Resistance Exercise Training Intervention Research Articles

Feasibility and preliminary efficacy of a theory-informed resistance exercise training single-arm intervention for major depression

Many adults with major depressive disorder (MDD) do not receive effective treatment. The potential benefits of resistance exercise training (RET) are understudied and may be mechanistically related to cerebral blood flow changes. PurposeTo assess feasibility, acceptability, and preliminary efficacy of a 16-week, theory-informed RET trial for the treatment of MDD and explore changes in cerebral blood flow. MethodsTen adults with DSM-5-diagnosed MDD were enrolled in a single-arm, 16-week, twice-weekly, whole-body RET intervention, consistent with US and WHO Physical Activity resistance exercise guidelines. To build intrinsic motivation and develop exercise-preparatory habits, motivators and commitment were discussed weekly. Screening, enrollment, and intervention attendance and compliance rates documented feasibility. At baseline and weeks 8, 16, and 26, current MDD diagnosis, clinician-rated, and self-reported symptom severity were evaluated along with cerebral blood flow which was assessed as middle cerebral artery (MCA) mean blood velocity, conductance, and pulsatility. ResultsNine participants completed the intervention. Strong feasibility and acceptability (98 % adherence, 93 % compliance, and 90 % retention) were found. MDD remission was reached by 8/9 participants at week 16 and persisted through week 26. There were large decreases in clinician-rated and self-reported symptoms at each assessment (Hedges’ g = 0.84–2.13). There were small-to-moderate increases in MCA velocity (g = 0.32–0.57) and conductance (g = 0.20–0.76) across time, with minimal changes in pulsatility (all g < 0.21). ConclusionsPreliminary results suggest RET for MDD treatment is feasible and plausibly efficacious, finding large antidepressant effects. A sufficiently powered randomized controlled trial to assess RET’s efficacy for treating MDD via potential cerebrovascular mechanisms is warranted.

Evaluation of sex-based differences in resistance exercise training-induced changes in muscle mass, strength, and physical performance in healthy older (≥60 y) adults: A systematic review and meta-analysis.

The objective of this systematic review and meta-analysis was to determine if there are sex-based differences in adaptations to resistance exercise training in healthy older adults. Following the screening process, data from 36 studies comparing older males and females (602 males; 703 females; ≥60 years of age) for changes in skeletal muscle size, muscle strength, and/or physical performance following the same resistance exercise training intervention were extracted. Mean study quality was 16/29 (modified Downs and Black checklist), considered moderate quality. Changes in absolute upper-body (Effect Size [ES] = 0.81 [95% CI 0.54, 1.09], P<0.001), and lower-body (ES = 0.40 [95% CI 0.24, 0.56], P<0.001) strength were greater in older males than females. Alternatively, changes in relative upper-body (ES = -0.46 [95% CI -0.77, -0.14], P<0.01), and lower-body (ES = -0.24 [95% CI -0.42, -0.06], P<0.01) strength were greater in older females than males. Changes in absolute, but not relative, whole-body fat-free mass (ES = 0.18 [95% CI 0.04, 0.33], P<0.05) were greater in older males than females. There were no sex-based differences for absolute or relative changes in limb muscle size, muscle fiber size, or physical performance.

Exercise Training to Improve Brain Health in Older People Living With HIV: Study Protocol for a Randomized Controlled Trial.

