Weeks Of Resistance Exercise Training Research Articles

Resting Systemic Irisin Concentrations Are Lower in Older versus Younger Males after 12 Weeks of Resistance-Exercise Training While Apelin and IL-15 Concentrations Were Increased in the Whole Cohort

Myokines released by exercise are identified as factors that can influence a person’s health and wellbeing. While myokine secretion in response to an acute bout of endurance and resistance-type exercise has been examined, the influence of resistance-exercise training on myokines at rest is less well established. Therefore, this study was designed to evaluate a panel of myokines at rest following a 12-week resistance-exercise training program in younger and older males. Participants (n = 15) completed a 12-week progressive resistance-exercise training program supervised by a certified fitness professional. The training protocol targeted all major muscle groups of the upper and lower body. Resting blood samples were collected before and after completion of the training program to determine concentrations of apelin, fibroblast growth factor-21 (FGF-21), interleukin (IL)-4, IL-6, IL-7, IL-15, leukemia inhibitory factor (LIF), and irisin. Two-way repeated ANOVAs were used to compare variables between time-points and age groups. There was a main effect of time found for apelin (p = 0.003) and IL-15 (p < 0.001), while no main effects for group or time were found for the other myokines (all p > 0.05). Age group × training status interactions were found for IL-6 (p = 0.04) and irisin (p = 0.014) without pairwise differences for IL-6 (p > 0.05), and younger males had higher concentrations of irisin compared to older males post-training (p = 0.036). Overall, the 12-week resistance-exercise training program significantly increased apelin and IL-15 over time but did not change the other resting myokine concentrations for the younger or older males. However, the higher concentration of irisin in younger versus older males post-training suggests a potential explanation for the anabolic resistance observed with aging.

Preliminary analysis of the THRIVE clinical trial on the effect of resistance exercise on skeletal muscle bioenergetics, strength and body composition in breast cancer survivors

Objective: Breast cancer survivors (BCS) are at high risk for loss in skeletal muscle mass, which can be exacerbated by cancer treatment and tumor related factors. While resistance exercise has been shown to be effective in improving strength and physical function in BCS, little is known as to how exercise modulates skeletal muscle bioenergetics in oncology populations. Uncovering these factors are critical for explaining adaptations to exercise among cancer survivors. Therefore, the objective of the THRIVE clinical trial is to determine the effects of resistance exercise training on modulating skeletal muscle bioenergetics in BCS. Hypothesis: We hypothesized that 12 weeks of resistance exercise would improve skeletal muscle bioenergetics, strength and body composition in BCS. Methodology: Preliminary analysis was performed on BCS (n=10; 45.7 ± 11.5 yr) who had completed chemotherapy within the previous 6 months and were recruited to complete 12 weeks of progressive, home-based resistance exercise program (3 supervised training bouts per week). Baseline and 12 weeks strength was assessed with isometric dynamometry and 1 rep max (RM) testing, body composition was measured with DEXA, and physical function was assessed with a 6 minute walk test. Changes in muscle bioenergetics, specifically changes in resting phosphorus metabolites, were assessed using 31-phosphorus magnetic resonance spectroscopy. In the original study design, participants were randomized to either receive creatinine supplement + exercise (n=5) or exercise alone (n=5); however, there were no significant differences between the interventions on the primary outcomes reported here, so the intervention groups were collapsed. Data: Handgrip strength, 1 RM chest press, 1 RM bicep curl, 1 RM leg press and 1 RM leg extension significantly increased (p<0.05) following 12 weeks of training in breast cancer survivors. Twelve weeks of resistance exercise training also significantly increased skeletal muscle phosphodiester (PDE) content and tended to increase total phosphocreatine and gammaATP. There were no significant changes in isometric knee strength, fat mass, lean mass, 6 minute walk testing distance or skeletal muscle inorganic phosphorous. Summary: This preliminary analysis indicates changes in strength and skeletal muscle bioenergetics occur in BCS following a 12-week home-based resistance exercise intervention. Further research is needed to validate these results. The ThriveWell Foundation, NIH (P30 CA054174 and P30 AG044271). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Muscle Mass and Strength Gains Following Resistance Exercise Training in Older Adults 65-75Years and Older Adults Above 85Years.

