Aerobic exercise training improves whole muscle and single myofiber size and function in older women

Physiological Adaptations to Progressive Endurance Exercise Training in Adult and Aged Rats: Insights from the Molecular Transducers of Physical Activity Consortium (MoTrPAC)

While regular physical activity is a cornerstone of health, wellness, and vitality, the impact of endurance exercise training on molecular signaling within and across tissues remains to be delineated. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) was established to characterize molecular networks underlying the adaptive response to exercise. Here, we describe the endurance exercise training studies undertaken by the Preclinical Animal Sites Studies component of MoTrPAC, in which we sought to develop and implement a standardized endurance exercise protocol in a large cohort of rats. To this end, Adult (6-mo) and Aged (18-mo) female (n = 151) and male (n = 143) Fischer 344 rats were subjected to progressive treadmill training (5 d/wk, ∼70%-75% VO2max) for 1, 2, 4, or 8 wk; sedentary rats were studied as the control group. A total of 18 solid tissues, as well as blood, plasma, and feces, were collected to establish a publicly accessible biorepository and for extensive omics-based analyses by MoTrPAC. Treadmill training was highly effective, with robust improvements in skeletal muscle citrate synthase activity in as little as 1-2 wk and improvements in maximum run speed and maximal oxygen uptake by 4-8 wk. For body mass and composition, notable age- and sex-dependent responses were observed. This work in mature, treadmill-trained rats represents the most comprehensive and publicly accessible tissue biorepository, to date, and provides an unprecedented resource for studying temporal-, sex-, and age-specific responses to endurance exercise training in a preclinical rat model.

Effects of weight-bearing dance aerobics on lower limb muscle morphology, strength and functional fitness in older women

Objective

To investigate the effects of 12-week weight-bearing dance aerobics (WBDA) on muscle morphology, strength and functional fitness in older women.

Methods

This controlled study recruited 37 female participants (66.31y ± 3.83) and divided them into intervention and control groups according to willingness. The intervention group received 90-min WBDA thrice a week for 12 weeks, while the control group maintained normal activities. The groups were then compared by measuring muscle thickness, fiber length and pennation angle by ultrasound, muscle strength using an isokinetic multi-joint module and functional fitness, such as 2-min step test, 30-s chair stand, chair sit-and-reach, TUG and single-legged closed-eyed standing test. The morphology, strength, and functional fitness were compared using ANCOVA or Mann-Whitney U test to study the effects of 12 weeks WBDA.

Results

Among all recruited participants, 33 completed all tests. After 12 weeks, the thickness of the vastus intermedius (F = 17.85, P < 0.01) and quadriceps (F = 15.62, P < 0.01) was significantly increased in the intervention group compared to the control group, along with a significant increase in the torque/weight of the knee flexor muscles (F = 4.47, P = 0.04). Similarly, the intervention group revealed a significant improvement in the single-legged closed-eyed standing test (z = -2.16, P = 0.03) compared to the control group.

Conclusion

The study concluded that compared to the non-exercising control group, 12-week WBDA was shown to thicken vastus intermedius, increase muscle strength, and improve physical function in older women. In addition, this study provides a reference exercise program for older women.

Frontiers in sarcopenia: Advancements in diagnostics, molecular mechanisms, and therapeutic strategies

The onset of sarcopenia is intimately linked with aging, posing significant implications not only for individual patient quality of life but also for the broader societal healthcare framework. Early and accurate identification of sarcopenia and a comprehensive understanding of its mechanistic underpinnings and therapeutic targets paramount to addressing this condition effectively. This review endeavors to present a cohesive overview of recent advancements in sarcopenia research and diagnosis. We initially delve into the contemporary diagnostic criteria, specifically referencing the European Working Group on Sarcopenia in Older People (EWGSOP) 2 and Asian Working Group on Sarcopenia (AWGS) 2019 benchmarks. Additionally, we elucidate comprehensive assessment techniques for muscle strength, quantity, and physical performance, highlighting tools such as grip strength, chair stand test, dual-energy X-ray Absorptiometry (DEXA), bioelectrical impedance analysis (BIA), gait speed, and short physical performance battery (SPPB), while also discussing their inherent advantages and limitations. Such diagnostic advancements pave the way for early identification and unequivocal diagnosis of sarcopenia. Proceeding further, we provide a deep-dive into sarcopenia's pathogenesis, offering a thorough examination of associated signaling pathways like the Myostatin, AMP-activated protein kinase (AMPK), insulin/IGF-1 Signaling (IIS), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways. Each pathway's role in sarcopenia mediation is detailed, underscoring potential therapeutic target avenues. From a mechanistic perspective, the review also underscores the pivotal role of mitochondrial dysfunction in sarcopenia, emphasizing elements such as mitochondrial oxidative overload, mitochondrial biogenesis, and mitophagy, and highlighting their therapeutic significance. At last, we capture recent strides made in sarcopenia treatment, ranging from nutritional and exercise interventions to potential pharmacological and supplementation strategies. In sum, this review meticulously synthesizes the latest scientific developments in sarcopenia, aiming to enhance diagnostic precision in clinical practice and provide comprehensive insights into refined mechanistic targets and innovative therapeutic interventions, ultimately contributing to optimized patient care and advancements in the field.

Effects of exercise on muscle fiber conversion, muscle development and meat quality of Sunit sheep

This study aimed to investigate the effects of exercise on muscle fiber conversion, muscle development and meat quality in the biceps femoris (BF) muscle of Sunit sheep. Twelve Sunit sheep with similar body weight were divided into two groups: control group (C group) and exercise group (E group), E group lambs underwent 6 km of exercise training per day for 90 d. The findings revealed that compared with the C group, exercise training enhanced the expression of MyHC IIa mRNA, decreased the number ratio of type IIB muscle fibers and the expression of MyHC IIb mRNA (P < 0.05). Furthermore, the E group lamb displayed higher creatine kinase (CK) activity, and lactic acid levels (P < 0.05), while glycogen content and lactic dehydrogenase (LDH) activity showed opposite trends (P < 0.05). Exercise significantly up-regulated the mRNA expression of AMP-activated protein kinase α1 (AMPKα1), sirtuin1 (SIRT1), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α), cytochrome c oxidase IV (COX IV), protein kinase B (Akt), mammalian target of rapamycin (mTOR) and p70 Ribosomal S6 Kinase 1 (p70s6k1) (P < 0.05), suggesting exercise promoted muscle fiber conversion by mediating AMPK/PGC-1α pathway, and improved skeletal muscle development via Akt/mTOR pathway. Besides, backfat thickness and pH45min value in the E group decreased significantly, while the pH24, a*, and shear force value increased significantly (P < 0.05). To conclude, this study suggested that exercise training can be used to alter muscle fiber characteristics and muscle development in lamb production.

Does Aerobic Exercise Increase Skeletal Muscle Mass in Female and Male Adults?

INTRODUCTION

It is uncertain whether aerobic exercise in the form of walking contributes to the preservation or increase in total or regional skeletal muscle mass (SMM).

PURPOSE

This study aimed to determine the effects of aerobic exercise on total and regional (upper body verses leg SMM) in male ( n = 105) and female ( n = 133) adults with overweight and obesity.

METHODS

A retrospective analysis of data from four randomized controlled trials. Participants included those who completed the given trial (control, n = 63; intervention, n = 175) and with complete magnetic resonance imaging (MRI) measured adipose tissue and SMM pre- and postintervention. Macronutrient intake was assessed for a subsample of participants. Supervised exercise was performed by walking on a treadmill for durations ranging from 12 to 24 wk at intensities between 50% and 75% of V̇O 2peak .

RESULTS

All MRI-measured adipose tissue depots were reduced, and cardiorespiratory fitness was increased by aerobic exercise compared with controls ( P < 0.001). Independent of baseline SMM, aerobic exercise was associated with a small reduction (estimated mean difference ± standard error) in whole-body SMM (-0.310 ± 0.150 kg, P = 0.039) and upper body SMM (-0.273 ± 0.121 kg, P = 0.025) compared with control. No between-group difference was observed for change in leg SMM ( P > 0.10). A negative association was observed between the relative change in body weight and change in total ( R2 = 0.37, P < 0.001), upper body ( R2 = 0.21, P < 0.001), and leg SMM ( R2 = 0.09, P = 0.701). The SMM-to-adipose tissue ratio increased in response to aerobic exercise and was positively associated with weight loss ( P < 0.001). Change in SMM was not associated with dietary protein intake ( P > 0.10).

CONCLUSIONS

Aerobic exercise performed while walking preserves, but does not increase, SMM in exercising muscle of adults. SMM not directly targeted by aerobic exercise may not be maintained.

Brisk walking improves motor function and lower limb muscle strength in Chinese women aged 80 years and older

This study investigates the effects of a 12-week brisk walking exercise regimen on motor function improvements in elderly women. Twenty-six elderly women, aged 84.2 ± 3.2 years, participated in a 12-week brisk walking exercise program. Fitness assessments and blood biomarker analyses (including CHO, HDLC, LDLC, TC) were conducted pre- and post-intervention. Additionally, targeted metabolomics was employed to measure short-chain fatty acids, amino acids, and vitamin metabolites. The intervention led to significant enhancements in participants' flexibility (p < 0.05), lower limb muscle strength (p < 0.01), and cardiorespiratory endurance (p < 0.01), while muscle mass showed no significant changes. Fifteen significant differential metabolites were identified (VIP > 1.0, FC > 1.2 or < 0.8, and p < 0.05), with arginine, ornithine, aspartic acid, glutamine, phenylalanine, tyrosine, and pantothenic acid playing key roles across seven metabolic pathways. A 12-week brisk walking exercise program significantly enhanced flexibility, lower limb muscle strength, and cardiorespiratory endurance among elderly women. These improvements did not extend to muscle mass or upper limb muscle strength. The observed enhancement in exercise capacity may be attributed to improved regulation of neurotransmitters.

