Low-intensity Resistance Exercise Research Articles

Low-Intensity Resistance Training and Compression Garment in the Management of Breast Cancer-Related Lymphedema: Single-Blinded Randomized Controlled Trial.

There is limited evidence regarding the combined effect of exercise and compression garment on breast cancer-related lymphedema (BCRL). Therefore, we investigate the effect of low-intensity resistance training alone or in combination with a compression garment on lymphedema volume, self-reported lymphedema symptoms, and shoulder mobility and function. A total of 60 women with unilateral BCRL were randomly assigned to low-intensity resistance exercises (Rex group, n = 30) or exercises and compression garment (Rex-Com-group, n = 30). Both groups take part in exercises program consisted of 10-12 repetitions at 50 to 60% of one repetition maximum (IRM), three times weekly, for 8weeks. The primary outcome was lymphedema volume determined by percentage reduction of excess limb volume (ELV). Secondary outcomes were lymphedema symptoms (pain, heaviness, and tightness) and shoulder mobility and function using the disabilities of the arm, shoulder, and hand (DASH) questionnaire. All measurements were standardized and performed before (week 0, W0), after the intervention (week 8, W8), and at follow-up (week 12, W12). A significant reduction in percentage of ELV (p < 0.01), pain severity (p < 0.05), a sensation of heaviness (p < 0.05) and tightness (p < 0.001), and improvement in shoulder range of motion (p < 0.05) and function on DASH scores (p < 0.05) were observed at W8 and W12 in both groups. However, no between-group differences were observed over time. These findings suggest that low-intensity resistance training, irrespective of garment use, can effectively reduce limb volume and lymphedema symptoms, and increase shoulder mobility and function.

B.F.R. For Proximal Benefit: Blood Flow Restriction Therapy For The Shoulder?

Blood flow restriction (BFR) therapy has been observed to improve post-operative recovery in the limbs when combined with low intensity resistance exercise (LIX). Little data exists regarding use of BFR for proximal benefit of the upper limbs (shoulders). PURPOSE: (1) Determine if rotator cuff (RC) exercises combined with BFR (BFR-Rx) promote greater increases in strength, muscular endurance, and lean mass compared to exercise alone (NoBFR-Rx); (2) Determine if BFR applied to the arm during acute LIX increases activation of RC muscles. METHODS: Eighteen healthy adults (♂11, 32±5yr, 92.3±15.2kg | ♀7, 34±7yr, 81.9±6.3kg) were recruited and randomized into 2 groups (BFR-Rx, NoBFR-Rx). Each performed 8wks of LIX (2/wk) using 4 RC exercises: cable external rotation (ER), cable internal rotation (IR), dumbbell scaption, and side-lying dumbbell ER; 20%1RM; 1set/30reps followed by 3sets/15reps (30s rest between sets, 2min rest between exercises, ^1lb resistance each week all repetitions achieved). For the BFR-Rx group, BFR was applied to using an tourniquet system (Delfi®) that maintained 50% limb occlusion pressure during each exercise with pressure released between exercises. A group x time ANCOVA (co-varied on baseline) followed by a tukey’s post hoc test was used to detect absolute & relative changes in strength (pre/post training), lean mass (pre/post training; DEXA, GE®), and achieved weekly exercise volume (sets x reps x resistance). A two-tailed paired samples t-test was used to detect differences in RC muscle activation (EMG, Delsys®) recorded during acute ER and IR fatigue tests in all subjects. Type I error was set at α=0.05. CONCLUSIONS: Combined BFR-Rx using RC exercises may yield greater increases in shoulder/arm lean mass, strength, and muscular endurance compared to exercise alone. These findings may be partially due to a greater activation of shoulder musculature while using BFR. Data collection is ongoing and will be completed prior to conference.

