Combining optimal nutrition and exercise in a multimodal approach for patients with active cancer and risk for losing weight: Rationale and practical approach

Weight loss and functional decline is a common and detrimental consequence of cancer. The interventions that are offered to patients with weight loss and functional decline often seem haphazard and varying from center to center. The lack of stringent management is probably based both on lack of knowledge of existing treatment guidelines and the current weak level of evidence of clinical effects of different nutritional and exercise interventions. Some studies evaluated multimodal interventions with various treatment combinations, including nutrition and exercise, that report clinically significant effects on cachexia outcomes. As of today, however, there is a paucity of large randomized controlled trials that incorporate both a fully structured exercise program and a well-described nutritional intervention. Studies investigating combinations of several interventions in patients with active cancer and risk for losing weight are too few and too heterogeneous to enable firm conclusions about effect, optimal dose, or timing of interventions. However, data presented in this review suggest an overall benefit, especially if interventions are started before weight loss and loss of function become too severe. Thus, the aim of this review was to examine the evidence for combined treatments targeting weight loss in cancer patients.

Potentials of Smart dynamometer use for clinical and self-management of rehabilitation in breast cancer survivors: a feasibility study

The aim of this study was to examine the feasibility of the Smart dynamometer as a rehabilitation exercise device in a daily care by comparing with the existing medical devices. We used and analyzed clinical and measurement data of breast cancer survivors who have used Smart dynamometer during their rehabilitation after breast cancer surgery. The Smart dynamometer was compared with the two existing devices of Takei dynamometer and surface electromyography (sEMG) that were used in routine care, respectively. Three key components of the rehabilitation exercise devices were analyzed to validate the feasibility of the Smart dynamometer: grip strength, reaction time, and grip endurance time. Pearson's correlation analysis was performed to compare the statistical significance between the devices. The data of 12 and 15 female breast cancer patients were analyzed for comparing the Smart dynamometer with Takei dynamometer and sEMG, respectively. There was a very weak correlation between the maximum values from the Takei and the Smart dynamometers in the affected and non-affected arms of breast cancer patients (r = 0.5321, 0.4733). Comparisons of 3 features between the Smart dynamometer and sEMG showed that there were strong positive correlations for both reaction time and endurance time in the affected and non-affected arms (r > 0.9). The feasibility of the Smart dynamometer for the possible use in a daily rehabilitation exercise was partially verified. Moreover, since the Smart dynamometer was highly correlated with time-related variables, it was important and significant to measure both grip strength and time-related information.

The Effects of Eccentric Cadence on Power and Velocity of the Bar during the Concentric Phase of the Bench Press Movement

Training at a specific movement tempo is a relatively new concept in resistance training. It is based on manipulation of the duration of particular phases of a movement. General studies have demonstrated that faster movement tempo in resistance training leads to an increase in muscle power, whereas lower movement speed is beneficial in the development of muscle strength and hypertrophy. However, the studies in this area are inconclusive and do not relate precisely to various tempos and movement speeds. The aim of the study was to determine the effect of duration of the eccentric cadence ECC_REG (2/0/X/0) and ECC_SLO (6/0/X/0) on muscular power generated in the concentric phase of the movement expressed in maximal P_MAX, V_MAX and average values P_AVE, V_AVE. For the ECC_SLO (6/0/X/0) cadence, a significantly lower value of P (401.95 ± 65.42 W) was observed compared to the ECC_REG 2/0/X/0 tempo (467.65 ± 79.18 W), at p = 0.007. The same was true for power evaluated in maximal values (P_MAX), as significantly higher values were recorded for the regular ECC_REG (2/0/X/0) (671.55 ± 115.79 W) compared to the slow tempo ECC_SLO (6/0/X/0) (565,70 ± 117,37 W), at the level of significance of p = 0.007. The velocity evaluated for ECC_REG (2/0/X/0) tempo expressed in average values (V_AVE) 0.60±0.09 m/s was significantly higher compared to the ECC_SLO (6/0/X/0) tempo (0.52 ± 0.08 m/s), with p=0.004. When maximal velocity (V_MAX), was considered higher values for ECC_REG (2/0/X/0) tempo was registered (0.79 ± 0.10 m/s) compared to the ECC_SLO (6/0/X/0) tempo (0.69 ± 0.13 m/s), at significance of p = 0.001. The main finding of the study indicates that the duration of the eccentric phase of the movement has a significant impact on muscular power and velocity during the concentric phase of the movement.

Prior cycling exercise does not prevent endothelial dysfunction after resistance exercise

PURPOSE

Resistance exercise impairs endothelial function acutely. Therefore, it becomes important to devise an effective strategy for preventing acute endothelial dysfunction after resistance exercise. Herein, we tested the hypothesis that resistance exercise-induced temporal endothelial dysfunction is prevented by prior cycling.

METHODS

Twelve young healthy subjects completed two randomized experimental trials: (1) resistance exercise only trial (RE trial), (2) resistance exercise with prior cycling trial (C + RE trial). Following baseline brachial artery flow-mediated dilation (FMD), the subjects maintained the supine position for 45 min in the RE trial; the subjects performed a 45 min of cycling (67.0 ± 1.7% HRmax) in the C + RE trial. After 45 min of resting or cycling, the subjects performed resistance exercise (69.7 ± 4.0 kg) at the same time points. Following the resistance exercise, they were asked to rest in the supine position for 60 min. Then FMD were repeated at 10, 30 and 60 min after the resistance exercise in both trials.

RESULTS

The increased blood flow and shear rate after resistance exercise did not differ between trials, and these changes disappeared following resting in the supine position for 60 min. There was no significant interaction in %FMD responses. Both trials caused impairment in %FMD after the resistance exercise, and statistical significance was observed at 30 and 60 min after resistance exercise in the RE trial.

CONCLUSION

The present study revealed that cycling for 45 min prior to resistance exercise was not sufficient to prevent the acute endothelial dysfunction after resistance exercise.

Impact of physical exercises on immune function, bone mineral density, and quality of life in people living with HIV/AIDS: a systematic review with meta-analysis

BACKGROUND

Compromised immune function, associated with human immune deficiency virus(HIV) infection, is improved by antiretroviral therapy(ART) which also decreases bone mineral density(BMD), and possibly the quality of life(QoL). However, physical(aerobic/resistance) exercises, were reported to induce reverse effects in uninfected individuals and were appraised in the literature for evidence of similar benefits in people living with HIV/AIDS(PLWHA). The main study objective was to evaluate the impact of physical (aerobic and resistance) exercises on CD4+ count, BMD and QoL in PLWHA.

METHODS

A systematic review was conducted using the Cochrane Collaboration protocol. Searching databases, up to June 2017, only randomized control trials investigating the effects of either aerobic, resistance or a combination of both exercise types with a control/other intervention(s) for a period of at least 4 weeks among adults living with HIV, were included. Two independent reviewers determined the eligibility of the studies. Data were extracted and risk of bias(ROB) was assessed with the Cochrane Collaboration ROB tool. Meta-analyses were conducted using random effect models using the Review Manager(RevMan) computer software.

RESULTS

Nineteen studies met inclusion criteria(n = 491 participants at study completion) comprising male and female with age range 22-66 years. Two meta-analyses across 13 sub-group comparisons were performed. However, there were no RCTs on the impact of physical exercises on BMD in PLWHA. The result showed no significant change in CD4+ count unlike a significant effect of 5.04 point(95%CI:-8.49,-3.74,p = 0.00001) for role activity limitation due to physical health(QoL sub-domain). Overall, the GRADE evidence for this review was of moderate quality.

CONCLUSIONS

There was evidence that engaging in moderate intensity aerobic exercises (55-85% Maximum heart rate-MHR), for 30-60 min, two to five times/week for 6-24 weeks significantly improves role activity limitation due to physical health problems, otherwise physical(aerobic or/and resistance) exercises have no significant effects on CD4+ count and other domains of QoL. Also, there is lack of evidence on the impact of exercises on BMD in PLWHA due to the paucity of RCTs. The moderate grade evidence for this review suggests that further research may likely have an important impact on our confidence in the estimate of effects and may change the estimate.

Associations between aerobic and muscle-strengthening exercise with depressive symptom severity among 17,839 U.S. adults

For the prevention and management of chronic diseases, global physical activity guidelines state that an adult should engage in regular moderate-to-vigorous aerobic physical activity (MVPA; e.g. walking, cycling, running) and muscle-strengthening exercise (MSE; e.g. strength/resistance training). However, the associations between combined MVPA-MSE with chronic health conditions are rarely examined in large population studies. In particular, little is known associations between combined MVPA-MSE with depressive disorders, one of the leading causes of disability worldwide. The aim of this study is to describe the associations between MVPA and MSE with depressive symptom severity among a large sample of U.S. adults. Data were drawn from the U.S. 2015 Behavioral Risk Factor Surveillance System. During phone interviews, MVPA, MSE and depressive symptom severity were assessed by validated questionnaires. Poisson regression with a robust error or variance were used to assess prevalence ratios (PR) of depressive symptom severity (mild, moderate, moderately severe/severe) across categories of physical activity guideline adherence (met neither [reference]; MSE only; MVPA only; met both), adjusting for a set of potential cofounders. Data were available on 17,839 adults (18-85 years). When compared with those meeting neither guideline, for mild, moderate and moderately severe/severe depressive symptoms, the PRs were lowest among meeting both guidelines (range: 0.26-0.54), followed by MVPA only (range: 0.36-0.62) and MSE only (range: 0.49-0.84). Among a large sample of U.S. adults, compared to other guideline adherence categories, meeting both MVPA-MSE guidelines was associated with a lowest likelihood of reporting depressive symptoms.