Resistance exercise training (RET) can be applied effectively to increase muscle mass and function in older adults (65-75years). However, it has been speculated that older adults above 85years are less responsive to the benefits of RET. This study compares the impact of RET on muscle mass and function in healthy older adults 65-75years versus older adults above 85years. We subjected 17 healthy older adults 65-75years (OLDER 65-75, n = 13/4 [female/male]; 68 ± 2years; 26.9 ± 2.3kg/m2) and 12 healthy older adults above 85years (OLDER 85+, n = 7/5 [female/male]; 87 ± 3years; 26.0 ± 3.6kg/m2) to 12weeks of whole-body RET (three times per week). Prior to, and after 6 and 12weeks of training, quadriceps and lumbar spine vertebra 3 muscle cross-sectional area (computed tomography scan), whole-body lean mass (dual-energy X-ray absorptiometry scan), strength (one-repetition maximum test), and physical performance (timed up and go and short physical performance battery) were assessed. Twelve weeks of RET resulted in a 10% ± 4% and 11% ± 5% increase in quadriceps cross-sectional area (from 46.5 ± 10.7 to 51.1 ± 12.1cm2, and from 38.9 ± 6.1 to 43.1 ± 8.0cm2, respectively; p < .001; η2 = .67); a 2% ± 3% and 2% ± 3% increase in whole-body lean mass (p = .001; η2 = .22); and a 38% ± 20% and 46% ± 14% increase in one-repetition maximum leg extension strength (p < .001; η2 = .77) in the OLDER 65-75 and OLDER 85+ groups, respectively. No differences in the responses to RET were observed between groups (Time × Group, all p > .60; all η2 ≤ .012). Physical performance on the short physical performance battery and timed up and go improved (both p < .01; η2 ≥ .22), with no differences between groups (Time × Group, p > .015; η2 ≤ .07). Prolonged RET increases muscle mass, strength, and physical performance in the aging population, with no differences between 65-75years and 85+years older adults.

Muscle fiber type grouping does not change in response to prolonged resistance exercise training in healthy older men

BackgroundAgeing of skeletal muscle is characterized in some by muscle fiber type grouping due to denervation-reinnervation cycles, but the severity of fiber type grouping varies widely across individuals of the same chronological age. It remains unknown whether fiber type grouping is associated with lower muscle mass and/or reduced physical function in elderly. Therefore, we assessed the relationship between fiber type grouping and indices of muscle mass and physical function in older adults. In addition, we assessed whether fiber type grouping is affected by prolonged resistance training in older adults. MethodsTwenty young (21 ± 2 y) and twenty older (70 ± 4 y) healthy men participated in the present study. Body composition (DXA-scan), quadriceps cross-sectional area (CT-scan) and muscle strength (1RM) were assessed at baseline (young and old) and following 12 weeks of resistance training (old only). Percutaneous skeletal muscle biopsies from the vastus lateralis were collected at baseline (young and old) and following exercise training (old only). Immunohistochemical analyses were performed to evaluate type I and type II muscle fiber distribution, size, myonuclear content and grouping. ResultsAt baseline, type II fibers were significantly (P < 0.05) smaller in older compared with young adults (5366 ± 1288 vs 6705 ± 1168 μm2). Whereas no differences were observed in type I, type II fiber grouping was significantly (P < 0.05) lower in older (18 ± 18 %) compared with young (32 ± 25 %) men. No significant correlations were observed between fiber type grouping and muscle mass or physical function. Prolonged resistance training in old men resulted in a significant increase (P < 0.05) in type II fiber size (from 5366 ± 1288 to 6165 ± 1484 μm2) with no significant changes in the proportion of type I muscle fibers found grouped. ConclusionMuscle fiber type grouping is not associated with lower body strength or muscle mass in healthy, older men. In addition, twelve weeks of resistance exercise training results in type II muscle fiber specific hypertrophy but does not affect fiber type grouping.

Dependability Of Exertion And Muscle Pain Ratings During Resistance Training In Veterans With Chronic Pain

