1,721,023 research outputs found
Strength training and gross-motor skill exercise as interventions to improve postural control, dynamic functional balance and strength in older individuals
No full textBACKGROUND: Loss of balance control is commonly experienced by older individuals. Despite the large amount of research on the effects of exercise on balance the optimal exercise regime is yet to be identified. Most studies have concentrated on strength training due to associations between muscle weakness, balance disfunction and fall risk. The effects of gross-motor skill exercise for balance and postural control have been less investigated. The study aimed to compare the effectiveness of strength training (STT) and gross-motor skill exercise (GMT) on static postural control, dynamic functional balance and strength in healthy older individuals. METHODS: Thirty-eight individuals (65-85 years) participated to GMT or STT for 12 weeks, twice weekly. They were tested pre- and post-training for postural control (Romberg and Tandem positions on a force platform), dynamic functional balance (maximal walking speed in balance-challenging conditions), maximal isometric handgrip strength, maximal knee flexor and extensor strength. RESULTS: Improvements were observed in static postural balance (tandem position, P<0.05, -1.07 mm/s), walking speed (hurdles P<0.01, +0.08 m/s; narrow path P<0.05, +0.07 m/s; picking up P<0.01, +0.07 m/s) knee extensor strength (P<0.001, +10.9 Nm); knee flexor strength improved significantly in the SST group only (P<0.001, +13.9 Nm). There was no correlation between changes in strength and balance. CONCLUSIONS: Static postural balance and dynamic functional balance in healthy elderly may be improved through exercise targeting either muscular strength or coordination, agility and mobility. The present study helps fill the gap in research on gross-motor skill exercise and proposes a suitable exercise alternative to strength for managing static and dynamic balance decline
Neuromuscular Junction Aging: A Role for Biomarkers and Exercise
Full text linkAge-related skeletal muscle degradation known as 'sarcopenia' exerts considerable strain on public health systems globally. While the pathogenesis of such atrophy is undoubtedly multifactorial, disruption at the neuromuscular junction (NMJ) has recently gained traction as a key explanatory factor. The NMJ, an essential communicatory link between nerve and muscle, undergoes profound changes with advancing age. Ascertaining whether such changes potentiate the onset of sarcopenia would be paramount in facilitating a timely implementation of targeted therapeutic strategies. Hence, there is a growing level of importance to further substantiate the effects of age on NMJs, in parallel with developing measures to attenuate such changes. As such, this review aimed to establish the current standpoint on age-related NMJ deterioration and consequences for skeletal muscle, while illuminating a role for biomarkers and exercise in ameliorating these alterations. Recent insights into the importance of key biomarkers for NMJ stability are provided, while the stimulative benefits of exercise in preserving NMJ function are demonstrated. Further elucidation of the diagnostic and prognostic relevance of biomarkers, coupled with the therapeutic benefits of regular exercise may be crucial in combatting age-related NMJ and skeletal muscle degradation
Reliability of walking speed in basic and complex conditions in healthy, older community-dwelling individuals
Full text linkLow Volume, Home-Based Weighted Step Exercise Training Can Improve Lower Limb Muscle Power and Functional Ability in Community-Dwelling Older Women
Full text linkStepping exercise can be used as a scalable form of high intensity exercise to enhance important aspects of physical fitness in older populations. The addition of supplementary weights increases the resistive element of stepping, with the potential for training improvements in muscular strength, power, and functional abilities alongside other fitness outcomes. The aim of this study was to evaluate the effects of a low-volume, home-based weighted step exercise programme on muscular strength, power, and functional ability in previously inactive community-dwelling older women. Eleven participants, aged between 65−74 years, independently completed a six-week individualised and progressive step exercise training programme wearing a weighted vest. Knee extensor strength, lower limb power output, and physical function using a battery of functional tests were measured at baseline, following a 6-week control period, and again following the 6-week training programme. Following training, lower limb power output improved by 10−11% (p < 0.05) and was accompanied by a corresponding 9% (p < 0.01) improvement in stair climb time and 10% (p < 0.01) improvement in normalised stair climbing power, highlighting the beneficial effects of weighted stepping for transferable improvements in functional fitness. The magnitude of observed training improvements suggest that weighted step training has the potential to prolong independence and prevent age-related health conditions such as sarcopenia
Dual-energy x-ray absorptiometry derived body composition trajectories across adulthood: reference values and associations with body roundness index and body mass index
Full text linkBackground
Population-specific reference values are needed to accurately contextualise age-related changes in body composition. This study aimed to a) establish age- and sex-specific reference values and cut-points for a range of dual-energy x-ray absorptiometry (DXA) derived metrics of lean mass (LM), fat mass (FM) and bone mineral density (BMD), across adulthood in a large adult cohort; and b) determine the association between DXA-derived body composition, body roundness index (BRI), and body mass index (BMI).
Methods
Cross-sectional data were collected from 10033 men and women aged from 18-92 years. Whole-body DXA scans were performed, and a range of metrics were calculated for LM (total LM, arm LM, leg LM, appendicular lean mass: ALM, skeletal muscle index: SMI), FM (total FM: kg and %, FMI, android to gynoid: A/G ratio) and bone (BMD). Cut-points equivalent to Z-scores of 1.0 - 2.5 SDs from the mean of a young reference population were established for each body composition metric.
