scholarly journals Effects of aging and Parkinson’s disease on motor unit remodeling: influence of resistance exercise training

2018 ◽  
Vol 124 (4) ◽  
pp. 888-898 ◽  
Author(s):  
Neil A. Kelly ◽  
Kelley G. Hammond ◽  
C. Scott Bickel ◽  
Samuel T. Windham ◽  
S. Craig Tuggle ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Exercise Training ◽  
Neuromuscular Junction ◽  
Resistance Exercise ◽  
Motor Unit ◽  
Type I ◽  
Resistance Exercise Training ◽  
Age Related ◽  
Myofiber Type

Aging muscle atrophy is in part a neurodegenerative process revealed by denervation/reinnervation events leading to motor unit remodeling (i.e., myofiber type grouping). However, this process and its physiological relevance are poorly understood, as is the wide-ranging heterogeneity among aging humans. Here, we attempted to address 1) the relation between myofiber type grouping and molecular regulators of neuromuscular junction (NMJ) stability; 2) the impact of motor unit remodeling on recruitment during submaximal contractions; 3) the prevalence and impact of motor unit remodeling in Parkinson’s disease (PD), an age-related neurodegenerative disease; and 4) the influence of resistance exercise training (RT) on regulators of motor unit remodeling. We compared type I myofiber grouping, molecular regulators of NMJ stability, and the relative motor unit activation (MUA) requirement during a submaximal sit-to-stand task among untrained but otherwise healthy young (YA; 26 yr, n = 27) and older (OA; 66 yr, n = 91) adults and OA with PD (PD; 67 yr, n = 19). We tested the effects of RT on these outcomes in OA and PD. PD displayed more motor unit remodeling, alterations in NMJ stability regulation, and a higher relative MUA requirement than OA, suggesting PD-specific effects. The molecular and physiological outcomes tracked with the severity of type I myofiber grouping. Together these findings suggest that age-related motor unit remodeling, manifested by type I myofiber grouping, 1) reduces MUA efficiency to meet submaximal contraction demand, 2) is associated with disruptions in NMJ stability, 3) is further impacted by PD, and 4) may be improved by RT in severe cases. NEW & NOTEWORTHY Because the physiological consequences of varying amounts of myofiber type grouping are unknown, the current study aims to characterize the molecular and physiological correlates of motor unit remodeling. Furthermore, because exercise training has demonstrated neuromuscular benefits in aged humans and improved innervation status and neuromuscular junction integrity in animals, we provide an exploratory analysis of the effects of high-intensity resistance training on markers of neuromuscular degeneration in both Parkinson’s disease (PD) and age-matched older adults.

scholarly journals Randomized, four-arm, dose-response clinical trial to optimize resistance exercise training for older adults with age-related muscle atrophy

2017 ◽  
Vol 99 ◽  
pp. 98-109 ◽  
Author(s):  
Michael J. Stec ◽  
Anna Thalacker-Mercer ◽  
David L. Mayhew ◽  
Neil A. Kelly ◽  
S. Craig Tuggle ◽  
...  
Keyword(s):  
Older Adults ◽  
Clinical Trial ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Atrophy ◽  
Dose Response ◽  
Resistance Exercise Training ◽  
Age Related

Effect of heavy-resistance exercise training on muscle fiber composition in young rats

1990 ◽  
Vol 69 (2) ◽  
pp. 434-437 ◽  
Author(s):  
K. E. Yarasheski ◽  
P. W. Lemon ◽  
J. Gilloteaux
Keyword(s):  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Fiber ◽  
Rectus Femoris ◽  
Type I ◽  
Resistance Exercise Training ◽  
Fiber Composition ◽  
Deep Region ◽  
Heavy Resistance Exercise ◽  
Type I Fibers