Understanding the variation in exercise responses to guide personalized physical activity prescriptions

Understanding the factors that contribute to exercise response variation is the first step in achieving the goal of developing personalized exercise prescriptions. This review discusses the key molecular and other mechanistic factors, both extrinsic and intrinsic, that influence exercise responses and health outcomes. Extrinsic characteristics include the timing and dose of exercise, circadian rhythms, sleep habits, dietary interactions, and medication use, whereas intrinsic factors such as sex, age, hormonal status, race/ethnicity, and genetics are also integral. The molecular transducers of exercise (i.e., genomic/epigenomic, proteomic/post-translational, transcriptomic, metabolic/metabolomic, and lipidomic elements) are considered with respect to variability in physiological and health outcomes. Finally, this review highlights the current challenges that impede our ability to develop effective personalized exercise prescriptions. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) aims to fill significant gaps in the understanding of exercise response variability, yet further investigations are needed to address additional health outcomes across all populations.

Effects of chronic alcohol intoxication on aerobic exercise-induced adaptations in female mice

Chronic alcohol intoxication decreases muscle strength/function and causes mitochondrial dysfunction. Aerobic exercise training improves mitochondrial oxidative capacity and increases muscle mass and strength. Presently, the impact of chronic alcohol on aerobic exercise-induced adaptations was investigated. Female C57BL/6Hsd mice were randomly assigned to one of four groups: control sedentary (CON SED; n = 26), alcohol sedentary (ETOH SED; n = 27), control exercise (CON EX; n = 28), and alcohol exercise (ETOH EX; n = 25). Exercise mice had running wheel access for 2 h a day, 7 days a week. All mice were fed either control or an alcohol-containing liquid diet. Grip strength testing and EchoMRI were performed before and after the interventions. After 6 wk, hindlimb muscles were collected for molecular analyses. A subset of mice performed a treadmill run to fatigue (RTF), then abstained from alcohol for 2 wk and repeated the RTF. Alcohol decreased lean mass and forelimb grip strength compared with control-fed mice. Alcohol blunted the exercise-induced increase in muscle mass (plantaris and soleus), type IIa fiber percentage in the plantaris, and run time to fatigue. Mitochondrial markers (Citrate synthase activity and Complex I-IV, COXIV and Cytochrome C protein expression) were increased with exercise regardless of ETOH in the gastrocnemius but not tibialis anterior muscle. Two weeks of alcohol abstinence improved RTF time in ETOH EX but not in ETOH SED. These data suggest that alcohol impairs some exercise-induced adaptations in skeletal muscle, but not all were negatively affected, indicating that exercise may be a beneficial behavior even while consuming alcohol.NEW & NOTEWORTHY Alcohol consumption during an aerobic exercise training period prevented training-induced increases in run to fatigue time and grip strength. Cessation of alcohol allowed for recovery of endurance performance within 2 wk. The worsened exercise performance after alcohol was unrelated to impairments in markers of mitochondrial health. Therefore, some adaptations to exercise training are impaired with alcohol use (endurance performance, muscle growth, and strength), while others remain mostly unaffected (mitochondrial health).

Functionality, muscular strength and cardiorespiratory capacity in the elderly: relationships between functional and physical tests according to sex and age

Introduction: There are several tests that provide information about physical fitness and functionality in older adults. The aims of this study were: (i) to analyze the differences between sex and age in functional, strength and cardiorespiratory tests; and (ii) to study the correlations between functional, strength and cardiorespiratory tests according to sex and age. Methods: A total of 171 older adults (72.09 ± 13.27 kg; 1.59 ± 0.09 m; 72.72 ± 6.05 years) were divided according to sex (men: n = 63; women: n = 108) and age (≥60 <70: n = 65; ≥70 <80: n = 89; ≥80: n = 18). Anthropometry, body composition, upper limb strength (hand grip; HG), lower limb strength (countermovement jump; CMJ), cardiorespiratory capacity (6 min walking test; 6MWT), timed up and go test (TUG) and Short Physical Performance Battery (SPPB) were assessed. Results: Men showed higher values in CMJ height, HG and expired volume (VE) (p < 0.05). There were no significant differences between sexes in TUG and SPPB. Regarding age, there were significant differences in CMJ, VE and peak oxygen uptake (VO2peak), TUG, gait speed, chair and stand test and SPPB total (p < 0.05). The test times were higher in older people. Regarding correlations, the TUG showed significant correlations in all strength and cardiorespiratory tests, regardless of sex and age. The CMJ correlated more significantly with functional tests compared to HG. Discussion: There were sex and age differences in functional, strength, and cardiorespiratory tests. The execution of quick and low-cost tests such as the CMJ and TUG could provide information on overall physical fitness in older adults.

Fast and slow muscle fiber transcriptome dynamics with lifelong endurance exercise

We investigated fast and slow muscle fiber transcriptome exercise dynamics among three groups of men: lifelong exercisers (LLE, n = 8, 74 ± 1 yr), old healthy nonexercisers (OH, n = 9, 75 ± 1 yr), and young exercisers (YE, n = 8, 25 ± 1 yr). On average, LLE had exercised ∼4 day·wk-1 for ∼8 h·wk-1 over 53 ± 2 years. Muscle biopsies were obtained pre- and 4 h postresistance exercise (3 × 10 knee extensions at 70% 1-RM). Fast and slow fiber size and function were assessed preexercise with fast and slow RNA-seq profiles examined pre- and postexercise. LLE fast fiber size was similar to OH, which was ∼30% smaller than YE (P < 0.05) with contractile function variables among groups, resulting in lower power in LLE (P < 0.05). LLE slow fibers were ∼30% larger and more powerful compared with YE and OH (P < 0.05). At the transcriptome level, fast fibers were more responsive to resistance exercise compared with slow fibers among all three cohorts (P < 0.05). Exercise induced a comprehensive biological response in fast fibers (P < 0.05) including transcription, signaling, skeletal muscle cell differentiation, and metabolism with vast differences among the groups. Fast fibers from YE exhibited a growth and metabolic signature, with LLE being primarily metabolic, and OH showing a strong stress-related response. In slow fibers, only LLE exhibited a biological response to exercise (P < 0.05), which was related to ketone and lipid metabolism. The divergent exercise transcriptome signatures provide novel insight into the molecular regulation in fast and slow fibers with age and exercise and suggest that the ∼5% weekly exercise time commitment of the lifelong exercisers provided a powerful investment for fast and slow muscle fiber metabolic health at the molecular level.NEW & NOTEWORTHY This study provides the first insights into fast and slow muscle fiber transcriptome dynamics with lifelong endurance exercise. The fast fibers were more responsive to exercise with divergent transcriptome signatures among young exercisers (growth and metabolic), lifelong exercisers (metabolic), and old healthy nonexercisers (stress). Only lifelong exercisers had a biological response in slow fibers (metabolic). These data provide novel insights into fast and slow muscle fiber health at the molecular level with age and exercise.

D-galactose might mediate some of the skeletal muscle hypertrophy-promoting effects of milk-A nutrient to consider for sarcopenia?

Sarcopenia is a process of progressive aging-associated loss of skeletal muscle mass (SMM) recognized as a serious global health issue contributing to frailty and increased all-cause mortality. Exercise and nutritional interventions (particularly intake of dairy products and milk) demonstrate good efficacy, safety, and broad applicability. Here, we propose that at least some of the well-documented favorable effects of milk and milk-derived protein supplements on SMM might be mediated by D-galactose, a monosaccharide present in large quantities in milk in the form of disaccharide lactose (milk sugar). We suggest that ingestion of dairy products results in exposure to D-galactose in concentrations metabolized primarily via the Leloir pathway with the potential to (i) promote anabolic signaling via maintenance of growth factor (e.g., insulin-like growth factor 1 [IGF-1]) receptor mature glycosylation patterns; and (ii) provide extracellular (liver glycogen) and intracellular substrates for short (muscle glycolysis) and long-term (muscle glycogen, intramyocellular lipids) energy availability. Additionally, D-galactose might optimize the metabolic function of skeletal muscles by increasing mitochondrial content and stimulating glucose and fatty acid utilization. The proposed potential of D-galactose to promote the accretion of SMM is discussed in the context of its therapeutic potential in sarcopenia.

Ferroptosis and aerobic training in ageing

 Ferroptosis is a form of programmed cell death that plays a significant role in causing several diseases such as heart attack and heart failure, through alterations in fat, amino acid, and iron metabolism. Comprehending the regulatory mechanisms of ferroptosis signaling is critical because it has a considerable effect on the elderly's mortality. Conversely, age-related changes in substrate metabolism and metabolite levels are recognized to give rise to obesity. Furthermore, research has proposed that aging and obesity-related changes in substrate metabolism may aggravate ferroptosis. The suppression of ferroptosis holds potential as a successful therapeutic approach for managing different diseases, including sarcopenia, cardiovascular diseases, and central nervous system diseases. However, the pathologic and biological mechanisms behind the function of ferroptosis are not fully comprehended yet. Physical activity could affect lipid, amino acid, and iron metabolism to modulate ferroptosis. The aim of this study is to showcase the current understanding of the molecular mechanisms leading to ferroptosis and discuss the role of aging and physical activity in this phenomenon.

