High-intensity Resistance Training Group Research Articles

Effects of Blood Flow Restriction Resistance Training on Autonomic and Endothelial Function in Persons with Parkinson's Disease.

Autonomic dysfunction precedes endothelial dysfunction in Parkinson's disease (PD) and causes blood pressure and circulation abnormalities that are highly disruptive to one's quality of life. While exercise interventions have proven helpful for motor symptoms of PD, improving associated non-motor symptoms is limited. Low-intensity resistance training with blood flow restriction (LIRT-BFR) improves autonomic dysfunction in non-PD patients and high-intensity resistance training (HIRT) is recommended for motor symptom improvements for people with PD (PwPD). To determine the effects of LIRT-BFR and HIRT on homocysteine and autonomic and endothelial function in PwPD and to determine the hemodynamic loads during LIRT-BFR and HIRT in PwPD using a novel exercise protocol. Thirty-eight PwPD were assigned LIRT-BFR, HIRT or to a control (CNTRL) group. The LIRT-BFR and HIRT groups exercised three days per week for four weeks. The LIRT-BFR protocol used 60% limb occlusion pressure (LOP) and performed three sets of 20 repetitions at 20% of the one-repetition maximum (1RM). The HIRT group performed three sets of eight repetitions at 80% 1RM. The CNTRL group was asked to continue their normal daily routines. LIRT-BFR significantly improved orthostatic hypotension (p = 0.026), homocysteine levels (p < 0.001), peripheral circulation (p = 0.003), supine blood pressure (p = 0.028) and heart rate variability (p = 0.041); LIRT-BFR improved homocysteine levels (p < 0.018), peripheral circulation (p = 0.005), supine blood pressure (p = 0.007) and heart rate variability (p = 0.047) more than HIRT; and hemodynamic loads for LIRT-BFR and HIRT were similar. LIRT-BFR may be more effective than HIRT for autonomic and endothelial function improvements in PwPD and hemodynamic loads may be lessened in LIRT-BFR protocols using single-joint exercises with intermittent blood flow restriction. Further research is needed to determine if non-motor symptoms improve over time and if results are sustainable.

Exercise-Induced Alterations in Irisin and Osteocalcin Levels: A Comparative Analysis Across Different Training Modalities.

Physical activity significantly influences physiological biomarkers, including irisin and osteocalcin, which are pivotal for metabolic and bone health. Understanding the differential impacts of various exercise modalities on these biomarkers is essential for optimizing health benefits. The study aimed to compare the effects of endurance training and high-intensity resistance training (HIRT) on the levels of irisin and osteocalcin and determine which exercise modality more effectively influences these health-related biomarkers. The study was conducted at the Nimra Institute of Medical Sciences in Andhra Pradesh, India, where 100 healthy male participants aged between 21 and 35 were recruited. These participants, who were not regularly active and had no metabolic or bone diseases, were divided into two groups to undergo an eight-week training from March to April 2022. One group participated in endurance training involving running and cycling, while the other engaged in HIRT, both targeting a heart rate set at 75% of the maximum. Baseline and follow-up measurements of irisin and osteocalcin were taken before and after the training using blood samples collected after fasting. The study used paired t-tests to analyze changes in biomarker levels, and Pearson correlation coefficients to explore the relationship between the biomarkers, with results processed using statistical software and presented as mean ± standard deviation (SD). Post-intervention, both exercise groups showed significant increases in irisin and a modest increase in osteocalcin levels. The HIRT group exhibited a higher increase in irisin levels (+119.33 pg/mL, p<0.015) compared to the endurance group (+108.32 pg/mL, p<0.023). Similarly, osteocalcin levels increased modestly in both groups, with the HIRT group showing a higher mean difference (+0.75 pg/mL, p<0.001) than the endurance group (+0.70 pg/mL). The study also found a link between changes in irisin and osteocalcin levels. This link was stronger in the HIRT group (r = +0.22; p < 0.039) than in the endurance group (r = +0.20; p < 0.038). Both endurance and high-intensity resistance training are effective in enhancing metabolic and bone health, evidenced by increases in irisin and osteocalcin levels. Although the differences in mean values suggest that HIRT may have a marginal advantage in boosting these biomarkers, confirming the statistical significance of this difference is essential. Further research is required to understand the mechanisms behind these effects and to assess their long-term impacts on health and disease prevention.