With the advent of antiretrovirals, people living with HIV are living near-normal lifespans. However, people living with HIV are at greater risk of experiencing cognitive impairment and reduced brain integrity despite well-controlled viremia. A robust literature supports exercise interventions as a method of improving cognition and structural brain integrity in older individuals without HIV. The effects of exercise on cardiometabolic, neurocognitive, and neural structures in middle-aged to older people living with HIV are less well known, with few prospective studies examining these measures. This prospective randomized clinical trial will examine the effects of a 6-month exercise training intervention compared to a 6-month stretching intervention (control) on cardiorespiratory fitness, physical function and strength, cognition, and neuroimaging measures of brain volumes and cerebral blood flow in people living with HIV. Sedentary middle-aged to older people living with HIV (ages≥40; n=150) with undetectable HIV viral load (<20 copies/mL) will be enrolled in the study. At the baseline and final visit, fasting plasma lipid, insulin, glucose, and brain neurotrophic factor concentrations; cardiorespiratory fitness; cognitive performance; brain volumes; and cerebral blood flow via a magnetic resonance imaging scan will be measured. Participants will be randomized in a 2:1 ratio to either the exercise or control stretching intervention. All participants will complete their assigned programs at a community fitness center 3 times a week for 6 months. A professional fitness trainer will provide personal training guidance at all sessions for individuals enrolled in both arms. Individuals randomized to the exercise intervention will perform endurance and strength training exercises, while those randomized to the control intervention will perform stretches to increase flexibility. A midpoint visit (at 3 months) will assess cognitive performance, and at the end point visit, subjects will undergo cardiorespiratory fitness and cognition testing, and a magnetic resonance imaging scan. Physical activity throughout the duration of the trial will be recorded using an actigraph. Recruitment and data collection are complete as of December 2020. Data processing, cleaning, and organization are complete as of December 2021. Data analysis began in January 2022, with the publication of study results for primary aims 1 and 2 expected by early 2023. This study will investigate the effects of a 6-month aerobic and resistance exercise training intervention to improve cardiometabolic risk factors, cognitive performance, cerebral structure, and blood flow in sedentary people living with HIV. Results will inform clinicians and patients of the potential benefits of a structured aerobic exercise training program on the cognitive, functional, and cardiometabolic health status of older people living with HIV. Assessment of compliance will inform the development and implementation of future exercise programs for people living with HIV. ClinicalTrials.gov NCT02663934; https://clinicaltrials.gov/ct2/show/NCT02663934. DERR1-10.2196/41421.

The role of resistance exercise training for improving cardiorespiratory fitness in healthy older adults: a systematic review and meta-analysis.

BackgroundDeclines in cardiorespiratory fitness (CRF) and muscle mass are both associated with advancing age and each of these declines is associated with worse health outcomes. Resistance exercise training (RET) has previously been shown to improve muscle mass and function in the older population. If RET is also able to improve CRF, as it has been shown to do in younger populations, it has the potential to improve multiple health outcomes in the expanding older population.MethodsThis systematic review aimed to identify the role of RET for improving CRF in healthy older adults. A search across CINAHL, MEDLINE, EMBASE and EMCARE databases was conducted with meta-analysis performed on eligible papers to identify improvements in established CRF parameters (VO2 peak, aerobic threshold (AT), 6-minute walking distance test (6MWT) following RET intervention. Main eligibility criteria included older adults (aged over 60), healthy cohorts (disease-specific cohorts were excluded) and RET intervention.ResultsThirty-seven eligible studies were identified. Meta-analysis revealed a significant improvement in VO2 peak (MD 1.89 ml/kg/min; 95% confidence interval (CI) 1.21–2.57 ml/kg/min), AT (MD 1.27 ml/kg/min; 95% CI 0.44–2.09 ml/kg/min) and 6MWT (MD 30.89; 95% CI 26.7–35.08) in RET interventions less than 24 weeks. There was no difference in VO2 peak or 6MWT in interventions longer than 24 weeks.DiscussionThis systematic review adds to a growing body of evidence supporting the implementation of RET in the older population for improving whole-body health, particularly in time-limited timeframes.

The effects of acute resistance exercise among young adults: A randomized controlled trial