Chronic muscle pain (CMP) is a primary complaint of US Veterans of the Persian Gulf War (GWV) currently suffering from Gulf War illness, a chronic multisymptom condition. Although the research literature often characterizes Veterans as stoic, previous research in our lab has demonstrated that GWV with CMP report greater perceived exertion (RPE) and muscle pain during exercise compared to healthy GWV. Given the potential use of these ratings as tools for monitoring and prescribing exercise intensity in patient groups, it is important to quantify their dependability and relationships to symptoms as training progresses. PURPOSE: To evaluate the dependability (i.e., reliability) and sources of variance in RPE and muscle pain ratings across 16 weeks of resistance exercise training (RET), as well as their association with self-reported pain symptoms in GWV with CMP. METHODS: Twenty-six GWV with CMP completed 16 weeks of individualized RET initiated at a low intensity (25-35% of est. max.) with progression as tolerated. Each session consisted of 10 exercises with 2 sets of each. RPE (6-20) and muscle pain (0-10) were reported for each set at its completion. Ratings at weeks 2, 9, and 15 were evaluated separately using generalizability theory, a technique which quantifies the dependability of responses and apportions their variability to the conditions of the testing procedure (i.e., respondents, sets, and exercises). Daily pain symptoms were also recorded for each session. Associations between symptom scores and RPE and muscle pain were calculated using Spearman’s rho. RESULTS: Generalizability coefficients were very high for both measures at each time point (ξρ2 > 0.89) indicating a high level of dependability. Respondents were the greatest source of variance throughout. Variance due to exercises, however, was reduced with training progression. No significant relationships between pain symptoms and RPE or muscle pain were noted at any time point (ρ: -0.28 - 0.34; p > 0.05). CONCLUSIONS: RPE and muscle pain ratings exhibit a high degree of dependability for GWV with CMP during exercise, even with training adaptations. This finding supports the use of these ratings as tools for monitoring and prescribing exercise intensity in this population. Supported by a grant from the U.S. Department of Veterans Affairs #I01 CX000383

Pharmacological hypogonadism impairs molecular transducers of exercise-induced muscle growth in humans.

BackgroundThe relative role of skeletal muscle mechano‐transduction in comparison with systemic hormones, such as testosterone (T), in regulating hypertrophic responses to exercise is contentious. We investigated the mechanistic effects of chemical endogenous T depletion adjuvant to 6 weeks of resistance exercise training (RET) on muscle mass, function, myogenic regulatory factors, and muscle anabolic signalling in younger men.MethodsNon‐hypogonadal men (n = 16; 18–30 years) were randomized in a double‐blinded fashion to receive placebo (P, saline n = 8) or the GnRH analogue, Goserelin [Zoladex (Z), 3.6 mg, n = 8], injections, before 6 weeks of supervised whole‐body RET. Participants underwent dual‐energy X‐ray absorptiometry (DXA), ultrasound of m. vastus lateralis (VL), and VL biopsies for assessment of cumulative muscle protein synthesis (MPS), myogenic gene expression, and anabolic signalling pathway responses.ResultsZoladex suppressed endogenous T to within the hypogonadal range and was well tolerated; suppression was associated with blunted fat free mass [Z: 55.4 ± 2.8 to 55.8 ± 3.1 kg, P = 0.61 vs. P: 55.9 ± 1.7 to 57.4 ± 1.7 kg, P = 0.006, effect size (ES) = 0.31], composite strength (Z: 40 ± 2.3% vs. P: 49.8 ± 3.3%, P = 0.03, ES = 1.4), and muscle thickness (Z: 2.7 ± 0.4 to 2.69 ± 0.36 cm, P > 0.99 vs. P: 2.74 ± 0.32 to 2.91 ± 0.32 cm, P < 0.0001, ES = 0.48) gains. Hypogonadism attenuated molecular transducers of muscle growth related to T metabolism (e.g. androgen receptor: Z: 1.2 fold, P > 0.99 vs. P: 1.9 fold, P < 0.0001, ES = 0.85), anabolism/myogenesis (e.g. IGF‐1Ea: Z: 1.9 fold, P = 0.5 vs. P: 3.3 fold, P = 0.0005, ES = 0.72; IGF‐1Ec: Z: 2 fold, P > 0.99 vs. P: 4.7 fold, P = 0.0005, ES = 0.68; myogenin: Z: 1.3 fold, P > 0.99 vs. P: 2.7 fold, P = 0.002, ES = 0.72), RNA/DNA (Z: 0.47 ± 0.03 to 0.53 ± 0.03, P = 0.31 vs. P: 0.50 ± 0.01 to 0.64 ± 0.04, P = 0.003, ES = 0.72), and RNA/ASP (Z: 5.8 ± 0.4 to 6.8 ± 0.5, P > 0.99 vs. P: 6.5 ± 0.2 to 8.9 ± 1.1, P = 0.008, ES = 0.63) ratios, as well as acute RET‐induced phosphorylation of growth signalling proteins (e.g. AKTser473: Z: 2.74 ± 0.6, P = 0.2 vs. P: 5.5 ± 1.1 fold change, P < 0.001, ES = 0.54 and mTORC1ser2448: Z: 1.9 ± 0.8, P > 0.99 vs. P: 3.6 ± 1 fold change, P = 0.002, ES = 0.53). Both MPS (Z: 1.45 ± 0.11 to 1.50 ± 0.06%·day−1, P = 0.99 vs. P: 1.5 ± 0.12 to 2.0 ± 0.15%·day−1, P = 0.01, ES = 0.97) and (extrapolated) muscle protein breakdown (Z: 93.16 ± 7.8 vs. P: 129.1 ± 13.8 g·day−1, P = 0.04, ES = 0.92) were reduced with hypogonadism result in lower net protein turnover (3.9 ± 1.1 vs. 1.2 ± 1.1 g·day−1, P = 0.04, ES = 0.95).ConclusionsWe conclude that endogenous T sufficiency has a central role in the up‐regulation of molecular transducers of RET‐induced muscle hypertrophy in humans that cannot be overcome by muscle mechano‐transduction alone.