Effects of therapeutic exercise on the motor function of adults with Down syndrome: a systematic review and meta-analysis

Therapeutic exercise exerts positive effects by mitigating or reducing the motor or cognitive changes that people with Down syndrome undergo throughout their life. There are no updated systematic reviews that integrate the evidence available in a way that facilitates decision-making for physical rehabilitation teams. This study therefore aimed to consolidate the information available and compare the effects of different types of physical exercise on the motor function of adults with DS. We conducted a systematic review and meta-analysis of randomized clinical trials and quasi-experimental studies. The literature search was performed between January 2023 and February 2023 using the PubMed, SCIELO, Epistemonikos, and Lilacs databases. Studies were selected according to pre-determined inclusion and exclusion criteria. The risk-of-bias assessment was performed using the risk-of-bias rating tool for randomized clinical trial (RoB) and the risk of bias of non-randomized comparative studies was assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool. Risk-of-bias assessment and meta-analyses were performed using the RevMan software package. Sixteen studies met the eligibility criteria for the qualitative synthesis and 4 were included in the meta-analyses. Combined exercise significantly increased muscle strength both in the upper limbs (SMD = 0.74 [95% CI 0.25-1.22]) and lower limbs (SMD = 0.56[95% CI 0.08-1.04]). Aerobic exercise improved spatiotemporal gait parameters. Aerobic exercise showed significant improvements in dynamic balance while combined exercise significantly increased dynamic and static balance. The certainty of the evidence was low to moderate for all outcomes. There was low and moderate certainty of evidence for the outcomes proposed in this review. However, therapeutic exercise could be effective in improving muscle strength and gait functionality.

Medium-chain triglycerides (8:0 and 10:0) increase muscle mass and function in frail older adults: a combined data analysis of clinical trials

Background

Three clinical trials have examined the chronic effects of medium-chain triglycerides (MCTs) on muscle mass and function in frail older adults (mean age 85 years old). However, significant increases in muscle mass and some muscle function relative to long-chain triglycerides (LCTs) have yet to be shown, possibly due to the small number of participants in each trial.

Objective

We re-analyzed these previous clinical trials to clarify whether MCT supplementation can increase muscle mass and function.

Analysis

After adding post hoc tests to the original report, we compared changes in measurement between the MCT and LCT groups in the first 2 trials and conducted a combined data analysis.

Methods

In a combined data analysis, changes from baseline in measurements at the 3 months intervention in the MCTs- and LCTs-containing groups were assessed by analysis of covariance adjusted for baseline values of each measurement, age, sex, BMI, allocation to trial, habitual intakes in energy, protein, leucine, octanoic acid, decanoic acid, and vitamin D during the baseline period. The Mann-Whitney U test was used to analyze data on right and left knee extension times.

Results

MCT supplementation for 3 months increased muscle function relative to LCT supplementation with and without an L-leucine (1.2 g) and vitamin D (cholecalciferol, 20 μg)-enriched supplement. In a combined data analysis (n = 29 in MCTs, n = 27 in LCTs), relative to supplementation with 6 g LCTs/day, supplementation with 6 g MCTs/day at dinner for 3 months significantly increased body weight (adjusted mean change from baseline: MCTs 1.2 vs. LCTs 0.2 kg, p = 0.023), right arm muscle area (MCTs 1.4 vs. LCTs-0.7 cm2, p = 0.002), left calf circumference (p = 0.015), right-hand grip strength (MCTs 1.6 vs. LCTs 0.3 kg, p = 0.017), right knee extension time (p = 0.021), left knee extension time (p = 0.034), walking speed (p = 0.002), and number of iterations in leg open and close test (p < 0.001) and decreased right triceps skinfold thickness (p = 0.016).

Conclusion

In frail older adults, supplementation for 3 months with a low dose (6 g/day) of MCTs (C8:0 and C10:0) increased muscle mass and function. These findings indicate the potential for the practical use of MCTs in daily life in treating sarcopenia.

The association between muscle mass quantity and its quality in physically active older women

In this study, the authors aim to determine whether lower limb strength is related to lower limb lean mass and whether this relationship is affected by lower limb functionality in physically active older women. Twenty-six women underwent measures of knee muscles strength and lean mass of lower limbs. Bilateral strength of the knee flexors and extensors was measured by an isokinetic dynamometer. The concentric peak torque was measured at an angular velocity of 60°/s. Lean mass of the lower limbs was measured by bio-impedance analysis. Pearson's correlation analysis revealed significant association between the strength of the knee flexors and lean mass on non-dominant limb only (r = .427, p = .03). Researchers revealed that strategies aiming to prevent lean mass and muscle strength losses should be specifically targeted to individual muscles or muscle groups, even in physically active older women. To improve overall mobility, the strengthening of larger muscle such as hamstring is crucial.

Multitissue responses to exercise: a MoTrPAC feasibility study

We assessed the feasibility of the Molecular Transducers of Physical Activity Consortium (MoTrPAC) human adult clinical exercise protocols, while also documenting select cardiovascular, metabolic, and molecular responses to these protocols. After phenotyping and familiarization sessions, 20 subjects (25 ± 2 yr, 12 M, 8 W) completed an endurance exercise bout (n = 8, 40 min cycling at 70% V̇o2max), a resistance exercise bout (n = 6, ∼45 min, 3 sets of ∼10 repetition maximum, 8 exercises), or a resting control period (n = 6, 40 min rest). Blood samples were taken before, during, and after (10 min, 2 h, and 3.5 h) exercise or rest for levels of catecholamines, cortisol, glucagon, insulin, glucose, free fatty acids, and lactate. Heart rate was recorded throughout exercise (or rest). Skeletal muscle (vastus lateralis) and adipose (periumbilical) biopsies were taken before and ∼4 h following exercise or rest for mRNA levels of genes related to energy metabolism, growth, angiogenesis, and circadian processes. Coordination of the timing of procedural components (e.g., local anesthetic delivery, biopsy incisions, tumescent delivery, intravenous line flushes, sample collection and processing, exercise transitions, and team dynamics) was reasonable to orchestrate while considering subject burden and scientific objectives. The cardiovascular and metabolic alterations reflected a dynamic and unique response to endurance and resistance exercise, whereas skeletal muscle was transcriptionally more responsive than adipose 4 h postexercise. In summary, the current report provides the first evidence of protocol execution and feasibility of key components of the MoTrPAC human adult clinical exercise protocols. Scientists should consider designing exercise studies in various populations to interface with the MoTrPAC protocols and DataHub.NEW & NOTEWORTHY This study highlights the feasibility of key aspects of the MoTrPAC adult human clinical protocols. This initial preview of what can be expected from acute exercise trial data from MoTrPAC provides an impetus for scientists to design exercise studies to interlace with the rich phenotypic and -omics data that will populate the MoTrPAC DataHub at the completion of the parent protocol.

Cycle exercise training and muscle mass: A preliminary investigation of 17 lower limb muscles in older men

Cycling exercise in older individuals is beneficial for the cardiovascular system and quadriceps muscles, including partially reversing the age-related loss of quadriceps muscle mass. However, the effect of cycling exercise on the numerous other lower limb muscles is unknown. Six older men (74 ± 8 years) underwent MRI before and after 12-weeks of progressive aerobic cycle exercise training (3-4 days/week, 60-180 min/week, 60%-80% heart rate reserve, VO2 max: +13%) for upper (rectus femoris, vastii, adductor longus, adductor magnus, gracilis, sartorius, biceps femoris long head, biceps femoris short head, semimembranosus, semitendinosus) and lower (anterior tibial, posterior tibialis, peroneals, flexor digitorum longus, lateral gastrocnemius, medial gastrocnemius, soleus) leg muscle volumes. In the upper leg, cycle exercise training induced hypertrophy (p ≤ 0.05) in the vastii (+7%) and sartorius (+6%), with a trend to increase biceps femoris short head (+5%, p = 0.1). Additionally, there was a trend to decrease muscle volume in the adductor longus (-6%, p = 0.1) and biceps femoris long head (-5%, p = 0.09). In the lower leg, all 7 muscle volumes assessed were unaltered pre- to post-training (-2% to -3%, p > 0.05). This new evidence related to cycle exercise training in older individuals clarifies the specific upper leg muscles that are highly impacted, while revealing all the lower leg muscles do not appear responsive, in the context of muscle mass and sarcopenia. This study provides information for exercise program development in older individuals, suggesting other specific exercises are needed for the rectus femoris and adductors, certain hamstrings, and the anterior and posterior lower leg muscles to augment the beneficial effects of cycling exercise for older adults.

