Can aerobic training improve muscle strength and power in older men?

Influence of exercise type and duration on cardiorespiratory fitness and muscular strength in post-menopausal women: a systematic review and meta-analysis

Background and aim

Both cardiorespiratory fitness (CRF) and muscular strength are reported to decrease with age and menopause, which considered to be risk for cardiovascular diseases (CVDs). Previous relevant meta-analyses are inconclusive on the beneficial effects of exercise, particularly in post-menopausal women. In this systematic review and meta-analysis, we investigated the effects of exercise modalities on CRF and muscular strength in post-menopausal women, and identified the effective exercise type and duration.

Methods

A comprehensive search was conducted on PubMed, Web of Science, CINAHL, and Medline to identify the randomized controlled trials, which evaluated exercise effect on CRF, lower- and upper-body muscular strength, and/or handgrip strength in post-menopausal women and compared the results with control. Standardized mean differences (SMD), weighted mean differences (WMD), and 95% confidence intervals (95% CIs) were calculated using random effects models.

Results

A total of 129 studies comprising 7,141 post-menopausal women with mean age and BMI ranging from ∼53 to 90 years and 22 to 35 kg/m², respectively, were included in the meta-analysis. Overall, exercise training effectively increased CRF (SMD: 1.15; 95% CI: 0.87, 1.42; p = 0.001), lower-body muscular strength (SMD: 1.06; 95% CI: 0.90, 1.22; p = 0.001), upper-body muscular strength (SMD: 1.11; 95% CI: 0.91, 1.31; p = 0.001), and handgrip strength (WMD: 1.78 kg; 95% CI: 1.24, 2.32; p = 0.001) in post-menopausal women. These increments were found to be irrespective of ages and intervention durations. Regarding exercise type, aerobic, resistance, and combined training significantly increased CRF and lower-body muscular strength, while resistance and combined training effectively increased handgrip strength. However, only resistance training increased the upper-body muscular strength in women.

Conclusion

Our findings suggest that exercise training is effective in increasing CRF and muscular strength in post-menopausal women, which might be cardioprotective. Both aerobic and resistance training alone or in combination increased CRF and lower-body muscular strength, but only resistance training increased upper-body strength in women.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=283425, identifier: CRD42021283425.

Muscle Power in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

This study aimed to review the impact of training on muscle power in patients with chronic obstructive pulmonary disease (COPD). Randomized controlled trials evaluating the effects of exercise-based interventions on limbs muscle power and rate of force development in COPD patients were investigated. Five international databases were searched until October 2022. Meta-analyses were performed calculating the mean difference or standardized mean difference. Risk of bias in studies was assessed using Cochrane Risk of Bias tool 2.0. A total of nine studies were included in the analysis. There were concerns about risk of bias in seven out of nine studies. Comparison of exercising and non-exercising groups showed a significant effect of exercise in improving muscle power (P=0.0004) and rate of force development (P<0.001), in five and three trials, respectively. Four studies comparing different trainings showed no significant results on muscle power (P=0.45). Eight to 16 weeks of exercise-based intervention versus no intervention might be beneficial to enhance upper and lower limbs muscle power and rate of force development in people with COPD. In contrast, muscle power did not improve when different training modalities were compared. Future studies performing power training in COPD patients are encouraged.

Sarcopenia and Ageing

Musculoskeletal ageing is a major health challenge as muscles and bones constitute around 55-60% of body weight. Ageing muscles will result in sarcopenia that is characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes. In recent years, a few consensus panels provide new definitions for sarcopenia. It was officially recognized as a disease in 2016 with an ICD-10-CM disease code, M62.84, in the International Classification of Diseases (ICD). With the new definitions, there are many studies emerging to investigate the pathogenesis of sarcopenia, exploring new interventions to treat sarcopenia and evaluating the efficacy of combination treatments for sarcopenia. The scope of this chapter is to summarize and appraise the evidence in terms of (1) clinical signs, symptoms, screening, and diagnosis, (2) pathogenesis of sarcopenia with emphasis on mitochondrial dysfunction, intramuscular fat infiltration and neuromuscular junction deterioration, and (3) current treatments with regard to physical exercises and nutritional supplement.