Low Intake of Choline Is Associated with Diminished Strength and Lean Mass Gains in Older Adults.

Choline is an essential micronutrient for many physiological processes related to exercise training including biosynthesis of acetylcholine. Though dietary choline intake has been studied in relation to endurance training and performance, none have studied it during resistance exercise training (RET) in older adults. The objective of the study was to examine the relationship between choline intake and muscle responses to RET in older adults. Forty-six, 60-69-year-old individuals (M=19, F=27) underwent 12 weeks of RET (3x/week, 3 sets, 8-12 reps, 75% of maximum strength [1RM], 8 exercises). Body composition (DEXA) and 1RM tests were performed before and after training. After analyzing 1,656 diet logs (3x/week, 46 participants, 12 weeks), participants' mean choline intakes were categorized into three groups: Low (2.9-5.5 mg/kg lean/d), Med-Low (5.6-8.0 mg/kg lean/d), or Adequate (8.1-10.6 mg/kg lean/d). These correspond to <50%, ~63%, and ~85% of Adequate Intake (AI) for choline, respectively. Gains in composite strength (leg press + chest press 1RM) were significantly lower in the Low group compared with the other groups (Low: 30.9 ± 15.1%, Med-Low: 70.3 ± 48.5%, Adequate: 81.9 ± 68.4%; p=0.004). ANCOVA with cholesterol, protein, or other nutrients did not alter this result. Reduced gains in lean mass were also observed in the Low group, compared with higher choline intake of 5.6-10.6 mg/kg lean/d (1.3 ± 0.6% vs. 3.2 ± 0.6%, p<0.05). These data suggest that this population of older adults does not consume adequate choline and lower choline intake is negatively and independently associated with muscle responses to RET.

Exploring the Effects of Greek Yogurt Supplementation and Exercise Training on Serum Lithium and Its Relationship With Musculoskeletal Outcomes in Men.

Dairy products can act as a dietary source of lithium (Li), and a recent study in university-aged males demonstrated that Greek yogurt (GY) supplementation augmented gains in fat free mass, strength and bone formation after 12 weeks of resistance exercise training compared to carbohydrate (CHO) pudding supplementation. Here, we performed secondary analyses to explore whether GY would alter serum Li levels and whether changes in serum Li would associate with changes in body composition, strength, and bone turnover markers. Results show that the GY group maintained serum Li levels after exercise training, whereas the CHO group did not. Maintaining/elevating serum Li levels was also associated with greater gains in strength and reductions in bone resorption. However, controlling for other dietary factors in GY such as protein and calcium weakened these associations. Thus, future studies should assess the causative role, if any, of dietary Li alone on strength and bone resorption in humans.

Exercise training and detraining effects on body composition, muscle strength and lipid, inflammatory and oxidative markers in breast cancer survivors under tamoxifen treatment

AimsThe present study aimed to verify the effects of resistance training (RT) and successive detraining on body composition, muscle strength and lipid profile as primary outcome, and the oxidative stress and inflammatory markers as second outcome of postmenopausal Breast Cancer (BC) survivors undergoing tamoxifen (TA). Main methodsFourteen postmenopausal BC survivors underwent 12 weeks of resistance exercise training and subsequently 12 weeks of detraining. Anthropometric parameters, lipid profile, muscle strength, inflammatory cytokines and the oxidative stress markers, were assessed before, after the training period and after detraining period. Key findingsOne-way ANOVA showed that fat mass decrease (39.4 ± 6.9 to 37.7 ± 6.8%) and free-fat mass increase (39.3 ± 4.9 to 40.3 ± 5.6%) after RT. Muscle strength increased in response to training but decreased after the detraining period. Triglycerides (156 ± 45 to 123 ± 43 mg/dL) and total cholesterol (202 ± 13 to 186 ± 16 mg/dL) decreased after the RT and HDL-cholesterol (47 ± 9 to 56 ± 9 mg/dL) increased after RT and remained higher (53 ± 10 mg/dL) than after detraining. IL-6 increases (24.65 ± 10.85 to 41.42 ± 22.88 pg/mL) and IL-17 (2.42 ± 0.32 to 1.69 ± 0.19 pg/mL), TBARS (1.91 ± 0.19 to 1.03 ± 0.1 μmol/L), SOD (24.65 ± 10.85 to 41.42 ± 22.88 U/gHb) and Catalase activity (445.9 ± 113.0 to 345.8 ± 81.7 k/gHb·s) reduced after RT and remained lower after detraining. SignificanceResistance exercise training improves health markers of BC survivors undergoing TA and detraining are not sufficient to reverse the positive effects in oxidative stress markers.