The purpose of this investigation was to determine whether heavy-resistance exercise training alters the skeletal muscle fiber composition of young rats. Ten male Long Evans rats (3 wk old) were trained to lift progressively heavier weights, which were secured to the rats' tails, while they ascended a 40-cm 90 degree mesh incline 20 times/day 5 days/wk for a food reward. After 8 wk of training, they lifted 406 +/- 19 (SD) g in addition to their body weight (261 +/- 9 g). Compared with 10 sedentary pair-fed rats, no hypertrophy of forelimb muscles (biceps brachii and brachialis) was observed, but rectus femoris wet and dry weights were greater (P less than 0.01) in the trained group. In the deep region of the rectus femoris, type I fiber area was similar between groups, but the trained rats had both a lower (P less than 0.05) percentage of type I fibers and a smaller (P less than 0.05) portion of the total area occupied by type I fibers. The percentage of type IIb fibers in the deep region of the rectus femoris was also similar between groups, but the portion of the deep area composed of type IIb fibers was greater (P less than 0.05) in the trained rats. In the superficial region of the rectus femoris, the trained rats' type IIb fibers were larger (P less than 0.01) and occupied a greater (P less than 0.05) portion of the superficial muscle area.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Preserved Capacity for Adaptations in Strength and Muscle Regulatory Factors in Elderly in Response to Resistance Exercise Training and Deconditioning

2020 ◽  
Vol 9 (7) ◽  
pp. 2188 ◽  
Author(s):  
Andreas Mæchel Fritzen ◽  
Frank D. Thøgersen ◽  
Khaled Abdul Nasser Qadri ◽  
Thomas Krag ◽  
Marie-Louise Sveen ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Myogenic Regulatory Factors ◽  
Resistance Exercise Training ◽  
Regulatory Factors ◽  
Age Related ◽  
Muscle Regulatory Factors

Aging is related to an inevitable loss of muscle mass and strength. The mechanisms behind age-related loss of muscle tissue are not fully understood but may, among other things, be induced by age-related differences in myogenic regulatory factors. Resistance exercise training and deconditioning offers a model to investigate differences in myogenic regulatory factors that may be important for age-related loss of muscle mass and strength. Nine elderly (82 ± 7 years old) and nine young, healthy persons (22 ± 2 years old) participated in the study. Exercise consisted of six weeks of resistance training of the quadriceps muscle followed by eight weeks of deconditioning. Muscle biopsy samples before and after training and during the deconditioning period were analyzed for MyoD, myogenin, insulin-like growth-factor I receptor, activin receptor IIB, smad2, porin, and citrate synthase. Muscle strength improved with resistance training by 78% (95.0 ± 22.0 kg) in the elderly to a similar extent as in the young participants (83.5%; 178.2 ± 44.2 kg) and returned to baseline in both groups after eight weeks of deconditioning. No difference was seen in expression of muscle regulatory factors between elderly and young in response to exercise training and deconditioning. In conclusion, the capacity to gain muscle strength with resistance exercise training in elderly was not impaired, highlighting this as a potent tool to combat age-related loss of muscle function, possibly due to preserved regulation of myogenic factors in elderly compared with young muscle.

Muscle Transcriptional Networks Linked to Resistance Exercise Training Hypertrophic Response Heterogeneity

2021 ◽  
Author(s):  
Kaleen M. Lavin ◽  
Margaret B. Bell ◽  
Jeremy S. McAdam ◽  
Bailey D Peck ◽  
R. Grace Walton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Thigh Muscle ◽  
Secondary Outcome ◽  
Transcriptional Networks ◽  
Type I ◽  
Resistance Exercise Training ◽  
Hypertrophic Response