Surface electromyographic activity of the erector spinae and multifidus during arm- and leg-ergometer exercises in young healthy men

Objectives: Ergometer exercise was considered a new loading method that can be used for participants who are unable to assume the core strengthening exercise posture commonly used to strengthen the erector spinae and multifidus. This study aimed to investigate with healthy participants whether arm and leg ergometers could be used for core strengthening exercises and whether different exercise sites would affect the results. Methods: The study was conducted with 15 healthy adult male participants aged 20-35 years. The intervention consisted of arm- and leg-ergometer exercises performed by the participants. The exercise protocol consisted of three 1-min sessions (rest, 50W, and 100 W), which were measured consecutively. Surface electromyography (sEMG) was measured during the sessions. Maximal voluntary contraction (MVC) of the erector spinae and multifidus was also measured, during which sEMG was measured. The sEMG during ergometer exercise was calculated as a percentage of the MVC (calculated as % MVC). The root mean square (RMS) was recorded from the sEMG activity. Muscle activity of the erector spinae and multifidus was compared between ergometer exercises and between intensity levels. Heart rate (HR) was recorded by electrocardiogram. Results: In the arm-ergometer exercise, the % MVC values of the erector spinae were 6.3 ± 3.1, 10.9 ± 5.4, and 16.9 ± 8.3% at rest, 50 W, and 100 W conditions, respectively. The multifidus was 4.6 ± 2.9, 9.2 ± 5.6, and 12.6 ± 7.6% at rest, 50 W, and 100 W conditions, respectively. The respective % MVC values during the leg-ergometer exercise were 3.8 ± 1.7, 7.2 ± 3.8, and 10.4 ± 4.0% at rest, 50 W, and 100 W conditions, respectively. Leg-ergometer exercises were 2.6 ± 2.1, 6.9 ± 5.7, and 10.3 ± 6.8% at rest, 50 W, and 100 W conditions, respectively. The activities of the two muscles increased at comparable levels with increased workload in both types of exercises (p < 0.01, each). HR increased with the increased workload and the increase was larger during arm-than leg-ergometer exercises. Conclusion: These results demonstrate that both arm- and leg-ergometer exercises are potentially alternative methods for erector spinae and multifidus training for healthy participants. Further research is needed to target elderly.

The effects of the home-based exercise during COVID-19 school closure on the physical fitness of preschool children in China

BACKGROUND

Social distancing and school closures during the COVID-19 pandemic reduced the physical activities of the preschool children living in China. However, the effects of home-based exercise on the physical fitness of Chinese preschool children during COVID-19 school closures are still unknown. This study aimed to investigate the effects of home-based exercise on the physical fitness of Chinese preschool children during COVID-19 school closure.

METHODS

In this retrospective analysis, data from 1,608 Chinese preschool children (aged 3-5.5 years) in a second-tier city of Guangdong Province of China (Zhongshan city) were extracted from three successive National Physical Fitness Measurement (NPFM) from 2019 to 2021. NPFM consists of weight, height, and six subtests of physical fitness including 10-m shuttle run test (SRT), standing long jump (SLJ), balance beam walking (BBW), sit-and-reach (SR), tennis throwing (TT), and double-leg timed hop (DTH) tests. The change differences or change ratios of all the items in NPFM between any two successive years from 2019 to 2021 were compared. The exercise profiles about home-based and outdoor exercise before, during, and after COVID-19 school closure were obtained from 185 preschool children via retrospective telephone survey.

RESULTS

Between 2019 and 2021, 1,608 preschool children were included in this study. We observed larger changes in SLJ, SR, TT, and DTH tests during school closure than after school closure. But the children showed lower reduction rates in the completion time of SRT and BBW. During school closure, higher change ratios in SLJ and TT were observed in the children primarily participating in home-based exercise than those primarily participating in outdoor exercise. However, no statistical differences were observed in the changes in SRT and BBW between home-based and outdoor training groups.

CONCLUSION

The home-based exercise program might be an alternative approach to improve the physical fitness of preschool children during COVID-19 school closure, but could not be beneficial to speed-agility and balance functions. A specific guideline geared toward a home-based exercise program during the COVID-19 outbreak is highly needed.