[Effect of aerobic exercise and resistance exercise in improving non-alcoholic fatty liver disease: a randomized controlled trial]

Objective: To investigate the effect of dietary control combined with different exercise modes on plasma vaspin, irisin, and metabolic parameters in patients with non-alcoholic fatty liver disease (NAFLD) through a randomized open parallel-controlled study. Methods: The patients aged 30-65 years who visited Tianjin Third Central Hospital from January 2013 to December 2014 and were diagnosed with NAFLD by liver ultrasound and fat content determination were screening, and 474 patients were enrolled in this randomized controlled trial and divided into aerobic exercise group, resistance exercise group, and control group. All patients received dietary intervention. The three groups were compared in terms of biochemical parameters, fat content, NFS score, energy metabolic parameters, body composition index, and levels of vaspin and irisin at baseline and after 6 months of intervention. SPSS 19.0 was used for statistical analysis. The t-test, the Mann-Whitney U test, the chi-square test, and an analysis of variance were used for comparison between groups. The multiple imputation method was used for missing data, and the results were included in the intention-to-treat analysis. Results: There were no significant differences in age, sex, anthropometrical parameters, and biochemical parameters between the three groups at baseline. Compared with dietary control alone, aerobic exercise and resistance exercise helped to achieve significant reductions in waist circumference, diastolic pressure, percentage of body fat, volatile fatty acid, fasting blood glucose, homeostasis model assessment of insulin resistance, triglyceride, low-density lipoprotein cholesterol, free fatty acid, uric acid, alanine aminotransferase, and liver fat content after 6 months of intervention (P < 0.05). The aerobic exercise group had a significant increase in non-protein respiratory quotient and significant reductions in body mass index and aspartate aminotransferase after intervention, as well as a significant increase in resting energy expenditure and significant reductions in abdominal fat ratio and total cholesterol after 6 months of resistance exercise (P < 0.05). The aerobic exercise group and the resistance exercise group had a significant reduction in vaspin and a significant increase in irisin after intervention (P < 0.05), and the resistance exercise group had significantly greater changes in these two adipokines than the aerobic exercise group (P < 0.05). Conclusion: Exercise therapy is an effective method for the treatment of metabolism-associated diseases, and a combination of resistance and aerobic exercises is more reasonable and effective in clinical practice. As a relatively safe exercise mode, resistance exercise can also effectively improve the metabolic state of NAFLD patients.

Sclerostin and parathyroid hormone responses to acute whole-body vibration and resistance exercise in young women

Whole-body vibration (WBV) has been shown to improve bone mineral density, and muscle strength and power. No studies to date have examined sclerostin and parathyroid hormone (PTH) responses to WBV combined with resistance exercise (RE). This randomized crossover study compared acute serum sclerostin and PTH responses to RE and WBV + RE in young women (n = 9) taking oral contraceptives. Participants were exposed to 5 1-min bouts of vibration (20 Hz, 3.38 peak-peak displacement, separated by 1 min of rest) before high intensity resistance exercise. Fasting blood samples were obtained before (PRE), immediately after WBV (POSTWBV), immediately post RE (IP) and 30 min post RE (30P). Pre-exercise sclerostin and PTH levels were not significantly different between conditions. Sclerostin levels significantly (p < 0.05) increased from PRE to IP for the WBV + RE condition, then decreased back to the pre-exercise level. PTH significantly decreased from PRE to 30P (p < 0.05) and IP to 30P (p < 0.01) for both conditions. Correcting for hemoconcentration eliminated the significant sclerostin responses, but the significant decrease in PTH remained (p < 0.05). There were no significant relationships found between sclerostin and PTH. In conclusion, sclerostin concentrations increased in response to the WBV + RE condition, which may have been mediated by plasma volume shifts. There was no transient PTH increase, but it showed a large decrease at 30P for both conditions. Based on these findings, the addition of WBV exposures prior to high intensity RE did not alter sclerostin and PTH responses to RE in young women.

Maximal power production as a function of sex and training status

Maximal muscular power is achieved at lower percentages of maximal strength (1RM); however, this notion has not been elucidated based on sex or training status. Therefore, the purpose of this investigation was to examine the influence of sex and training status on maximal power production. Sixty men and women (resistance trained or untrained) completed 1RM testing for the two-leg press (2LP) and bench press (BP). Participants then returned to perform single repetitions at 20, 30, 40, 50, 60, 70 and 80% of their 1RM to determine muscular power. Factorial analyses determined significant interactions (training status by sex by intensity) for the BP (F=35.6, p<0.001) and 2LP (F=8.2, p<0.001). Subsequent analyses indicated that during the BP trained men produce maximal power between 30-40% 1RM compared to untrained men at 60-70% 1RM. Trained women produced maximal power at 50% 1RM compared to untrained women at 60-70% 1RM. During the 2LP, trained men produced maximal power at 40% 1RM compared to untrained men at 60% 1RM. Trained women produced maximal power at 50% 1RM compared to 60-70% 1RM in untrained women. These data suggest that resistance trained individuals and men display maximal power at a lower relative intensity than untrained individuals and women.

Changes in Titin and Collagen Modulate Effects of Aerobic and Resistance Exercise on Diabetic Cardiac Function

Diastolic dysfunction is a common complication that occurs early in diabetes mellitus. Titin and collagen are two important regulators of myocardial passive tension, which contributes to diabetic myocardial diastolic dysfunction. Exercise therapy significantly improves the impaired diabetic cardiac function, but its benefits appear to depend on the type of exercise used. We investigated the effect of aerobic and resistance exercise on cardiac diastolic function in diabetic rats induced by high-fat diet combined with low-dose streptozotocin injection. Interestingly, although resistance training had a more pronounced effect on blood glucose control than did aerobic training in type 2 diabetic rats, improvements in cardiac diastolic parameters benefited more from aerobic training. Moreover, aerobic exercise did significantly increase the expression levels of titin and decrease collagen I, TGFβ1 expression level. In summary, out data suggest that aerobic exercise may improve diabetic cardiac function through changes in titin-dependent myocardial stiffness rather than collagen-dependent interstitial fibrosis.

The acute effects of caffeine intake on time under tension and power generated during the bench press movement

BACKGROUND

The ability to generate high levels of power is one of the key factors determining success in many sport disciplines. Although there are studies confirming ergogenic effects of caffeine (CAF) on different physical and mental abilities, much controversy remains about its influence on power. The main goal of this study was to assess the effects of caffeine supplementation on time under tension (TUT) and the number of performed repetitions (REP). The second objective was to determine the effects of CAF supplementation on power (P) and movement velocity (V) during the bench press movement. Additionally the authors evaluated whether CAF has a significant effect on velocity of the bar in the eccentric (ECC) phase (VEMEAN) of the bench press movement.

METHODS

The study included 20 men (20-31 yrs., 87.3 ± 7.7 kg) with at least 2 years of experience in resistance training. The study participants were divided randomly into two groups: the supplemented group ingested caffeine before exercise (GCAF), while the control group was given a placebo (GCON). The exercise protocol consisted of performing the bench press movement with a load equal to 70%1RM with maximal possible velocity (X/0/X/0). The experimental sets were performed to momentary muscular failure.

RESULTS

The repeated measures ANOVA between the GCAF and GCON groups revealed statistically significant differences in 2 variables. Post-hoc tests demonstrated statistically significant differences in TUT when comparing the group supplemented with caffeine (13.689 s GCAF) to the one ingesting a placebo (15.332 s GCON) at p = 0.002. Significant differences were also observed in mean velocity during the eccentric phase of movement (0.690 m/s in the GCAF to 0.609 in GCON with p = 0.002). There were no significant differences in generated power and velocity in the CON phase of the movement between the GCAF and GCON. CONCLUSIONS: The main finding of the study is that CAF ingestion increases movement velocity of the bar in the eccentric phase of the movement, what results in shortening of the time under tension (TUT) needed for performing a specific number of repetitions, without decreasing power and velocity in the CON phase of the movement.

Effects of aerobic and resistance exercises on circulating apelin-12 and apelin-36 concentrations in obese middle-aged women: a randomized controlled trial

BACKGROUND

The risk for obesity-related diseases increases with the prevalence of obesity. In obesity, adipokines secreted from adipose tissue induce inflammation, causing adverse effects. Recently, adipokines such as apelin, visfatin, and chemerin have been studied. Long-term resistance training improves health in middle-aged women by improving metabolic risk factors, body composition, and muscle strength. However, there is still a lack of evidence on the association of apelin concentration with different exercise types in middle-aged obese women This study aimed to investigate the effects of 8 weeks of aerobic and resistance exercises on apelin-12 and apelin-36 levels and thereby verify the effects of different exercise types in obese, middle-aged women.

METHODS

Participants were middle-aged women aged 50-61 years, with no experience of systematic exercise in the last 6 months, and met the WHO obesity criteria for the Asia-Pacific region of waist circumference ≥ 80 cm and body fat percentage ≥ 30%. Subjects were selected and allocated to the aerobic exercise, resistance exercise, or no exercise group by block randomization. Body weight, body fat, and body mass index were measured by bioelectrical impedance analysis. Analysis of variance, the t-test, and Tukey's post-hoc test were performed.

RESULTS

A total of 24 participants were selected with eight participants in each group. Both aerobic and resistance exercises were effective in altering the physical composition, showing significant decreases in weight, waist circumference, BMI, and body fat. The aerobic and resistance exercise group showed a significant, positive change in apelin-12 levels.

CONCLUSIONS

In obese individuals, aerobic and resistance exercise were effective in improving obesity and reducing blood apelin-12 concentration, which is closely correlated with indicators of metabolic syndrome. Future research should focus on comparing the response of apelin to exercise in obese subjects treated with only dietary control and the response in the obese subjects of different ages and sex.

TRIAL REGISTRATION

No. 1040917-201,506-BR-153-04 , Clinical Research Information Service (CRIS), Republic of Korea (05 October 2018, retrospectively registered).

Effect of concentric and eccentric hamstring training on sprint recovery, strength and muscle architecture in inexperienced athletes

OBJECTIVES

To investigate whether five-weeks of concentric (CON) or eccentric (ECC) hamstring strength training have different effects on recovery from sprint running, eccentric strength and architecture of the biceps femoris long head (BF_LH).

DESIGN

Cohort study.

METHODS

Thirty males (age, 22.8±4.1y; height, 180.1±6.4cm; weight, 85.2±14.6kg) were allocated into either a CON or ECC group, both performing nine sessions of resistance training. Prior to and immediately after the five-week intervention, each participant's BF_LH fascicle length (FL), pennation angle (PA), muscle thickness (MT), peak isometric KF torque and Nordic eccentric strength were assessed. Post-intervention, participants performed two timed sprint sessions (10×80m) 48h apart. Blood samples and passive KF torques were collected before, immediately after, 24h and 48h after the first sprint session.