Background The effects of a single bout of resistance exercise (RE) on state anxiety and worry symptoms are understudied. Further, how resistance exercise training (RET) changes response to acute RE is unknown.Methods Sixty-two untrained young adults (mean age (y):26.6; RET n = 27, Wait-list (WL): n = 35, 62.9% female) were randomized to an eight-week, ecologically-valid, guidelines-based RET condition, or eight-week WL control condition. Two acute RE trials were nested within the design at week one and eight, to determine RE response, and change in RE response following RET. The RET condition completed a twice-weekly RET intervention. The WL condition completed 30-minute bouts of quiet-rest at week one and eight. Two-condition (RE/quiet-rest) x two-time (pre/post) x two-session (weeks one/eight) RM-ANCOVAs examined differences between acute RE and quiet-rest pre-post and between acute sessions. Sub-analyses were conducted among young adults with analogue-Generalized Anxiety Disorder (AGAD). Primary outcomes were anxiety and worry symptoms.Results Compliance was 99% (Rate of perceived exertion (6–20) = 14±1, Muscle soreness (1–10)=4 ± 2), with no adverse events. There were no significant three-way interactions for anxiety symptoms or worry symptoms (all p ≥ 0.51) among the total sample or AGAD sample. The magnitude of change in outcomes at each session for both samples were small and non-significant (Hedges’ d = -0.26 to 0.23).Limitations Post-condition assessment of primary outcomes was only conducted at a single time point.Conclusion RE did not elicit significant reductions in state anxiety or worry symptoms ten minutes post-RE. RET did not change response to acute RE. Clinicians should encourage RET for maximum anxiolytic benefits.

MiR-19b-3p is associated with a diametric response to resistance exercise in older adults and regulates skeletal muscle anabolism via PTEN inhibition.

Understanding paradoxical responses to anabolic stimulation and identifying the mechanisms for this inconsistency in mobility-limited older adults may provide new targets for the treatment of sarcopenia. Our laboratory has discovered that dysregulation in microRNA (miRNA) that target anabolic pathways is a potential mechanism resulting in age-associated decreases in skeletal muscle mass and function (sarcopenia). The objective of the current study was to assess circulating miRNA expression profiles in diametric response of leg lean mass in mobility-limited older individuals after a 6-mo progressive resistance exercise training intervention (PRET) and determine the influence of differentially expressing miRNA on regulation of skeletal muscle mass. Participants were dichotomized by gain (Gainers; mean +561.4 g, n = 33) or loss (Losers; mean −589.8 g, n = 40) of leg lean mass after PRET. Gainers significantly increased fat-free mass 2.4% vs. −0.4% for Losers. Six miRNA (miR-1-3p, miR-19b-3p, miR-92a, miR-126, miR-133a-3p, and miR-133b) were significantly identified to be differentially expressed between Gainers and Losers, with miR-19b-3p being the miRNA most highly associated with increases in fat-free mass. Using an aging mouse model, we then assessed if miR-19b-3p expression was different in young mice with larger muscle mass compared with older mice. Circulating and skeletal muscle miR-19b-3p expression was higher in young compared with old mice and was positively associated with muscle mass and grip strength. We then used a novel integrative approach to determine if differences in circulating miR-19b-3p potentially translate to augmented anabolic response in human skeletal muscle cells in vitro. Results from this analysis identified that overexpression of miR-19b-3p targeted and downregulated PTEN by 64% to facilitate significant ∼50% increase in muscle protein synthetic rate as measured with SUnSET. The combine results of these three models identify miR-19b-3p as a potent regulator of muscle anabolism that may contribute to an inter-individual response to PRET in mobility-limited older adults.

Resistance exercise training among young adults with analogue generalized anxiety disorder

IntroductionThe objective of this randomized controlled trial (RCT) was to quantify the effects of eight weeks of World Health Organization and American College of Sports Medicine guidelines-based resistance exercise training (RET) among participants meeting criteria for subclinical, or analogue-GAD (AGAD) MethodsForty-four participants (mean age (y): 25.4.6±4.9.2) were randomized to either an eight-week, fully-supervised, one-on-one RET intervention or wait-list control. AGAD status was determined using validated cut-scores for both the Psychiatric Diagnostic Screening Questionnaire-GAD subscale (≥6) and Penn State Worry Questionnaire (≥45). Remission, based on change in AGAD status, was assessed post-intervention, and quantified with number needed to treat (NNT). Primary analyses focused on participants missing outcome data at ≤1 time point (RET: n=12, Wait-list: n=15). RM-ANCOVA examined differences between RET and wait-list across time. Simple effects analysis decomposed significant interactions. Hedges’ d quantified magnitude of differences in change between conditions over time. ResultsAttendance was 81% and compliance to the RET was 77%. Participants significantly increased strength (all d≥1.24, p≤0.006) with no adverse events. RET improved AGAD status (NNT=3, 95%CI: 2 to 7). Significant group X time interactions were found for worry (F(3,66) = 3.12, p≤0.043; d=0.93, 95%CI: 0.13 to 1.73) and anxiety symptoms (F(3,57.84)=2.91, ε=0.88, p≤0.045; d=0.71, 95%CI: -0.08 to 1.49). RET significantly reduced worry (mean difference=-6.49, p≤0.045) and anxiety symptoms (mean difference=-10.50, p≤0.001). LimitationsLimitations include a small sample size, and lack of attention-matched control condition. ConclusionRET significantly improved AGAD severity, and elicited large, clinically meaningful improvements in worry and anxiety symptoms among young adults with AGAD.