Concurrent endurance and resistance training enhances muscular adaptations in individuals with metabolic syndrome

The purpose of the study was to determine if concurrent training (endurance and resistance in a single session) elicits leg muscular adaptations beyond the ones obtained by endurance training alone in sedentary individuals with metabolic syndrome (MetS). Sixty-six MetS individuals (37% women, age 56 ± 7 years, BMI 32 ± 5 kg m^-2 and 3.8 ± 0.8 MetS factors) were randomized to undergo one of the following 16-week isocaloric exercise programs: (i) 4 + 1 bouts of 4 min at 90% of HR_MAX of intense aerobic cycling (IAC + IAC group; n = 33), (ii) 4 IAC bouts followed by 3 sets of 12 repetitions of 3 lower-limb free-weight exercises (IAC + RT group; n = 33). We measured the effects of training on maximal cycling power, leg press maximum strength (1RM), countermovement jump height (CMJ), and mean propulsive velocity (MPV) at workloads ranging from 10% to 100% of baseline 1RM leg press. After intervention, MetS components (Z-score) improved similarly in both groups (p = 0.002). Likewise, maximal cycling power during a ramp test improved similarly in both groups (time effect p < 0.001). However, leg press 1RM improved more in IAC + RT than in IAC + IAC (47 ± 5 vs 13 ± 5 kg, respectively, interaction p < 0.001). CMJ only improved with IAC + RT (0.8 ± 0.2 cm, p = 0.001). Leg press MPV at heavy loads (ie, 80%-100% 1RM) improved more with concurrent training (0.12 ± 0.01 vs 0.06 ± 0.02 m s^-1 , interaction p = 0.013). In conclusion, in unconditioned MetS individuals, intense aerobic cycling alone improves leg muscle performance. However, substituting 20% of intense aerobic cycling by resistance training further improves 1RM leg press, MPV at high loads, and jumping ability while providing similar improvement in MetS components.

Dose-Response Relationship between Endurance Training Prescription Variables and Increases in Aerobic Performance of Healthy and Unhealthy Middle and Very Old Individuals Aged 70 Years and Older: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: The objectives of this systematic review and meta-analysis were to quantify the effectiveness of endurance training (ET) on aerobic performance (i.e., peak oxygen uptake (VO_2peak)) in healthy and unhealthy middle and very old adults aged 70 years and older, and to provide dose–response relationships of training prescription variables (in terms of frequency, and volume). Methods: Several scholarly databases (i.e., PubMed/MEDLINE, SpringerLink, ScienceDirect Journals, and Taylor & Francis Online—Journals) were searched, identifying randomized controlled studies that investigated the effectiveness of ET on VO_2peak in older adults. Standardized mean differences (SMD) were calculated. Results: In terms of changes differences between experimental and control group, ET produced significant large effects on VO_2peak performance (SMD = 2.64 (95%CI 0.97–4.31)). The moderator analysis revealed that “health status” variable moderated ET effect onVO_2peak performance. More specifically, ET produced larger SMD magnitudes on VO_2peak performance in healthy compared with unhealthy individuals. With regard to the dose–response relationships, findings from the meta-regression showed that none of the included training prescription variables predicted ET effects on VO_2peak performance. Conclusions: ET is an effective mean for improving aerobic performance in healthy older adults when compared with their unhealthy counterparts.

Perspective: Pragmatic Exercise Recommendations for Older Adults: The Case for Emphasizing Resistance Training

Optimal health benefits from exercise are achieved by meeting both aerobic and muscle strengthening guidelines, however, most older adults (OAs) do not exercise and the majority of those who do only perform one type of exercise. A pragmatic solution to this problem may be emphasizing a single exercise strategy that maximizes health benefits. The loss of muscle mass and strength at an accelerated rate are hallmarks of aging that, without intervention, eventually lead to physical disability and loss of independence. Additionally, OAs are at risk of developing several chronic diseases. As such, participating in activities that can maintain or increase muscle mass and strength, as well as decrease chronic disease risk, is essential for healthy aging. Unfortunately, there is a widely held belief that adaptations to aerobic and resistance exercise are independent of each other, requiring the participation of both types of exercise to achieve optimal health. However, we argue that this assertion is incorrect, and we discuss crossover adaptations of both aerobic and resistance exercise. Aerobic exercise can increase muscle mass and strength, though not consistently and may be limited to exercise that overloads a particular muscle group, such as stationary bicycling. In contrast, resistance exercise is effective at maintaining muscle health with increasing age, and also has significant effects on cardiovascular disease (CVD) risk factors, type 2 diabetes (T2D), cancer, and mortality. We posit that resistance exercise is the most effective standalone exercise strategy for improving overall health in OAs and should be emphasized in future guidelines.