The effects of low-intensity resistance training with blood flow restriction versus traditional resistance exercise on lower extremity muscle strength and motor functionin ischemic stroke survivors: a randomized controlled trial

ABSTRACT Background Blood flow restriction (BFR) training can temporarily reduce cortical GABA concentrations and increase the size of motor volleys to deafferented muscles, which can promote motor recovery in stroke survivors. Objective To determine the effect of low-intensity resistance training with BFR (LIRT-BFR) on lower extremity muscle strength, balance, functional mobility, walking capacity, gait speed, anxiety, and depression in stroke survivors and to compare the results with high-intensity resistance training (HIRT). Method It was a two-arm, single-blinded, randomized controlled trial in which 32 ischemic stroke participants were randomly allocated to LIRT-BFR or HIRT group. The LIRT-BFR group received low load resistance training (40% of 1-Repetition Maximum (1-RM)) with BFR, whereas HIRT group received high load resistance training (80% of 1-RM). The 6-Minute Walk Test (6-MWT), five-time sit-to-stand test (5TSTST), Timed Up and Go (TUG) test, and Barthel index were the primary outcome measures. The secondary outcome measures included gait speed (m/s), stride length (cm), cadence (steps/min), and Hospital Anxiety and Depression. Results All the primary and secondary outcome measures were significantly improved in both groups (p < 0.05). The LIRT-BFR group showed a slightly greater, but non-significant, improvement as compared to the HIRT group in terms of mean change observed in 6-MWT (81 m vs 62 m), 5TSTST (−5.27 vs −4.81), gait speed (0.19 vs 0.12), stride length (18 vs 13), and cadence (8 vs 6). No adverse event was reported. Conclusion LIRT-BFR produced a significant improvement in muscle strength, balance, walking capacity, and anxiety and depression in ischemic stroke patients, and the improvement are comparable to HIRT. Clinical Trial Registration NCT05281679

Effect of High-Intensity Resistance Training Versus Endurance Training on Irisin and Adipomyokine Levels in Healthy Individuals: An 8-Week Interventional Study.

Background: Irisin and adipomyokine are proteins secreted by the body during exercise and exhibit potential therapeutic effects for chronic disorders. Gaining insights into how high-intensity resistance training and endurance training influence irisin and adipomyokine secretion could shed light on optimizing exercise regimens for potential therapeutic applications. Such knowledge could pave the way for personalized exercise prescriptions and contribute to the development of novel treatments for chronic conditions, enhancing overall health and well-being. Objectives: To investigate the effects of high-intensity resistance training (HIRT) and endurance training on irisin and adipomyokine levels in healthy individuals. Methods: An 8-week interventional comparative study was conducted at Nimra Institute of Medical Sciences, Andhra Pradesh, India. One hundred healthy male individuals aged 21 to 35 were divided into two groups: HIRT and endurance. The HIRT group performed high-intensity resistance training, while the endurance group performed endurance training. Ethical approval was obtained, and baseline and post-intervention values of the participants were recorded and analyzed using SPSS software. Results: After 8 weeks, irisin levels were significantly elevated in the HIRT group (167.39±11.27) compared to the endurance group (155.39±11.28). A positive correlation was observed between skeletal muscle and irisin levels in both the HIRT group (χ2-16.38; p=0.04) and the endurance group (χ2-18.36; p=0.01). Additionally, TNF-α (HIRT: 81.47±4.02 and Endurance: 61.19±4.00) and interleukin-6 (IL-6) (HIRT: 46.84±4.46 and Endurance: 36.15±3.89) levels significantly increased in the HIRT group. However, there was no significant change in leptin levels in either group (HIRT: 3.75±0.58 0.58 and 4.15±0.58). Conclusion: The findings of this study indicate that HIRTis more effective in increasing irisin levels compared to endurance training. However, the notable elevation of IL-6and TNF-α in the HIRT group raises concerns about potential chronic inflammation. To optimize outcomes, a combined approach, coupling HIRT and endurance training, may be beneficial. Additionally, the results emphasize the significance of skeletal muscle as a primary source of irisin secretion, implying that increased muscle contraction contributes to higher irisin release even in healthy individuals. These insights can guide exercise prescriptions and potentially enhance therapeutic strategies for chronic disorders.

Cartilage tissue turnover increases with high- compared to low-intensity resistance training in patients with knee OA

ObjectivesTo investigate cartilage tissue turnover in response to a supervised 12-week exercise-related joint loading training program followed by a 6-month period of unsupervised training in patients with knee osteoarthritis (OA). To study the difference in cartilage tissue turnover between high- and low-resistance training.MethodPatients with knee OA were randomized into either high-intensity or low-intensity resistance supervised training (two sessions per week) for 3 months and unsupervised training for 6 months. Blood samples were collected before and after the supervised training period and after the follow-up period. Biomarkers huARGS, C2M, and PRO-C2, quantifying cartilage tissue turnover, were measured by ELISA. Changes in biomarker levels over time within and between groups were analyzed using linear mixed models with baseline values as covariates.ResultshuARGS and C2M levels increased after training and at follow-up in both low- and high-intensity exercise groups. No changes were found in PRO-C2. The huARGS level in the high-intensity resistance training group increased significantly compared to the low-intensity resistance training group after resistance training (p = 0.029) and at follow-up (p = 0.003).ConclusionCartilage tissue turnover and cartilage degradation appear to increase in response to a 3-month exercise-related joint loading training program and at 6-month follow-up, with no evident difference in type II collagen formation. Aggrecan remodeling increased more with high-intensity resistance training than with low-intensity exercise.These exploratory biomarker results, indicating more cartilage degeneration in the high-intensity group, in combination with no clinical outcome differences of the VIDEX study, may argue against high-intensity training.