RESULTS

After five-weeks of strength-training, fascicles lengthened in the ECC (p<0.001; d=2.0) and shortened in the CON group (p<0.001; d=0.92), while PA decreased for the ECC (p=0.001; d=0.52) and increased in the CON group (p<0.001; d=1.69). Nordic eccentric strength improved in both ECC (p<0.001; d=1.49) and CON (p<0.001; d=0.95) groups. No between-group differences were observed in peak isometric strength (p=0.480), passive KF torques (p=0.807), sprint performance decrements between sprint sessions (p=0.317) and creatine kinase (p=0.818).

CONCLUSIONS

Despite inducing significant differences in BF_LH muscle architecture, there were no significant between group differences in sprint performance decrements across two sprint sessions.

Effects of bilateral or unilateral lower body resistance exercises on markers of skeletal muscle damage

BACKGROUND

It is known that different intensity exercises create skeletal muscle damage at different levels. The purpose of the study was to compare effects of bilateral or unilateral lower body resistance exercise on markers of skeletal muscle damage.

METHODS

The Brzycki Formula was used to calculate participants' one repetition maximum strength for each movement and limb, separately. Blood samples were obtained before exercise, immediately after exercise, and 30 min after exercise for both types of exercise. Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), and Alanine Aminotransferase (ALT) levels were analyzed. Data was analyzed using two-way repeated measures ANOVA.

RESULTS

When CK, AST, and ALT levels were compared according to time points, a statistical difference was found (p < 0.05). Furthermore, it was revealed that LDH levels were statistically significant according to exercise types (p < 0.05).

CONCLUSION

Unilateral lower body resistance exercise caused higher skeletal muscle damage than the bilateral lower body resistance exercise. This result suggests that unilateral lower body resistance exercise should be preferred for short preparation period as opposed to bilateral lower body resistance exercise.

Effect of a Resistance Training Program on Sarcopenia and Functionality of the Older Adults Living in a Nursing Home

IMPORTANCE

There are currently few evidence about resistance training as a treatment for sarcopenia in the nursing home setting.

OBJECTIVE

To evaluate the effect of a resistance training program on the sarcopenia and functionality of the elderly living in a nursing home.

DESIGN, SETTING, AND PARTICIPANTS

A blinded longitudinal intervention study conducted in elderly people living in a nursing home from August to November 2016. Participants included a convenience sample of 19 older adults.

INTERVENTION

We prescribed a resistance exercise program three times a week for 12 weeks. The scheme was two to three sets with eight to 15 repetitions per exercise.

MAIN OUTCOME AND MEASURES

The primary outcome was an increase in muscle strength and an improvement in physical performance of the elderly people living in nursing homes.

RESULTS

19 older adults between 77.7 ± 8.9 years old, completed the 12 week resistance exercise program achieving a significant increase in muscle strength to 5.7 Kg (p = 0.0001) as well as nutritional intake for the first four weeks (p = 0.001); we found an improvement in physical performance (p = 0.0001) in balance (p = 0.0001), chair stand (p = 0.036) and gait speed (p = 0.0001). Of the 47.4% that reached sarcopenia degree, in the end it was 33.3%. A relationship with nutritional status (p = 0.004) and age (p = 0.019) was found with the initial and final handgrip strength (p = 0.041).

CONCLUSIONS AND RELEVANCE

The resistance training program improves the functionality (muscle strength and physical performance), with the benefit of the decrease in severe sarcopenia.

Effects of Taurine Supplementation on Vascular Endothelial Function at Rest and After Resistance Exercise

High-intensity resistance exercise has been shown to increase arterial stiffness and reduce vascular endothelial function. Taurine supplementation has a favorable effect on maintaining vascular function. We had previously reported that taurine supplementation attenuated increases in resistance exercise-induced arterial stiffness. In the present study, we further investigate the effects of taurine supplementation on vascular endothelial function at rest and after resistance exercise.Twenty-nine healthy men were recruited and randomly assigned to either the placebo supplement group (n = 14) or the taurine supplement group (n = 15) in a double-blinded manner. Subjects were required to ingest 6 g of either a placebo or the taurine supplement for 2 weeks prior to and 3 days following the exercise. Two weeks after the commencement of supplementation, the subjects were asked to perform 2 sets of 20 repetitive unilateral maximal-effort resistance exercise of the elbow flexors on a Biodex isokinetic dynamometer, with each contraction lasting 3 s, with 1 repetition performed every 9 s and 4 min rest in between sets. We evaluated the changes in brachial artery flow-mediated dilation (FMD) in the non-exercised arm as an index of vascular endothelial function. Relative and absolute FMDs were measured prior to supplementation, before exercise, and 24, 48, and 96 h after exercise.Two weeks of taurine supplementation significantly increased both relative and absolute FMDs. Baseline diameter significantly increased at 96 h following the exercise in both groups. However, there was no change in the peak diameter. Consequently, both relative and absolute FMDs were significantly reduced at 96 h after the exercise in both groups. Taurine supplementation does not affect resistance exercise-induced reduction in FMD.Two weeks of taurine supplementation (6 g/day) significantly increased vascular endothelial function at rest; however, taurine supplementation did not improve resistance exercise-induced reduction in FMD.

Resistance training downregulates macrophages infiltration in the kidney of 5/6 nephrectomized rats

INTRODUCTION

Chronic kidney disease (CKD) is considered a significant world health problem with elevated mortality rates. Patients with CKD are restricted to mild physical activity, present chronic inflammatory state and loss of muscle strength. Currently, the influence of resistance exercise (RE) on the progression of renal disease has not being fully elucidated.

PURPOSE

To evaluate the effects of RE on the progression of CKD in a remnant kidney model (5/6Nx) in rats.

METHODS

Eight-week-old Wistar rats were submitted to 5/6 nephrectomy and were divided into four groups: Sham sedentary (Sham SD); Sham RE (Sham RE); 5/6Nx SD and 5/6Nx RE. The animals were trained for 8 weeks in a vertical climbing ladder for 3 days per week, on non-consecutive days.

RESULTS

As expected, 5/6Nx SD group presented a markedly loss of renal function, increased plasma inflammatory cytokines and increased oxidative stress with a reduced activity of nitric oxide. The higher macrophage infiltration and fibrosis confirmed these conditions. RE attenuated systolic blood pressure and renal function decrease and also improved serum lipid parameters in 5/6 Nx animals. It was evident the increase of muscle strength and mass in the trained groups while the sedentary group showed reduced muscle weight and strength compared to Sham SD.

CONCLUSIONS

RE implemented following 5/6Nx retard the progression of chronic kidney injury while simultaneously allowed the maintenance of skeletal muscle strength.

Resistance exercise mediates remote ischemic preconditioning by limiting cardiac eNOS uncoupling

BACKGROUND

Currently viewed as a complementary non-pharmacological intervention for preventing cardiac disorders, long-term aerobic training produces cardioprotection through remote ischemic preconditioning (RIPC) mechanisms. However, RIPC triggered by acute exercise remains poorly understood. Although resistance exercise (RE) has been highly recommended by several public health guidelines, there is no evidence showing that RE mediates RIPC. Hence, we investigated whether RE induces cardiac RIPC through nitric oxide synthase (NOS)-dependent mechanism.

METHODS AND RESULTS

Acute RE at 40% of the maximal load augmented systemic nitrite levels, associated with increased cardiac eNOS phosphorylation, without affecting nNOS activity. Using an experimental model of myocardial infarction (MI) through ischemia-reperfusion (IR), RE fully prevented the loss of cardiac contractility and the extent of MI size compared to non-exercised (NE) rats. Moreover, RE mitigated aberrant ST-segment and reduced life-threatening arrhythmias induced by IR. Importantly, inhibition of NOS abolished the RE-mediated cardioprotection. After IR, NE rats showed increased cardiac eNOS activity, associated with reduced dimer/monomer ratio. Supporting the pivotal role of eNOS coupling during MI, non-exercised rats displayed a marked generation of reactive oxygen species (ROS) and oxidative-induced carbonylation of proteins, whereas RE prevented these responses. We validated our data demonstrating a restoration of physiological ROS levels in NE + IR cardiac sections treated with BH₄, a cofactor oxidatively depleted during eNOS uncoupling, while cardiac ROS generation from exercised rats remained unchanged, suggesting no physiological needs of supplemental eNOS cofactors.

CONCLUSION

Together, our findings strongly indicate that RE mediates RIPC by limiting eNOS uncoupling and mitigates myocardial IR injury.

Effects of knee extension with different speeds of movement on muscle and cerebral oxygenation

Background

One of the mechanisms responsible for enhancing muscular hypertrophy is the high metabolic stress associated with a reduced muscular oxygenation occurring during exercise, which can be achieved by reducing the speed of movement. Studies have tested that lowered muscle oxygenation artificially induced by an inflatable cuff, could provoke changes in prefrontal cortex oxygenation, hence, to central fatigue. It was hypothesized that (1) exercising with a slow speed of movement would result in greater increase in cerebral and greater decrease in muscle oxygenation compared with exercises of faster speed and (2) the amount of oxygenation increase in the ipsilateral prefrontal cortex would be lower than the contralateral one.

Methods

An ISS Imagent frequency domain near infrared spectroscopy (NIRS) system was used to quantify oxygenation changes in the vastus lateralis muscle and prefrontal cortex (contra- and ipsilateral) during unilateral resistance exercises with different speeds of movement to voluntary fatigue. After one maximal repetition (1RM) test, eight subjects performed three sets of unilateral knee extensions (∼50% of 1RM), separated by 2 min rest periods, following the pace of 1 s, 3 s and 5 s for both concentric and eccentric phases, in a random order, during separate sessions. The amount of change for NIRS parameters for muscle (ΔHb: deoxyhemoglobin, ΔHbO: oxyhemoglobin, ΔHbT: total hemoglobin, ΔStO₂: oxygen saturation) were quantified and compared between conditions and sets by two-way ANOVA RM. Differences in NIRS parameters between contra- and ipsilateral (lobe) prefrontal cortex and conditions were tested.