Effect of high-intensity interval training and continuous endurance training on peak oxygen uptake among seniors aged 65 or older: A meta-analysis of randomized controlled trials

BACKGROUND

Ageing is intrinsically associated with a progressive decline in cardiorespiratory fitness (CRF) as measured by peak oxygen uptake (VO_2peak ). Improving CRF through physical activity contribute to better and healthy ageing. High-intensity interval training (HIIT) is a potent method of improving CRF among seniors, yet comparisons between this type of training and traditional endurance training (ET) are equivocal especially among older adults.

PURPOSE

To analyse the effects of HIIT and ET on the VO_2peak of seniors aged 65 years or older when compared with controls and also when the two types of training were compared with one another.

METHODS

A comprehensive, systematic database search for manuscripts was performed in Embase, Medline, PubMed Central, ScienceDirect, Scopus and Web of Science using key words. Two reviewers independently assessed interventional studies for potential inclusion. Fifteen randomized controlled trials (RCTs) were included totalling 480 seniors aged 65 years or over. Across the trials, no high risk of bias was measured.

RESULTS

In pooled analysis of the RCTs, the VO_2peak was significantly higher after ET sessions compared with controls (mean difference-MD = 1.35; 95% confidence interval-CI: 0.73-1.96). Furthermore, VO_2peak was found significantly higher not only when compared HIIT with controls (MD = 4.61; 95% CI: 3.21-6.01), but also when compared HIIT with ET (MD = 3.76; 95% CI: 2.96-4.56).

CONCLUSION

High-intensity interval training and ET both elicit large improvements in the VO_2peak of older adults aged 65 or over. When compared with ET, the gain in VO_2peak was greater following HIIT. Nevertheless, further RCTs are therefore needed to confirm our results in senior's population.

Skeletal muscle size, function, and adiposity with lifelong aerobic exercise

We examined the influence of lifelong aerobic exercise on skeletal muscle size, function, and adiposity. Young exercisers [YE; n = 20, 10 women (W), 25 ± 1 yr], lifelong exercisers (LLE; n = 28, 7 W, 74 ± 2 yr), and old healthy nonexercisers (OH; n = 20, 10 W, 75 ± 1 yr) were studied. On average, LLE exercised 5 days/wk for 7 h/wk over the past 52 ± 1 yr. The LLE men were subdivided by exercise intensity [Performance (LLE-P), n = 14; Fitness (LLE-F), n = 7]. Upper and lower leg muscle size and adiposity [intermuscular adipose tissue (IMAT)] were determined via MRI, and quadriceps isotonic and isometric function was assessed. For the quadriceps, aging decreased muscle size, isotonic and isometric strength, contraction velocity (men only), and power (P < 0.05). In women, LLE did not influence muscle size or function. In men, LLE attenuated the decline in muscle size and isometric strength by ~50% (P < 0.05). LLE did not influence other aspects of muscle function, nor did training intensity influence muscle size or function. For the triceps surae, aging decreased muscle size only in the women, whereas LLE (both sexes) and training intensity (LLE men) did not influence muscle size. In both sexes, aging increased thigh and calf IMAT by ~130% (P < 0.05), whereas LLE attenuated the thigh increase by ~50% (P < 0.05). In the LLE men, higher training intensity decreased thigh and calf IMAT by ~30% (P < 0.05). In summary, aging and lifelong aerobic exercise influenced muscle size, function, and adipose tissue infiltration in a sex- and muscle-specific fashion. Higher training intensity throughout the life span provided greater protection against adipose tissue infiltration into muscle.NEW & NOTEWORTHY This is the first study to examine skeletal muscle size, function, and adiposity in women and men in their eighth decade of life that have engaged in lifelong aerobic exercise. The findings reveal sex and upper and lower leg muscle group-specific benefits related to skeletal muscle size, function, and adiposity and that exercise intensity influences intermuscular adiposity. This emerging cohort will further our understanding of the health implications of maintaining exercise throughout the life span.