Fat infiltration and muscle hydration improve after high-intensity resistance training in women with sarcopenia. A randomized clinical trial

BackgroundResistance training is recommended for preventing sarcopenia, but the benefits for the quality and quantity of muscle mass are uncertain. ObjectiveTo assess the effects of high-intensity resistance training (HIRT) on clinical and magnetic resonance imaging (MRI) parameters in women with sarcopenia. MethodsA researcher-blinded randomized clinical trial was conducted. Community-dwelling older women with sarcopenia were randomized to six months of HIRT or a control group (CG). Body composition was assessed with bioimpedance equipment, and participants underwent strength and functional performance tests (short physical performance battery [SPPB] and gait speed). MRI scans of the thigh were taken to quantify muscle mass and quality. ResultsThirty-eight women completed the study (20 in the HIRT group). Sarcopenia remitted in 50 % of the HIRT group. HIRT elicited a significant group × time interaction effect for muscle mass (p = 0.027; Ƞ2 = 0.129), muscle mass index (p = 0.023; Ƞ2 = 0.135), fat mass (p = 0.048; Ƞ2 = 0.103) and all strength variables (p < 0.05; Ƞ2 > 0.120). Moreover, the HIRT group obtained higher scores on the SPPB (mean difference [MD] 1.2; p = 0.005) and the 5 times sit-to-stand test (MD = 0.7; p = 0.009). Regarding MRI parameters, infiltrated microscopic fat decreased significantly (HIRT: MD = −0.01; p < 0.05), while hydration (T2) decreased in the CG (MD = 3.6 ms; p = 0.053) at six months. There were significant between-group differences at six months for water diffusion (HIRT: 1.09 × 10−3 mm2/s vs CG: 1.26 × 10−3 mm2/s) and total muscular volume (HIRT: 832.4 L vs CG: 649.2 L). ConclusionsHIRT led to the remission of sarcopenia in half of the older women, as seen in muscle mass, strength, and functional performance and MRI biomarkers, with significant increases in muscle quality. Registered in ClinicalTrials.govNCT03834558.

High-intensity resistance training in people with multiple sclerosis experiencing fatigue: A randomised controlled trial

BackgroundExercise studies including only fatigued persons with multiple sclerosis (PwMS) with fatigue as primary endpoint are lacking. ObjectiveTo evaluate the effects of high-intensity resistance training (HIRT) on self-reported fatigue in fatigued PwMS in a single center randomised controlled trial. MethodsWe recruited 71 PwMS scoring ≥ 53 on the Fatigue Scale for Motor and Cognitive Functions (FSMC), who were randomised 1:1 to either twice (group A) or once (group B) weekly supervised HIRT for twelve weeks. A non-randomised FSMC score-matched group (n=69) served as non-intervention control. ResultsBetween HIRT-group differences were non-significant for primary and most secondary endpoints. Mean difference in FSMC score (95% confidence intervals) was -10.9 (-14.8; -6.9) in group A and -9.8 (-13.2; -6.3) in group B. Corresponding values for combined HIRT groups vs non-intervention control were -10.3 (-12.9; -7.7) and 1.5 (-0.6;3.6), respectively, p<0.001. Secondary endpoints also improved in both HIRT groups, though only Hospital Anxiety and Depression Scale anxiety and MS Impact Scale-29 psychological subscales significantly favoured the twice a week HIRT (group A). As an exploratory endpoint, changes in plasma inflammatory protein markers were associated with reduced FSMC scores in the pooled material. ConclusionThe finding that HIRT in fatigued PwMS leads to clinically relevant reductions in self-reported fatigue, associated with changes in plasma inflammatory protein levels, provide evidence for recommending HIRT for fatigued PwMS.

Effects of High-Intensity Resistance Training on Physical Fitness, Hormonal and Antioxidant Factors: A Randomized Controlled Study Conducted on Young Adult Male Soccer Players.