Resistance exercise training for anxiety and worry symptoms among young adults: a randomized controlled trial

This trial quantified the effects of ecologically-valid resistance exercise training (RET) on anxiety and worry symptoms among young adults. Young adults not meeting criteria for subclinical, or analogue Generalized Anxiety Disorder (AGAD) were randomized to an eight-week RET intervention, or eight-week wait-list. AGAD status was determined using validated cut-scores for both the Psychiatric Diagnostic Screening Questionnaire-Generalized Anxiety Disorder subscale (≥ 6) and Penn State Worry Questionnaire (≥ 45). The primary outcome was anxiety symptoms measured with the Trait Anxiety subscale of the State-Trait Anxiety Inventory. The RET was designed according to World Health Organization and American College of Sports Medicine guidelines. RM-ANCOVA examined differences between RET and wait-list over time. Significant interactions were decomposed with simple effects analysis. Hedges’ d effect sizes quantified magnitude of differences in change between RET and wait-list. Twenty-eight participants (64% female) fully engaged in the trial (mean age: 26.0 ± 6.2y, RET: n = 14; Wait-list: n = 14). A significant group X time interaction was found for anxiety symptoms (F(3,66) = 3.60, p ≤ 0.019; d = 0.85, 95%CI: 0.06 to 1.63). RET significantly reduced anxiety symptoms from baseline to post-intervention (mean difference = − 7.89, p ≤ 0.001). No significant interaction was found for worry (F(3,69) = 0.79, p ≥ 0.50; d = − 0.22, 95%CI: − 0.96 to 0.53). Ecologically-valid RET significantly improves anxiety symptoms among young adults.Trial Registration: Clinicaltrials.gov Identifier: NCT04116944, 07/10/2019.

Acute and chronic effects of resistance exercise training among young adults with and without analogue Generalized Anxiety Disorder: A protocol for pilot randomized controlled trials

ObjectivesRecent meta-analyses support the chronic anxiolytic effects of resistance exercise training (RET) among women with diagnosed Generalized Anxiety Disorder (GAD). However, the effects of RET among those with subclinical, or analogue, GAD (AGAD) is unknown. The purpose of the pilot randomized controlled trial (RCT) detailed in this protocol was to quantify the acute and chronic effects of RET on signs and symptoms of GAD among young adults with and without AGAD. MethodsThis protocol details the full methods of two parallel, RCTs of an eight-week RET intervention compared to a wait-list control condition among young adults with and without AGAD. AGAD status was determined using validated cut-scores for both the Psychiatric Diagnostic Screening Questionnaire GAD subscale (≥6) and the Penn State Worry Questionnaire (≥45). The ecologically-valid RET was designed according to World Health Organization and American College of Sports Medicine guidelines. The primary outcome was AGAD status, assessed pre- and post-intervention. Secondary outcomes were assessed weekly. Two acute RET trials were nested within the design at pre- and post-intervention to determine response and change in response to a single bout of RET. ConclusionsThis pilot RCT examines the effect of an ecologically-valid RET intervention among young adults with subclinical levels of GAD. Given that GAD most often emerges during young adulthood, and young adults who display elevated subclinical symptoms are more likely to develop clinically significant psychopathology, investigating the effects of RET among individuals with emerging signs and symptoms of an anxiety disorder is particularly important. Trial registrationClinicalTrials.gov Identifier: NCT04116944.

Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men.

We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.