A Randomized Clinical Trial Comparing Three Different Exercise Strategies for Optimizing Aerobic Capacity and Skeletal Muscle Performance in Older Adults: Protocol for the DART Study

Background: Age-related declines in physical function lead to decreased independence and higher healthcare costs. Individuals who meet the endurance and resistance exercise recommendations can improve their physical function and overall fitness, even into their ninth decade. However, most older adults do not exercise regularly, and the majority of those who do only perform one type of exercise, and in doing so are not getting the benefits of endurance or resistance exercise. Herein we present the study protocol for a randomized clinical trial that will investigate the potential for high-intensity interval training (HIIT) to improve maximal oxygen consumption, muscular power, and muscle volume (primary outcomes), as well as body composition, 6-min walk distance, and muscular strength and endurance (secondary outcomes). Methods and Analysis: This is a single-site, single-blinded, randomized clinical trial. A minimum of 24 and maximum of 30 subjects aged 60-75 that are generally healthy but insufficiently active will be randomized. After completion of baseline assessments, participants will be randomized in a 1:1:1 ratio to participate in one of three 12-week exercise programs: stationary bicycle HIIT, stationary bicycle moderate-intensity continuous training (MICT), or resistance training. Repeat assessments will be taken immediately post intervention. Discussion: This study will examine the potential for stationary bicycle HIIT to result in both cardiorespiratory and muscular adaptations in older adults. The results will provide important insights into the effectiveness of interval training, and potentially support a shift from volume-driven to intensity-driven exercise strategies for older adults. Clinical Trial Registration: This trial is registered with ClinicalTrials.gov (registration number: NCT03978572, date of registration June 7, 2019).

Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease: A review of the English-language literature

Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcome measures. This review uses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies (n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, and water-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients.

"Slow walking with turns" increases quadriceps and erector spinae muscle activity

[Purpose] To maintain an independent lifestyle, older adults should improve muscle strength and mass, or aerobic capacity. A new exercise pattern, called slow walking with turns, which incorporates turning as an extra load additional to walking. The purpose of this study was to measure oxygen consumption during exercise and muscle activity while turning. [Subjects and Methods] Recreationally active volunteers participated. The participants performed 20 turns per minute while walking back and forth over distances of 1.5 to 3.5 m. We measured oxygen consumption, heart rate, and rating of perceived exertion and performed electromyography during the exercise. [Results] The metabolic equivalents of the exercise were 4.0 ± 0.4 to 6.3 ± 4.0 Mets. Activity was significantly greater in the vastus medialis, vastus lateralis, and erector spinae during the turn phase of slow walking with turns than during the stance phase of treadmill walking. [Conclusion] These findings suggest that slow walking with turns may help to preserve the muscle strength and mass of the trunk and lower limbs that are needed to maintain an independent lifestyle. Slow walking can be performed easily by older people, and in slow walking with turns, the exercise intensity can be adjusted as required for each individual.

Health benefits of aerobic training programs in adults aged 70 and over: a systematic review

Aging is intrinsically associated with a progressive decline in muscle strength and mass, and aerobic capacity. This contributes to reduced mobility and impaired quality of life (QoL) among seniors. Regular physical activity, and more particularly aerobic training (AT), has demonstrated benefits on adults' health. The aim of this review was to assess the current level of evidence regarding the health benefits of AT in the population aged 70 years and over. A comprehensive, systematic database search for manuscripts was performed. Two reviewers independently assessed interventional studies for potential inclusion. Cardiovascular, metabolic, functional, cognitive, and QoL outcomes were targeted. Fifty-three studies were included totalling 2051 seniors aged 70 years and over. Studies selected were divided into 5 categories according to their main outcomes: cardiovascular function (34 studies), metabolic outcomes (26 studies), functional fitness (19 studies), cognitive functions (8 studies), and QoL (3 studies). With a good level of evidence but a wide heterogeneity between study designs, a significant and beneficial effect of AT was measured on the 5 outcomes. For QoL results showed a significant but slighter improvement. This systematic review highlights the benefits of AT on seniors' health outcome such as cardiovascular, functional, metabolic, cognitive, and QoL outcomes although the optimal program remains unclear. When more studies regarding this specific population are needed to determine the most favourable exercise program, clinicians should nevertheless encourage older adults over 70 to participate in AT programs to favour active and healthy ageing.