Results

Exercising with slow speed of movement was associated to larger muscle deoxygenation than normal speed of movement, as revealed by significant interaction (set × condition) for ΔHb (p = 0.01), and by significant main effects of condition for ΔHbO (p = 0.007) and ΔStO₂ (p = 0.016). With regards to the prefrontal cortex, contralateral lobe showed larger oxygenation increase than the ipsilateral one for ΔHb, ΔHbO, ΔHbT, ΔStO₂ in each set (main effect of lobe: p < 0.05). Main effects of condition were significant only in set1 for all the parameters, and significant interaction lobe × condition was found only for ΔHb in set1 (p < 0.05).

Discussion

These findings provided evidence that speed of movement influences the amount of muscle oxygenation. Since the lack of oxygen in muscle is associated to increased metabolic stress, manipulating the speed of movement may be useful in planning resistance-training programs. Moreover, consistent oxygenation increases in both right and left prefrontal lobes were found, suggesting a complementary interaction between the ipsi- and contralateral prefrontal cortex, which also seems related to fatigue.

Effects of preconditioning hamstring resistance exercises on repeated sprinting-induced muscle damage in female soccer players

To examine whether adding preconditioning hamstring resistance exercises to a regular warm-up prior to a repeated sprinting exercise provides protection against the sprinting-induced muscle damage. Ten female soccer players (mean ± SD age: 21.3 ± 4.5yrs; height: 171.34 ± 8.29 cm; weight: 68.53 ± 11.27 kg) participated in this study. After the familiarization visit, the subjects completed three separate randomly sequenced experimental visits, during which three different warm-up interventions were performed before the muscle-damaging protocol (12 sets of 30-m maximal repeated sprints): 1. Regular running and static stretching (Control); 2. Control with hyperextensions (HE); 3. Control with single leg Romanian deadlift (SLRD). Before (Pre), immediately (Post0), 24 hours (24hr), and 48 hours after (48hr) the sprints, hamstring muscle thickness, muscle stiffness, knee flexion eccentric peak torque, knee extension concentric peak torque, and functional hamstring to quadriceps ratios were measured. Repeated sprints have induced muscle damage (e.g., an average of 42% knee flexion eccentric strength reduction) in all three conditions. After the SLRD, hamstring muscle thickness decreased from 24hr to 48hr (p < 0.001). Additionally, muscle stiffness and eccentric strength for the SLRD showed no difference from baseline at 24hr and 48hr, respectively. When compared with the SLRD at 48hr, the muscle stiffness and the eccentric strength were greater and lower, respectively, in other protocols. The SLRD protocol had protective effect on sprinting-induced muscle damage markers than other protocols. Athletes whose competitions/training are densely scheduled may take advantage of this strategy to facilitate muscle recovery.

Exercise recovery increases skeletal muscle H2O2 emission and mitochondrial respiratory capacity following two-weeks of limb immobilization

Extended periods of skeletal muscle disuse result in muscle atrophy. Following limb immobilization, increased mitochondrial reactive oxygen species (ROS) production may contribute to atrophy through increases in skeletal muscle protein degradation. However, the effect of skeletal muscle disuse on mitochondrial ROS production remains unclear. This study investigated the effect of immobilization, followed by two subsequent periods of restored physical activity, on mitochondrial H₂O₂ emissions in adult male skeletal muscle. Middle-aged men (n = 30, 49.7 ± 3.84 y) completed two weeks of unilateral lower-limb immobilization, followed by two weeks of baseline-matched activity, consisting of 10,000 steps a day, then completed two weeks of three times weekly supervised resistance training. Vastus lateralis biopsies were taken at baseline, post-immobilization, post-ambulatory recovery, and post-resistance-training. High-resolution respirometry was used simultaneously with fluorometry to determine mitochondrial respiration and hydrogen peroxide (H₂O₂) production in permeabilized muscle fibres. Mitochondrial H₂O₂ emission with complex I and II substrates, in the absence of ADP, was greater following immobilization, however, there was no effect on mitochondrial respiration. Both ambulatory recovery and resistance training, following the period of immobilization, increased in mitochondrial H₂O₂ emissions. These data demonstrated that 2 weeks of immobilization increases mitochondrial H₂O₂ emissions, but subsequent retraining periods of ambulatory recovery and resistance training also led to in robust increases in mitochondrial H₂O₂ emissions in skeletal muscle.

Effect, process, and economic evaluation of a combined resistance exercise and diet intervention (ProMuscle in Practice) for community-dwelling older adults: design and methods of a randomised controlled trial

BACKGROUND

Exercise and nutrition are important for older adults to maintain or to regain their muscle mass, function, strength, and ultimately quality of life. The effectiveness of combined resistance exercise and diet interventions is commonly evaluated in controlled clinical studies, but evidence from real-life settings is lacking. This article describes the effectiveness, process, and economic evaluation design of a combined nutrition and exercise intervention for community-dwelling older adults in a Dutch real-life setting.

METHODS

The ProMuscle in Practice study is a randomised controlled multicentre intervention study, conducted in five municipalities in the Netherlands. Two hundred community-dwelling older adults (≥65 years) who are frail or pre-frail based on Fried frailty criteria or who experience strength loss are randomised over an intervention and control group by municipality. In the first 12-week intensive support intervention, participants in the intervention group perform resistance exercise training guided by a physiotherapist twice a week and increase protein intake by consuming protein-rich products under the supervision of a dietitian. Afterwards, they continue with a 12-week moderate support intervention. The control group receives only regular care during the two 12-week periods. Effect outcomes are measured at all locations at baseline, 12 weeks, 24 weeks, 36 weeks and only at three locations at 52 weeks. The primary outcome is physical functioning (Short Physical Performance Battery). Secondary outcomes include leg muscle strength, lean body mass, activities of daily living, social participation, food intake, and quality of life. Qualitative and quantitative implementation process data are collected during the intervention. Healthcare use and intervention costs are registered for the economic evaluation.

DISCUSSION

Evaluating the effects, implementation, and costs of this combined intervention provides valuable insight into the feasibility of this intervention for community-dwelling older adults and into the intervention's ability to improve or to maintain physical functioning and quality of life.

TRIAL REGISTRATION

Netherlands Trial Register ( NTR6038 ) since 30 August 2016.

Effect of 8-week leucine supplementation and resistance exercise training on muscle hypertrophy and satellite cell activation in rats

We investigated the effects of regular leucine intake and/or resistance exercise training on skeletal muscle hypertrophy and satellite cell activity after the administration of different doses of leucine. Ten-week-old Sprague-Dawley rats were assigned to six groups (n = 7 per group): a control group (Con), two groups receiving either 10% (0.135 g/kg.wt) (Leu10) or 50% (0.675 g/kg.wt) (Leu50) leucine supplementation, and three exercise groups receiving 0% (Ex), 10% (Leu10Ex), and 50% (Leu50Ex) leucine supplementation. The rats performed ladder climbing exercises thrice per week for 8 weeks, and received leucine supplements at the same time daily. Muscle phenotypes were assessed by immunohistochemistry. MyoD, myogenin, and IGF1 protein levels were determined by western blot. The Leu50Ex group displayed significantly higher numbers of positive embryonic myosin fibers (0.35 ± 0.08, 250%) and myonuclei (3.29 ± 0.3, 118.7%) than all other groups. And exercise training groups increased the cross-sectional area, the number of satellite cells and protein expression of MyoD, myogenin, and IGF1alpha relative to the Control group (P < 0.05). However, Only leucine supplementation group did not increase skeletal muscle hypertrophy and satellite cell activity, regardless of the dose (P > 0.05). Leucine intake accompanied by regular exercise training may increase satellite cell activation in skeletal muscles, and improve muscle quality more effectively than continuous leucine ingestion alone.

Skeletal muscle amino acid transporter and BCAT2 expression prior to and following interval running or resistance exercise in mode-specific trained males

Endurance (END)- and resistance (RES)-trained males performed interval running or resistance exercise during three consecutive days (bouts 1-3). Muscle biopsies were obtained at baseline, 2 h post-bout 1, and 72 h post-bout 3. Amino acid transporter SNAT2 mRNA was 75% greater in END (group p = 0.008), and increased ~ 70% 2 h post in both groups (time p = 0.023). Amino acid transporter PAT1 mRNA was 2.7-fold greater in RES (group p = 0.002). Baseline protein levels of the mitochondrial aminotransferase BCAT2 were 79% greater in END (p = 0.015).

Long-term resistance exercise-induced muscular hypertrophy is associated with autophagy modulation in rats

Elevation of anabolism and concurrent suppression of catabolism are critical metabolic adaptations for muscular hypertrophy in response to resistance exercise (RE). Here, we investigated if RE-induced muscular hypertrophy is acquired by modulating a critical catabolic process autophagy. Male Wistar Hannover rats (14 weeks old) were randomly assigned to either sedentary control (SC, n = 10) or resistance exercise (RE, n = 10). RE elicited significant hypertrophy of flexor digitorum profundus (FDP) muscles in parallel with enhancement in anabolic signaling pathways (phosphorylation of AKT, mTOR, and p70S6K). Importantly, RE-treated FDP muscle exhibited a significant decline in autophagy evidenced by diminished phosphorylation levels of AMPK, a decrease in LC3-II/LC3-I ratio, an increase in p62 level, and a decline in active form of lysosomal protease CATHEPSIN L in the absence of alterations of key autophagy proteins: ULK1 phosphorylation, BECLIN1, and BNIP3. Our study suggests that RE-induced hypertrophy is achieved by potentiating anabolism and restricting autophagy-induced catabolism.

Reduced Muscle Strength in Barth Syndrome May Be Improved by Resistance Exercise Training: A Pilot Study

BACKGROUND

Cardioskeletal myopathy is thought to contribute to exercise intolerance, and reduced quality of life (QOL) in Barth syndrome (BTHS). The objectives of this study were to examine: (1) skeletal muscle strength/performance in adolescents and young adults with BTHS and (2) the safety, feasibility, and initial efficacy of 12 weeks of progressive resistance exercise training (RET) on muscle strength, mass, and performance, bone mineral density, exercise tolerance, cardiac function, and QOL in individuals with BTHS.