The Effects of Low Intensity Resistance Exercise Training on Cardiac Autonomic Function in Obese Postmenopausal Women

Menopause and obesity are associated with a deterioration of cardiac autonomic dysfunction (CAF) and are independent risk factors for cardiovascular disease (CVD). Heart rate variability (HRV) is a non-invasive tool for the evaluation of CAF. HRV is adversely influenced by menopause and obesity in women. Resistance exercise has emerged as an important strategy for the prevention and treatment of CVD. Low intensity resistance exercise training (LIRET) appears to be a useful modality for promoting improvements in muscular mass and strength, while being relatively safe for populations with increased cardiovascular risk. However, the possibility of improving CAF in obese postmenopausal women is currently unknown. PURPOSE: The purpose of this study was to examine the effects of LIRET on HRV and strength in obese postmenopausal women. METHODS: Twenty obese postmenopausal women [age (54 ± 1 years) and body mass index (34.4 ± 0.8 kg/m2)] were randomized to either (n= 10) or no-exercise control group (n= 10) for 12 weeks. LIRET consisted on 4 different exercises for the leg musculature per session 3 x week. Participants performed 2-3 sets involving 18-22 repetitions for each exercise per session. Total power (TP), low-frequency power (LF), high-frequency power (HF) (vagal tone), the LF to HF ratio (LF/HF) (sympathovagal balance), heart rate (HR) and leg strength were measured before and after 12 weeks. LF and HF were normalized to TP resulting in nLF (sympathetic activity) and nHF. Logarithmic transformation (Ln) was performed to normalize the HRV variables in absolute units. RESULTS: There were significant group-by-time interactions (P < 0.05) for nLF, nHF, LnLF/LnHF, and (P<0.01) for leg strength. There were significant decreases (P<0.01) in nLF (-6 ± 1%) and LnLF/LnHF (-0.7± 0.1) as well as significant increases (P < 0.01) in nHF (5 ± 1%) and leg strength (27 ± 2 kg) following LIRET compared with no changes after control. No significant changes were observed in LnTP or HR after 8 weeks for both groups. CONCLUSIONS: Our findings indicate that LIRET improves CAF by improving sympathovagal balance in obese postmenopausal women.

The Effects of High-Versus Low-Intensity Resistance Exercise on Acute Hyperglycemia in Young Healthy Males

The Effects of High-Versus Low-Intensity Resistance Exercise on Acute Hyperglycemia in Young Healthy Males

Comparison of Acute Hormonal Responses to High and Low-Intensity Resistance Exercise with Blood Flow Restriction in Young Wrestlers

Background: The traditional resistance training is the most effective way known to increase muscle mass. However, high-intensity resistance training may be difficult for some individuals and specific groups. In addition, most people are not encouraged to engage in high-intensity resistance training. Therefore, an alternative intervention is needed to solve this problem. Objectives: The aim of this study was to compare the acute hormonal responses to high and low-intensity resistance exercise with blood flow restriction in young wrestlers. Methods: Thirty young wrestlers (age: 16.51 ± 2.1 years, weight: 53.23 ± 7.13 kg, height: 165.14 ± 8.42 cm, body mass index (BMI): 18.64 ± 1.35 kg/m2) participated in a quasi-experimental research. The subjects were randomly divided into three groups of resistance training: Low-intensity (LI), high-intensity (HI), and low-intensity with blood flow restriction (LI-BFR). The training protocol included three exercises: Leg extension, arm curl, and bench press. Blood samples were collected before and 30 minutes after the training sessions. Results: The results showed that the creatine kinase level in the HI group, as well as the cortisol level in the HI and LI-BFR groups, increased significantly after resistance training (P 0.05). Conclusions: Based on the results of the present study, it can be concluded that blood flow restriction training with the same anabolic effects, lower muscle damage index, less fatigue, and lower intensity is a better choice for training compared to high-intensity resistance training.

A Review of Beneficial Low-Intensity Exercises in Diabetic Peripheral Neuropathy Patients.