Association of Efficacy of Resistance Exercise Training With Depressive Symptoms

ImportanceThe physical benefits of resistance exercise training (RET) are well documented, but less is known regarding the association of RET with mental health outcomes. To date, no quantitative synthesis of the antidepressant effects of RET has been conducted.ObjectivesTo estimate the association of efficacy of RET with depressive symptoms and determine the extent to which logical, theoretical, and/or prior empirical variables are associated with depressive symptoms and whether the association of efficacy of RET with depressive symptoms accounts for variability in the overall effect size.Data SourcesArticles published before August 2017, located using Google Scholar, MEDLINE, PsycINFO, PubMed, and Web of Science.Study SelectionRandomized clinical trials included randomization to RET (n = 947) or a nonactive control condition (n = 930).Data Extraction and SynthesisHedges d effect sizes were computed and random-effects models were used for all analyses. Meta-regression was conducted to quantify the potential moderating influence of participant and trial characteristics.Main Outcomes and MeasuresRandomized clinical trials used validated measures of depressive symptoms assessed at baseline and midintervention and/or postintervention. Four primary moderators were selected a priori to provide focused research hypotheses about variation in effect size: total volume of prescribed RET, whether participants were healthy or physically or mentally ill, whether or not allocation and/or assessment were blinded, and whether or not the RET intervention resulted in a significant improvement in strength.ResultsFifty-four effects were derived from 33 randomized clinical trials involving 1877 participants. Resistance exercise training was associated with a significant reduction in depressive symptoms with a moderate-sized mean effect ∆ of 0.66 (95% CI, 0.48-0.83; z = 7.35; P < .001). Significant heterogeneity was indicated (total Q = 216.92, df = 53; P < .001; I2 = 76.0% [95% CI, 72.7%-79.0%]), and sampling error accounted for 32.9% of observed variance. The number needed to treat was 4. Total volume of prescribed RET, participant health status, and strength improvements were not significantly associated with the antidepressant effect of RET. However, smaller reductions in depressive symptoms were derived from randomized clinical trials with blinded allocation and/or assessment.Conclusions and RelevanceResistance exercise training significantly reduced depressive symptoms among adults regardless of health status, total prescribed volume of RET, or significant improvements in strength. Better-quality randomized clinical trials blinding both allocation and assessment and comparing RET with other empirically supported treatments for depressive symptoms are needed.

Relationship of Physical Function to Single Muscle Fiber Contractility in Older Adults: Effects of Resistance Training With and Without Caloric Restriction.

Previous studies support beneficial effects of both resistance exercise training (RT) and caloric restriction (CR) on skeletal muscle strength and physical performance. The goal of this study was to determine the effects of adding CR to RT on single-muscle fiber contractility responses to RT in older overweight and obese adults. We analyzed contractile properties in 1,253 single myofiber from muscle biopsies of the vastus lateralis, as well as physical performance and thigh muscle volume, in 31 older (65-80 years), overweight or obese (body mass index = 27-35 kg/m2) men (n = 19) and women (n = 12) who were randomly assigned to a standardized, progressive RT intervention with CR (RT+CR; n = 15) or without CR (RT; n = 16) for 5 months. Both interventions evoked an increase in force normalized to cross-sectional area (CSA), in type-I and type-II fibers and knee extensor quality. However, these improvements were not different between intervention groups. In the RT group, changes in total thigh fat volume inversely correlated with changes in type-II fiber force (r = -.691; p = .019). Within the RT+CR group, changes in gait speed correlated positively with changes in type-I fiber CSA (r = .561; p = .030). In addition, increases in type-I normalized fiber force were related to decreases in thigh intermuscular fat volume (r = -0.539; p = .038). Single muscle fiber force and knee extensor quality improve with RT and RT+CR; however, CR does not enhance improvements in single muscle fiber contractility or whole muscle in response to RT in older overweight and obese men and women.

Adipose tissue inflammation in breast cancer survivors: effects of a 16-week combined aerobic and resistance exercise training intervention.

