Low-intensity Blood Flow Restriction Research Articles

Low-intensity blood flow restriction (LI-BFR) and moderate-intensity improves quadriceps strength and thigh circumference in older women

Background and objectives. Weakness and atrophy in the quadriceps femoris lead to decreased functional capacity, heightened fall risk, and increased mortality among older women. While moderate-intensity strength training is generally recommended for the elderly, higher-intensity exercises carry a greater risk of injury. Low-intensity exercises with blood flow restriction offer an alternative, providing comparable benefits to high-intensity training. This study aims to evaluate the effects of moderate-intensity and low-intensity blood flow restriction exercises on quadriceps femoris strength and thigh circumference in healthy elderly women. Materials and methods. The sample size was of 88 subjects equally randomized into a moderate-intensity group and a blood-flow restriction group. The moderate-intensity group performed strengthening exercises with a load of ≥40–60% of 1RM, 3 sets, 36 repetitions. The blood-flow restriction group conducted exercises at 20–30% of 1RM, completing 75 repetitions across 4 sets, using a pressure cuff applied to the upper thigh at 50 mmHg or 40% of the Arterial Occlusion Pressure (AOP). Both groups exercised twice a week over a 6-week period. Muscle strength (assessed via dynamometer and 1RM) and thigh circumference were recorded before and after the intervention. Results. After six weeks of intervention, both groups showed a significant increase in muscle strength and thigh circumference (p <0.001). However, no notable differences were observed between the moderate intensity group and the blood flow restriction group regarding quadriceps strength (dynamometer), quadriceps 1RM strength, or thigh circumference (p >0.05). Muscle soreness was reported in 18% of participants in the moderate intensity group. Conclusion. Low-intensity resistance exercises with blood flow restriction in older women can promote strength gains and muscle hypertrophy comparable to moderate-intensity training, while offering a safer alternative.

Enhancing upper extremity muscle strength in individuals with spinal cord injury using low-intensity blood flow restriction exercise.

This study explores the feasibility and effects of low-intensity blood flow restriction exercise on forearm muscle strength and function in individuals with spinal cord injury. Pilot randomized clinical trial. Ten male and female adult participants with chronic cervical and thoracic spinal cord injury underwent an 8-week low-intensity blood flow restriction exercise programme that targeted forearm muscles. Each participant's contralateral forearm served as the control. Grip strength was the primary outcome measure, and participants also provided qualitative feedback on their experiences. The study revealed a significant increase in participants' forearm muscle strength on the experimental side engaged in low-intensity blood flow restriction training, with an average strength gain of 7.5 ± 0.36 kg after 16 exercise sessions (Cohen's d = -6.32, 95% CI -8.34, -6.68). In comparison, the control side, following a conventional high- intensity exercise regimen without BFR, showed a more modest strength increase of 4.4 ± 0.67 kg. A mean Patient's Global Impression of Change score of 2.2 reflected overall improvements in participants' daily activities and health status. This study highlights the feasibility and effectiveness of low-intensity blood flow restriction exercise as a safe and promising approach to enhancing forearm muscle strength in individuals with spinal cord injury. The observed positive outcomes, coupled with a high level of participant satisfaction, underscore the potential of this innovative method to significantly improve limb muscle strength, thereby contributing to greater functional independence in this population.

Regional morphological adaptations of vastus lateralis muscle in response to different progressive resistance training programs: A randomised controlled trial.

Resistance training often increases muscle size, a phenomenon known as muscle hypertrophy. These morphological adaptations were typically documented to occur in a non-uniform pattern. Investigating the specific morphological adaptations to different training programs was of interest. This study aimed to investigate two resistance training programs, a high-intensity program (HI) and a combined high-intensity with low-intensity blood flow restriction program (MIX), on morphological adaptations of vastus lateralis muscle in healthy young men. Eighteen active participants were recruited and randomly assigned to the HI (n = 10) or MIX (n = 8) groups, undergoing different 6-week resistance training programs. The training volume set was equated and progressively increased from three sets in weeks 1 and 2 to six sets, and eight sets in weeks 3-4 and 5-6, respectively. Three specific regions of vastus lateralis were assessed by magnetic resonance imaging (MRI) and ultrasound imaging (US) during pre-and post-intervention. Statistical analysis revealed statistically significant increases in muscle area at the proximal (HI: Δ12%, MIX: Δ9.2%), middle (HI: Δ8.7%, MIX: Δ9.0%), and distal (HI: Δ14%, MIX: Δ13%) regions. Additionally, both HI and MIX groups showed statistically significant increases in the sum of muscle thickness post-intervention (HI: Δ12%, MIX: Δ19%) and in the sum of fascia thickness post-intervention (HI: Δ27%, MIX: Δ54%). Despite the MIX group training with higher volume load, no statistical differences were observed between groups for any week. These findings suggested that both HI and MIX programs effectively induced increases in muscle area and sums of muscle and fascia thickness in healthy young men, allowing practitioners to choose either program based on individual preferences and constraints.

