 12.9% in 2045. With the definition providing the highest prevalence estimates, the number of individuals with sarcopenia would rise from 19,740,527 in 2016 to 32,338,990 in 2045 (a 63.8% increase), corresponding to overall prevalence rates in the elderly of 20.2% and 22.3% for 2016 and 2045, respectively. We showed that the number of sarcopenic patients will dramatically increase in the next 30 years, making consequences of muscle wasting a major public health issue.
Pub.: 25 Dec '16, Pinned: 14 Apr '17
Abstract: Fall-related injuries are a leading cause of institutionalization and morbidity in older adults. Limitations in cognition, including deficits in higher cognitive processes, like executive function (EF), contribute to a higher risk of falling in older adults. Specifically, declines in EF have been associated with changes in gait, limited mobility, and an increased frequency of falling. It is unknown whether associations between performance on commonly used clinical assessments of EF and performance on commonly used physical performance measures of fall risk are present. The purpose of this study was to examine the relationship between a clinical measure of EF, the Trail Making Test Part B (TMT-B), and 3 physical performance measures of fall risk: the Timed Up and Go (TUG) test, gait speed, and the Five Times Sit to Stand (FTSTS) test, in a group of community-dwelling older adults.Forty-seven community-dwelling older adults met the inclusion/exclusion criteria. Demographic information was obtained and measures of fall risk and cognition were performed. Correlations and linear regression analyses to assess relationships between measures were completed. To account for the high prevalence of mild cognitive impairment (MCI) in this population, the sample was screened and stratified for MCI in post hoc analyses.The EF performance was not significantly correlated with performance on the FTSTS test (ρ = 0.26, P > .05) but was significantly correlated with the TUG test (ρ = 0.31, P < .05) and gait speed (r = -0.36, P < .05). These relationships remained after adjusting for age and education in multivariate models. Results from post hoc analyses demonstrated that only those with MCI had significant relationships between EF and physical performance measures. TMT-B scores in the MCI group were significantly correlated with gait speed (ρ = -0.51, P < .05) and TUG test (ρ = 0.58, P < .05).A significant relationship exists between performance on clinical assessments of EF and fall risk assessments that integrate a mobility task for those individuals who screen positive for MCI. For those who screened negative, no significant relationship exists. Given the large prevalence of undiagnosed MCI in community-dwelling older adults, this finding could be used as an indication to screen older adults for MCI.Screening tools that require cognitive resources such as gait speed appear to have significant relationships with performance of EF for those who screen positive for MCI. This information could be used clinically to identify older adults with cognitive limitations, which could put them at higher risk for falling.
Pub.: 08 Jun '15, Pinned: 14 Apr '17
Abstract: A consensus conference convened by the Society of Sarcopenia, Cachexia and Wasting Disorders has concluded that "Sarcopenia, ie, reduced muscle mass, with limited mobility" should be considered an important clinical entity and that most older persons should be screened for this condition. "Sarcopenia with limited mobility" is defined as a person with muscle loss whose walking speed is equal to or less than 1 m/s or who walks less than 400 m during a 6-minute walk, and who has a lean appendicular mass corrected for height squared of 2 standard deviations or more below the mean of healthy persons between 20 and 30 years of age of the same ethnic group. The limitation in mobility should not clearly be a result of otherwise defined specific diseases of muscle, peripheral vascular disease with intermittent claudication, central and peripheral nervous system disorders, or cachexia. Clinically significant interventions are defined as an increase in the 6-minute walk of at least 50 meters or an increase of walking speed of at least 0.1 m/s.