The American Diabetic Association standards of medical care for diabetic patients recommends moderate intensity exercise to help manage diabetes; however, this recommendation may be unmanageable for patients who have become inactive or unable to reach this intensity. The purpose of this review is to determine if low-intensity exercises demonstrate improvement in diabetic peripheral neuropathy symptoms in order to utilize these exercises as a starting point for inactive patients. Studies in low-intensity exercises from 2013 to May 2018 were systematically searched in PubMed, SCOPUS, and Cochrane Library databases. The studies in this research have shown that low-intensity resistance exercises have promising outcomes such as improvements in pain interference with daily activities, pain thresholds, and reductions in neuropathy symptoms. Low-intensity aerobic therapy adds to the quality of life of the patient, and increases in strength of the lower limbs show an improvement in foot sensation and a reduction in pain and tingling symptoms.

일회성 전신 저항성 운동의 강도 및 운동량에 따른 동맥경직도의 변화

The purpose of this study was to compare the acute effects of intensity and volume of whole body resistance exercise on arterial stiffness in healthy adults. Twenty healthy adults randomly performed an acute bout of high intensity and volume resistance exercise (1RM 80%, HIV group) and low intensity and volume resistance exercise (1RM 50%, LIV group). Exercise program consisted of upper body (lat-pull down, bench press, triceps push-down, dumbbell curl) and low body program (leg extension, leg flexion, leg press, squat). Heart rate (HR), brachial and ankle blood pressure (BP), pulse pressure (PP), mean arterial pressure (MAP), brachial-ankle pulse wave velocity (baPWV), ankle brachial index (ABI), as indices of cardiovascular and arterial stiffness were measured for analysis. All variables were measured at pre-exercise, 0, 15 and 30 minutes after each exercise. The collected data were analyzed by two-way repeated ANOVA using a SPSS program. HIV group significantly decreased baPWV (p.05, p.05) at 0 and 15 minutes post exercise, but there were no significant changes to LIV group. HIV group significantly decreased ABI (p.05) at 0 and 15minutes post exercise and LIV group significantly decreased ABI (p.05) immediately post exercise. These findings suggest that high intensity and volume resistance exercise has been shown to reduce blood pressure and arterial stiffness but not low intensity and volume resistance exercise.

Lower occlusion pressure during resistance exercise with blood-flow restriction promotes lower pain and perception of exercise compared to higher occlusion pressure when the total training volume is equalized.

Low-intensity resistance exercise with blood-flow restriction (BFR) promotes similar adaptations to high-intensity resistance exercise (HI-RE). Interestingly, BFR has been demonstrated to be effective for a wide range of occlusion pressures. However, the occlusion pressure magnitude may alter the psychophysiological stress related to BFR as measured by rating of perceived exertion scale (RPE) and rating of pain. We aimed to compare the RPE and pain levels across different magnitudes of occlusion pressures, promoting new knowledge regarding occlusion pressure on stress related to BFR. All BFR protocols ranging between 40% and 80% of total arterial occlusion (BFR40, BFR50, BFR60, BFR70, and BFR80) were compared to HI-RE in 12 participants using a randomized and crossover design 72h apart. BFR protocols and HI-RE were performed with 30% and 80% of one-repetition maximum (1RM) test value, respectively. RPE and pain levels were measured before exercise and immediately after each set. BFR protocols (i.e.,BFR40 and BFR50) presented overall lower RPE response compared to higher-pressure BFR (i.e.,BFR70 and BFR80) and HI-RE conditions. For pain levels, low-pressure BFRs (i.e.,BFR40 and BFR50), and HI-RE showed lower values than high-pressure BFR protocols (i.e.,BFR60, BFR70, and BFR80). In conclusion, low-pressure BFR protocols promote lower RPE and pain compared to high-pressure BFR protocols (between 60% and 80% of occlusion pressure), when total training volume (TTV) is equalized. In addition, HI-RE promotes similar levels of pain, but higher RPE than low-pressure BFR, probably due to the higher TTV.

Low- and high-intensity one-week occlusion training improves muscle oxygen consumption and reduces muscle fatigue.