METHODS

Individuals with BTHS (n = 9, 23 ± 6 years), and age-, sex-, and activity level-matched unaffected Controls (n = 7, 26 ± 5 years) underwent baseline testing to assess muscle performance, exercise capacity, cardiac structure and function, body composition, and health-related QOL. Subsequently, n = 3 participants with BTHS performed 12 weeks of supervised RET (60 min per session, 3 sessions/week). All testing was repeated post-RET.

RESULTS

BTHS had lower strength and lean muscle mass compared to Controls (all p < 0.05). BTHS also had diminished lower extremity, upper extremity, thoracic spine, lumbar spine, and pelvic bone mineral density (all p < 0.05) and reduced exercise capacity (p < 0.001) compared to Controls. RET was well-tolerated and attended, was not associated with any adverse events, and significantly increased muscle strength (p < 0.05).

CONCLUSIONS

Individuals with BTHS demonstrate reduced muscle strength and mass, bone mineral density, and exercise capacity. RET appears safe and well-tolerated in BTHS and promotes increased muscle strength. Larger studies are needed to confirm these improvements and to fully determine the effects of RET in individuals with BTHS.

Exercise Improves Recognition Memory and Acetylcholinesterase Activity in the Beta Amyloid-Induced Rat Model of Alzheimer's Disease

Objective

A correlation between physical exercise and cognitive improvement has been found in Alzheimer's disease (AD). This study aimed to investigate the effects of aerobic and resistance exercise on the recognition memory and acetylcholinesterase (AChE) activity in beta amyloid (Aβ) model of AD in rat.

Materials and Methods

Fifty male 8-week-old Wistar rats (250-280 g) were divided into 5 groups (n = 10 each) of control, sham surgery, Aβ-received sedentary, Aβ-received with aerobic exercise and Aβ-received with resistance exercise. AD was induced by intracerebroventricular injection of Aβ_25-35 peptide. The sham surgery group received normal saline using the same route and condition. Two groups of Aβ-received animals were trained by treadmill for aerobic exercise and by ladder for strength exercise for 8 weeks (4 days/week). Novel object recognition (NOR) task was used to assess recognitional memory in groups. AChE activity in the brain tissue was assessed using the Spectrophotometry method.

Results

There was no significant difference in memory index and AChE activity between the sham surgery and control groups (p > 0.05). Also, impairment of NOR indices was seen in the Aβ-injected sedentary rats (p < 0.05). However, both aerobic and strength training improved the exploration index in this test (p < 0.05). Further, AChE activity increased in the Aβ-injected sedentary group but declined in the aerobic and resistance exercise groups (p < 0.01).

Conclusion

Aerobic and resistance exercise could improve recognition memory and decrease AChE activity in Aβ-induced AD in rats. The decrease in AChE activity may be one of the mechanisms by which exercise improves cognition and memory in AD.

Resistance exercise decreases heroin self-administration and alters gene expression in the nucleus accumbens of heroin-exposed rats

RATIONALE

Preclinical studies consistently report that aerobic exercise decreases drug self-administration and other forms of drug-seeking behavior; however, relatively few studies have examined other types of physical activity.

OBJECTIVES

The purpose of the present study was to examine the effects of resistance exercise (i.e., strength training) on heroin self-administration and mRNA expression of genes known to mediate opioid reinforcement and addictive behavior in the nucleus accumbens (NAc) of heroin-exposed rats.

METHODS

Female rats were obtained during late adolescence and divided into two groups. Resistance exercise rats were trained to climb a vertical ladder wearing a weighted vest; sedentary control rats were placed repeatedly on the ladder oriented horizontally on its side. All rats were implanted with intravenous catheters and trained to self-administer heroin on a fixed ratio (FR1) schedule of reinforcement. mRNA expression in the NAc core and shell was examined following behavioral testing.

RESULTS

Resistance exercise significantly decreased heroin self-administration, resulting in a downward shift in the dose-effect curve. Resistance exercise also reduced mRNA expression for mu opioid receptors and dopamine D1, D2, and D3 receptors in the NAc core. Resistance exercise increased mRNA expression of dopamine D5 receptors in the NAc shell and increased mRNA expression of brain-derived neurotrophic factor (exons I, IIB, IIC, IV, VI, IX) in the NAc core.

CONCLUSIONS

These data indicate that resistance exercise decreases the positive reinforcing effects of heroin and produces changes in opioid and dopamine systems in the NAc of heroin-exposed rats.

The putative leucine sensor Sestrin2 is hyperphosphorylated by acute resistance exercise but not protein ingestion in human skeletal muscle

PURPOSE

Dietary protein and resistance exercise (RE) are both potent stimuli of the mammalian target of rapamycin complex 1 (mTORC1). Sestrins1, 2, 3 are multifunctional proteins that regulate mTORC1, stimulate autophagy and alleviate oxidative stress. Of this family, Sestrin2 is a putative leucine sensor implicated in mTORC1 and AMP-dependent protein kinase (AMPK) regulation. There is currently no data examining the responsiveness of Sestrin2 to dietary protein ingestion, with or without RE.

METHODS

In Study 1, 16 males ingested either 10 or 20 g of milk protein concentrate (MPC) with muscle biopsies collected pre, 90 and 210 min post-beverage consumption. In Study 2, 20 males performed a bout of RE immediately followed by the consumption of 9 g of MPC or carbohydrate placebo. Analysis of Sestrins, AMPK and antioxidant responses was examined.

RESULTS

Dietary protein ingestion did not result in Sestrin2 mobility shift. After RE, Sestrin2 phosphorylation state was significantly altered and was not further modified by post-exercise protein or carbohydrate ingestion. With RE, AMPK phosphorylation remained stable, while the mRNA expressions of several antioxidants were upregulated.

CONCLUSIONS

Dietary protein ingestion did not affect the signalling by the family of Sestrins. With RE, Sestrin2 was hyperphosphorylated, with no further evidence of a relationship to AMPK signalling.

Acute alterations in the hematological and hemorheological profile induced by resistance training and possible implication for microvascular functionality

Depending on the exercise variables and training design, resistance exercise can be applied to gain muscle mass, prevent diseases like osteoporosis and sarcopenia or generally increase strength capacity. But the influence on blood flow parameters and possible consequences in health and disease are less understood. To examine the possible impact of resistance exercise of different duration on hemorheology, oxidative stress and microvascular function, participants (n = 6) performed lower-limb resistance exercise of the quadriceps femoris. Loading consisted of 1 (S1), 5 (S5) and 10 (S10) sets, on separated days, at the individual 10 repetition maximum. Blood samples were taken before (Pre) and after (Post0) each set as well after a 25-min recovery period (Post25). Hemograms were measured to analyze hematocrit, white blood cell (WBC) count and red blood cell (RBC) count. RBC deformability and aggregation were measured by ektacytometry and syllectometry to determine hemorheological responses. Plasma and RBC nitrate were measured by chemiluminescence detection to determine nitric oxide production. Formation of N-tyrosine and plasma malondialdehyde to determine oxidative stress and lipid peroxidation were measured by immunostaining and ELISA, respectively. Hematocrit, RBC, WBC count and aggregation increased Post0 in each protocol with subsequently decreased values Post25 below Pre values. High effect size was observed regarding deformability during the different sets. RBC nitrite analysis revealed effect size alterations between the trainings, whereas plasma nitrite was not affected. Effects size was evident in lipid peroxidation, whereas N-tyrosine concentration was not altered. Lower-limb resistance exercise induced acute changes in hematological and hemorheological parameters, whereby intermittent hemodilution and plasma shifts seemed the major contributor. The acute adaptations of RBC function seen during short duration resistance exercise might contribute to beneficial effects on microvascular circulation with a low oxidative stress response.

The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: a randomized, double-blind, placebo-controlled, crossover study

AIM

The purpose of this study was to examine the effect of CYP1A2 -163C>A polymorphism on the ergogenic effects of caffeine supplementation during a resistance exercise (RE) session.

METHODS

In a randomized, double-blind, placebo (PL)-controlled, crossover study, 30 resistance-trained men took part in two RE sessions (three sets to failure at 85% of one repetition maximum, 2-min rest between sets), including bench press (BP), leg press (LP), seated cable row, and shoulder press (SP) following caffeine (CAF) (6 mg kg^-1) or PL (6 mg kg^-1 of maltodextrin) ingestion 1 h prior to the trial. The number of repetitions was recorded after each set, along with calculation of total number of repetitions for each exercise. Genomic DNA was isolated from the whole blood samples for analyzing the CYP1A2 -163C>A polymorphism through amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Subjects were classified as either AA (n = 14) or AC/CC genotypes (n = 16).

RESULTS

The two-way ANOVA with repeated measures revealed differences between AAs and AC/CCs under CAF conditions for repetitions performed in sets 1, 2, and 3 of BP (F_{(1, 28)} = 14.84, P = 0.001, ƞ² = 0.34), LP (F_{(1, 28)} = 8.92, P = 0.006, ƞ² = 0.24), SR (F_{(1, 28)} = 17.38, P = 0.0001, ƞ² = 0.38), and SP (F_{(1, 28)} = 3.76, P = 0.063, ƞ² = 0.11). CAF also increased the total number of repetitions performed for all three sets in AAs versus AC/CCs for BP (F_{(1, 28)} = 8.72, P = 0.006, ƞ² = 0.23), LP (F_{(1, 28)} = 4.67, P = 0.03, ƞ² = 0.14), SR (F_{(1, 28)} = 5.54, P = 0.02, ƞ² = 0.16), and SP (F_{(1, 28)} = 3.89, P = 0.058, ƞ² = 0.12) in athletes who were homozygous carriers of the A allele, compared to the C allele carriers. Therefore, AA homozygotes were able to carry out a greater total volume of RE work under CAF but not PL conditions, compared to the C allele carriers.