Simple SummaryWe aimed to analyze the effects of high-intensity resistance training (HIRT) on physical fitness and hormonal and antioxidant factors of adult young male soccer players. We have compared an 8-week intervention using HIRT period with a control group that only performed regular technical/tactical sessions. The soccer players were assessed before and after the intervention for their physical fitness, and hormonal and antioxidant factors. We have found that using HIRT for 8 weeks, with three sessions a week, results in significant improvements in aerobic capacity, sprint at short (10 m) and medium (20 and 30 m) distances, repeated sprint ability, and change-of-direction. This suggests that HIRT combined with regular field-based practice can provide an additional benefit to physical fitness development. Additionally, the group enrolled on HIRT also exhibited significantly decreased levels of cortisol and malondialdehyde, whereas it exhibited significantly increased growth hormone, testosterone, dis-mutase, and glutathione. The results suggest that HIRT can be an interesting approach for improving physical fitness and adjusting the hormonal and antioxidant levels of adult male soccer players.Purpose: The aim of this study was to test the effects of high-intensity resistance training (HIRT) intervention on the physical fitness, hormonal and antioxidant factors of adult male soccer players. Methods: A randomized controlled study design was implemented. Eighteen soccer players (age: 20.3 ± 0.66 years; stature: 174.0 ± 6.01 cm; body mass: 69.1 ± 6.4 kg; body mass index: 22.8 ± 1.6 kg/m2) voluntarily participated in this study. Players were assessed before and after an intervention lasting 8 weeks, with three training sessions a week. Assessments of physical fitness included the Yo-Yo intermittent recovery test level 1 (YYIRT1), 10-, 20-, and 30 m sprint time (ST), running-based anaerobic sprint test (RAST) and change-of-direction time (COD). Hormonal tests included cortisol, testosterone and growth hormone (GH), whereas the antioxidant assessment included superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH). Results: Between-group analysis revealed no significant differences at baseline, whereas it revealed that HIRT presented significant better results than the control group on YYIRT (p = 0.032), 10 m ST (p = 0.041), 20 m ST (p = 0.040), 30 m ST (p = 0.044), RAST (p = 0.013), and COD (p = 0.031) after the intervention period. The within group analysis revealed that the HIRT group significantly improved the YYIRT1 (p < 0.001), VO2max (p < 0.001), 10 m ST (p < 0.001), 20 m ST (p = 0.006), 30 m ST (p < 0.001), RAST (p < 0.001) and COD (p < 0.001). Moreover, HIRT group significantly reduced the cortisol (p < 0.001) and MDA (p = 0.021), whereas it significantly increased the GH (p < 0.001), testosterone (p < 0.001), SOD (p = 0.009) and GSH (p = 0.005). Conclusions: The HIRT is effective for improving physical fitness, revealing significant better adaptations than controls. Moreover, hormonal and antioxidant adaptations are also confirmed after HIRT intervention.

High-Intensity Resistance Training Suppresses Exacerbation of Atopic Dermatitis in Mice

PURPOSE: Training generally promotes health and inhibits diseases. However, in patients with atopic dermatitis (AD), training and sweating are significant aggravating factors. This study examined the effect of high-intensity resistance training (HIRT) on AD-like skin lesions in mice.METHODS: Eight-week-old female BALB/c mice were divided into four groups (control, HIRT, AD-only, and AD+HIRT). The mice in the HIRT group performed vertical ladder climbing for four weeks.RESULTS: After four weeks of HIRT, histopathological examination revealed reduced epidermis/dermis and dermal infiltration of inflammatory cells in the mice ear tissue. Additionally, HIRT suppressed serum immunoglobulin (Ig) levels and mRNA expression of pathogenic cytokines in the ear tissue; further, it reduced the size and weight of the draining lymph node (dLN) and non-dLN (ndLN), and the pathogenic cytokine-related mRNA expression of CD4+T cells from dLNs and ndLNs. We thus observed a negative correlation between HIRT and AD symptoms in mice.CONCLUSIONS:The results show that HIRT exerts positive effects in patients with AD.

Intensity of resistance training via self-reported history is critical in properly characterizing musculoskeletal health

BackgroundIntensity of resistance training history might be omitted or poorly ascertained in prescreening or data questionnaires involving musculoskeletal health. Failure to identify history of high-versus low-intensity training may overlook higher effect sizes with higher intensities and therefore diminish the precision of statistical analysis with resistance training as a covariate and bias the confirmation of baseline homogeneity for experimental group designation. The purpose was to determine the degree to which a single question assessing participant history of resistance training intensity predicted differences in musculoskeletal health.MethodsIn the first research aim, participants were separated into groups with a history (RT) and no history (NRT) of resistance training. The second research aim evaluated the history of resistance training intensity on muscular strength, lean mass, and bone mineral density (BMD), RT participants were reassigned into a low- (LIRT) or high-intensity resistance training group (HIRT). 83 males and 87 females (19.3 ± 0.6 yrs., 171.1 ± 9.9 cm, 67.1 ± 10.5 kg, 22.9 ± 2.8 BMI, 26.2 ± 7.2% body fat) completed handgrip dynamometry (HG) and dual-energy x-ray absorptiometry scans (DXA) for BMD and bone mineral-free lean mass (BFLM).ResultsA 3-group method (NRT, LIRT, HIRT) reduced type-I error compared with the 2-group method (NRT, RT) in characterizing the likely effects of one’s history of resistance training. For the second aim, HIRT had significantly (p < 0.05) greater HG strength (76.2 ± 2.2 kg) and arm BFLM (6.10 ± 0.16 kg) than NRT (67.5 ± 1.3 kg; 4.96 ± 0.09 kg) and LIRT (69.7 ± 2.0 kg; 5.42 ± 0.14 kg) while also showing significantly lower muscle quality (HG/BFLM) than NRT (13.9 ± 0.2 vs. 12.9 ± 0.3). HIRT had greater BMD at all sites compared to NRT (whole body = 1.068 ± 0.008 vs. 1.120 ± 0.014; AP spine = 1.013 ± 0.011 vs. 1.059 ± 0.019; lateral spine = 0.785 ± 0.009 vs. 0.846 ± 0.016; femoral neck = 0.915 ± 0.013 vs. 0.970 ± 0.022; total hip = 1.016 ± 0.012 vs. 1.068 ± 0.021 g/cm2) while LIRT revealed no significant skeletal differences to NRT.ConclusionsRetrospective identification of high-intensity history of resistance training appears critical in characterizing musculoskeletal health and can be ascertained easily in as little as a single, standalone question. Both retrospective-questionnaire style investigations and pre-screening for potential participation in prospective research studies should include participant history of resistance training intensity.