Blood Flow Restriction Training Improves Muscular Outcomes in Patients With Chronic Ankle Instability: A Critically Appraised Topic

Clinical Scenario: The high recurrence of lateral ankle sprains progresses to chronic ankle instability (CAI) and can affect many athletes in all sports. CAI is often associated with a decrease in muscle strength, an increase in pain, a decrease in the range of motion, and a decrease in balance or neuromuscular control. The use of blood flow restriction (BFR) with CAI can increase muscular outcomes and be used as a rehabilitation tool. Clinical Question: Is there evidence to suggest that BFR improves strength, muscle activation, and/or cross-sectional area of the lower leg musculature in those with CAI? Clinical Bottom Line: There is moderate evidence to support therapeutic exercise with low-intensity BFR in patients with CAI. The evidence concluded a significant improvement in BFR to increase muscle activation of the fibularis longus, anterior tibialis, vastus lateralis, and soleus. There is moderate evidence suggesting BFR can induce strength gains in the muscles of the lower extremity in patients with CAI. Strength of Recommendation: The comprehensive evidence is a Strength of Recommendation Taxonomy (SORT) Grade B, with a level of evidence of 2, according to the Centre for Evidence-Based Medicine (CEBM) for the studies included.

A Review of the Efficacy and Mechanisms of Blood Flow Restriction Training in Enhancing Somatic Function and Preventing Falls in Older Adults.

Falls have become an important public health problem that seriously affects the quality of survival of older adultsand are a major cause of fractures, death, and reduced quality of life. With the advent of an aging society, the social, economic, and medical burdens of falls in older adults are increasing. Currently, there is a lack of effective means to prevent falls in older adults, and traditional health education and clinical interventions are not effective. It is urgent to find a safe and effective training method that can improve balance function and is suitable for the elderly. Low-intensity blood flow restriction training (BFRT) is an emerging training modality that, by restricting blood flow to the limbs and combining it with low-intensity exercise, can effectively improve muscle mass, aerobic capacity, and bone density, and has been shown to enhance somatic function in older adults. However, the effectiveness and specific mechanisms of BFRT in preventing falls in older adults are unclear. Based on recent research progress, this paper explores the possibility of BFRT in preventing falls in older adults by analyzing its positive effects on muscle mass, balance function, and cognitive function, the risk factors of falling in the elderly are summarized, as well as its potential role in reducing fall risk factors. It aims to provide new thinking for academia and clinical practice and to provide a scientific basis for reducing the risk of falls in the elderly.

Are calves trainable? Low-intensity calf muscle training with or without blood flow restriction: a randomized controlled trial

Abstract Objectives Whether low-load resistance training (RT) without muscle failure, with or without blood flow restriction (BFR), is sufficient to increase strength and muscle growth of calf muscles in trained individuals is still unclear. This study aimed to compare the effects of low-intensity BFR RT vs. traditional low-intensity RT (noBFR) with moderate training volume on strength and circumference. Methods We designed a parallel, randomized controlled trial including 36 RT-trained participants (BFR: 7 females, 32.9 ± 8.8 years, 11 males, 28.4 ± 3.6 years; noBFR; 8 females, 29.6 ± 3.4 years; 10 males, 28.6 ± 4.9 years) who underwent eight weeks of twice-weekly low-load RT with 16 weekly RT sets (30 % of one-repetition maximum [1RM]). RT consisted of bilateral calf raises and seated unilateral calf raises, each conducted with 4 sets (30, 15, 15, 15 repetitions not to failure) of either BFR or noBFR. Outcome measures included calf circumference (CC), leg stiffness (LS), and various strength tests (seated and standing calf raise 1RM, isokinetic strength of plantar- and dorsiflexion). Results There were no significant interactions or group effects for most measures. Both groups showed significant improvements in seated calf raise strength (p=0.046, η 2 p=0.17). Pairwise comparisons indicated moderate to large effect sizes for strength improvements (standardized mean differences: 0.35–1.11), but no changes in calf circumference were observed in either group. Conclusions Low-load RT with and without BFR are useful to increase strength without necessarily affecting hypertrophy. Low-intensity BFR training did not confer additional benefits over traditional low-intensity RT for calf muscle strength or circumference, questioning its general advantage under such conditions.

Comparison of Adaptations in the Gastrocnemius Muscle from an Exercise Program with and without Low-Intensity Blood Flow Restriction Banding in 18 Male Amateur Basketball Players Aged 16-45 Years.