Development of Continuum of Care for McArdle disease: A practical tool for clinicians and patients

McArdle disease (glycogen storage disease type V; GSDV) is a rare genetic disease caused by the inability to break down glycogen in skeletal muscle due to a deficiency in myophosphorylase. Glycolysis is only partially blocked in GSDV, as muscle fibres can take up circulating glucose and convert it to glucose-6-phosphate downstream of the metabolic block. Because skeletal muscle predominantly relies on anaerobic energy during the first few minutes of transition from rest to activity, and throughout more intense activities, individuals with GSDV experience muscle fatigue/pain, tachypnea, and tachycardia during these activities. If warning signs are not heeded, a muscle contracture may rapidly occur, and if significant, may lead to acute rhabdomyolysis. Without a cure or treatment, individuals with GSDV must be consistent in employing proper management techniques; however, this can be challenging due to the nuances inherent in this metabolic myopathy. The International Association for Muscle Glycogen Storage Disease collaborated with an international team of five expert clinicians to identify areas of learning to achieve an optimal state. A Continuum of Care model was developed that outlines five pivotal steps (diagnosis; understanding; acceptance; learning and exercise) to streamline assessments and more succinctly assist clinicians in determining patient-specific learning needs. This model serves as a translational tool to help optimize care for this patient population.

The effects of exercise training on body composition in postmenopausal women: a systematic review and meta-analysis

Introduction

We conducted a systematic review and meta-analysis to investigate the effect of exercise training on body composition outcomes in postmenopausal women.

Methods

PubMed, Web of Science, CINAHL, and Medline were searched to identify the randomized controlled trials which evaluated effect of exercise training versus control in postmenopausal women. Standardized mean differences (SMD), weighted mean differences (WMD) and 95% confidence intervals (95% CIs) were calculated using random effects model.

Results

One hundred and one studies involving 5,697 postmenopausal women were included in the meta-analysis. Results indicated that exercise training effectively increased muscle mass/ volume, muscle and fiber cross-sectional area and fat-free mass, and decreased fat mass, body fat percentage, waist circumference and visceral fat. Furthermore, subgroup analyses results revealed that aerobic and combined training had greater beneficial effects on fat mass outcomes, whereas resistance and combined training had greater beneficial effects on muscle mass outcomes.

Discussion

Overall, our results revealed that exercise training is effective for improving body composition in postmenopausal women. To be specific, aerobic training is effective on fat loss, whereas resistance training is effective on muscle gain. However, combination of aerobic and resistance trainings may be considered a viable strategy to improve body composition in postmenopausal women.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021283425.

Low rectus femoris mass index is closely associated with diabetic peripheral neuropathy

Aims

To assess the association of rectus femoris mass index (RFMI) with diabetic peripheral neuropathy (DPN) in individuals with type 2 diabetes mellitus (T2DM).

Methods

Totally 948 T2DM cases were enrolled. Nerve conduction parameters, quantitative sensory threshold and rectus femoris cross-sectional area (RFCSA) were obtained, and rectus femoris mass index (RFMI=RFCSA/height²) was derived. The patients were assigned to four groups based on interquartile spacing of RFMI.

Results

Motor/sensory nerve amplitude and conduction velocity (CV) were significantly lower in the low-level RFMI groups (all P<0.05). RFMI was positively associated with mean motor/sensory nerve amplitude and CV (both P<0.05). T2DM duration above 10 years and RFMI below 2.37cm²/m² had significant associations with DPN (both P<0.001). Receiver operating characteristic (ROC) curve analysis demonstrated cutoffs for T2DM duration and RFMI of 7 years and 2.2 cm²/m², respectively (AUC=0.75, 95% CI: 0.72-0.79; sensitivity, 68.4%; specificity, 66.8%).

Conclusion

DPN is significantly associated with reduced RFMI in T2DM patients. Decreased muscle mass seems to be associated with motor/sensory nerve amplitude and CV. RFMI combined with T2DM duration may represent a potent tool for predicting DPN occurrence in T2DM cases.

Clinical trial registration

http://www.chictr.org.cn, identifier ChiCTR2100049150.

Effects of a Pedometer-Based Walking Home Program Plus Resistance Training on Inflammatory Cytokines and Depression in Thai Older People with Sarcopenia: A Three-Arm Randomized Controlled Trial

OBJECTIVE

To examine the effects of daily walking steps plus resistive exercise on chronic inflammatory markers and depressive symptoms in older adults with sarcopenia.

METHODS

Ninety men and women aged over 60 years were enrolled and divided into 60 and 30 adults with and without sarcopenia, respectively. Older individuals were screened for sarcopenia using the Asian Working Group for Sarcopenia in 2019. A simple random sample was conducted to divide the older adults with sarcopenia into two groups: control and intervention. Thirty older adults with sarcopenia were assigned to perform 12 weeks of step walking (>7500 steps) daily for 5 days/week plus resistance exercise with an elastic band twice/week; the control groups (i.e., no sarcopenia and sarcopenia) performed routine daily life Changes in depression and expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) were measured before and after the 12-week intervention program. Two-way mixed ANOVA models were computed for group and interaction effects for each variable.

RESULTS

Changes in depressive symptom scores (Δ2.86 ± 0.92) and TNF-α levels (Δ22.16 ± 2.30) were observed in the intervention group after the 12-week program. In addition, an interaction effect between the intervention (Δ4.04 ± 3.10) and control groups (Δ8.10 ± 4.88) was found for the symptoms of depression.

CONCLUSION

Older people with sarcopenia who accumulated >7,500 steps/day, 5 days/week plus resistive elastic band twice /week show improvements in inflammation and depressive symptoms.

CLINICAL IMPLICATIONS

Encourage physical activity had a positive effect on reducing inflammation and depression among older people with sarcopenia.

Long-term high loading intensity of aerobic exercise improves skeletal muscle performance via the gut microbiota-testosterone axis

Exercise is reported to play a crucial role in skeletal muscle performance. However, the underlying mechanism is still unknown. Thus, we investigated the effect of high-intensity aerobic exercise on skeletal muscle performance. In this study, the male C57BL/6J mice were accepted by high-intensity aerobic exercise for 8 weeks to establish an exercise model. It was observed that high-intensity aerobic exercise markedly affected the expression of genes in skeletal muscle. Moreover, high-intensity aerobic exercise significantly improved skeletal muscle grip strength and serum testosterone levels. HE staining showed that the cross-sectional area (CSA) of the skeletal muscle was successfully increased after 8 weeks of high-intensity aerobic exercise. Additionally, we found that high-intensity aerobic exercise changed gut microbiota structure by altering the abundance of Akkermansia, Allobaculum, and Lactobacillus, which might be related to testosterone production. However, the beneficial effects disappeared after the elimination of the gut microbiota and recovered after fecal microbiota transplantation (FMT) experiments for 1 week. These results indicated that the beneficial effects of high-intensity aerobic exercise on skeletal muscle were partly dependent on the gut microbiota. Our results suggested that long-term high loading intensity of aerobic exercise could improve skeletal muscle performance, which was probably due to the gut microbiota-testosterone axis.

Small-Scale Randomized Controlled Trial to Explore the Impact of β-Hydroxy-β-Methylbutyrate Plus Vitamin D3 on Skeletal Muscle Health in Middle Aged Women

β-Hydroxy-β-methylbutyrate (HMB), a leucine metabolite, can increase skeletal muscle size and function. However, HMB may be less effective at improving muscle function in people with insufficient Vitamin D3 (25-OH-D < 30 ng/mL) which is common in middle-aged and older adults. Therefore, we tested the hypothesis that combining HMB plus Vitamin D3 (HMB + D) supplementation would improve skeletal muscle size, composition, and function in middle-aged women. In a double-blinded fashion, women (53 ± 1 yrs, 26 ± 1 kg/m2, n = 43) were randomized to take placebo or HMB + D (3 g Calcium HMB + 2000 IU D per day) during 12 weeks of sedentary behavior (SED) or resistance exercise training (RET). On average, participants entered the study Vitamin D3 insufficient while HMB + D increased 25-OH-D to sufficient levels after 8 and 12 weeks. In SED, HMB + D prevented the loss of arm lean mass observed with placebo. HMB + D increased muscle volume and decreased intermuscular adipose tissue (IMAT) volume in the thigh compared to placebo but did not change muscle function. In RET, 12-weeks of HMB + D decreased IMAT compared to placebo but did not influence the increase in skeletal muscle volume or function. In summary, HMB + D decreased IMAT independent of exercise status and may prevent the loss or increase muscle size in a small cohort of sedentary middle-aged women. These results lend support to conduct a longer duration study with greater sample size to determine the validity of the observed positive effects of HMB + D on IMAT and skeletal muscle in a small cohort of middle-aged women.

Adaptations to a Concurrent Exercise Training Program in Inactive Aging Women

ABSTRACT

Wadsworth, DD, Rodriguez-Hernandez, M, Huffman, LS, McDonald, JR, Spring, KE, and Pascoe, DD. Adaptations to a concurrent exercise training program in inactive aging women. J Strength Cond Res XX(X): 000-000, 2021-This study assessed the effect of a 10-week, sprint interval concurrent exercise training program on body composition and muscular strength in aging women. Sixty-five inactive women (age, 40-64 years) were randomized into 2 sprint interval exercise programs, 0% incline and 6% incline. Sprint interval training was performed to achieve 95% of each subject's age-predicted maximal heart rate for a series of 40 seconds of work followed by 20 seconds of passive recovery. An undulating resistance training protocol, composed of 30 sessions, was performed by each group throughout the study. Dual-energy X-ray absorption scans were assessed body composition, and 1 repetition maximum was performed to assess muscular strength. Subjects in both groups significantly reduced fat mass by approximately 0.35 kg (p = 0.002), and visceral adipose tissue by 0.05 kg (p = 0.032). There were significant increases in lean body mass by approximately 0.50 kg (p = 0.005), lower-body muscular strength by approximately 46.83 kg (p < 0.001), and upper-body muscular strength by approximately 11.68 kg (p < 0.001). No significant between-groups interactions were observed. A sprint interval training concurrent exercise training program is an effective strategy to improve body composition and muscular strength in inactive, aging women. Muscular strength improvements resulting from this intervention are particularly important because muscular strength losses are strong predictors of morbidity and mortality.