Resistance exercise training with protein supplementation improves skeletal muscle strength and improves quality of life in late adolescents and young adults with Barth syndrome: A pilot study.

BackgroundMuscle weakness and exercise intolerance contribute to reduced quality of life (QOL) in Barth syndrome (BTHS). Our group previously found that 12 weeks of resistance exercise training (RET) improved muscle strength, however, did not increase muscle (lean) mass or QOL in n = 3 young adults with BTHS. The overall objective of this pilot study was to examine the safety and effectiveness of RET plus daily protein supplementation (RET + protein) on muscle strength, skeletal muscle mass, exercise tolerance, cardiac function, and QOL in late adolescents/young adults with BTHS.MethodsParticipants with BTHS (n = 5, age 27 ± 7) performed 12 weeks of supervised RET (60 minutes per session, three sessions/week) and consumed 42 g/day of whey protein. Muscle strength, muscle mass, exercise capacity, cardiac function, and health‐related QOL were assessed pre‐post intervention.ResultsRET + protein was safe, increased muscle strength and quality of life, and tended to increase lean mass.ConclusionsRET + protein appears safe, increases muscle strength and quality of life and tends to increase lean mass. Larger studies are needed to confirm these findings and to fully determine the effects of RET + protein in individuals with BTHS.

Randomized Trial Of Resistance Exercise And Follow-up In Gulf War Veterans With Chronic Musculoskeletal Pain

Approximately 30% of US Veterans of the Persian Gulf War currently suffer from Gulf War illness, a chronic multisymptom condition without clear pathology. Chronic muscle pain (CMP) is a primary complaint of Veterans with Gulf War illness. Generally, prognosis is poor and few effective treatments have been substantiated. Structured aerobic and resistance exercise have both proven beneficial in civilians with similar conditions (e.g., fibromyalgia), but have not been rigorously tested in Gulf Veterans with CMP. PURPOSE: To evaluate the influence of a progressive, 16-week, resistance exercise training (RET) program on fitness, symptoms, mood, and Patients’ Global Impression of Change (PGIC) in Gulf Veterans with CMP during training and at 6- and 12-months follow-up. METHODS: Fifty-four Gulf Veterans with CMP were randomly assigned to 16 weeks of RET (n = 28) or a wait-list control (n = 26). Exercise consisted of twice weekly sessions with a personal trainer, initiated at a low intensity (25-35% of estimated maximum) with progression as tolerated. At baseline, 6, 11, and 17 weeks, all participants were evaluated on symptoms, mood, and PGIC. Participants returned for further evaluation 6 and 12 months after the intervention. Analyses of symptom and mood outcomes were conducted via separate linear mixed models with group and time as fixed effects and baseline values as a covariate to control for initial differences. A similar model, without a baseline covariate, was employed to evaluate PGIC scores. RESULTS: No adverse events due to the intervention were reported. Gulf Veterans assigned to RET completed 88% of training sessions and exhibited strength increases of >20% for 7 of 8 lifts. Estimates for the fixed effects and their interactions were not significant for symptom or mood outcomes (p > 0.05). A significant interaction between factors was observed for PGIC (F1,163 = 16.94, p = 0.00006). This interaction was characterized by greater improvement since baseline for RET at each time point, until the 12-month follow-up. CONCLUSIONS: RET appears to be a safe and effective method of improving fitness and patient perception, without symptom exacerbation, in Gulf Veterans with CMP. Supported by a grant from the U.S. Department of Veterans Affairs #I01 CX000383

Effects of Protein-Rich Nutritional Composition Supplementation on Sarcopenia Indices and Physical Activity during Resistance Exercise Training in Older Women with Knee Osteoarthritis.