Are resistance and aerobic exercise training equally effective at improving knee muscle strength and balance in older women?

This study aimed to compare the magnitude of knee muscle strength and static and dynamic balance change in response to 8 months of progressive RE and AE training in healthy community-dwelling older women. A secondary aim was to assess the relationship between muscle strength and balance changes (up and go test (UGT), one-leg stance test, and center of pressure measures). This study was a secondary analysis of longitudinal data from a randomized controlled trial, a three-arm intervention study in older women (n=71, mean age 69.0y). The results suggest that both interventions elicited likely to almost certain improvements (using magnitude-based inference) in balance performance. Leg strength was improved after RE whereas it was unclear following AE. Improvements in strength were almost certainly moderate after RE and possibly trivial after AE, with very likely greater improvements following RE compared to AE. A large and significant negative correlation (r=-0.5; CI 90%: -0.7 to -0.2) was found between ΔUGT and change in both knee extension and knee flexion strength after 8-month RE. In conclusion, our results showed that both types of training improve balance, but RE was also effective at improving leg strength. In addition, improvements in both knee extension and flexion strength after RE appear to make an important contribution to meaningful improvements in static and dynamic balance.

Health benefits of cycle ergometer training for older adults over 70: a review

As the number of older adults continues to increase worldwide, more attention is being paid to geriatric health care needs, and successful ageing is becoming an important topic in the medical literature. A preventive approach to the care of older adults is thus a priority in our aging societies. The purpose of this study was to update evidence for the health benefits of cycle ergometer training for older adults over 70. We searched online electronic databases up to September 2014 for original observational and intervention studies on the relationship between cycle ergometer training and health among older patients over 70. Twenty-five studies examined interventions aimed specifically at promoting cycling for older adults over 70. These studies reported a positive effect on the prevention of cardiovascular disease, and a significant improvement in metabolic responses. Improving functional status, muscle strength and cognitive performance are also well established. Overall, this review demonstrates a positive effect of cycle ergometer training with functional benefits and positive health outcomes for older adults over 70. Based on this evidence, clinicians can now encourage older adults to profit from the health benefits of cycle ergometer training to be able to pursue their daily activities independently.

Making Olympic lizards: the effects of specialised exercise training on performance

Exercise training is well known to affect a suite of physiological and performance traits in mammals, but effects of training in other vertebrate tetrapod groups have been inconsistent. We examined performance and physiological differences among green anole lizards (Anolis carolinensis) that were trained for sprinting or endurance, using an increasingly rigorous training regimen over 8 weeks. Lizards trained for endurance had significantly higher post-training endurance capacity compared with the other treatment groups, but groups did not show post-training differences in sprint speed. Although acclimation to the laboratory environment and training explain some of our results, mechanistic explanations for these results correspond with the observed performance differences. After training, endurance-trained lizards had higher haematocrit and larger fast glycolytic muscle fibres. Despite no detectable change in maximal performance of sprint-trained lizards, we detected that they had significantly larger slow oxidative muscle fibre areas compared with the other treatments. Treatment groups did not differ in the proportion of number of fibre types, nor in the mass of most limb muscles or the heart. Our results offer some caveats for investigators conducting training research on non-model organisms and they reveal that muscle plasticity in response to training may be widespread phylogenetically.

Responsiveness of muscle size and strength to physical training in very elderly people: a systematic review

The purpose of this review was to determine whether very elderly muscle (>75 years) hypertrophies in response to physical training. The databases MEDLINE; EMBASE; CINAHL Plus and SPORTDiscus were systematically literature searched with reference lists of all included studies and relevant reviews. Controlled trials (inactive elderly control group) involving healthy elderly participants over 75 years participating in an intervention complying with an established definition of physical training were included. Data extraction and quality assessment were performed using the PEDro scale. Data analysis was performed on muscle size and strength using RevMan (software version 5.1). Four studies were included of which four of four measured changes in gross muscle size. Training induced increases in muscle size from 1.5%-15.6% were reported in three of four studies, and one of four studies reported a decrease in muscle size (3%). The greatest gain in muscle mass was observed in a study of whole body vibration training. Meta-analysis of three studies found an increase of thigh muscle cross-sectional area (mean difference 2.31 cm(2) or 0.2%, 95% confidence interval (CI): 0.62 to 4.00; P = 0.008) and muscle strength (standardized mean difference 1.04, 95% CI: 0.65 to 1.43; P < 0.001). Physical training when delivered as resistance training has the ability to elicit hypertrophy and increase muscle strength in very elderly muscle.