&lt;p&gt;The Favorable Effects of a High-Intensity Resistance Training on Sarcopenia in Older Community-Dwelling Men with Osteosarcopenia: The Randomized Controlled FrOST Study&lt;/p&gt;

PurposeSarcopenia, the loss of muscle mass combined with the loss of muscle function, has become a public health issue. There is an urgent need for interventions. The study aimed to determine the effect of high-intensity resistance training (HI-RT), a time- and cost-efficient training modality, on sarcopenia in osteosarcopenic (OS) older men.MethodsForty-three community-dwelling men aged ≥72 years from Northern Bavaria, Germany, with OS were randomly assigned to either an active HI-RT group (HI-RT) or an inactive control group (CG). Both received dietary protein (up to 1.5 g/kg/day in HI-RT and 1.2 g/kg/day in CG) and Vitamin-D (up to 800 IE/d) supplements. The HI-RT was applied as a consistently supervised single-set training on resistance exercise machines using intensifying strategies, with two training sessions/week, structured into three phases (ranging from 8 to 12 weeks) totaling 28 weeks. The primary study endpoint was the Sarcopenia Z-score; secondary endpoints were changes in the underlying physiological parameters, skeletal muscle mass index (SMI), handgrip-strength and gait velocity.ResultsThe results show a significant effect of the exercise intervention on the sarcopenia Z-score in the HI-RT (p<0.001) and a significant worsening of it in the CG (p=0.012) in the intention-to-treat analysis, as well as a significant intergroup change (p<0.001). Analysis upon the underlying parameters showed a significant increase of skeletal muscle mass index (SMI) in the HI-RT group (p<0.001) and a significant intergroup difference of SMI (p<0.001) and handgrip strength (p<0.001). There were no adverse effects related to dietary supplementation or training.ConclusionThe results clearly confirm the favorable effects of HI-RT on sarcopenia. We conclude that HI-RT is a feasible, highly efficient and safe training modality for combating sarcopenia, also in the elderly.

The Effect of Ankle TheraBand Training on Dynamic Balance Index Among Elite Male Basketball Players

Objectives: The purpose of this study is to determine the effect of ankle TheraBand resistance training on dynamic balance index among elite male basketball players. Methods: This was a randomized trial performed on 24 male professional basketball players without lower extremity injury. The participants were selected using purposeful sampling and were randomly assigned into 3 groups of 8, including: (1) high-intensity resistance training using TheraBand (80% - 95% 1RM), (N = 8); (2) moderate-intensity resistance training using TheraBand (65% - 80% 1RM), (N = 8); and (3) control group with regular basketball training (N = 8). The groups were trained in three sessions for 8 weeks. Trial and error table for TheraBand resistance from American Physical Therapy Organization (APTA) 2012 was used to measure maximum 1RM in each participant. In addition, the dynamic balance index in the APSI (anterior - posterior stability index), MLSI (medial-lateral stability index) and OSI (overall stability index) were measured using Biodex stability system. Covariance analysis was used to analyze the data (P < 0.05). Results: Results showed that the high-intensity resistance training and moderate-intensity resistance training significantly improved dynamic stability index in the anterior - posterior axis, medial - lateral axis and overall axis (P = 0.0001). No significant changes were observed in the anterior - posterior and medial - lateral axes after a detraining period (4 weeks), “durability rate”. However, the overall axis values of the dynamic balance index in the moderate intensity training group indicated a higher durability rate than the high intensity resistance training group after detraining (P = 0.02). Conclusions: It can be concluded that the high and moderate intensity resistance training improved dynamic balance index, and even moderate intensity resistance training was effective after a period of detraining, so it can be recommended for basketball players.

Low-Intensity Exercise with Blood Flow Restriction Increases Muscle Strength without Altering hsCRP and Fibrinogen Levels in Healthy Subjects.