Older adults with knee osteoarthritis (KOA) are at high risk of sarcopenia. Protein-rich nutritional composition supplementation (PS) combined with resistance exercise training (RET) improves muscle gains and facilitates physical activity in older adults. However, whether PS augments the effects of RET on muscle mass and PA in patients with KOA remains unclear. Therefore, this study identified the effects of PS on sarcopenic indices and PA in older women with KOA subjected to an RET program. Eligible older women aged 60–85 years and diagnosed as having KOA were randomly assigned to either the experimental group (EG) or the control group (CG). Both groups performed RET twice a week for 12 weeks. The EG received additional PS during this period. Outcome measures included appendicular lean mass index, walking speed, physical activity, and scores on the Western Ontario and McMaster Universities Osteoarthritis Index—WOMAC). All measures were tested at baseline and after intervention. With participant characteristics and baseline scores as covariates, analysis of variance was performed to identify between-group differences in changes in all outcome measures after intervention. Statistical significance was defined as p < 0.05. Compared with the CG, the EG achieved greater changes in appendicular lean mass index (adjusted mean difference (aMD) = 0.19 kg/m2, p < 0.01), physical activity (aMD = 30.0 MET-hour/week, p < 0.001), walking speed (aMD = 0.09 m/s, p < 0.05), and WOMAC global function (aMD = −8.21, p < 0.001) after intervention. In conclusion, PS exerted augmentative effects on sarcopenic indices, physical activity, and perceived global WOMAC score in older women with KOA through 12 weeks of RET.

Safety and efficacy of short-term structured resistance exercise in Gulf War Veterans with chronic unexplained muscle pain: A randomized controlled trial

AimsChronic widespread musculoskeletal pain (CMP) is a primary condition of Veterans suffering from Gulf War illness. This study evaluated the influence of resistance exercise training (RET) on symptoms, mood, perception of improvement, fitness, and total physical activity in Gulf War Veterans (GWV) with CMP. Main methodsFifty-four GWV with CMP were randomly assigned to 16 weeks of RET (n = 28) or wait-list control (n = 26). Supervised exercise was performed twice weekly starting at a low intensity. Outcomes, assessed at baseline, 6, 11 and 17 weeks and 6- and 12-months post-intervention, were: pain, fatigue, mood, sleep quality, perception of improvement, and physical activity via self-report and accelerometry. Muscular strength was assessed at baseline, 8 and 16 weeks. Accelerometer data yielded estimates of time spent in sedentary, light, and moderate-to-vigorous physical activities. Analyses used separate linear mixed models with group and time point as fixed effects. All models, except for perceived improvement, included baseline values as a covariate. Key findingsParticipants assigned to RET completed 87% of training sessions and exhibited strength increases between 16 and 34% for eight lifts tested (Hedges' g range: 0.47–0.78). The treatment by time interaction for perceived improvement (F1,163 = 16.94, p < 0.001) was characterized by greater perceived improvement since baseline for RET at each time point, until the 12-month follow-up. Effects were not significant for other outcomes (p > 0.05). RET caused no adverse events. SignificanceAfter 16 weeks of RET, GWV with CMP reported improvements in their condition and exhibited increases in muscular strength, without symptom exacerbation or reductions in total physical activity.

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

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 < 0.050). LAT1 protein increased following training (p < 0.001) and increased more in PLA than LEU and WPC (p < 0.050). BCKDHα protein increased and ATF4 protein decreased following training (p < 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.

Myonuclear content and domain size in small versus larger muscle fibres in response to 12 weeks of resistance exercise training in older adults.

AimTo assess the relation between muscle fibre hypertrophy and myonuclear accretion in relatively small and large muscle fibre size clusters following prolonged resistance exercise training in older adults.MethodsMuscle biopsies were collected before and after 12 weeks of resistance exercise training in 40 healthy, older men (70 ± 3 years). All muscle fibres were ordered by size and categorized in four muscle fibre size clusters: ‘Small’: 2000‐3999 µm2, ‘Moderate’: 4000‐5999 µm2, ‘Large’: 6000‐7999 µm2 and ‘Largest’: 8000‐9999 µm2. Changes in muscle fibre size cluster distribution were related to changes in muscle fibre size, myonuclear content and myonuclear domain size.ResultsWith training, the percentage of muscle fibres decreased in the Small (from 23 ± 12 to 17 ± 14%, P < .01) and increased in the Largest (from 11 ± 8 to 15 ± 10%, P < .01) muscle fibre size clusters. The decline in the percentage of Small muscle fibres was accompanied by an increase in overall myonuclear domain size (r = −.466, P = .002) and myonuclear content (r = −.390, P = .013). In contrast, the increase in the percentage of the Largest muscle fibres was accompanied by an overall increase in myonuclear content (r = .616, P < .001), but not in domain size.ConclusionProlonged resistance‐type exercise training induces a decline in the percentage of small as well as an increase in the percentage of the largest muscle fibres in older adults. Whereas the change in the percentage of small fibres is best predicted by an increase in overall myonuclear domain size, the change in the percentage of the largest fibres is associated with an overall increase in myonuclear content.