CONCLUSION

In conclusion, acute ingestion of CAF significantly enhanced RE performance in resistance-trained men who were homozygous for the A allele, but not for C allele carriers. Further studies are needed to replicate the potential role of the CYP1A2 -163C>A polymorphism on the ergogenic effects of CAF in other modes of exercise and in other populations.

Menstrual phase and the vascular response to acute resistance exercise

INTRODUCTION

Aerobic exercise has a favorable effect on systemic vascular function, reducing both central (large elastic artery) and peripheral (smaller muscular artery) stiffness. The effects of resistance exercise (RE) on arterial stiffness are more complex. Acute RE increases central artery stiffness while decreasing peripheral stiffness. To date, the majority of studies have been performed in predominantly male participants.

PURPOSE

To examine the effect of acute RE on central and peripheral arterial stiffnesses in women, a secondary purpose was to explore the influence of cyclic changes in estrogen status across the menstrual cycle on the arterial response to acute RE.

METHODS

18 healthy women [28 ± 7 years, body mass index (BMI) 22.6 ± 2.9 kg/m²] completed an acute RE bout during the early follicular and the early luteal phase of their menstrual cycle. Salivary 17β-Estradiol concentration was measured during each phase, using a passive drool technique. Pulse-wave velocity (PWV) was obtained from the carotid-femoral and carotid-radial pulse sites to measure central and peripheral stiffness, respectively, using applanation tonometry. PWV was measured at rest, immediately, 10, 20, and 30 min post-RE.

RESULTS

17β-Estradiol concentration was significantly lower in the early follicular vs. the early luteal phase of the menstrual cycle (1.78 ± 0.51 vs. 2.40 ± 0.26 pg/ml, p = 0.01). Central PWV significantly increased (p < 0.05) and peripheral PWV significantly decreased (p < 0.05) post-RE in both the early follicular and early luteal phases. No phase-by-time interaction was detected for either vascular segment (p > 0.05).

CONCLUSION

Women experience increases in central arterial stiffness and reductions in peripheral arterial stiffness following acute RE. Menstrual cycle phase may not influence changes in arterial stiffness in response to acute RE.

Short-term l-arginine supplementation attenuates elevation of interleukin 6 level after resistance exercise in overweight men

BACKGROUND AND AIM

l-Arginine (l-arg) supplementation and resistance exercise can induce changes in inflammatory and anti-inflammatory cytokines; however, it has not been investigated in obese hypertensive men. This study examines the effects of short-term l-arg supplementation and acute resistance exercise (AREX) on cytokine levels in obese hypertensive men.

METHODS

Eight obese hypertensive men aged 46 ± 6 yrs. with an average body weight of 92.56 ± 9.9 kg and a BMI of 31.68 ± 2.18 kg/m² participated in a randomized, double-blinded, crossover study. The patients were distributed into exercise groups based on the type of supplementation (6 g/day of placebo or l-arg for 7 days). Supplementation periods were separated by a seven-day washout period. The AREX regimen consisted of eight exercises with an exercise intensity of 60% of 1 repetition maximum. The interleukins IL-1ra, IL-6, and IL-10 and the IL-6/IL10 ratio were determined at rest, immediately after exercise and 1 h after exercise sessions.

RESULTS

IL-1ra levels exhibited a significant difference both immediately and 1 h after exercise when the l-arg and placebo groups were compared (P < 0.05). IL-6 levels increased significantly after exercise in the placebo group compared with the l-arg group (P < 0.05). The placebo group showed a decrease in the IL-10 levels 1 h after exercise compared with resting levels (P < 0.05). The IL-6/IL-10 ratio showed a statistically significant increase in the placebo group after exercise compared to the l-arg group (P < 0.05).

CONCLUSIONS

LARG supplementation attenuates the cytokine increase after AREX, in particular peak IL-6 levels decrease and exercise induced decreases in IL-10 levels are attenuated.

Muscular activity patterns of female and male athletes during the flat bench press

The bench press (BP) is a complex upper body exercise in which substantial external loads can be used, demanding high neuromuscular activity. The aim of this study was to compare electromyographic (EMG) activity between female and male athletes during the flat bench press. Five male and five female athletes participated in this study. The main session included four sets of one repetition of the flat bench press with the load of 55, 70, 85 and 100% of the one-repetition maximum (1RM). The activity of four muscles was analysed: the pectoralis major (PM), the anterior deltoid (AD), the lateral head of the triceps brachii (TBlat) and the long head of the triceps brachii (TBlong). The main finding of the study was that the muscle activity pattern differed between women and men during the bench press depending on the external load. The non-parametric Kruskal-Wallis ANOVA for males showed differences between the TLpeak values recorded for different loads (55%-100% 1RM) during the bench press (chi-square = 15.3, p = 0.009) and AD_peak (chi-square = 19.5, p = 0.001). The non-parametric Kruskal-Wallis ANOVA for females showed differences between the AD_peak values recorded for different loads (55%-100% 1RM) during the bench press (chi-square = 12.1, p = 0.018).

The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis

Resistance training (RT)-induced skeletal muscle hypertrophy is a highly intricate process. Despite substantial advances, we are far from understanding exactly how muscle hypertrophy develops during RT. The aim of the present review is to discuss new insights related to the role of skeletal muscle damage and muscle protein synthesis (MPS) in mediating RT-induced hypertrophy. Specifically, the thesis that in the early phase of RT (≤ 4 previous RT sessions) increases in muscle cross-sectional area are mostly attributable to muscle damage-induced muscle swelling; then (after ~ 10 sessions), a modest magnitude of muscle hypertrophy ensues; but only during a latter phase of RT (after ~ 18 sessions) is true muscle hypertrophy observed. We argue that the initial increases in MPS post-RT are likely directed to muscle repair and remodelling due to damage, and do not correlate with eventual muscle hypertrophy induced by several RT weeks. Increases in MPS post-RT session only contribute to muscle hypertrophy after a progressive attenuation of muscle damage, and even more significantly when damage is minimal. Furthermore, RT protocols that do not promote significant muscle damage still induce similar muscle hypertrophy and strength gains compared to conditions that do promote initial muscle damage. Thus, we conclude that muscle damage is not the process that mediates or potentiates RT-induced muscle hypertrophy.

[Effects of aerobic exercise combined with resistance training on the cardiorespiratory fitness and exercise capacity of patients with stable coronary artery disease]

Objective: To observe the effects of aerobic exercise combined with resistance training on the cardiorespiratory fitness and exercise capacity of patients with stable coronary artery disease (CAD) . Methods: From June 2014 to December 2015, 73 patients with stable CAD in our department were recruited and randomly assigned to two groups: the control group (n=38) and the exercise group (n=35) . Patients in both groups received conventional medical treatment for CAD and related cardiac health education. While for patients in exercise group, a twelve-week aerobic exercise combined with resistance training program were applied on top of conventional treatment and health education. Cardiorespiratory fitness and exercise capacity were evaluated by cardiopulmonary exercise testing. Results: (1) The exercise capacity was significantly increased in the exercise group after 12 weeks training as compared to baseline level: peak oxygen uptake per kilogram ( (26.25±5.14) ml·kg(-1)·min(-1) vs. (20.88±4.59) ml·kg(-1)·min(-1)) , anaerobic threshold ( (15.24±2.75) ml·kg(-1)·min(-1) vs. (13.52±2.92) ml·kg(-1)·min(-1)], peak oxygen pulse ( (11.91±2.89) ml/beat vs. (9.77±2.49) ml/beat) , peak Watts ( (113.2±34.0) W vs. (103.7±27.9) W) , peak metabolic equivalent ( (7.57±1.46) METs vs. (6.00±1.32) METs) (all P<0.05 vs. baseline) . (2) The degree of improvement of peak oxygen uptake per kilogram ( (26.25±5.14) ml·kg(-1)·min(-1) vs. (22.32±4.00) ml·kg(-1)·min(-1)) , anaerobic threshold ( (15.24±2.75) ml·kg(-1)·min(-1) vs. (13.76±2.51) ml·kg(-1)·min(-1)) , peak oxygen pulse ( (11.91±2.89) ml/beat vs. (9.99±2.15) ml/beat) and peak metabolic equivalent ( (7.57±1.46) METs vs. (6.47±1.17) METs) were significantly higher in exercise group than in control group (all P<0.05) . Conclusion: Aerobic training at an aerobic threshold level combined with Thera-band resistance training is safe for patients with stable coronary artery disease. This combined exercise program can significantly improve the cardiorespiratory fitness and exercise capacity of patients with stable coronary artery disease.

Resistance training during a 12-week protein supplemented VLCD treatment enhances weight-loss outcomes in obese patients

BACKGROUND

This investigation evaluated the efficacy by which resistance training enhances body composition, metabolic, and functional outcomes for obese patients undergoing a 12-week medically supervised hypocaloric treatment.

METHODS

This was a single-blind, randomized, parallel-group prospective trial. Morbidly obese patients were prescribed a 12-week proprietary very low calorie diet (VLCD) treatment (Optifast^®) with supplemental protein (1120 kcals/day) and were placed in one of two groups for 14 weeks: 1) Standard Treatment Control (CON) (n = 5) or 2) Resistance Training (RT) (n = 6). Both groups underwent a pedometer-based walking program; however only RT performed resistance training 3 days/week for 12 weeks. Body composition, resting energy expenditure (REE), neuromuscular function, and serum biomarkers were measured at weeks 0, 6, and 13.

RESULTS

Both groups exhibited a significant loss of total body mass (TBM) (CON: -19.4 ± 2.3 kg, p = 0.0009 vs. RT: -15.8 ± 1.5 kg, p = 0.0002) and fat mass (FM) (CON: -14.7 ± 1.8 kg, p = 0.0002 vs. RT: -15.1 ± 2.1 kg, p = 0.0002) with no group differences. CON lost 4.6 ± 0.8 kg (p = 0.004) of lean mass (LM) while RT demonstrated no changes. Group differences were found for the relative proportion of total weight-loss due to FM-loss (CON: 75.6 ± 3.4% vs. RT: 96.0 ± 6.0%, p = 0.03) and LM-loss (CON: 24.4 ± 3.2% vs. RT: 4.0 ± 6.5%, p = 0.03). CON demonstrated a 328.6 ± 72.7 kcal/day (-14.3 ± 2.4%) (p = 0.02) decrease in REE while RT exhibited a non-significant decrease of 4.6 ± 1.6% (p = 0.78). RT demonstrated greater improvements in all measures of contractile function and strength when compared to CON (p < 0.05). At post-treatment, RT exhibited greater serum free fatty acids (p = 0.01), glycerol (p = 0.003), and β-hydroxybutyrate (p = 0.005) than CON.