Strengthening exercise combined with blood flow restriction potentially increases muscle strength. This type of exercise does not require heavy weight liftings and is a feasible method to be performed by persons suffering illnesses. However, strengthening exercise may induce inflammatory responses due to muscle and vascular endothelial damage. This study aimed to investigate alterations of high-sensitivity C-reactive protein (hsCRP) and fibrinogen levels in healthy subjects after five weeks of low intensity resistance training (LIRT) with blood flow restriction (BFR) on increasing strength in comparison with high intensity resistance training (HIRT) and LIRT alone, and to evaluate aspects related to the relative safety of LIRT + BFR. Eighteen healthy subjects were randomized into 3 groups. The HIRT group: 70% of One-Repetition Maximum (1-RM); LIRT + BFR group: 30% of 1-RM with BFR (a modified 13-cm wide cuff was used); LIRT group: 30% of 1-RM. The peak torque of isokinetic contraction of the left elbow flexor in each subject was measured before and after 5 weeks of resistance exercises to determine any increases in the left biceps brachii muscle strength. Blood markers of homeostasis (fibrinogen) and inflammation (hsCRP) were also measured before and after five weeks of training. Significant increases of strength were demonstrated between the five weeks of resistance exercises in the HIRT group (P = 0.003) and the LIRT + BFR group (P = 0.001). Peak torque of isokinetic contraction of the left flexor elbow joint at 60° per second angular velocity showed that the LIRT + BFR group produced the greatest peak torque increase than the HIRT group. There were no significant changes in the hsCRP levels in all the groups (P > 0.05) after five weeks of intervention. No significant differences of fibrinogen levels were found in the HIRT group (P = 0.500) and the LIRT + BFR group (P = 0.405), but significant decreases were found in the fibrinogen levels in the LIRT group (P = 0.017). The LIRT + BFR increases in the muscle strength were as significant as in HIRT without altering the fibrinogen and hsCRP levels in the healthy subjects. In this study, LIRT + BFR showed increase muscle strength without any vascular problems.

WALKING WITH BLOOD FLOW RESTRICTION IMPROVES THE DYNAMIC STRENGTH OF WOMEN WITH OSTEOPOROSIS

ABSTRACT Introduction: Improving strength levels is important to women with osteoporosis. Resistance and aerobic exercise are effective means of reaching this goal; however, the use of low-load exercises with blood flow restriction is an alternative to traditional methods of exercise to achieve the same strength gains in this population. Objective: To analyze the chronic effects of aerobic and resistance training combined with blood flow restriction on the maximal dynamic strength (MDS) of women with osteoporosis. Methods: Twenty women (61.40±4.63 years of age, 61.82±12.54 kg, 1.51±0.05 m, 27.16±5.55 kg/m²) were randomly assigned to four groups: 1 - high-intensity resistance training (HI); 2 - low-intensity resistance training with blood flow restriction (LI-BFR); 3 - aerobic training with blood flow restriction (ABFR); and 4 - control group (CG). Unilateral knee extension MDS was assessed using the one-repetition maximum (1RM) strength test before and after the 6th and 12th weeks of intervention. The data were analyzed using repeated measures analysis of variance (ANOVA) with a Bonferroni post-hoc test performed using SPSS (version 21.0), considering a significance level of P&lt;0.05 for all tests. Results: Baseline comparisons showed that HI and CG had lower strength levels than LI-BFR and ABFR groups (P&lt;0.05). The ABFR group exhibited a significant increase in MDS between the 1st and the 6th week (9%, P=0.001) and between the 1st and the 12th week (21.6%, P=0.008). The LI-BFR group exhibited increased MDS between the 1st and the 6th week (10.1%, P=0.001), between the 1st and the 12th week (24.2%, P=0.003) and between the 6th and 12th week (12.8%, P=0.030). The HI group exhibited a significant difference between the 1st and the 6th week (38.7%, P&lt;0.001), between the 1st and the 12th week (62%, P&lt;0.001) and between the 6th and 12th weeks (17.4%, P=0.020), whereas the CG had no significant differences between the timepoints (P&gt;0.05). Conclusions: ABFR and LI-BFR effectively increased the MDS of women with osteoporosis.

Comparisons between Low-Intensity Resistance Training with Moderate Blood Flow Restriction and High-Intensity Resistance Training on Quadriceps Muscle Strength and Mass