Low-intensity resistance exercises with blood flow restriction have been shown is effective to increase muscular strength and hypertrophy. However, the effects of combined training: one-week occlusion training with various exercise intensities by using less occlusion pressure on muscle strength improvement, fatigability and their work capacity are not clear. Participants (N.=24) were middle-distance runners with 4-6 years of training experience. A control group without blood flow restriction (N.=12, age 23±1 years) and an experimental group with blood flow restriction (N.=12, age 22±1 years). In this study, the calf muscles were impacted by the training with occlusion 120 mmHg. We used intensive one-week daily training, whereby exercise intensity was gradually increased daily from 20% to 80% of maximal voluntary contraction (MVC) and then decreased to 60% by the end of the week. MVC of foot flexion muscles after the one-week occlusion training in the experimental group and control group increased (P<0.05) by 5.6±1.3% and 5.3±1.2%, respectively. Meanwhile in experimental group work capacity improved only 2.4±3.5% (P>0.05) and in control group it significantly decreased 11.8±2.5% (P<0.05). StO2 decreased during exercise test from the baseline 100% to 45.2±4.3% before occlusion training and to 34.6±6.2% after the week of occlusion training (P<0.05). Intensive one-week training with occlusion with varying intensity improves resistance to fatigue and recovery after training. This kind of training improves oxygen consumption while exercising.

Resistance exercise-induced muscle fatigue is not accompanied by increased phosphorylation of ryanodine receptor 1 at serine 2843.

Skeletal muscle fatigue has been shown to be associated with hyperphosphorylation of the ryanodine receptor 1 at serine 2843 (pRyR1Ser2843), due to chronic overloading exercise. We investigated whether pRyR1Ser2843, is a mechanism relevant for muscle fatigue also under acute, in contrast to chronic, muscle loading. 24 male subjects (age: 24,8±3,8; height: 182,8±7,2 cm; weight: 82,5±9,9 kg) were evenly (n = 6) assigned to the following four different resistance exercise (RE) groups: hypertrophy- (HYP), strength endurance- (SE), maximum power- (MAX) at the subjects’ 10, 25 and 3 repetition maximum, respectively, and low intensity (LI) RE with 70% of the 10 repetition maximum. Each group completed three different RE volumes (1 set, 5, and 10 sets). Muscle biopsies from the vastus lateralis were taken before and after exercise, analyzed for pRyR1Ser2843 and examined for association with RE-induced muscle fatigue which was determined as reduction in maximum isometric force (isoFmax) in the quadriceps femoris muscle also before and after exercise.The degree of RE-induced muscle fatigue was specific in terms of set volume as well as of RE mode. isoFmax was not reduced in any group after one set of RE. Five sets led to a significant reduction of isoFmax in HYP and SE but not in LI and MAX (p<0,05). Ten sets of RE, as compared to five sets, exclusively induced further muscle fatigue in LI. In terms of RE mode differences, isoFmax reduction was generally higher in HYP and SE than in MAX and Li after five and ten sets of RE (p<0,05). However, pRyR1Ser2843 did not show any significant regulation, regardless of exercise condition. We conclude that despite its relevance in reducing muscle contractility in chronic overloading, pRyR1Ser2843 does not reflect the degree of muscle fatigue exerted by acute hypertrophy-, strength endurance-, maximum power and low intensity-oriented exercise.

Blood Flow Restriction Therapy for Stimulating Skeletal Muscle Growth: Practical Considerations for Maximizing Recovery in Clinical Rehabilitation Settings

Inactivity following injury and surgery due to pain, instability, or immobilization results in loss of muscle mass and function. As a result, both risk of reinjury and overall recovery time are a prime concern for clinicians and therapists trying to minimize these deleterious effects. While resistance exercise has been demonstrated to be highly effective in combating loss of muscle mass and function, it is often not advised for postoperative or injured patients because of elevated risk of injury or exacerbating existing injury sites. Low-intensity resistance exercise (&lt;30% 1 repetition-maximum) performed with mild to moderate blood flow restriction (BFR) has been observed to elicit beneficial anabolic and functional responses in skeletal muscle that are governed by mechanisms that regulate muscle protein metabolism and myogenesis similar to the responses following high-intensity resistance exercise. On the basis of these findings, practical applications of BFR in clinical and sport settings have been developed to mitigate skeletal muscle loss following injury and accelerate rehabilitation. However, many aspects of the physiological effects of BFR therapy in rehabilitation settings remain unclear. This review provides current information regarding skeletal muscle responses to BFR with a focus on skeletal muscle protein metabolism, anabolic signaling, applied outcomes, and applications in the clinical setting.