CONCLUSION

Resistance training was advantageous for weight-loss composition by preservation of LM without compromising overall weight- or fat-loss in morbidly obese men and women undergoing a protein supplemented VLCD. These changes accompanied positive adaptations for resting metabolism and muscular function.

A mathematical model of the effects of resistance exercise-induced muscle hypertrophy on body composition

PURPOSE

Current diet and exercise methods used to maintain or improve body composition often have poor long-term outcomes. We hypothesize that resistance exercise (RE) should aid in the maintenance of a healthy body composition by preserving lean mass (LM) and metabolic rate.

METHOD

We extended a previously developed energy balance model of human metabolism to include muscle hypertrophy in response to RE. We first fit model parameters to a hypothetical individual to simulate an RE program and then compared the effects of a hypocaloric diet only to the diet with either cardiovascular exercise (CE) or RE. We then simulated a cohort of individuals with different responses to RE by varying the parameters controlling it using Latin Hypercube Sampling (LHS). Finally, we fit the model to mean data from an elderly population on an RE program.

CONCLUSION

The model is able to reproduce the time course of change in LM in response to RE and can be used to generate a simulated cohort for in silico clinical studies. Simulations suggest that the additional LM generated by RE may shift the body composition to a healthier state.

The Individual, Joint, and Additive Interaction Associations of Aerobic-Based Physical Activity and Muscle Strengthening Activities on Metabolic Syndrome

PURPOSE

Previous research has demonstrated that physical activity and muscle strengthening activities are independently and inversely associated with metabolic syndrome. Despite a number of studies examining the individual associations, only a few studies have examined the joint associations, and to our knowledge, no previous studies have examined the potential additive interaction of performing muscle strengthening activities and aerobic-based physical activity and their association with metabolic syndrome.

METHOD

Using data from the 2003 to 2006 National Health and Nutrition Examination Survey (NHANES), we computed three separate multivariable logistic regression models to examine the individual, combined, and additive interaction of meeting guidelines for accelerometer-assessed physical activity and self-reported muscle strengthening activities, and their association with metabolic syndrome.

RESULTS

We found that individuals meeting physical activity and muscle strengthening activity guidelines, respectively, were at 61 and 25 % lower odds of having metabolic syndrome. Furthermore, individuals meeting both guidelines had the lowest odds of having metabolic syndrome (70 %), in part due to the additive interaction of performing both modes of exercise.

CONCLUSION

In this national sample, accelerometer-assessed physical activity and muscle strengthening activities were synergistically associated with metabolic syndrome.

Immediate effect of passive static stretching versus resistance exercises on postprandial blood sugar levels in type 2 diabetes mellitus: a randomized clinical trial

The prevalence of diabetes is rapidly rising all over the globe at an alarming rate. In India, more than 61.3 million people have been presently diagnosed with type 2 diabetes mellitus. It is possible to control the circulating blood glucose levels by reducing life style risk factors through physical activities comprising of muscle stretches, aerobic training, resistance exercises (REs), yoga, etc. The aim of this study is to identify and compare the immediate effect of passive static stretching (PSS) versus RE on blood glucose level in individuals with type 2 diabetes mellitus. The present study included 51 participants between the age of 40–65 years with type 2 diabetes mellitus, to study the immediate effect of 60-min PSS (n=25) and 60-min RE (n=26). The outcome measure was blood glucose level which was checked by glucometer (free-style neo). Blood sugar was assessed at 3 points of time that included fasting blood sugar level, 2 hr after the meal and immediately after the exercise regimen. Results of this study showed significant reduction in blood glucose level in subjects according to glucometer with PSS (P=0.000) and RE (P=0.00). However, both groups demonstrated equal effect in terms of lowering blood sugar level immediately after the exercise. The conclusion is both PSS and RE are effective in reducing postprandial blood glucose level in type 2 diabetes mellitus and must be prescribed for the patients who demonstrate difficulty in controlling post prandial spike.

Satellite cell response to concurrent resistance exercise and high-intensity interval training in sedentary, overweight/obese, middle-aged individuals

Purpose

Sarcopenia can begin from the 4–5th decade of life and is exacerbated by obesity and inactivity. A combination of resistance exercise (RE) and endurance exercise is recommended to combat rising obesity and inactivity levels. However, work continues to elucidate whether interference in adaptive outcomes occur when RE and endurance exercise are performed concurrently. This study examined whether a single bout of concurrent RE and high-intensity interval training (HIIT) alters the satellite cell response following exercise compared to RE alone.

Methods

Eight sedentary, overweight/obese, middle-aged individuals performed RE only (8 × 8 leg extensions at 70% 1RM), or RE + HIIT (10 × 1 min at 90% HR_max on a cycle ergometer). Muscle biopsies were collected from the vastus lateralis before and 96 h after the RE component to determine muscle fiber type-specific total (Pax7⁺ cells) and active (MyoD⁺ cells) satellite cell number using immunofluorescence microscopy.

Results

Type-I-specific Pax7⁺ (P = 0.001) cell number increased after both exercise trials. Type-I-specific MyoD⁺ (P = 0.001) cell number increased after RE only. However, an elevated baseline value in RE + HIIT compared to RE (P = 0.046) was observed, with no differences between exercise trials at 96 h (P = 0.21). Type-II-specific Pax7⁺ and MyoD⁺ cell number remained unchanged after both exercise trials (all P ≥ 0.13).

Conclusion

Combining a HIIT session after a single bout of RE does not interfere with the increase in type-I-specific total, and possibly active, satellite cell number, compared to RE only. Concurrent RE + HIIT may offer a time-efficient way to maximise the physiological benefits from a single bout of exercise in sedentary, overweight/obese, middle-aged individuals.

Resistance exercise improves cardiac function and mitochondrial efficiency in diabetic rat hearts

Metabolic disturbance and mitochondrial dysfunction are a hallmark of diabetic cardiomyopathy (DC). Resistance exercise (RE) not only enhances the condition of healthy individuals but could also improve the status of those with disease. However, the beneficial effects of RE in the prevention of DC and mitochondrial dysfunction are uncertain. Therefore, this study investigated whether RE attenuates DC by improving mitochondrial function using an in vivo rat model of diabetes. Fourteen Otsuka Long-Evans Tokushima Fatty rats were assigned to sedentary control (SC, n = 7) and RE (n = 7) groups at 28 weeks of age. Long-Evans Tokushima Otsuka rats were used as the non-diabetic control. The RE rats were trained by 20 repetitions of climbing a ladder 5 days per week. RE rats exhibited higher glucose uptake and lower lipid profiles, indicating changes in energy metabolism. RE rats significantly increased the ejection fraction and fractional shortening compared with the SC rats. Isolated mitochondria in RE rats showed increase in mitochondrial numbers, which were accompanied by higher expression of mitochondrial biogenesis proteins such as proliferator-activated receptor-γ coactivator-1α and TFAM. Moreover, RE rats reduced proton leakage and reactive oxygen species production, with higher membrane potential. These results were accompanied by higher superoxide dismutase 2 and lower uncoupling protein 2 (UCP2) and UCP3 levels in RE rats. These data suggest that RE is effective at ameliorating DC by improving mitochondrial function, which may contribute to the maintenance of diabetic cardiac contractility.

Effects of a pre-workout supplement on hyperemia following leg extension resistance exercise to failure with different resistance loads

Background

We sought to determine if a pre-workout supplement (PWS), containing multiple ingredients thought to enhance blood flow, increases hyperemia associated with resistance training compared to placebo (PBO). Given the potential interaction with training loads/time-under-tension, we evaluated the hyperemic response at two different loads to failure.

Methods

Thirty males participated in this double-blinded study. At visit 1, participants were randomly assigned to consume PWS (Reckless™) or PBO (maltodextrin and glycine) and performed four sets of leg extensions to failure at 30% or 80% of their 1-RM 45-min thereafter. 1-wk. later (visit 2), participants consumed the same supplement as before, but exercised at the alternate load. Heart rate (HR), blood pressure (BP), femoral artery blood flow, and plasma nitrate/nitrite (NOx) were assessed at baseline (BL), 45-min post-PWS/PBO consumption (PRE), and 5-min following the last set of leg extensions (POST). Vastus lateralis near infrared spectroscopy (NIRS) was employed during leg extension exercise. Repeated measures ANOVAs were performed with time, supplement, and load as independent variables and Bonferroni correction applied for multiple post-hoc comparisons. Data are reported as mean ± SD.

Results

With the 30% training load compared to 80%, significantly more repetitions were performed (p < 0.05), but there was no difference in total volume load (p > 0.05). NIRS derived minimum oxygenated hemoglobin (O₂Hb) was lower in the 80% load condition compared to 30% for all rest intervals between sets of exercise (p < 0.0167). HR and BP did not vary as a function of supplement or load. Femoral artery blood flow at POST was higher independent of exercise load and treatment. However, a time*supplement*load interaction was observed revealing greater femoral artery blood flow with PWS compared to PBO at POST in the 80% (+56.8%; p = 0.006) but not 30% load condition (+12.7%; p = 0.476). Plasma NOx was ~3-fold higher with PWS compared to PBO at PRE and POST (p < 0.001).

Conclusions

Compared to PBO, the PWS consumed herein augmented hyperemia following multiple sets to failure at 80% of 1-RM, but not 30%. This specificity may be a product of interaction with local perturbations (e.g., reduced tissue oxygenation levels [minimum O₂Hb] in the 80% load condition) and/or muscle fiber recruitment.

Satellite cell activation and mTOR signaling pathway response to resistance and combined exercise in elite weight lifters

PURPOSE

Our aim was to compare the effects of a single exercise training mode (resistance exercise) with a combined exercise training (resistance and plyometric exercise) mode on satellite cell activity and anabolic signaling at the molecular level.