The association of aerobic, resistance, and combined exercises with the handgrip strength of middle-aged and elderly Korean adults: a nationwide cross-sectional study

Background

Handgrip strength (HGS), an indicator of overall muscle strength, is a key component in sarcopenia diagnosis. Although exercise is an effective strategy to prevent sarcopenia, the most appropriate exercise type targeting sarcopenia needs to be established. This study aimed to investigate the relationship between the physical activity (PA) patterns and HGS.

Methods

This was a cross-sectional study using the data from the 7th Korea National Health and Nutrition Examination Survey (2016–2018). The study population included 12,814 adults aged ≥ 40 years. According to the World Health Organization PA guidelines for public health, both aerobic (moderate to vigorous PA ≥ 150 min/week) and resistance exercises (≥ 2 sessions/week) are recommended. Study participants were categorized into one of the four groups depending on their adherence to each of two exercise guidelines (“neither,” “aerobic only,” “resistance only,” and “combined”). By defining normal HGS cutoff values as the lowest quartile of HGS from the population aged 20 years and above, we classified participants as “preserved” HGS group if their HGS was equal to or above the cutoff values. A Poisson regression model was used to calculate adjusted prevalence ratios (APRs) for preserved HGS across the four PA guideline adherences stratified by age and sex groups.

Results

In middle-aged adults, the “combined” exercise group was independently associated with the preserved HGS (male, age 50–59 years, APR = 1.072; male, age 60–69 years, APR = 1.180; female, age 50–59 years, APR = 1.112; female, age 60–69 years, APR = 1.188). For adults aged ≥ 70 years, meeting only aerobic or resistance exercise guidelines showed a positive association with HGS before adjusting for other health-related variables. In males of ≥ 70 years, the APR of preserved HGS was highest in the “combined” exercise group (“resistance only,” APR = 1.459, “combined,” APR = 1.664), while in women aged ≥ 70 years, the significance was lost after adjusting for covariates.

Conclusions

Adults meeting both aerobic and resistance exercise guidelines were associated with the highest prevalence of preserved HGS. Performing both types of exercise might be the most effective way to prevent sarcopenia that should be investigated in future clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03293-z.

Implication of diet and exercise on the management of age‐related sarcopenic obesity in Asians

The incidence of sarcopenic obesity among adults aged ≥65 years is rising worldwide. Sarcopenic obesity is a high‐risk geriatric syndrome defined as a gain in the amount of adipose tissue along with the age‐related loss of muscle mass and strength or physical performance. Sarcopenic obesity is associated with increased risks of falls, physical limitations, cardiovascular diseases, metabolic diseases, and/or mortality. Thus, the identification of preventive and treatment strategies against sarcopenic obesity is important for healthy aging. Diet and exercise are the reasons for the development of sarcopenic obesity and are key targets in its prevention and treatment. Regarding weight reduction alone, it is most effective to maintain a negative energy balance with dietary calorie restriction and aerobic exercise. However, it is important to preserve skeletal muscle mass while reducing fat mass. Resistance exercise and appropriate protein supply are the main ways of preserving skeletal muscle mass, as well as muscle function. Therefore, in order to improve sarcopenic obesity, a complex treatment strategy is needed to limit energy ingestion with proper nutrition and to increase multimodal exercises. In this review, we focus on recently updated interventions for diet and exercise and potential future management strategies for Asian individuals with aging‐related sarcopenic obesity. Geriatr Gerontol Int 2022; 22: 695–704.

Body Composition and Nutrients Dietary Intake Changes during COVID-19 Lockdown in Spanish Healthy Postmenopausal Women

(1) Background: During the COVID-19 lockdown, high rates of physical inactivity and dietary imbalances were reported in both adults and adolescents. Physical separation and isolation not only have a significant impact on the performance of physical activity but also affect people’s lives, particularly their dietary habits. In the present study, we aimed to examine whether or not bioelectrical impedance-derived body composition parameters and dietary habits were affected during the pandemic-associated lockdown in postmenopausal Spanish women. (2) Methods: Sixty-six women participated in the study (58.7 ± 5.4 years) before (between July−October 2019) and after (August−October 2020) the lockdown, which occurred as a consequence of the COVID-19 pandemic in Spain. Body composition parameters were measured by bioelectrical impedance analysis while dietary intake of proteins, fat, carbohydrates, and energy was measured by a food frequency questionnaire. (3) Results Regarding body composition, no differences were observed in fat mass in % (mean increase 0.05 (2.74); p = 0.567), fat mass in kg (mean increase −0.07 (4.137); p = 0.356) or lean mass in kg (mean increase 0.20 (1.424); p = 0.636). Similarly, no statistically significant differences were observed between the two study periods for any of the nutrients studied, nor for energy intake (p > 0.05 in all cases). (4) Conclusions: After comprehensively assessing body composition and dietary intake of protein, fat, carbohydrates, and energy before and after COVID-19 lockdown in healthy adult women in Spain no changes in the parameters studied were observed during the period analyzed in the women examined.

Muscle-Specific Cellular and Molecular Adaptations to Late-Life Voluntary Concurrent Exercise

Murine exercise models can provide information on factors that influence muscle adaptability with aging, but few translatable solutions exist. Progressive weighted wheel running (PoWeR) is a simple, voluntary, low-cost, high-volume endurance/resistance exercise approach for training young mice. In the current investigation, aged mice (22-mo-old) underwent a modified version of PoWeR for 8 wk. Muscle functional, cellular, biochemical, transcriptional, and myonuclear DNA methylation analyses provide an encompassing picture of how muscle from aged mice responds to high-volume combined training. Mice run 6-8 km/d, and relative to sedentary mice, PoWeR increases plantarflexor muscle strength. The oxidative soleus of aged mice responds to PoWeR similarly to young mice in every parameter measured in previous work; this includes muscle mass, glycolytic-to-oxidative fiber type transitioning, fiber size, satellite cell frequency, and myonuclear number. The oxidative/glycolytic plantaris adapts according to fiber type, but with modest overall changes in muscle mass. Capillarity increases markedly with PoWeR in both muscles, which may be permissive for adaptability in advanced age. Comparison to published PoWeR RNA-sequencing data in young mice identified conserved regulators of adaptability across age and muscles; this includes Aldh1l1 which associates with muscle vasculature. Agrn and Samd1 gene expression is upregulated after PoWeR simultaneous with a hypomethylated promoter CpG in myonuclear DNA, which could have implications for innervation and capillarization. A promoter CpG in Rbm10 is hypomethylated by late-life exercise in myonuclei, consistent with findings in muscle tissue. PoWeR and the data herein are a resource for uncovering cellular and molecular regulators of muscle adaptation with aging.

Human skeletal muscle size with ultrasound imaging: a comprehensive review

Skeletal muscle size is an important factor in assessing adaptation to exercise training and detraining, athletic performance, age-associated atrophy and mobility decline, clinical conditions associated with cachexia, and overall skeletal muscle health. Magnetic resonance (MR) imaging and computed tomography (CT) are widely accepted as the gold standard methods for skeletal muscle size quantification. However, it is not always feasible to use these methods (e.g., field studies, bedside studies, large cohort studies). Ultrasound has been available for skeletal muscle examination for more than 50 years and the development, utility, and validity of ultrasound imaging are underappreciated. It is now possible to use ultrasound in situations where MR and CT imaging are not suitable. This review provides a comprehensive summary of ultrasound imaging and human skeletal muscle size assessment. Since the first study in 1968, more than 600 articles have used ultrasound to examine the cross-sectional area and/or volume of 107 different skeletal muscles in more than 27,500 subjects of various ages, health status, and fitness conditions. Data from these studies, supported by decades of technological developments, collectively show that ultrasonography is a valid tool for skeletal muscle size quantification. Considering the wide-ranging connections between human health and function and skeletal muscle mass, the utility of ultrasound imaging will allow it to be employed in research investigations and clinical practice in ways not previously appreciated or considered.

Evaluating the Effects of Increased Protein Intake on Muscle Strength, Hypertrophy and Power Adaptations with Concurrent Training: A Narrative Review

Concurrent training incorporates dual exercise modalities, typically resistance and aerobic-based exercise, either in a single session or as part of a periodized training program, that can promote muscle strength, mass, power/force and aerobic capacity adaptations for the purposes of sports performance or general health/wellbeing. Despite multiple health and exercise performance-related benefits, diminished muscle hypertrophy, strength and power have been reported with concurrent training compared to resistance training in isolation. Dietary protein is well-established to facilitate skeletal muscle growth, repair and regeneration during recovery from exercise. The degree to which increased protein intake can amplify adaptation responses with resistance exercise, and to a lesser extent aerobic exercise, has been highly studied. In contrast, much less focus has been directed toward the capacity for protein to enhance anabolic and metabolic responses with divergent contractile stimuli inherent to concurrent training and potentially negate interference in muscle strength, power and hypertrophy. This review consolidates available literature investigating increased protein intake on rates of muscle protein synthesis, hypertrophy, strength and force/power adaptations following acute and chronic concurrent training. Acute concurrent exercise studies provide evidence for the significant stimulation of myofibrillar protein synthesis with protein compared to placebo ingestion. High protein intake can also augment increases in lean mass with chronic concurrent training, although these increases do not appear to translate into further improvements in strength adaptations. Similarly, the available evidence indicates protein intake twice the recommended intake and beyond does not rescue decrements in selective aspects of muscle force and power production with concurrent training.