Pub.: 07 Jun '11, Pinned: 14 Apr '17
Abstract: Age-related loss of muscle mass and function represents personal and socioeconomic challenges. The purpose of this study was to determine the adaptation of skeletal musculature in very old individuals (83+ years) performing 12weeks of heavy resistance training (3×/week) (HRT) compared to a non-training control group (CON). Both groups received similar protein supplementations. We studied 26 participants (86.9±3.2 (SD) (83-94, range) years old) per-protocol. Quadriceps cross-sectional area (CSA) differed between groups at post-test (P<0.05) and increased 1.5±0.7cm(2) (3.4%) (P<0.05) in HRT only. The relative increase in CSA correlated inversely with the baseline level of CSA (R(2)=0.43, P<0.02). Thigh muscle isometric strength, isokinetic peak torque and power increased significantly only in HRT by 10-15%, whereas knee extension one-repetition maximum (1 RM) improved by 91%. Physical functional tests, muscle fiber type distribution and size did not differ significantly between groups. We conclude that in protein supplemented very old individuals, heavy resistance training can increase muscle mass and strength, and that the relative improvement in mass is more pronounced when initial muscle mass is low.
Pub.: 02 Apr '17, Pinned: 14 Apr '17
Abstract: Muscle physiology in the aging athlete is complex. Sarcopenia, the age-related decrease in lean muscle mass, can alter activity level and affect quality of life. This review addresses the microscopic and macroscopic changes in muscle with age, recognizes contributing factors including nutrition and changes in hormone levels, and identifies potential pharmacologic agents in clinical trial that may aid in the battle of this complex, costly, and disabling problem.Level 5.
Pub.: 16 Jan '14, Pinned: 13 Apr '17
Abstract: Aging in humans is associated with a loss in neuromuscular function and performance. This is related, in part, to the reduction in muscular strength and power caused by a loss of skeletal muscle mass (sarcopenia) and changes in muscle architecture. Due to these changes, the force-velocity (f-v) relationship of human muscles alters with age. This change has functional implications such as slower walking speeds. Different methods to reverse these changes have been investigated, including traditional resistance training, power training and eccentric (or eccentrically-biased) resistance training. This review will summarise the changes of the f-v relationship with age, the functional implications of these changes and the various methods to reverse or at least partly ameliorate these changes.
Pub.: 04 Nov '09, Pinned: 13 Apr '17
Abstract: Changes in the neuromuscular system affecting the ageing motor unit manifest structurally as a reduction in motor unit number secondary to motor neuron loss; fibre type grouping due to repeating cycles of denervation‐reinnervation; and instability of the neuromuscular junction that may be due to either or both of a gradual perturbation in postsynaptic signalling mechanisms necessary for maintenance of the endplate acetylcholine receptor clusters or a sudden process involving motor neuron death or traumatic injury to the muscle fibre. Functionally, these changes manifest as a reduction in strength and coordination that precedes a loss in muscle mass and contributes to impairments in fatigue. Regular muscle activation in postural muscles or through habitual physical activity can attenuate some of these structural and functional changes up to a point along the ageing continuum. On the other hand, regular muscle activation in advanced age (>75 years) loses its efficacy, and at least in rodents may exacerbate age‐related motor neuron death. Transgenic mouse studies aimed at identifying potential mechanisms of motor unit disruptions in ageing muscle are not conclusive due to many different mechanisms converging on similar motor unit alterations, many of which phenocopy ageing muscle. Longitudinal studies of ageing models and humans will help clarify the cause and effect relationships and thus, identify relevant therapeutic targets to better preserve muscle function across the lifespan.