저강도 유산소운동과 저항운동의 빈도에 따른 근감소증 비만 여성노인의 염증인자에 대한 변화

저강도 유산소운동과 저항운동의 빈도에 따른 근감소증 비만 여성노인의 염증인자에 대한 변화

Acute Cardiovascular Responses To Resistance Training With And Without Blood Flow Restriction

Recently, it has been suggested that resistance exercise (RE) can be applied for cardiovascular function, maintenance and/or for rehabilitation purposes. PURPOSE: To compare the acute effects of high intensity RE (HI), low intensity RE (LI) and low intensity RE with blood flow restriction (LI-BFR) on heart rate (HR) and blood pressure (BP) in healthy subjects. METHODS: 52 subjects ((27.3±7 years; BMI: 27.3±3.1) were assigned into three groups: High intensity (HI, 75%-1RM; n=15); low intensity (LI, 30%- 1RM; n=13); and low intensity with blood flow restriction training (LI-BFR, 30%-1RM and 30% of total vascular restriction; n=24). All participants performed 4 sets of plantar flexion in the leg press machine with 1 set of 30 repetitions following 3 sets of 15 (for LI and LI-BFR group) or 10 repetitions (HI group). Blood flow restriction was achieved using a cuff positioned on the dominant calf. The cuff was inflated at 30% of total vascular restriction of each individual (mean: 47.6 ± 19.8 mmHg). Cardiovascular variables were obtained during and after the session. RESULTS: Results indicated that HR increased significantly during the 4 exercise set for all groups (p <0.05), although the highest increases were found during the last set for the HI group (pre: 70.0±10.0 bpm; post: 81.6±11.7 bpm; p<0.001) and during the first set for the LI-BFR group (pre: 66.1±12.9 bpm; post: 73.7±15.1bpm; p<0.001). There were no significant differences in BP for any group. However, significant intergroup differences were observed in systolic BP during the first set for HI and LI-BFR groups when compared to LI group (p=0.03). HI and LI-BFR promoted significant systolic BP reductions (p<0.001) 30min post-exercise (pre: 126.1±11.7 mmHg; post: 112.3±14.0 mmHg), 45min post-exercise (pre: 126.1±11.7 mmHg; post: 113.1±10.2 mmHg) and for HI group post-15min (pre: 123.6±15.7 mmHg; post: 115.0±15.9 mmHg), post-45min (pre: 123.6±15.7 mmHg; post: 114.4±16.7 mmHg) and post-60min (pre: 123.6±15.7 mmHg; post: 113.3±14.7 mmHg). There were no significant changes (p>0.05) for diastolic BP and HR of the LI-BFR group. CONCLUSION: LI-BFR resistance training is able to generate an acute hemodynamic and cardiovascular response similar to HI and LI resistance exercise. HI and LI-BFR seem to promote a hypotensive post-exercise response.