The Aging Athlete: Paradigm of Healthy Aging

The Exercise Boom of the 1970's resulted in the adoption of habitual exercise in a significant portion of the population. Many of these individuals are defying the cultural norms by remaining physically active and competing at a high level in their later years. The juxtaposition between masters athletes and non-exercisers demonstrate the importance of remaining physically active throughout the lifespan on physiological systems related to healthspan (years of healthy living). This includes ~50% improved maximal aerobic capacity (VO₂max) and enhanced skeletal muscle health (size, function, as well as metabolic and communicative properties) compared to non-exercisers at a similar age. By taking a reductionist approach to VO₂max and skeletal muscle health, we can gain insight into how aging and habitual exercise affects the aging process. Collectively, this review provides a physiological basis for the elite performances seen in masters athletes, as well as the health implications of lifelong exercise with a focus on VO₂max, skeletal muscle metabolic fitness, whole muscle size and function, single muscle fiber physiology, and communicative properties of skeletal muscle. This review has significant public health implications due to the potent health benefits of habitual exercise across the lifespan.

Muscle Protein Synthesis Responses Following Aerobic-Based Exercise or High-Intensity Interval Training with or Without Protein Ingestion: A Systematic Review

BACKGROUND

Systematic investigation of muscle protein synthesis (MPS) responses with or without protein ingestion has been largely limited to resistance training.

OBJECTIVE

This systematic review determined the capacity for aerobic-based exercise or high-intensity interval training (HIIT) to stimulate post-exercise rates of MPS and whether protein ingestion further significantly increases MPS compared with placebo.

METHODS

Three separate models analysed rates of either mixed, myofibrillar, sarcoplasmic, or mitochondrial protein synthesis (PS) following aerobic-based exercise or HIIT: Model 1 (n = 9 studies), no protein ingestion; Model 2 (n = 7 studies), peri-exercise protein ingestion with no placebo comparison; Model 3 (n = 14 studies), peri-exercise protein ingestion with placebo comparison.

RESULTS

Eight of nine studies and all seven studies in Models 1 and 2, respectively, demonstrated significant post-exercise increases in either mixed or a specific muscle protein pool. Model 3 observed significantly greater MPS responses with protein compared with placebo in either mixed or a specific muscle fraction in 7 of 14 studies. Seven studies showed no difference in MPS between protein and placebo, while three studies reported no significant increases in mitochondrial PS with protein compared with placebo.

CONCLUSION

Most studies reporting significant increases in MPS were confined to mixed and myofibrillar PS that may facilitate power generating capacity of working skeletal muscle with aerobic-based exercise and HIIT. Only three of eight studies demonstrated significant increases in mitochondrial PS post-exercise, with no further benefits of protein ingestion. This lack of change may be explained by the acute analysis window in most studies and apparent latency in exercise-induced stimulation of mitochondrial PS.

Skeletal Muscle Adaptations to Exercise Training in Young and Aged Horses

In aged humans, low-intensity exercise increases mitochondrial density, function and oxidative capacity, decreases the prevalence of hybrid fibers, and increases lean muscle mass, but these adaptations have not been studied in aged horses. Effects of age and exercise training on muscle fiber type and size, satellite cell abundance, and mitochondrial volume density (citrate synthase activity; CS), function (cytochrome c oxidase activity; CCO), and integrative (per mg tissue) and intrinsic (per unit CS) oxidative capacities were evaluated in skeletal muscle from aged (n = 9; 22 ± 5 yr) and yearling (n = 8; 9.7 ± 0.7 mo) horses. Muscle was collected from the gluteus medius (GM) and triceps brachii at wk 0, 8, and 12 of exercise training. Data were analyzed using linear models with age, training, muscle, and all interactions as fixed effects. At wk 0, aged horses exhibited a lower percentage of type IIx (p = 0.0006) and greater percentage of hybrid IIa/x fibers (p = 0.002) in the GM, less satellite cells per type II fiber (p = 0.03), lesser integrative and intrinsic (p ≤ 0.04) CCO activities, lesser integrative oxidative phosphorylation capacity with complex I (PCI; p = 0.02) and maximal electron transfer system capacity (ECI+II; p = 0.06), and greater intrinsic PCI, ECI+II, and electron transfer system capacity with complex II (ECII; p ≤ 0.05) than young horses. The percentage of type IIx fibers increased (p < 0.0001) and of type IIa/x fibers decreased (p = 0.001) in the GM, and the number of satellite cells per type II fiber increased (p = 0.0006) in aged horses following exercise training. Conversely, the percentage of type IIa/x fibers increased (p ≤ 0.01) and of type IIx fibers decreased (p ≤ 0.002) in young horses. Integrative maximal oxidative capacity (p ≤ 0.02), ECI+II (p ≤ 0.07), and ECII (p = 0.0003) increased for both age groups from wk 0 to 12. Following exercise training, aged horses had a greater percentage of IIx (p ≤ 0.002) and lesser percentage of IIa/x fibers (p ≤ 0.07), and more satellite cells per type II fiber (p = 0.08) than young horses, but sustained lesser integrative and intrinsic CCO activities (p ≤ 0.04) and greater intrinsic PCI, ECI+II, and ECII (p ≤ 0.05). Exercise improved mitochondrial measures in young and aged horses; however, aged horses showed impaired mitochondrial function and differences in adaptation to exercise training.

Effects of Three Different Exercise Strategies for Optimizing Aerobic Capacity and Skeletal Muscle Performance in Older Adults: A Pilot Study

This Brief Report describes a pilot study of the effect of 12 weeks of stationary bicycle high-intensity interval training, stationary bicycle moderate-intensity continuous training, and resistance training on cardiorespiratory, muscular, and physical function measures in insufficiently-active older adults (N=14; 66.4±3.9 years; 3 male, 11 female). After baseline testing, participants were randomly assigned to one of the exercise groups. High-intensity interval training and moderate-intensity continuous training had small-to-large effect sizes on cardiorespiratory/endurance and physical function measures, but very small effect sizes on muscular measures. Resistance training had small-to-large effect sizes on cardiorespiratory, muscular, and physical function measures. This pilot study should be interpreted cautiously, but findings suggest that resistance exercise may be the most effective of the three studied exercise strategies for older adults as it can induce beneficial adaptations across multiple domains. These effect sizes can be used to determine optimal sample sizes for future investigations.

Four Weeks of Probiotic Supplementation Alters the Metabolic Perturbations Induced by Marathon Running: Insight from Metabolomics

Few data are available that describe how probiotics influence systemic metabolism during endurance exercise. Metabolomic profiling of endurance athletes will elucidate mechanisms by which probiotics may confer benefits to the athlete. In this study, twenty-four runners (20 male, 4 female) were block randomised into two groups using a double-blind matched-pairs design according to their most recent Marathon performance. Runners were assigned to 28-days of supplementation with a multi-strain probiotic (PRO) or a placebo (PLB). Following 28-days of supplementation, runners performed a competitive track Marathon race. Venous blood samples and muscle biopsies (vastus lateralis) were collected on the morning of the race and immediately post-race. Samples were subsequently analysed by untargeted ¹H-NMR metabolomics. Principal component analysis (PCA) identified a greater difference in the post-Marathon serum metabolome in the PLB group vs. PRO. Univariate tests identified 17 non-overlapped metabolites in PLB, whereas only seven were identified in PRO. By building a PLS-DA model of two components, we revealed combinations of metabolites able to discriminate between PLB and PRO post-Marathon. PCA of muscle biopsies demonstrated no discernible difference post-Marathon between treatment groups. In conclusion, 28-days of probiotic supplementation alters the metabolic perturbations induced by a Marathon. Such findings may be related to maintaining the integrity of the gut during endurance exercise.

The effects of acute aerobic and resistance exercise on mTOR signaling and autophagy markers in untrained human skeletal muscle

PURPOSE

Aerobic (AE) and resistance (RE) exercise elicit unique adaptations in skeletal muscle. The purpose here was to compare the post-exercise response of mTOR signaling and select autophagy markers in skeletal muscle to acute AE and RE.

METHODS

In a randomized, cross-over design, six untrained men (27 ± 3 years) completed acute AE (40 min cycling, 70% HRmax) and RE (8 sets, 10 repetitions, 65% 1RM). Muscle biopsies were taken at baseline, and at 1 h and 4 h following each exercise. Western blot analyses were performed to examine total and phosphorylated protein levels. Upstream regulator analyses of skeletal muscle transcriptomics were performed to discern the predicted activation states of mTOR and FOXO3.

RESULTS

Compared to AE, acute RE resulted in greater phosphorylation (P < 0.05) of mTOR^Ser2448 at 4 h, S6K1^Thr389 at 1 h, and 4E- BP1^Thr37/46 during the post-exercise period. However, both AE and RE increased mTOR^Ser2448 and S6K1^Thr389 phosphorylation at 4 h (P < 0.05). Upstream regulator analyses revealed the activation state of mTOR was increased for both AE (z score, 2.617) and RE (z score, 2.789). No changes in LC3BI protein were observed following AE or RE (P > 0.05), however, LC3BII protein was decreased after both AE and RE at 1 h and 4 h (P < 0.05). p62 protein content was also decreased at 4 h following AE and RE (P < 0.05).