Markers of human skeletal muscle mitochondrial biogenesis and quality control: effects of age and aerobic exercise training

Perturbations in mitochondrial health may foster age-related losses of aerobic capacity (VO2peak) and skeletal muscle size. However, limited data exist regarding mitochondrial dynamics in aging human skeletal muscle and the influence of exercise. The purpose of this study was to examine proteins regulating mitochondrial biogenesis and dynamics, VO2peak, and skeletal muscle size before and after aerobic exercise training in young men (20 ± 1 y) and older men (74 ± 3 y). Exercise-induced skeletal muscle hypertrophy occurred independent of age, whereas the improvement in VO2peak was more pronounced in young men. Aerobic exercise training increased proteins involved with mitochondrial biogenesis, fusion, and fission, independent of age. This is the first study to examine pathways of mitochondrial quality control in aging human skeletal muscle with aerobic exercise training. These data indicate normal aging does not influence proteins associated with mitochondrial health or the ability to respond to aerobic exercise training at the mitochondrial and skeletal muscle levels.

Effect of ecological walking training in sedentary elderly people: act on aging study

PURPOSE OF THE STUDY

This study aims to investigate the effects of a walking program on aerobic endurance and function in a sample of sedentary elderly people.

DESIGN AND METHODS

For this study, 126 sedentary individuals were recruited: 63 individuals (mean age = 74.1±6.0 years) for the control group and 63 (mean age = 72.0±4.5 years) for the intervention group. The intervention consisted of walking training including balance exercises and lower limb strength activities twice a week for 4 months. We collected baseline and post-test measurements of aerobic endurance, lower limb strength, and mobility. We also measured aerobic endurance at increments of 4, 8, and 12 weeks between the baseline and the post-test. We used analyses of covariance with baseline value, gender, age, and body mass index scores as covariates (p < . 05) and calculated the effect size for the effects of the intervention. The changeover time of aerobic endurance was also analyzed with the repeated analysis of variance (p < .05).

RESULTS

The intervention group showed steady and significant improvements with respect to the 6-min walk (aerobic endurance) from 447.89 m (SD 73.87) to 561.51 m (SD 83.96), as well as the 30-s chair stand (lower limb strength) from 10 (SD 3) to 13 (SD 3) number of times and the Timed Up and Go Test (mobility) from 8.53 s (SD 2.86) to 7.13 s (SD 1.76) at the post-test, whereas the control group showed significant decrease in all measurements.

IMPLICATION

These results underline that an ecological walking training program can be used to improve physical functioning among sedentary elderly people.

The role of mTORC1 in regulating protein synthesis and skeletal muscle mass in response to various mechanical stimuli

Skeletal muscle plays a fundamental role in mobility, disease prevention, and quality of life. Skeletal muscle mass is, in part, determined by the rates of protein synthesis, and mechanical loading is a major regulator of protein synthesis and skeletal muscle mass. The mammalian/mechanistic target of rapamycin (mTOR), found in the multi-protein complex, mTORC1, is proposed to play an essential role in the regulation of protein synthesis and skeletal muscle mass. The purpose of this review is to examine the function of mTORC1 in relation to protein synthesis and cell growth, the current evidence from rodent and human studies for the activation of mTORC1 signaling by different types of mechanical stimuli, whether mTORC1 signaling is necessary for changes in protein synthesis and skeletal muscle mass that occur in response to different types of mechanical stimuli, and the proposed molecular signaling mechanisms that may be responsible for the mechanical activation of mTORC1 signaling.