The Influence of Total Load on Cardiac Autonomic Recovery Following Resistance Exercise in Young and older adults

IntroductionThe delay in cardiac autonomic recovery (CAR) following physical activity is associated with increased risk of cardiovascular events. Aging is a major risk factor for cardiovascular disease, and older adults have altered resting cardiac autonomic modulation than young individuals. The intensity of exercise also influences autonomic recovery in young individuals.ObjectiveTo compare the CAR following resistance exercise (RE) in young (Y) and older (O) men, using high and low intensity RE.MethodsThe two groups (Y: n=9, age=26.3±4y, BMI=22.3±1.5Kg/m2 and O: n=9, age=64.3±4y, BMI=26.2±1.8 Kg/m2) performed 4 sets of RE, using leg press equipment, until failure. Subjects performed two different protocols; RE at 80% of 1RM (RE80) and at 30% of 1RM (RE30) in a random sequence. Heart rate was measured via a heart rate monitor and CAR was obtained through heart rate variability analysis pre and 30‐min post‐RE. The change values for heart rate variability (post 30‐min – pre) were assessed by root mean square (RMSSD) of successive RR intervals (iRR), high and low frequency in normalized units (HF and LF, respectively) and analyzed by 2‐way ANOVA (group*load).ResultsThe table shows a greater reduction of iRR, RMSSD and HF and a greater increase of LF in Y compared to O. Since the total load was higher in Y compared to O in RE80 and RE30 (Y RE30: 13767 ± 4738 kg vs. O RE30: 7812 ± 2094 kg, p &lt; 0.05, and Y RE80: 10921 ± 4201 kg vs. O RE80: 7488 ± 2040 kg, p &lt; 0.05), we evaluated the change in heart rate variability as a function of TL. This correction eliminated differences between Y and O for iRR and RMSSD (p &gt; 0.05), while HF and LF remained different between Y and O (p &lt; 0.05).ConclusionY showed delayed CAR in protocols with both RE80 and RE30. The higher TL in Y did not explain the delayed CAR in this group, thus other factors are involved. It is possible the lower heart rate variability adjustments of O is associated with limiting increases in sympathetic and reductions in parasympathetic modulation during RE but this needs further investigation.Support or Funding InformationWe thanks the support of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), FAEPEX (Fundo de Apoio ao Ensino, à Pesquisa e Extensão da Universidade Estadual de Campinas) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Impact of Blood Flow Restriction Exercise on Muscle Fatigue Development and Recovery.

The present study was designed to provide mechanistic insight into the time course and etiology of muscle fatigue development and recovery during and after low-intensity exercise when it is combined with blood flow restriction (BFR). Seventeen resistance-trained males completed four sets of low-intensity isotonic resistance exercise under two experimental conditions: knee extension exercise (i) with BFR and (ii) without BFR (CON). Neuromuscular tests were performed before, during (immediately after each set of knee extension exercise), and 1, 2, 4, and 8 min after each experimental condition. Maximal voluntary torque, quadriceps twitch torque in response to paired electrical stimuli at 10 Hz (PS10) and 100 Hz (PS100), PS10·PS100 ratio as an index of low-frequency fatigue, and voluntary activation were measured under isometric conditions. Perceptual and EMG data were recorded during each exercise condition. After the first set of exercise, BFR induced significantly greater reductions in maximal voluntary torque, PS100, and PS10·PS100 ratio compared with CON. These parameters progressively declined throughout the BFR protocol but recovered substantially within 2 min postexercise when blood flow was restored. Neither a progressive decline in the course of the exercise protocol nor a substantial recovery of these parameters occurred during and after CON. Only at exercise termination, voluntary activation differed significantly between BFR and CON with greater reductions during BFR. At the early stage of exercise, BFR exacerbated the development of muscle fatigue mainly due to a pronounced impairment in contractile function. Despite the high level of muscle fatigue during BFR exercise, the effect of BFR on muscle fatigue was diminished after 2 min of reperfusion, suggesting that BFR has a strong but short-lasting effect on neuromuscular function.

Aging-related frailty and sarcopenia. Exercise and rehabilitation for frailty and sarcopenia.

Exercise is the core of prevention and treatment for frailty and sarcopenia. Progressive and individualized physical activity program including resistance movement should be applied in community-dwelling older adults with frailty or sarcopenia. Combined use of balance exercise and aerobic exercise is also recommended. In hospitals, in addition to disease-specific rehabilitation, implementation of low-intensity resistance exercise such as the sit-to-stand exercise should be considered. Protein intake is indispensable in those with frailty or sarcopenia. If protein intake of is insufficient in daily meals, supplementation of protein, branched chain amino acid, etc. after exercise should be promoted.