Obesity is a leading modifiable contributor to breast cancer mortality due to its association with increased recurrence and decreased overall survival rate. Obesity stimulates cancer progression through chronic, low-grade inflammation in white adipose tissue, leading to accumulation of adipose tissue macrophages (ATMs), in particular, the pro-inflammatory M1 phenotype macrophage. Exercise has been shown to reduce M1 ATMs and increase the more anti-inflammatory M2 ATMs in obese adults. The purpose of this study was to determine whether a 16-week exercise intervention would positively alter ATM phenotype in obese postmenopausal breast cancer survivors. Twenty obese postmenopausal breast cancer survivors were randomized to a 16-week aerobic and resistance exercise (EX) intervention or delayed intervention control (CON). The EX group participated in 16weeks of supervised exercise sessions 3 times/week. Participants provided fasting blood, dual-energy X-ray absorptiometry (DXA), and superficial subcutaneous abdominal adipose tissue biopsies at baseline and following the 16-week study period. EX participants experienced significant improvements in body composition, cardiometabolic biomarkers, and systemic inflammation (all p<0.03 vs. CON). Adipose tissue from EX participants showed a significant decrease in ATM M1 (p<0.001), an increase in ATM M2 (p<0.001), increased adipose tissue secretion of anti-inflammatory cytokines such as adiponectin, and decreased secretion of the pro-inflammatory cytokines IL-6 and TNF- α (all p<0.055). A 16-week aerobic and resistance exercise intervention attenuates adipose tissue inflammation in obese postmenopausal breast cancer survivors. Future large randomized trials are warranted to investigate the impact of exercise-induced reductions in adipose tissue inflammation and breast cancer recurrence.

Effects of elastic resistance exercise on body composition and physical capacity in older women with sarcopenic obesity: A CONSORT-compliant prospective randomized controlled trial.

Sarcopenia is associated with loss of muscle mass and an increased risk of physical disability in elderly people. However, the prevalence of sarcopenia has increased in obese elderly populations. The purpose of this study was to identify the clinical efficacy of elastic resistance exercise training (RET) in patients with sarcopenic obesity. This study was conducted at the rehabilitation center of a university-based teaching hospital and was designed as a prospective and randomized controlled trial with an intention-to-treat analysis. A total of 46 women aged 67.3 (5.2) years were randomly assigned to an experimental group (EG) and control group (CG). The EG underwent elastic RET for 12 weeks, and the CG received no RET intervention. All outcome measures were assessed at the baseline and posttest, including body composition measured using dual-energy X-ray absorptiometry, muscle quality (MQ) defined as a ratio of muscular strength to muscle mass, and physical capacity assessed using functional mobility tests. One-way analysis of covariance and Pearson correlation were used to compare outcomes between the 2 groups and to identify the relationship between changes in body composition and physical outcomes, respectively. A chi-square test was performed to identify differences in qualitative data between the 2 groups. At the posttest, a significant between-group difference was observed in fat-free mass, MQ, and physical capacity (all P < .05); and a significant correlation was found between leg-lean-mass change and gait speed (r = 0.36; P < .05). After 12 weeks of elastic RET intervention, the EG had significantly fewer patients exhibiting sarcopenia (P < .05) and experiencing physical difficulty (P < .001) than the CG. The present data suggest that elastic resistance exercise exerted benefits on the body composition, MQ, and physical function in patients with sarcopenic obesity. Regular exercise incorporating elastic RET should be used to attenuate muscle mass loss and prevent physical difficulty in obese older adults with sarcopenia on reconditioning therapy. Chinese Clinical Trial Registry, ChiCTR-IPR-15006069.

Resistance exercise training increases lower limb speed of strength generation during stair ascent and descent in people with diabetic peripheral neuropathy.

To examine the effects of a 16-week resistance exercise training intervention on the speed of ankle and knee strength generation during stair ascent and descent, in people with neuropathy. A total of 43 people: nine with diabetic peripheral neuropathy, 13 with diabetes but no neuropathy and 21 healthy control subjects ascended and descended a custom-built staircase. The speed at which ankle and knee strength were generated, and muscle activation patterns of the ankle and knee extensor muscles were analysed before and after a 16-week intervention period. Ankle and knee strength generation during both stair ascent and descent were significantly higher after the intervention than before the intervention in the people with diabetes who undertook the resistance exercise intervention (P < 0.05). Although muscle activations were altered by the intervention, there were no observable patterns that underpinned the observed changes. The increased speed of ankle and knee strength generation observed after the intervention would be expected to improve stability during the crucial weight acceptance phase of stair ascent and descent, and ultimately contribute towards reducing the risk of falling. Improvements in muscle strength as a result of the resistance exercise training intervention are likely to be the most influential factor for increasing the speed of strength generation. It is recommended that these exercises could be incorporated into a multi-faceted exercise programme to improve safety in people with diabetes and neuropathy.