Objective: Elderly and rehabilitating populations who are unable to exercise under high loads are likely to experience muscle atrophy. Low intensity blood flow restriction training (LI-BFRT) can promote increases muscle mass comparable to conventional high-intensity resistance training (HI). However, strength discrepancies have been reported between LI-BFRT and HI programs. Therefore, the purpose of this study is to examine whether similar muscle strength and power improvements are found in both 1RM and non-specific strength tests between LI-BFRT and HI groups. Methods: Six male subjects (x̅ age 20.8 years ± 1.6) free of any musculoskeletal disorders with no anaerobic resistance training in the 6 weeks prior to testing participated in 4 week strength exercise program. Pre- and post- force and power tests were assessed using a 1RM test and a triaxial accelerometer (Myotest® SA) to measure power and velocity during a squat jump (SJ) and countermovement jump (CMJ). Subjects were randomly assigned one of two groups: LI-BFRT (40% 1RM at 40% arterial occlusion for 3 sets of 15 reps) or HI (80% 1RM for 3 sets of 8 reps). Both groups completed leg extensions twice a week for 4 weeks on a leg-extension machine. Results: Significant increase in LI-BFRT for SJ power x̄= 42.2 W/ kg ± 3.6, SJ Power x̄= 45.7 W/kg ± 3.3; p=0.037, CMJ Velocity x̄= 245 cm/s ± 1.4, CMJ Velocity x̄= 269 cm/s ± 2.1; p=0.014 and 1RM x̄= 112.5kg ± 18.4, 1RM x̄ =138.8kg ± 20.4; p=0.006.) was observed. No significant change was observed in the HI group. Conclusion: The LI-BFRT subjects power output increased over the 4-week program. Improvements may be attributed to the neuromuscular adaptation that occurred through intervention. This pilot study suggests that BFRT could promote or increases muscle power comparable to results observed after conventional highintensity(HI) resistance training, when measured via non-specific muscular strength tests.

Low-level laser therapy associated with high intensity resistance training on cardiac autonomic control of heart rate and skeletal muscle remodeling in wistar rats.

Phototherapy plus dynamic exercise can enhance physical performance and improve health. The aim of our study was to evaluate the effect of low-level laser therapy (LLLT) associated with high intensity resistance training (HIT) on cardiac autonomic and muscle metabolic responses in rats. Forty Wistar rats were randomized into 4 groups: sedentary control (CG), HIT, LLLT and HIT + LLLT. HIT was performed 3 times/week for 8 weeks with loads attached to the tail of the animal. The load was gradually increased by 10% of body mass until reaching a maximal overload. For LLLT, irradiation parameters applied to the tibialis anterior (TA) muscle were as follows: infrared laser (780 nm), power of 15 mW for 10 seconds, leading to an irradiance of 37.5 mW/cm(2), energy of 0.15 J per point and fluency of 3.8 J/cm(2). Blood lactate (BL), matrix metalloproteinase gelatinase A (MMP(-2)) gene expression and heart rate variability (HRV) indices were performed. BL significantly increased after 8-weeks for HIT, LLLT and HIT + LLLT groups. However, peak lactate when normalized by maximal load was significantly reduced for both HIT and HIT + LLLT groups (P<0.05). MMP-2 in the active form was significantly increased after HIT, LLLT and HIT + LLLT compared tom the CG (P<0.05). There was a significant reduction in low frequency [LF (ms(2))] and increase in high frequency [HF (un)] and HF (ms(2))] for the HIT, LLLT and HIT + LLLT groups compared with the CG (P < 0.05). However, the LF/HF ratio was further reduced in the LLLT and HIT + LLLT groups compared to the CG and HIT group (P < 0.05). These results provide evidence for the positive benefits of LLLT and HIT with respect to enhanced muscle metabolic and cardiac autonomic function in Wistar rats.

Inflammation marker, damage marker and anabolic hormone responses to resistance training with vascular restriction in older males

The goal of this study was to examine anabolic hormone, muscle damage marker and inflammation marker responses to two types of resistance training protocols in older men. Thirty-six healthy older males (mean age = 56.6 ± 0.6 years) completed 6 weeks of high-intensity resistance training (HI-RT), low-intensity resistance training with vascular restriction (LI-BFR) or no exercise control group (CON) three times per week. Three upper body exercises were performed by both exercise groups at the same intensity (at 80% 1-RM), but lower body exercises were performed by the HI-RT group at 80% 1-RM and by the LI-BFR group at 20% 1-RM with vascular restriction. Resting serum creatine kinase (CK), interleukin 6 (IL-6), insulin-like growth factor-I (IGF-I), IGF binding protein 3 (IGFBP-3) and testosterone (T) were measured before and after training. No significant group differences in resting CK, IL-6, IGF-I, IGFBP-3 and T were detected following training (P>0.05). In addition, there were no significant changes in muscle cross-sectional area (CSA), but a trend for significant decreases in the percent changes in thigh subcutaneous fat (P = 0.051). Although training-induced anabolic hormone response did not reach statistical significance, our findings on CK and IL-6 indicated that the LI-BFR training protocol was safe and well tolerated for older men to perform to improve muscular strength.