METHODS

Eighteen male weight lifters (20 ± 4 years, BMI 27 ± 6 kg/m²) were randomly assigned to either a series of resistance exercise or a series of combined exercise group. The intensity of the exercise was set at 60% of their 1 RM weight and subjects completed three sets each of six repetitions. The combined exercise group performed three different types of resistance exercise alternating with three different types of plyometric exercise, whereas the resistance exercise group performed only the three different types of resistance exercise which was repeated twice. Muscle biopsies were obtained the vastus lateralis muscle immediately before and 3 h after one bout of exercise.

RESULTS

Exercise induced increases in satellite cell activation and myofibrillar protein synthesis following both exercise modes, but the resistance exercise group was superior compared to the combined exercise group in satellite cell activity expressed by Ki67/CD56 (165 vs 232%) and PI3K/Akt protein expression (121 vs 157%), mTOR protein expression (117 vs 288%), p70S6K protein expression (253 vs 809%), and 4E-BP1 protein expression (70 vs 139%) of anabolic signaling pathway.

CONCLUSIONS

These results suggest that the previous findings showing a greater effect of combined as opposed to a single exercise mode could be the effect of a greater training volume rather than a true-training effect of a combined exercise program.

There are no no-responders to low or high resistance training volumes among older women

OBJECTIVES

To assess the prevalence of non-responders to different tests and to compare the effects of different resistance training (RT) volumes on muscle strength, anthropometric and functional performance of older women.

METHODS

Three hundred seventy six women performed 12weeks of RT with either low or high volume (LV, 71.29±5.77years and HV 69.73±5.88years, respectively). Both groups performed the same exercises, and all parameters were held constant except for the number of sets performed per week. LV performed 8-12 for upper and 4-6 for lower body, while HV performed 16-20 and 8-10, respectively. Before and after the training period, the participants were tested for bench press and leg press 1RM, 30-s chair stand, 30-s arm curl, six-minute walk test, sit and reach, body weight and waist circumference.

RESULTS

Both groups significantly improved in all strength and functional tests and reduced their body weight and waist circumference. ANOVA revealed higher gains in the leg press 1RM, 30-s arm curls and 6-min walk test for the HV group and higher increases in the results of the sit and reach test for the LV group. However, the differences were negligible and may be attributable to a type I error due to the large sample size. Non-responsiveness was not apparent in any subject, as a positive response on at least one outcome was present in every participant.

CONCLUSIONS

Our results suggest that RT, even at low volume, improves waist circumference, muscle strength and physical function in the older population, with no evidence of non-responsiveness. Therefore, we should not be restrictive in prescribing this type of exercise to this population.

Effects of different strength training frequencies on maximum strength, body composition and functional capacity in healthy older individuals

There is controversy in the literature regarding the dose-response relationship of strength training in healthy older participants. The present study determined training frequency effects on maximum strength, muscle mass and functional capacity over 6months following an initial 3-month preparatory strength training period. One-hundred and six 64-75year old volunteers were randomly assigned to one of four groups; performing strength training one (EX1), two (EX2), or three (EX3) times per week and a non-training control (CON) group. Whole-body strength training was performed using 2-5 sets and 4-12 repetitions per exercise and 7-9 exercises per session. Before and after the intervention, maximum dynamic leg press (1-RM) and isometric knee extensor and plantarflexor strength, body composition and quadriceps cross-sectional area, as well as functional capacity (maximum 7.5m forward and backward walking speed, timed-up-and-go test, loaded 10-stair climb test) were measured. All experimental groups increased leg press 1-RM more than CON (EX1: 3±8%, EX2: 6±6%, EX3: 10±8%, CON: -3±6%, P<0.05) and EX3 improved more than EX1 (P=0.007) at month 9. Compared to CON, EX3 improved in backward walk (P=0.047) and EX1 in timed-up-and-go (P=0.029) tests. No significant changes occurred in body composition. The present study found no evidence that higher training frequency would induce greater benefit to maximum walking speed (i.e. functional capacity) despite a clear dose-response in dynamic 1-RM strength, at least when predominantly using machine weight-training. It appears that beneficial functional capacity improvements can be achieved through low frequency training (i.e. 1-2 times per week) in previously untrained healthy older participants.

Training load does not affect detraining's effect on muscle volume, muscle strength and functional capacity among older adults

Research underlines the potential of low-load resistance exercise in older adults. However, while the effects of detraining from high-load protocols have been established, it is not known whether gains from low-load training would be better/worse maintained. The current study evaluated the effects of 24weeks of detraining that followed 12weeks of high- and low-load resistance exercise in older adults. Fifty-six older adults (68.0±5.0years) were randomly assigned to leg press and leg extension training at either HIGH load (2×10-15 repetitions at 80% of one-repetition maximum (1-RM)), LOW load (1×80-100 repetitions at 20% of 1-RM), or LOW+ load (1×60 repetitions at 20% of 1-RM, immediately followed by 1×10-20 repetitions at 40% 1-RM). All protocols ended with volitional fatigue. The main outcome measures included mid-thigh muscle volume, leg press 1-RM, leg extension isometric and isokinetic strength, and functional performance. Tests were performed at baseline, post-intervention and after 24weeks of detraining. Results show no effect of load on preservation of muscle volume, which returned to baseline after detraining. Training-induced gains in functional capacity and isometric strength were maintained, independent of load. HIGH and LOW+ were more beneficial than LOW for long-lasting gains in training-specific 1-RM. To conclude, gains in muscle volume are reversed after 24weeks of detraining, independent of load. This emphasises the need for long-term resistance exercise adherence. The magnitude of detraining in neuromuscular and functional adaptations was similar between groups. These findings underline the value of low-load resistance exercise in older age. Clinical Trial Registration NCT01707017.

Muscle strength and stiffness in resistance exercise: Force transmission in tissues

Physical therapists and osteopaths want to know the quantitative force transmitted in the tissues during resistance exercise and also the relationship between tissue strength and the specific type of resistance exercise of the skeletal muscles. This paper uses the strain energy function for large deformations associated with the active and passive response of transversely isotropic skeletal muscle tissue to evaluate muscle strength and force transmitted in tissues during resistance exercises for the quadriceps muscle at the knee during isometric training exercise at different knee angles in vivo. It is found that after an exercise program, the muscle stiffness is halved when the bending angle of the knee increases from 50° to 100°. The muscle strength generated is marginally greater at 100° than at 50°. The stress transmitted in the lateral direction for 100° bending is double that for 50°.

Cardiovascular responses during resistance exercise after an aerobic session

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Diastolic and mean BP were higher during resistance exercise after aerobic exercise.

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Peak heart rate values were higher during resistance exercise after aerobic exercise.

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Aerobic exercise before resistance exercise promoted higher cardiovascular work.

Objective

To analyze the influence of previous aerobic exercise on cardiovascular responses during resistance exercise.

Methods

This is a crossover observational study. The sample included 19 normotensive men aged between 19 and 39 years. Subjects performed two experimental sessions in random order: resistance exercise (R: three sets of knee extension exercises with 40% of one repetition maximum) and aerobic exercise + resistance exercise (A + R: 30 min of aerobic exercise followed by R protocol). In both sessions, blood pressure (BP) and heart rate were monitored beat-by-beat by finger photoplethysmography.

Results

After aerobic exercise in the A + R session, there was a maintenance of systolic BP −2 (95% CI: −6; 2) mmHg (P = 0.35), diastolic 1 (95% CI: −2; 5) mmHg (P = 0.40) and mean BP 0 (95% CI: −4; 4) mmHg (P = 0.91) and an increase in heart rate 11 (95% CI: 7; 16) bpm (P < 0.001). Diastolic and mean BP increased and peak heart rate was higher during resistance exercise in the A + R session compared to the R session. Differences between sessions: diastolic BP 7 (95% CI: 2; 12) mmHg (P = 0.03); mean BP 8 (95% CI: 2; 13) mmHg (P = 0.05); and peak heart rate 18 (95% CI: 13; 23) bpm (P < 0.001). The increases in systolic BP during resistance exercise were similar between sessions 16 (95% CI: 6; 26) mmHg (P = 0.43).

Conclusion

Aerobic exercise before resistance exercise increased diastolic and mean BP and heart rate. However, due to the sample size of 19 individuals, the results must be interpreted with caution.

Effectiveness of resistance exercise compared to aerobic exercise without insulin therapy in patients with type 2 diabetes mellitus: a meta-analysis

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Resistance exercise (> 12 weeks) appears to increase in VO_2max in diabetic patients.

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Resistance exercise didn’t decrease the glycemic level compared to aerobic exercises.

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The lipid profile of DM patients was the same in both types of exercise.

Background

Physical exercise has been used to mitigate the metabolic effects of diabetes mellitus.

Objective

To evaluate the effect of resistance exercise when compared to aerobic exercise without insulin therapy on metabolic and clinical outcomes in patients with type 2 diabetes mellitus.

Methods

Papers were searched on the databases MEDLINE/PubMed, CINAHL, SPORTDiscus, LILACS, and SCIELO, without language or date of publication limits. Clinical trials that compared resistance exercise to aerobic exercise in adults with type 2 diabetes mellitus who did not use insulin therapy were included. The quality of evidence and risk of bias were assessed using the GRADE system and the Cochrane Risk of Bias tool, respectively. Meta-analysis was also used, whenever possible. Two reviewers extracted the data independently. Eight eligible articles were included in this study, with a total of 336 individuals, with a mean age of 48–58 years. The protocols of aerobic and resistance exercise varied in duration from eight to 22 weeks, 30–60 min/day, three to five times/week.

Results

Overall the available evidence came from a very low quality of evidence and there was an increase in Maximal oxygen consumption (mean difference: −2.86; 95% CI: −3.90 to −1.81; random effect) for the resistance exercise and no difference was found in Glycated hemoglobin, Body mass index, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, triglycerides, and total cholesterol.

Conclusions

Resistance exercise appears to be more effective in promoting an increase in Maximal oxygen consumption in protocols longer than 12 weeks and there is no difference in the control of glycemic and lipid levels between the two types of exercise.