Randomized controlled trial to evaluate the effects of combined progressive exercise on metabolic syndrome in breast cancer survivors: rationale, design, and methods

BackgroundMetabolic syndrome (MetS) is increasingly present in breast cancer survivors, possibly worsened by cancer-related treatments, such as chemotherapy. MetS greatly increases risk of cardiovascular disease and diabetes, co-morbidities that could impair the survivorship experience, and possibly lead to cancer recurrence. Exercise has been shown to positively influence quality of life (QOL), physical function, muscular strength and endurance, reduce fatigue, and improve emotional well-being; however, the impact on MetS components (visceral adiposity, hyperglycemia, low serum high-density lipoprotein cholesterol, hypertriglyceridemia, and hypertension) remains largely unknown. In this trial, we aim to assess the effects of combined (aerobic and resistance) exercise on components of MetS, as well as on physical fitness and QOL, in breast cancer survivors soon after completing cancer-related treatments.Methods/DesignThis study is a prospective randomized controlled trial (RCT) investigating the effects of a 16-week supervised progressive aerobic and resistance exercise training intervention on MetS in 100 breast cancer survivors. Main inclusion criteria are histologically-confirmed breast cancer stage I-III, completion of chemotherapy and/or radiation within 6 months prior to initiation of the study, sedentary, and free from musculoskeletal disorders. The primary endpoint is MetS; secondary endpoints include: muscle strength, shoulder function, cardiorespiratory fitness, body composition, bone mineral density, and QOL. Participants randomized to the Exercise group participate in 3 supervised weekly exercise sessions for 16 weeks. Participants randomized to the Control group are offered the same intervention after the 16-week period of observation.DiscussionThis is the one of few RCTs examining the effects of exercise on MetS in breast cancer survivors. Results will contribute a better understanding of metabolic disease-related effects of resistance and aerobic exercise training and inform intervention programs that will optimally improve physiological and psychosocial health during cancer survivorship, and that are ultimately aimed at improving prognosis.Trial registrationNCT01140282; Registration: June 10, 2010

Changes in Motivational Outcomes After a Supervised Resistance Exercise Training Intervention in Lung Cancer Survivors

Short-term supervised exercise interventions improve health-related fitness in lung cancer survivors; however, sustained exercise is required to maintain the health benefits. The impact of exercise interventions on motivational outcomes may be important for long-term exercise adoption. The objective of this study was to examine the effects of a 10-week supervised progressive resistance exercise training program on lung cancer survivors' motivational outcomes based on the Theory of Planned Behavior (TPB). Posttreatment lung cancer survivors were recruited to undergo a 10-week supervised resistance exercise training intervention. The 2-component model of the TPB was measured at baseline and after intervention. Fifteen participants completed assessments of TPB measures. Significant increases in self-efficacy (P = .022) and perceived controllability (P = .032) and a nonsignificant increase in affective attitude (P = .090) were observed after intervention. Intention was significantly lower at postintervention (P = .044). Significant correlates of postintervention intention were instrumental attitude (P = .001), self-efficacy (P = .004), perceived behavioral control (P = .009), and affective attitude (P = .044). At postintervention, self-efficacy was significantly correlated with planning (P < .046). Short-term supervised resistance exercise training may improve some motivational outcomes for lung cancer survivors. Intentions appeared to be weakened after the intervention, but there are methodological explanations for this finding. Participation in short-term supervised resistance exercise may be an effective method to improve some motivational factors related to exercise in lung cancer survivors. More research is needed to examine the long-term effects of supervised resistance exercise on motivational outcomes in lung cancer survivors. Strategies to maintain motivational changes that occur following a supervised resistance exercise intervention need to be investigated.