Effects of high-intensity and blood flow-restricted low-intensity resistance training on carotid arterial compliance: role of blood pressure during training sessions

We examined the effects of high-intensity resistance training (HIT) and low-intensity blood flow-restricted (LI-BFR) resistance training on carotid arterial compliance. Nineteen young men were randomly divided into HIT (n = 9) or LI-BFR (n = 10) groups. The HIT and LI-BFR groups performed 75 and 30 %, respectively, of one-repetition maximum (1-RM) bench press exercise, 3 days per week for 6 weeks. During the training sessions, the LI-BFR group wore elastic cuffs around the most proximal region of both arms. Muscle cross-sectional area (CSA), 1-RM strength, and carotid arterial compliance were measured before and 3 days after the final training session. Acute changes in systolic arterial pressure (SAP), plasma endothelin-1 (ET-1), nitrite/nitrate (NOx), and noradrenalin concentrations were also measured during and after a bout of training session. The training led to significant increases (P < 0.01) in bench press 1-RM and arm and chest muscle CSA in the two training groups. Carotid arterial compliance decreased significantly (P < 0.05) in the HIT group, but not in the LI-BFR group. There was a significant correlation (r = -0.533, P < 0.05) between the change in carotid arterial compliance and the acute change in SAP during training sessions; however, ET-1 and NOx did not correlate with carotid arterial compliance. Our results suggest that muscle CSA and strength increased following 6 weeks of both HIT and LI-BFR training. However, carotid arterial compliance decreased in only the HIT group, and the changes were correlated with SAP elevations during exercise sessions.

Metabolic and Cardiac Autonomic Effects of High-Intensity Resistance Training Protocol in Wistar Rats

The aim of this study was to assess the effects of metabolic and autonomic nervous control on high-intensity resistance training (HRT) as determined by pancreatic glucose sensitivity (GS), insulin sensitivity (IS), blood lactate ([La]), and heart rate variability (HRV) in rats. Thirty male, albino Wistar rats (292 ± 20 g) were divided into 3 groups: sedentary control (SC), low-resistance training (LRT), and HRT. The animals in the HRT group were submitted to a high-resistance protocol with a progressively increasing load relative to body weight until exhaustion, whereas the LRT group performed the same exercise regimen with no load progression. The program was conducted 3 times per week for 8 weeks. The [La], parameters related to the functionality of pancreatic tissue, and HRV were measured. There was a significant increase in peak [La] only in the HRT group, but there was a reduction in [La] when corrected to the maximal load in both trained groups (LRT and HRT, p < 0.05). Both trained groups exhibited an increase in IS; however, compared with SC and LRT, HRT demonstrated a significantly higher GS posttraining (p < 0.05). With respect to HRV, the low-frequency (LF) band, in milliseconds squared, reduced in both trained groups, but the high-frequency band, in milliseconds squared and nu, increased, and the LF in nu, decreased only in the HRT group (p < 0.05). The HRT protocol produced significant and beneficial metabolic and cardiac autonomic adaptations. These results provide evidence for the positive benefits of HRT in counteracting metabolic and cardiovascular dysfunction.

Is There a Relationship Between Limb and Trunk Muscle Hypertrophy After High-Intensity and Low-Intensity-BFR Training

It has been reported that high-intensity resistance training or low-intensity resistance training combined with blood flow restriction (BFR) results in significant increases in limb muscle size and improved muscle function. However, it is unknown whether there is a significant correlation between limb and trunk muscle hypertrophy following the two types of resistance training programs. PURPOSE: To investigate the relationship between training-induced limb and trunk muscle hypertrophy in the high-intensity resistance training and low-intensity BFR training groups. METHODS: Twenty untrained young men (24.4±2.4 years; BMI = 21.5±2.4 kg/m2) were divided into two training groups: high-intensity resistance training group (HIT, 75% of one repetition maximum [1RM] and total 30 reps [10 reps × 3 sets], n=10) or low-intensity BFR resistance training group (LI-BFR, 30% of 1RM and total 75 reps [30, 15, 15, 15 reps], n=10). Both training groups performed free weight bench press training, 3 days/week for 6 weeks. During LI-BFR exercise sessions, subjects wore pressure cuffs (3-cm width) on both arms that were inflated to 100-160 mmHg. MRI-measured triceps brachii (TB) and pectoralis major (PM) muscle cross-sectional areas (CSA) and maximal dynamic (1RM) bench press strength were measured before and 3 days after the final training session. RESULTS: Total training volumes (lifting weight x repetition) for all of the sessions were similar between HIT [19063 (SD 3398) kg] and LI-BFR [19994 (SD 3546) kg] groups. The training led to an increase in 1RM bench press strength in both groups. TB and PM muscle CSA increased 8.8% and 15.8% (P <.01), respectively, in the HIT group and 4.9% (P <.05) and 8.3% (P <.01), respectively, in the LI-BFR group. The relative increase in PM muscle CSA was greater (P <.05) than that of TB muscle CSA in the HIT group, but not in the LI-BFR group. There was significant correlation (r = 0.70, P <.05) between increases in PM and TB muscle CSA in the HIT group. However, a significant correlation was not found in the LI-BFR group (r = 0.54, P = 0.11). CONCLUSIONS: Our results suggest that limb and trunk muscle hypertrophy occurs simultaneously during HIT training but not during low-intensity BFR training, possibly due to individual differences in muscle activation of the arm and chest muscles during the training sessions.