CONCLUSION

Both acute AE and RE stimulate mTOR signaling and similarly impact select markers of autophagy. These findings indicate the early adaptive response of untrained human skeletal muscle to divergent exercise modes is not likely mediated through large differences in mTOR signaling or autophagy.

Effect of a 12-week endurance training program on force transfer and membrane integrity proteins in lean, obese, and type 2 diabetic subjects

The mechanisms accounting for the loss of muscle function with obesity and type 2 diabetes are likely the result of a combination of neural and muscular factors. One muscular factor that is important, yet has received little attention, is the protein machinery involved in longitudinal and lateral force transmission. The purpose of this study was to compare the levels of force transfer and membrane integrity proteins before and after a 12‐week endurance training program in lean, obese, and obese type 2 diabetic adults. Nineteen sedentary subjects (male = 8 and female = 11) were divided into three groups: Lean (n = 7; 50.3 ± 4.1 y; 69.1 ± 7.2 kg); Obese (n = 6; 49.8 ± 4.1 y; 92.9 ± 19.5 kg); and Obese with type 2 diabetes (n = 6; 51.5 ± 7.9 years; 88.9 ± 15.1 kg). Participants trained 150 min/week between 55% and 75% of VO_2max for 12 weeks. Skeletal muscle biopsies were taken before and after the training intervention. Baseline dystrophin and muscle LIM protein levels were higher (~50% p < .01) in lean compared to obese and type 2 diabetic adults, while the protein levels of the remaining force transfer and membrane integrity proteins were similar between groups. After training, obese individuals decreased (−53%; p < .01) the levels of the muscle ankyrin repeat protein and lean individuals decreased dystrophin levels (−45%; p = .01), while the levels of the remaining force transfer and membrane integrity proteins were not affected by training. These results suggest that there are modest changes to force transfer and membrane integrity proteins in middle‐aged individuals as a result of 12 weeks of lifestyle and training interventions.

Effects and Moderators of Exercise on Sarcopenic Components in Sarcopenic Elderly: A Systematic Review and Meta-Analysis

Background: Sarcopenia is a muscle disease in loss of muscle strength, mass, and function associated with aging. Although protective effects of exercise on muscle mass and function are generally recognized, research findings in sarcopenic adults are inconsistent. It is necessary to conduct a systematic review to determine the effects of exercise on muscle strength, body composition, and physical performance in older adults with sarcopenia, and to examine the potential moderators including sociodemographic characteristics and exercise-related factors.

Methods: Six electronical academic databases (Medline, Embase, CINAHL, Scopus, Cochrane Library, and SPORTDiscus) were used to retrieve the eligible studies from inception to May 2020. Two reviewers independently selected and extracted the data from each included study, and effect sizes were calculated by employing random-effect models with 95% confidential interval (CI). The Physiotherapy Evidence Database (PEDro) scale was used to assess study quality.

Results: Seventeen studies (985 participants with sarcopenia, aged 67.6–86 years) were included in this review study. The meta-analytic results showed significant improvements in muscle strength [grip strength, SMD = 0.30, 95% CI (0.15, 0.45), I² = 6%, p < 0.01; knee extension, SMD = 0.32, 95% CI (0.15, 0.50), I² = 0%, p < 0.01; and chair and stand, SMD = 0.56, 95% CI (0.30, 0.81), I² = 36%, p < 0.01], in physical performance [timed up and go, SMD = 0.74, 95% CI (0.48, 1.00), I² = 0%, p < 0.01; and gait speed, SMD = 0.59, 95% CI (0.35, 0.82), I² = 62%, p < 0.01], and in body composition [skeletal muscle mass index, SMD = 0.37, 95% CI (0.15, 0.58), I² = 16%, p < 0.01; and appendicular skeletal muscle, SMD = 0.31, 95% CI (0.13, 0.49), I² = 20%, p < 0.01]. However, there were no significant differences in other body composition (SMD = 0.20–0.36). Additionally, meta-regression revealed that the higher percent of female participants was significantly associated with improved gait speed (β = 0.0096, p = 0.03) and decreased skeletal muscle mass index (β = −0.0092, p = 0.01).

Conclusions: The current meta-analysis suggests that exercise is a beneficial therapy, which has protective effects for older adults with sarcopenia. Some beneficial effects may be moderated by gender and exercise intensity.

Impact of current or past physical activity level on functional capacities and body composition among elderly people: a cross-sectional analysis from the YMCA study

Background

Physical activity (PA) is recognized as important predictor of healthy aging. However, the influence of the type of voluntary PA as well as age or sex in this relationship is unclear. Thus, we assess the association between current and past PA level and physical performances among voluntary active older adults.

Methods

Functional capacities (timed Up and Go, sit-to-stand, alternate step test, unipodal balance, grip strength, knee extension strength, estimated muscle power and VO2 max) as well as body composition (DXA: total and appendicular lean masses (LM; kg), fat mass (FM; %)) were measured. Current and last 5-years PA level (time spent on total, aerobic, resistance and body & mind activities) were assessed using an interview. Multiple regressions, adjusted on age, sex and BMI, were performed to assess the relationship between current or past PA level and physical performances. Sub-group analysis, according to the sex (men/women) or age (< 65 yrs. vs. ≥65 yrs) were performed.

Results

525 subjects (age:61.7 ± 8.1 yrs.; women:68.9%; BMI:26.4 ± 4.8 kg/m²) were enrolled in this study. After adjustment on confounding factors, total current PA level has positive impact on total FM (β = − 2.09, p = 0004) and balance (β = 0.10; p = 0.05). Moreover, current body & mind activities influence total LBM (β = − 0.22, p = 0.02) and balance (β = 0.17; p = 0.001) whereas resistance activities influence total LBM (β = 0.17; p = 0.05), FM (β = − 0.16; p = 0.04) and sit-to-stand capacities (β = − 0.10; p = 0.05). Globally, these results were more pronounced in women than in men and among people aged over 65 years. Past level of PA has low impact on functional capacities and body composition, regardless of sex. Among people < 65 years, there is no relationship between time spent on total PA and functional capacities or body composition. However, a significant correlation was found between past total PA and balance (r=` 0.19; p = 0.01), alternate-step test (r = 0.24; p = 0.02) and VO2max (r = 0.19; p = 0.02) in people aged over 65 years. More precisely, the past time spent on aerobic and resistance activities influence balance (r = 0.16; p = 0.03 and r = 0.15; p = 0.04, respectively) after 65 yrs. old.

Conclusion

Even if physical activity history has little influence on physical aging process, being active is associated with body composition and functional capacities, especially among women aged 65 years and over.

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.

Development of Maximal Dynamic Strength During Concurrent Resistance and Endurance Training in Untrained, Moderately Trained, and Trained Individuals: A Systematic Review and Meta-analysis

Background

The effect of concurrent training on the development of maximal strength is unclear, especially in individuals with different training statuses.

Objective

The aim of this systematic review and meta-analysis study was to compare the effect of concurrent resistance and endurance training with that of resistance training only on the development of maximal dynamic strength in untrained, moderately trained, and trained individuals.

Methods

On the basis of the predetermined criteria, 27 studies that compared effects between concurrent and resistance training only on lower-body 1-repetition maximum (1RM) strength were included. The effect size (ES), calculated as the standardised difference in mean, was extracted from each study, pooled, and analysed with a random-effects model.

Results

The 1RM for leg press and squat exercises was negatively affected by concurrent training in trained individuals (ES =  – 0.35, p < 0.01), but not in moderately trained ( – 0.20, p = 0.08) or untrained individuals (ES = 0.03, p = 0.87) as compared to resistance training only. A subgroup analysis revealed that the negative effect observed in trained individuals occurred only when resistance and endurance training were conducted within the same training session (ES same session =  – 0.66, p < 0.01 vs. ES different sessions =  – 0.10, p = 0.55).

Conclusion

This study demonstrated the novel and quantifiable effects of training status on lower-body strength development and shows that the addition of endurance training to a resistance training programme may have a negative impact on lower-body strength development in trained, but not in moderately trained or untrained individuals. This impairment seems to be more pronounced when training is performed within the same session than in different sessions. Trained individuals should therefore consider separating endurance from resistance training during periods where the development of dynamic maximal strength is prioritised.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01426-9.

Differential effects of pre-exercise on cancer cachexia-induced muscle atrophy in fast- and slow-twitch muscles

We hypothesized that pre-exercise may effectively prevent cancer cachexia-induced muscle atrophy in both fast- and slow-twitch muscle types. Additionally, the fast-twitch muscle may be more affected by cancer cachexia than slow-twitch muscle. This study aimed to evaluate the effects of pre-exercise on cancer cachexia-induced atrophy and on atrophy in fast- and slow-twitch muscles. Twelve male Wistar rats were randomly divided into sedentary and exercise groups, and another 24 rats were randomly divided into control, pre-exercise, cancer cachexia induced by intraperitoneal injections of ascites hepatoma AH130 cells, and pre-exercise plus cancer cachexia groups. We analyzed changes in muscle mass and in gene and protein expression levels of major regulators and indicators of muscle protein degradation and synthesis pathways, angiogenic factors, and mitochondrial function in both the plantaris and soleus muscles. Pre-exercise inhibited muscle mass loss, rescued protein synthesis, prevented capillary regression, and suppressed hypoxia in the plantaris and soleus muscles. Pre-exercise inhibited mitochondrial dysfunction differently in fast- and slow-twitch muscles. These results suggested that pre-exercise has the potential to inhibit cancer-cachexia-induced muscle atrophy in both fast- and slow-twitch muscles. Furthermore, the different progressions of cancer-cachexia-induced muscle atrophy in fast- and slow-twitch muscles are related to differences in mitochondrial function.