Sports Physical Therapy Section Poster Presentations (Abstracts SPO1-SPO166).

These abstracts are presented here as prepared by the authors. The accuracy and content of each abstract remain the responsibility of the authors. In the identification number above each abstract, SPO designates a Sports Physical Therapy Section poster presentation. J Orthop Sports Phys Ther 2018;48(1):A203-A276. doi:10.2519/jospt.2018.48.1.A203.

Low intensity resistance exercise attenuates the relationship between glucose and autonomic nervous system indicators during 24 hours in women with type 2 diabetes

Summary Objectives The aim of this study was to investigate the relationship between glucose and heart rate variability (HRV) during 24 h after different resistance exercise (RE) intensities in women with type 2 diabetes (T2D). Equipment and methods Twelve women with T2D (55.2 ± 4.0 years; 70.1 ± 11.4 kg; 155.7 ± 3.3 cm) performed experimental sessions divided in two blocks separated by seven days and in a randomized order: block-A (session 1: control–CON40% and session 2: RE at 40% of the one repetition maximum test–1RM) and block-B (session 3: CON80% and session 4: RE at 80%1RM). The glucose and R-R interval (RRi) of HRV were evaluated during 24 h every 5 min of each experimental session by continuous glucose monitoring system (Guardian/REAL-Time) and cardiofrequencimeter Polar/RS800CX, which generated 288 measurement points for correlation. Pearson's correlation was performed among glucose and RRi values, low frequency (LF), high frequency (HF) and LF:HF ratio. Results Correlations (P

The acute physiological and perceptual responses to blood-flow restriction applied during un-resisted knee exercise: a potential treatment adjunct for physiotherapists

Purpose: Blood-flow restriction [BfR] training involves the temporary, artificial reduction of blood flow through a limb. Evidence suggests that BfR combined with low-intensity resistance exercise can minimise the loss of thigh muscle size and strength during periods of impaired weight-bearing. However, evidence is scarce as to the specific utility of adding BfR to un-resisted or ‘no-load’ exercise during injury rehabilitation. Therefore, this case series examined the effects of applying BfR during a no-load lower-limb knee exercise completed by athletes recovering from significant lower limb injuries.

Effects of Acute Exercise with Blood Flow Restriction on Oxidative Stress Biomarkers

The aim of this study was to assess the effects of an acute session of resistance exercise with blood flow restriction in modulation of oxidative stress parameters at different moments. Eleven participants (23.72 ± 3.49 years and 81.51 ± 6.10 kg) were recruited to perform a crossover design with three protocols: high intensity resistance exercise (HI 80% 1RM), low intensity resistance exercise (LI 30% 1RM), and with blood flow restriction (LI-BFR 30% 1RM). The oxidative profile in an acute session at four moments was assessed: baseline, immediately after exercise, and 24 and 48 hours later. The Ethics Committee at the Methodist University Center-IPA (Porto Alegre, Brazil) approved this study. The results did not show statistical significance (p>0.05) among moments and among groups for TBARS and protein carbonyls. Likewise, for the antioxidant activity there was also no difference (p>0.05) among moments and groups for sulfhydryl groups. The superoxide dismutase enzyme demonstrated a significant reduction (p<0.05) between baseline and immediately after exercise in the LI-BFR group. After group comparison, the HI group showed a significant increase (p<0.05) in baseline and 24 hours when compared to the LI-BFR. An equal increase was observed in the HI group at the moment of 24 hours later when compared to the LI group. The catalase enzyme levels in the LI group were significantly higher than in the LI-BFR and HI groups at baseline and 24 hours (p<0.05) later. Lastly, the low intensity resistance exercise with blood flow restriction in maximum repetition appears not to have modified the oxidative profile in young and healthy subjects, suggesting that the hypertrophy mechanism of that methodology of training occurred in other molecular ways.