Results
Detailed age- and sex-specific percentile curves were generated using the LMS method. Metrics of LM, central adiposity and BMD were higher in men, compared to women, whereas metrics of general FM accumulation were higher in women, compared to men. In both sexes, all LM metrics remained broadly stable during early and middle adulthood, after which progressively lower quantities were shown, whereas progressively higher FM metrics were shown from early adulthood through to late adulthood. In men, BMD was broadly stable across adulthood, whereas in women, markedly lower BMD was observed from the fifth decade of life. Significantly higher quantities of LM were shown across BMI categories, but not across BRI categories. The BRI was better correlated with FM%, FMI, and A/G ratio, compared to the BMI.
Conclusion
The reference values presented herein may support the interpretation of body composition in public health settings and the identification of people who may benefit from intervention to improve musculoskeletal and metabolic health. The BRI better reflects DXA-derived body composition and may provide screening utility beyond that of the BMI
The effect of a worksite based walking programme on cardiovascular risk in previously sedentary civil servants
Full text linkBackground: A significant proportion of Europeans do not meet the recommendations for 30 mins of physical activity 5 times per week. Whether lower frequency, moderate intensity exercise alters cardiovascular disease (CVD) risk has received little attention. This study examined the effects of 45 minutes self-paced walking, 2 d· wk-1 on aerobic fitness, blood pressure (BP), body composition, lipids and C-Reactive Protein (CRP) in previously sedentary civil servants. Methods: 37 subjects (24 women) aged 41.5 ± 9.3 years were randomly assigned to either two 45 minute walks per week (walking group) or no training (control group). Aerobic fitness, body composition, blood pressure (BP), CRP and lipoprotein variables were measured at baseline and following 8 weeks. Steps counts were measured at baseline and during weeks 4 and 8 of the intervention. Results: Compared to the control group, the walking group showed a significant reduction in systolic BP and maintained body fat levels (P < 0.05). There were no changes other risk factors. Subjects took significantly more steps on the days when prescribed walking was performed (9303 ± 2665) compared to rest days (5803 ± 2749; P < 0.001). Conclusion: These findings suggest that walking twice per week for 45 minutes at ~ 62% HRmax, improves activity levels, reduces systolic BP and prevents an increase in body fat in previously sedentary adults. This walking prescription, however, failed to induce significant improvements in other markers of cardiovascular disease risk following eight weeks of training
Handgrip strength asymmetry as a new biomarker for sarcopenia and individual sarcopenia signatures
Full text linkBackground: Although handgrip strength (HGS) asymmetry has clinical screening utility, its relevance to sarcopenia is unknown. This study examined the relationship between HGS asymmetry and sarcopenia signatures, and explored the relevance of circulating neural/neuromuscular markers. Methods: 9403 individuals aged 18-92 years participated in this study. Maximal HGS and skeletal muscle index (SMI) were determined using hand dynamometry and DXA. Sarcopenia was diagnosed upon the presence of low HGS and low SMI, according to cohort-specific thresholds. Plasma biomarkers were measured by ELISA in a sub-group of 269 participants aged 50-83 years. Asymmetry was determined as the highest recorded HGS divided by the highest recorded HGS of the opposite hand. Individuals with a ratio > 1.10 were classified as having asymmetrical HGS. Results: Subjects with asymmetrical HGS had significantly lower SMI (7.67 kg/m2 vs 7.71 kg/m2, p = 0.004) and lower HGS (37.82 kg vs 38.91 kg, p < 0.001) than those with symmetrical HGS. In those aged ≥ 50 years asymmetrical HGS was associated with 2.67 higher odds for sarcopenia [95% confidence interval: (CI) = 1.557-4.561, p < 0.001], 1.83 higher odds for low HGS only (CI 1.427-2.342, p < 0.001), and 1.79 higher odds for low SMI only (CI 1.257-2.554, p = 0.001). HGS asymmetry demonstrated acceptable diagnostic accuracy for sarcopenia (AUC = 0.727, CI 0.658-0.796, p < 0.001). Plasma neural cell adhesion molecule concentrations were 19.6% higher in individuals with asymmetrical HGS (185.40 ng/mL vs 155.00 ng/mL, p < 0.001) than those with symmetrical HGS. Discussion: Our findings demonstrate the utility of HGS asymmetry as a screening tool that may complement existing strategies seeking to combat sarcopenia. Biomarker analyses suggest that heightened denervation may be an important aetiological factor underpinning HGS asymmetry
Genetic Associations with Aging Muscle: A Systematic Review
Full text linkThe age-related decline in skeletal muscle mass, strength and function known as 'sarcopenia' is associated with multiple adverse health outcomes, including cardiovascular disease, stroke, functional disability and mortality. While skeletal muscle properties are known to be highly heritable, evidence regarding the specific genes underpinning this heritability is currently inconclusive. This review aimed to identify genetic variants known to be associated with muscle phenotypes relevant to sarcopenia. PubMed, Embase and Web of Science were systematically searched (from January 2004 to March 2019) using pre-defined search terms such as "aging", "sarcopenia", "skeletal muscle", "muscle strength" and "genetic association". Candidate gene association studies and genome wide association studies that examined the genetic association with muscle phenotypes in non-institutionalised adults aged ≥50 years were included. Fifty-four studies were included in the final analysis. Twenty-six genes and 88 DNA polymorphisms were analysed across the 54 studies. The ACTN3, ACE and VDR genes were the most frequently studied, although the IGF1/IGFBP3, TNFα, APOE, CNTF/R and UCP2/3 genes were also shown to be significantly associated with muscle phenotypes in two or more studies. Ten DNA polymorphisms (rs154410, rs2228570, rs1800169, rs3093059, rs1800629, rs1815739, rs1799752, rs7412, rs429358 and 192 bp allele) were significantly associated with muscle phenotypes in two or more studies. Through the identification of key gene variants, this review furthers the elucidation of genetic associations with muscle phenotypes associated with sarcopenia
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