The skeletal muscle hypertrophic response to resistance exercise training (RT) is highly variable across individuals. The molecular underpinnings of this heterogeneity are unclear. This study investigated transcriptional networks linked to RT-induced muscle hypertrophy, classified as (i) predictive of hypertrophy, (ii) responsive to RT independent of muscle hypertrophy, or (iii) plastic with hypertrophy. Older adults (n=31, 18F/13M, 70±4y) underwent 14-wk RT (3d/wk, alternating high-low-high intensity). Muscle hypertrophy was assessed by pre- to post-RT change in mid-thigh muscle cross-sectional area (CSA) [computed tomography (CT), primary outcome], and thigh lean mass [dual-energy x-ray absorptiometry (DXA), secondary outcome]. Transcriptome-wide poly-A RNA-seq was performed on vastus lateralis tissue collected pre- (n=31) and post-RT (n=22). Prediction networks (using only baseline RNAseq) were identified by Weighted Gene Correlation Network Analysis (WGCNA). To identify Plasticity networks, WGCNA change indices for paired samples were calculated and correlated to changes in muscle size outcomes. Pathway-Level Information ExtractoR (PLIER) was applied to identify Response networks and link genes to biological annotation. Predictionnetworks (n=6) confirmed transcripts previously connected to resistance/ aerobic training adaptations in the MetaMEx database while revealing novel member genes that should fuel future research to understand the influence of baseline muscle gene expression on hypertrophy. Response networks (n=6) indicated RT-induced increase in aerobic metabolism and reduced expression of genes associated with spliceosome biology and type-I myofibers. A single exploratory Plasticity network was identified. Findings support that inter-individual differences in baseline gene expression may contribute more than RT-induced changes in gene networks to muscle hypertrophic response heterogeneity.

scholarly journals The Importance of Resistance Exercise Training to Combat Neuromuscular Aging

Physiology ◽  
2019 ◽  
Vol 34 (2) ◽  
pp. 112-122 ◽  
Author(s):  
Kaleen M. Lavin ◽  
Brandon M. Roberts ◽  
Christopher S. Fry ◽  
Tatiana Moro ◽  
Blake B. Rasmussen ◽  
...  
Keyword(s):  
Exercise Training ◽  
Resistance Exercise ◽  
Exercise Prescription ◽  
Current Knowledge ◽  
Functional Mobility ◽  
Resistance Exercise Training ◽  
Age Related ◽  
Muscle Health ◽  
Performance Gains ◽  
Whole Muscle

Older adults undergoing age-related decrements in muscle health can benefit substantially from resistance exercise training, a potent stimulus for whole muscle and myofiber hypertrophy, neuromuscular performance gains, and improved functional mobility. With the use of advancing technologies, research continues to elucidate the mechanisms of and heterogeneity in adaptations to resistance exercise training beyond differences in exercise prescription. This review highlights the current knowledge in these areas and emphasizes knowledge gaps that require future attention of the field.

Resistance exercise training improves age-related declines in leg vascular conductance and rejuvenates acute leg blood flow responses to feeding and exercise

2012 ◽  
Vol 112 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Bethan Phillips ◽  
John Williams ◽  
Philip Atherton ◽  
Kenneth Smith ◽  
Wulf Hildebrandt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Vascular Function ◽  
Whole Body ◽  
Middle Aged ◽  
Resistance Exercise Training ◽  
Vascular Conductance ◽  
Leg Blood Flow ◽  
Age Related

One manifestation of age-related declines in vascular function is reduced peripheral (limb) blood flow and vascular conduction at rest and in response to vasodilatory stimuli such as exercise and feeding. Since, even in older age, resistance exercise training (RET) represents an efficacious strategy for increasing muscle mass and function, we hypothesized that likewise RET would improve age-related declines in leg blood flow (LBF) and vascular conductance (LVC). We studied three mixed-sex age groups (young: 18–28 yr, n = 14; middle aged: 45–55 yr, n = 20; older: 65–75 yr, n = 17) before and after 20 wk of whole body RET in the postabsorptive state (BASAL) and after unilateral leg extensions (6 × 8 repetitions; 75% 1 repetition maximum) followed by intermittent mixed-nutrient liquid feeds (∼6.5 kJ·kg−1·30 min−1), which allowed us to discern the acute effects of feeding (nonexercised leg; FED) and exercise plus feeding (exercised leg; FEDEX) on vascular function. We measured LBF using Doppler ultrasound and recorded mean arterial pressure (MAP) to calculate LVC. Our results reveal that although neither age nor RET influenced BASAL LBF, age-related declines in LBF responses to FED were eradicated by RET. Moreover, increases in LBF after FEDEX, which occurred only in young and middle-aged groups before RET (+73 ± 9%, and +90 ± 13%, P < 0.001, respectively), increased in all groups after RET (young +78 ± 10%, middle-aged +96 ± 15%, older +80 ± 19%, P < 0.001). Finally, RET robustly improved LVC under FASTED, FED, and FEDEX conditions in the older group. These data provide novel information that supports the premise that RET represents a valuable strategy to counter age-related impairments in LBF/LVC.