Pub.: 21 Dec '15, Pinned: 13 Apr '17
Abstract: three major strategies have been tested for combating the losses in muscle mass and strength that accompany ageing. Those strategies are testosterone replacement for men, growth hormone replacement and resistance exercise training. This review will cover the risks and benefits associated with each of these interventions.searches of PubMed and Web of Science through May 2004 yielded 85 relevant citations for the following descriptors: sarcopenia, aging/ageing, elderly, testosterone, hormone replacement, growth hormone, resistance training, exercise, muscle mass, nutrition and strength.testosterone replacement in elderly hypogonadal men produces only modest increases in muscle mass and strength, which are observed in some studies and not in others. Higher doses have not been given for fear of accelerating prostate cancer. Growth hormone replacement in elderly subjects produces a high incidence of side-effects, does not increase strength and does not augment strength gains resulting from resistance training. Some alternate strategies for stimulating the growth hormone/insulin-like growth factor (IGF) pathway continue to hold promise. The latter include growth hormone releasing hormone (GHRH) and the complex of IGF-I with its major circulating binding protein (IGF-I/IGFBP-3). Resistance training remains the most effective intervention for increasing muscle mass and strength in older people. Elderly people have reduced food intake and increased protein requirements. As a result, adequate nutrition is sometimes a barrier to obtaining full benefits from resistance training in this population.
Pub.: 24 Sep '04, Pinned: 13 Apr '17
Abstract: The present review describes several age related changes in the neuromuscular system of humans and animals which may underlie the marked strength decline of ageing muscle. Studies describing the effects of resistance training on the muscle strength of ageing humans and animals are also reviewed. From a survey of these studies, the strength decline with age appears to be due, in part, to a loss of muscle mass. While not conclusive, the effect of resistance training has been to attenuate the extent of the atrophy occurring with age, and to improve strength. A better understanding of the neuromuscular mechanisms of ageing, as well as the adaptive response of ageing mammalian muscle to resistance training, could enable physical therapists to critically evaluate the merits of strength training intervention for improving the physical ability of an ageing individual.
Pub.: 01 Jan '92, Pinned: 13 Apr '17
Abstract: In the ageing muscle, many changes occur. Some are on an architectural level, like alterations in muscle composition, or modifications in the characteristics of the muscle fiber itself, where muscle fiber length, orientation and type change. Other changes are neuronal, which occur on all levels, from the central activation over the spinal properties down to the level of the motor unit and the neuromuscular junction. There are also hormonal factors that undergo agerelated concentration variations. All these alterations in the muscle have an effect on both strength and function. In this matter, they contribute to the process of sarcopenia. Although many different components are identified, it is still unclear to what degree these components contribute to the loss of muscle mass, strength and function. This review summarizes the occurring physiological and anatomical changes within the ageing muscle and links them to outcomes such as strength and function.
Pub.: 22 Jan '16, Pinned: 13 Apr '17
Abstract: To determine the association between loss of muscle strength, mass, and quality and functional limitation and physical disability in older men.Cross-sectional study of older men participating in the Concord Health and Ageing in Men Project (CHAMP).Elderly men living in a defined geographical region in Sydney, Australia.One thousand seven hundred five community-dwelling men aged 70 and older who participated in the baseline assessments of CHAMP.Upper and lower extremity strength were measured using dynamometers for grip and quadriceps strength. Appendicular skeletal lean mass was assessed using dual X-ray absorptiometry. Muscle quality was defined as the ratio of strength to mass in upper and lower extremities. For each parameter, subjects in the lowest 20% of the distribution were defined as below normal. Functional limitation was assessed according to self-report and objective lower extremity performance measures. Physical disability was measured according to self-report questionnaire.After adjusting for important confounders, the prevalence ratio (PR) for poor quadriceps strength and self-reported functional limitation was 1.91 (95% confidence interval (CI) = 1.10-2.40); for performance-based functional limitation the PR was 1.81 (95% CI = 1.45-2.24). The adjusted PR for poor grip strength and physical disability in instrumental activities of daily living (IADLs) was 1.37 (95% CI = 1.20-1.56). The adjusted PR for low skeletal lean mass (adjusted for fat mass) and physical disability in basic activities of daily living was 2.08 (95% CI = 1.37-3.15). For muscle quality, the PR for lower extremity specific force and functional limitation and physical disability was stronger than upper extremity specific force.Muscle strength is the single best measure of age-related muscle change and is associated with physical disability in IADLs and functional limitation.
Pub.: 09 Nov '10, Pinned: 13 Apr '17
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