Aerobic exercise training induces skeletal muscle hypertrophy and age-dependent adaptations in myofiber function in young and older men

To examine potential age-specific adaptations in skeletal muscle size and myofiber contractile physiology in response to aerobic exercise, seven young (YM; 20 ± 1 yr) and six older men (OM; 74 ± 3 yr) performed 12 wk of cycle ergometer training. Muscle biopsies were obtained from the vastus lateralis to determine size and contractile properties of isolated slow [myosin heavy chain (MHC) I] and fast (MHC IIa) myofibers, MHC composition, and muscle protein concentration. Aerobic capacity was higher (P < 0.05) after training in both YM (16 ± 2%) and OM (13 ± 3%). Quadriceps muscle volume, determined via MRI, was 5 ± 1 and 6 ± 1% greater (P < 0.05) after training for YM and OM, respectively, which was associated with an increase in MHC I myofiber cross-sectional area (CSA), independent of age. MHC I peak power was higher (P < 0.05) after training for both YM and OM, while MHC IIa peak power was increased (P < 0.05) with training in OM only. MHC I and MHC IIa myofiber peak and normalized (peak force/CSA) force were preserved with training in OM, while MHC I peak force/CSA and MHC IIa peak force were lower (P < 0.05) after training in YM. The age-dependent adaptations in myofiber function were not due to changes in protein content, as total muscle protein and myofibrillar protein concentration were unchanged (P > 0.05) with training. Training reduced (P < 0.05) the proportion of MHC IIx isoform, independent of age, whereas no other changes in MHC composition were observed. These data suggest relative improvements in muscle size and aerobic capacity are similar between YM and OM, while adaptations in myofiber contractile function showed a general improvement in OM. Training-related increases in MHC I and MHC IIa peak power reveal that skeletal muscle of OM is responsive to aerobic exercise training and further support the use of aerobic exercise for improving cardiovascular and skeletal muscle health in older individuals.

A controlled clinical trial investigating the effects of cycle ergometry training on exercise tolerance, balance and quality of life in patients with Parkinson's disease

PURPOSE

To establish the effect of a 6-week programme of cycle ergometry training on exercise tolerance, balance, activities of daily living (ADL) and quality of life in individuals with Parkinson's disease (PD).

METHOD

Twenty-three subjects were recruited from the Parkinson's database of the neurology service in a large urban teaching hospital. Quasi-experimental study of interrupted time-series design was conducted with subjects acting as their own control. Assessments were carried out at baseline, week 7 following the control phase, and week 14 following the intervention phase. Intervention consisted of 30-min cycle ergometry training once weekly. Outcome measures included Six Minute Walk Test, Physiological Cost Index, Berg Balance Scale, Timed Up and Go Test (TUAG), ADL and mobility sections of the Unified Parkinson's disease Rating Scale (UPDRS) and the Parkinson's disease questionnaire (PDQ).

RESULTS

Statistically significant improvements were noted for the Berg Balance Scale (p = 0.003), TUAG (p = 0.019) and ADL (p = 0.006) and mobility (p = 0.021) sections of the UPDRS. A trend towards improvement was found for exercise tolerance. No significant effect on quality of life was found.

CONCLUSION

A 6-week programme of cycle ergometry training did not significantly influence exercise tolerance in this sample, but improved balance, functional abililty and PD-related disability were noted.

The hormonal response of older men to sub-maximum aerobic exercise: the effect of training and detraining

The hormonal response of 32 older men (70-80years) to a bout of sub-maximum aerobic exercise was examined before, after 16weeks of resistance or aerobic training and again after 4weeks of detraining. Blood samples were obtained at rest and immediately post sub-maximum exercise (30min @ 70% VO(2) max) to determine the concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone (Test), sex hormone-binding globulin (SHBG) and the calculation of free testosterone (FT). Both training groups had significant increases in leg strength and VO(2) max after 16weeks training but leg strength and VO(2) max returned to pre-training levels in the aerobic training and resistance training groups, respectively. During the 20week study there was no change in resting concentrations of any hormones among the three groups. There was no increase in GH, IGF-1 or SHBG immediately post sub-maximum exercise in any of the groups before training, after 16weeks training or after 4weeks detraining. Testosterone and FT increased immediately post sub-maximum exercise within all groups before training, after 16weeks training and after 4weeks detraining with the increase in Test and FT higher after 16weeks of resistance training compared to before training and after 4weeks detraining within the resistance training group. The increased responsiveness of Test and FT after 16weeks of resistance training was lost after 4weeks of detraining. Our results indicate that some physiological and hormonal adaptations gained after 16weeks training are lost after only 4weeks detraining.