Effect of aging and obesity on GLUT12 expression in small intestine, adipose tissue, muscle, and kidney and its regulation by docosahexaenoic acid and exercise in mice

Obesity is characterized by excessive fat accumulation and inflammation. Aging has also been characterized as an inflammatory condition, frequently accompanied by accumulation of visceral fat. Beneficial effects of exercise and n-3 long-chain polyunsaturated fatty acids in metabolic disorders have been described. Glucose transporter 12 (GLUT12) is one of the less investigated members of the GLUT family. Glucose, insulin, and tumor necrosis factor alpha (TNF-α) induce GLUT12 translocation to the membrane in muscle, adipose tissue, and intestine. We aimed to investigate GLUT12 expression in obesity and aging, and under diet supplementation with docosahexaenoic acid (DHA) alone or in combination with physical exercise in mice. Aging increased GLUT12 expression in intestine, kidney, and adipose tissue, whereas obesity reduced it. No changes on the transporter occurred in skeletal muscle. In obese 18-month-old mice, DHA further decreased GLUT12 in the 4 organs. Aerobic exercise alone did not modify GLUT12, but the changes triggered by exercise were able to prevent the DHA-diminishing effect, and almost restored GLUT12 basal levels. In conclusion, the downregulation of metabolism in aging would be a stimulus to upregulate GLUT12 expression. Contrary, obesity, an excessive energy condition, would induce GLUT12 downregulation. The combination of exercise and DHA would contribute to restore basal function of GLUT12. Novelty In small intestine, kidney and adipose tissue aging increases GLUT12 protein expression whereas obesity reduces it. Dietary DHA decreases GLUT12 in small intestine, kidney, adipose tissue and skeletal muscle. Exercise alone does not modify GLUT12 expression, nevertheless exercise prevents the DHA-diminishing effect on GLUT12.

Açaí (Euterpe oleracea Mart.) seed extract improves aerobic exercise performance in rats

The purpose of this study was to examine whether the supplementation with an açai (Euterpe oleracea Mart.) seed extract (ASE) would affect the aerobic exercise performance in rats and correlate with the vascular function, muscle oxidative stress and mitochondrial biogenesis. Male Wistar rats were divided into five groups: Sedentary, Sedentary with chronic supplementation of ASE, Training, Training with chronic (200 mg/Kg/day intragastric gavage for 5 weeks) or acute (30 min before the maximal treadmill stress test (MST) supplementation with ASE. The exercise training was performed on a treadmill (30 min/day; 5 days/week) for 4 weeks. The chronic supplementation with ASE increased the exercise time (58%) and the running distance (129%) in relation to the MST, while the Training group increased 40% and 78% and the Training with acute ASE group increased 30% and 63%, respectively. The training-induced increase of ACh vasodilation was not changed by ASE, but the norepinephrine-induced vasoconstriction was reduced by chronic and acute supplementation with ASE. The increased levels of malondialdehyde in soleus muscle homogenates from the Training group was reduced only by chronic supplementation with ASE. The muscle antioxidant defense, NO₂ levels, and expression of the mitochondrial biogenesis-related proteins (PGC1α, SIRT-1, p-AMPK/AMPK, Nrf-2) were not different between Training and Sedentary groups, but all these parameters were increased in the Training with Chronic ASE compared with the Sedentary groups. In conclusion, chronic supplementation with ASE improves aerobic physical performance by increasing the vascular function, reducing the oxidative stress, and up-regulating the mitochondrial biogenesis key proteins.

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.

Skeletal Muscle Aging Atrophy: Assessment and Exercise-Based Treatment

In the ordinary course of aging, individuals change their body composition, mainly reducing their skeletal muscle mass and increasing their fat mass. In association, muscle strength and functionality also decrease. The geriatric assessment allows knowing the baseline situation of the patients, determines the impact of diseases, and defines specific treatments. There are various tools to evaluate the health condition of older people. These tools include the assessment scales of necessary Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL), physical and functional assessment scales, and instruments that assess the cognitive state of the person. There are several strategies that have been proposed to combat skeletal muscle atrophy due to aging, such as physical exercise, nutritional supplements, or drugs. Some researchers have highlighted the efficacy of the combination of the mentioned strategies. In this chapter, we will focus only on physical exercise as a strategy to reduce skeletal muscle loss during aging.

Physical exercise: An inducer of positive oxidative stress in skeletal muscle aging

Oxidative stress is the core of most pathological situations, and its attribution toward disease conversion is not yet well established. The adaptive capacity of a cell can overcome ROS-induced pathology. However, when a cell fails to extend its maximum adaptive capacity against oxidative stress, it could lead a cell to misbehave or defunct from its normal functions. Any type of physical activity can increase the cells' maximum adaptive capacity, but aging can limit this. However, whether aging is the initiating point of reducing cells' adaptive capacity against oxidative stress or oxidative stress can induce the aging process is a mystery, and it could be the key to solving several uncured diseases. Paradoxically, minimum ROS is needed for cellular homeostasis. Nevertheless, finding factors that can limit or nullify the production of ROS for cellular homeostasis is a million-dollar question. Regular physical exercise is considered to be one of the factors that can limit the production of ROS and increase the ROS-induced benefits in the cells through inducing minimum oxidative stress and increasing maximum adapting capacity against oxidative stress-induced damages. The type and intensity of exercise that can produce such positive effects in the cells remain unclear. Therefore, this review discusses how physical exercise can help to produce minimal positive oxidative stress in preventing skeletal muscle aging.

RaceRunning training improves stamina and promotes skeletal muscle hypertrophy in young individuals with cerebral palsy

Background

Individuals with cerebral palsy (CP) are less physically active, spend more time sedentary and have lower cardiorespiratory endurance as compared to typically developed individuals. RaceRunning enables high-intensity exercise in individuals with CP with limited or no walking ability, using a three-wheeled running bike with a saddle and a chest plate for support, but no pedals. Training adaptations using this type of exercise are unknown.

Methods

Fifteen adolescents/young adults (mean age 16, range 9–29, 7 females/8 males) with CP completed 12 weeks, two sessions/week, of RaceRunning training. Measurements of cardiorespiratory endurance (6-min RaceRunning test (6-MRT), average and maximum heart rate, rate of perceived exertion using the Borg scale (Borg-RPE)), skeletal muscle thickness (ultrasound) of the thigh (vastus lateralis and intermedius muscles) and lower leg (medial gastrocnemius muscle) and passive range of motion (pROM) of hip, knee and ankle were collected before and after the training period.

Results

Cardiorespiratory endurance increased on average 34% (6-MRT distance; pre 576 ± 320 m vs. post 723 ± 368 m, p < 0.001). Average and maximum heart rate and Borg-RPE during the 6-MRT did not differ pre vs. post training. Thickness of the medial gastrocnemius muscle increased 9% in response to training (p < 0.05) on the more-affected side. Passive hip flexion increased (p < 0.05) on the less-affected side and ankle dorsiflexion decreased (p < 0.05) on the more affected side after 12 weeks of RaceRunning training.

Conclusions

These results support the efficacy of RaceRunning as a powerful and effective training modality in individuals with CP, promoting both cardiorespiratory and peripheral adaptations.

Skeletal Muscle Protein Composition Adaptations to 10 Weeks of High-Load Resistance Training in Previously-Trained Males

While high-load resistance training increases muscle hypertrophy, the intramuscular protein responses to this form of training remains largely unknown. In the current study, recreationally resistance-trained college-aged males (N = 15; mean ± SD: 23 ± 3 years old, 6 ± 5 years training) performed full-body, low-volume, high-load [68–90% of one repetition maximum (1RM)] resistance training over 10 weeks. Back squat strength testing, body composition testing, and a vastus lateralis biopsy were performed before (PRE) and 72 h after the 10-week training program (POST). Fiber type-specific cross-sectional area (fCSA), myofibrillar protein concentrations, sarcoplasmic protein concentrations, myosin heavy chain and actin protein abundances, and muscle tissue percent fluid were analyzed. The abundances of individual sarcoplasmic proteins in 10 of the 15 participants were also assessed using proteomics. Significant increases (p < 0.05) in type II fCSA and back squat strength occurred with training, although whole-body fat-free mass paradoxically decreased (p = 0.026). No changes in sarcoplasmic protein concentrations or muscle tissue percent fluid were observed. Myosin heavy chain protein abundance trended downward (−2.9 ± 5.8%, p = 0.069) and actin protein abundance decreased (−3.2 ± 5.3%, p = 0.034) with training. Proteomics indicated only 13 sarcoplasmic proteins were altered with training (12 up-regulated, 1 down-regulated, p < 0.05). Bioinformatics indicated no signaling pathways were affected, and proteins involved with metabolism (e.g., ATP-PCr, glycolysis, TCA cycle, or beta-oxidation) were not affected. These data comprehensively describe intramuscular protein adaptations that occur following 10 weeks of high-load resistance training. Although previous data from our laboratory suggests high-volume resistance training enhances the ATP-PCr and glycolytic pathways, we observed different changes in metabolism-related proteins in the current study with high-load training.