Influence Of Resistance-exercise Training On Total Physical Activity In Gulf War Veterans With Chronic Pain

Nearly 30% of US military Veterans of the Persian Gulf War are currently suffering from debilitating multisymptom illnesses. A primary complaint among these individuals is chronic widespread musculoskeletal pain (CMP). Previously our lab has observed lower levels of total physical activity (PA) in civilian CMP patients compared to their healthy peers. In general, CMP patients with lower levels of PA are at risk for greater disability. While exercise-training interventions may have demonstrated benefits for fitness and health related outcomes, their influence on total PA, particularly in CMP patients, is an open question. PURPOSE: To quantify the influence of a 16-week resistance exercise training (RET) trial on self-reported and actigraphy measures of total PA in Gulf War Veterans (GV) with CMP. METHODS: Fifty-five GV with CMP were randomly assigned to 16 weeks of RET (n=28) or a wait-list control (n=27). The RET consisted of twice weekly sessions with a personal trainer, initiated at a low intensity (25-35% 1 RM) with progression as tolerated. At baseline, 6 weeks, 11 weeks, and 17 weeks, all participants completed the International Physical Activity Questionnaire (IPAQ) and wore a waist-mounted actigraphy monitor (ACTI) for 7 d during waking hours. Total PA was defined for the IPAQ as the summative total score (MET-min/week) and for the ACTI as total counts per day relative to wear time (counts/d/min). Analyses were limited to GV with valid measures at baseline and at least one additional time point. Data were log transformed and extreme outliers (> 3 SD) were excluded. Separate linear mixed models with group and time point as fixed effects were computed for the IPAQ and ACTI measures, using baseline values as a covariate to control for initial differences. RESULTS: GV assigned to RET completed 88% of training sessions and exhibited strength increases of >20% for 7 of 8 lifts. Estimates for the fixed effects and their interaction were not significant for either measure (IPAQ: FG =0.17, FTP = 0.02, FG×TP = 0.09, p < 0.05; ACTI: FG =0.47, FTP = 0.09, FG×TP = 0.22, p < 0.05). CONCLUSION: Although 16 weeks of RET were well attended and resulted in improvements in fitness for GV with CMP, total PA level, outside of the exercise sessions, did not appear to be impacted. Supported by US Department of Veterans Affairs grant #I01CX000383

Aging Induces A Differential Muscle Transcriptome Profile Following Resistance Exercise Training

PURPOSE: Resistance exercise training (RET) in older adults produces a lesser muscle hypertrophy response as compared to young adults. We hypothesized that this anabolic resistance to exercise may be associated with a differential muscle transcriptome profile. We enrolled 10 young and 10 older men into a 12-week progressive RET program. Skeletal muscle biopsies were obtained from the vastus lateralis before and after RET. METHODS: The transcriptome profiles of skeletal muscle from both young and older adults were obtained by utilizing next-generation RNA sequencing. RESULTS: We analyzed a total of 26,486 genes (i.e., RNA transcripts) in skeletal muscle and found that 11,262 genes in young subjects and 11,830 genes in the older adults were up-regulated after 12 weeks of RET. On the other hand, we observed a down-regulation of 11,079 and 11,214 genes in the young and old groups, respectively. In particular, we found that autophagy linked gene expression (e.g., ATG 12, PIK3R4, ULK 2, ULK3) and transcripts related to muscle hypertrophy (e.g., AKT, EIF2S2, GSK3b) were differentially expressed between young and older adults. Interestingly, we identified 21 genes (e.g., COL5A2, COL3A1 COL1A1) encoding extracellular matrix (ECM) and ECM-associated proteins that were significantly upregulated only in the elderly (P<0.05). CONCLUSIONS: Skeletal muscle gene expression is differentially regulated in older adults in response to RET which may contribute to anabolic resistance and reduced muscle hypertrophy with aging. Future studies will include mechanistic experiments to identify how aging alters gene expression and whether anabolic resistance can be reversed. Funding: NIH/NIA R56 AG051267

Adaptive responses of histone modifications to resistance exercise in human skeletal muscle.