scholarly journals LAT1 Protein Content Increases Following 12 Weeks of Resistance Exercise Training in Human Skeletal Muscle

2021 ◽  
Vol 7 ◽  
Author(s):  
Paul A. Roberson ◽  
C. Brooks Mobley ◽  
Matthew A. Romero ◽  
Cody T. Haun ◽  
Shelby C. Osburn ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Metabolic Enzymes ◽  
Whey Protein Concentrate ◽  
Amino Acid Transporters ◽  
Type I ◽  
Resistance Exercise Training

Introduction: Amino acid transporters are essential for cellular amino acid transport and promoting protein synthesis. While previous literature has demonstrated the association of amino acid transporters and protein synthesis following acute resistance exercise and amino acid supplementation, the chronic effect of resistance exercise and supplementation on amino acid transporters is unknown. The purpose herein was to determine if amino acid transporters and amino acid metabolic enzymes were related to skeletal muscle hypertrophy following resistance exercise training with different nutritional supplementation strategies.Methods: 43 college-aged males were separated into a maltodextrin placebo (PLA, n = 12), leucine (LEU, n = 14), or whey protein concentrate (WPC, n = 17) group and underwent 12 weeks of total-body resistance exercise training. Each group's supplement was standardized for total energy and fat, and LEU and WPC supplements were standardized for total leucine (6 g/d). Skeletal muscle biopsies were obtained prior to training and ~72 h following each subject's last training session.Results: All groups increased type I and II fiber cross-sectional area (fCSA) following training (p &lt; 0.050). LAT1 protein increased following training (p &lt; 0.001) and increased more in PLA than LEU and WPC (p &lt; 0.050). BCKDHα protein increased and ATF4 protein decreased following training (p &lt; 0.001). Immunohistochemistry indicated total LAT1/fiber, but not membrane LAT1/fiber, increased with training (p = 0.003). Utilizing all groups, the change in ATF4 protein, but no other marker, trended to correlate with the change in fCSA (r = 0.314; p = 0.055); however, when regression analysis was used to delineate groups, the change in ATF4 protein best predicted the change in fCSA only in LEU (r2 = 0.322; p = 0.043). In C2C12 myoblasts, LAT1 protein overexpression caused a paradoxical decrease in protein synthesis levels (p = 0.002) and decrease in BCKDHα protein (p = 0.001).Conclusions: Amino acid transporters and metabolic enzymes are affected by resistance exercise training, but do not appear to dictate muscle fiber hypertrophy. In fact, overexpression of LAT1 in vitro decreased protein synthesis.

scholarly journals Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease

2014 ◽  
Vol 116 (5) ◽  
pp. 582-592 ◽  
Author(s):  
Neil A. Kelly ◽  
Matthew P. Ford ◽  
David G. Standaert ◽  
Ray L. Watts ◽  
C. Scott Bickel ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Exercise Training ◽  
Muscle Tissue ◽  
High Intensity ◽  
Physical Capacity ◽  
High Intensity Exercise ◽  
Type I ◽  
Type Ii

We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2–3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations ( P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45–56%, IV: +39–54%). These adaptations were accompanied by a host of functional and clinical improvements ( P < 0.05): total body strength (+30–56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (−30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, −7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (−5.7 pts) and motor (−2.7 pts); and fatigue severity (−17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON ( P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception.

Sign in / Sign up

Export Citation Format

Share Document