Exercise training causes epigenetic changes in skeletal muscle, although it is unclear how resistance exercise (RE) affects histone modifications. The present study was carried out to investigate the effects of acute RE and RE training on gene expression profiles and histone modifications in human skeletal muscle. Healthy male adults were assigned to acute RE (n = 9, age = 20.5±4.3yr, BMI = 28.0±6.8kg/m2) or RE training (n = 21, age = 23.7±2.5yr, BMI = 24.2±2.7kg/m2) groups. Biopsy samples were obtained from the vastus lateralis muscle before and three hours after a single bout of acute RE, or 3-days after 10 weeks of RE training. RNA sequencing analysis revealed that 153 genes with GO terms including muscle development, stress response, metabolism, cell death, and transcription factor were significantly up-regulated (+291% vs. pre-acute RE) upon acute RE. Expressions of these genes were also greater (+9.6% vs. pre-RE training, p<0.05) in RE trained subjects. Significant up-regulation of acetylated histone 3 (H3) (+235%) and H3 mono-methylated at lysine 4 (+290%) and tri-methylated at lysine 27 (+849%), whereas down-regulation of H3.3 variant (-39%) distributions relative to total H3 were observed at transcriptionally activated loci after acute RE compared to pre-acute RE levels. Interestingly, the distribution of acetylated H3 was found to be up-regulated as compared to the level of total H3 after RE training (+40%, p<0.05). These results indicate that a single bout of RE drastically alters both gene expressions and histone modifications in human skeletal muscle. It is also suggested that enhanced histone acetylation is closely related to up-regulation of gene expressions after RE training.

Effects of Resistance Exercise on Symptoms, Physical Function, and Quality of Life in Gastrointestinal Cancer Patients Undergoing Chemotherapy

This research aimed to investigate the effects of resistance exercise on symptoms, physical function, and quality of life (QoL) in gastrointestinal cancer patients undergoing chemotherapy. Patients were quasi-randomly divided into the resistance exercise group and the relaxation control group, and machine-based resistance exercise was performed twice a week for 12 weeks under the guidance of experienced therapists. The QoL of patients was analyzed by EORTC-QLQ-C30. Resistance exercise training significantly reduced the incidences of lack of energy (inter-group P = .011), nausea (inter-group P = .007), acid reflux (inter-group P = .042), and back pain (inter-group P = .0009). Twelve weeks of resistance exercise training significantly elevated the muscular strength of leg press (inter-group P = .021) and leg extension (inter-group P = .041), and the muscular endurance of leg press (inter-group P = .005). The participants’ performance in 6-m fast walk (inter-group P = .008), 6-m backwards walk (inter-group P = .016), and chair rise (inter-group P = .031) were dramatically improved. Fatigue (inter-group P = .024) and appetite loss (inter-group P = .012) in the resistance exercise group were significantly lower than the relaxation control group. In conclusion, the beneficial effects of resistance exercise on symptoms, physical function and QoL in gastrointestinal cancer patients undergoing chemotherapy were demonstrated. Resistance exercise training reduced the incidences of nausea and acid reflux, improved physical function, and alleviated fatigue and appetite loss in gastrointestinal cancer patients undergoing chemotherapy.

저항성 운동 트레이닝이 비만 남자 대학생의 신체구성, 인슐린저항성, 성장호르몬 및 인슐린유사성장인자-1에 미치는 영향

The purpose of this study was to examine the effects of 11 weeks of resistance exercise training on body composition, insulin resistance, growth hormone and insulin-like growth factor-1 of obese college male students. Twenty obese college male students were volunteered to participate in this study as subjects, and they were randomly assigned to either resistance exercise training group(n=10) or control group(n=10). The subjects in resistance exercise program for intensity of 65% 1RM, three times per week for 11 weeks, whereas subjects in control were asked to maintain their normal life pattern for the same intervention period. All subjects were asked not to change their physical activity pattern throughout the intervention period. Main results of the present study were as follows: 1) Weight, BMI and % body fat were significantly decreased in resistance exercise training group. 2) Insulin and insulin resistance were significantly decreased in resistance exercise training group. but Insulin and insulin resistance were significantly increased in control group. 3) Growth hormone was significantly increased in resistance exercise training group. 4) Insulin-like growth factor-1 was significantly increased in resistance exercise training group. It was concluded that 11 weeks of resistance exercise training would be beneficial for body composition, Insulin resistance, growth hormone and insulin-like growth factor-1 in obese college male students.