BACKGROUND Basketball is a sport with a global impact and recognized major leagues, and is one of the most studied and analyzed sports for improvement at the level of the high-performance athlete. Increasing the jump height of basketball players is an essential factor for high athletic performance. MATERIAL AND METHODS This study aimed to identify the effect of low-intensity training with flow restriction versus the eccentric exercise protocol on amateur athletes. Eighteen amateur basketball players aged 16-45 years were divided into 2 groups: Group A consisted of 9 participants with low-intensity training with flow restriction (40% intensity) with 200 mmHg occlusion applying flow restriction bands in the popliteal area, while Group B consisted of 9 participants who performed an eccentric exercises protocol on the gastrocnemius. An anthropometric evaluation was applied, which consisted of perception of effort, range of movement (ROM), muscle strength intensity, and the power of the jump measured with a jump platform. RESULTS Notable changes were observed in favor of Group A for the right dorsiflexion, with mean difference (MD)=-2.444 (P=0.018); left dorsiflexion with MD=-2.778 (P=0.027) and left foot perimeter variable with MD=-0.667 (P=0.026) at 95% confidence interval (CI); while the vertical jump was in favor of Group B, with MD=-2.899 (P=0.006). CONCLUSIONS Low-intensity training with flow restriction and eccentric exercise protocol were both effective in improving jumping performance. A significant improvement was shown in the jump height and ROM of the 2 study groups.

WALKING WITH BLOOD FLOW RESTRICTION: A NOVEL METHOD TO IMPROVE PHYSICAL FITNESS IN OLDER ADULTS?

INTRODUCTION AND AIMS Alternative physical activity modalities and methods are needed to combat low adherence among older populations. Therefore, we are investigating whether blood flow restricted (BFR) walking improves measures of lower limb strength, and functional performance, compared to traditional walking in older adults. METHODS Healthy adults ≥60 years were randomised into BFR (n=5) or non-BFR (n=4) walking groups. Both groups walked outdoors, 3 days/week for 12 weeks starting at 4km/h and increasing walking speed by 0.5km/h every 4 weeks. The BFR group walked for 25min with BFR applied (60% arterial occlusion pressure) to the lower limbs in 2x 10mins bouts (separated by 5mins walking without occlusion). The non-BFR group walked for 50mins without occlusion, matching current best practice for low-moderate intensity physical activity. Participants were assessed at baseline and post-intervention (12 weeks) for knee extension maximal voluntary torque (MVTpeak) and functional capacity (four square step test [4SST], 5x sit-to-stand [STS], timed up and go [TUG], gait speed, and 6-minute walk test [6mWT]). RESULTS There were no differences at baseline between groups (p>0.05). Both groups improved across all measures from baseline to post-intervention, with significant effects for time observed for: 4SST (7.92±1.2s – 6.83±1.39s; p=0.035), TUG (6.16±0.81s – 5.58±0.9s; p=0.04), STS (11.30±1.70s – 10.14±1.7s; p=0.032), but not for gait speed (3.98±0.69s – 3.71±0.69s; p=0.456), 6mWT (564.72±72.13m – 601.27±64.2m; p=0.129) and MVTpeak (112.33±25.8Nm – 120.55±23.5Nm; p=0.995). No group x time effect was observed from baseline to 12 weeks (p>0.05). SUMMARY The current results demonstrate significant improvements in functional measures (4SST, TUG, STS) from baseline to post-intervention, with no differences observed between groups. This indicates that low-intensity BFR walking may provide comparable physical fitness improvements to non-BFR walking while completing only 50% of the volume.

Five-Week, Low-Intensity Blood Flow Restriction Rowing Improves V̇ o2 max in Elite Rowers.

Held, S, Rappelt, L, Rein, R, Deutsch, J-P, Wiedenmann, T, and Donath, L. Five-week, low-intensity, blood flow restriction rowing improves V̇ o2 max in elite rowers. J Strength Cond Res 38(6): e299-e303, 2024-This controlled intervention study examined the effects of low-intensity rowing with blood flow restriction (BFR) on maximal oxygen uptake (V̇ o2 max), peak power output during ramp testing (PPO), and 2000-m time trial performance (P2k). Eleven, highly elite, male rowers (22.1 ± 1.6 years; 92.6 ± 3.8 kg; 1.93 ± 0.04 m; 7.9. ± 2.2 years rowing experience; 20.4 ± 2.0 h·w -1 training volume; 11.9 ± 1.1 session per week) trained 5 weeks without BFR (Base) followed by a 5-week BFR intervention period. BFR of the lower limb was applied through customized elastic wraps. BFR took place 3 times a week (accumulated net pBFR: 60 min·wk -1 ; occlusion per session: 2 times 10 min·session -1 ) and was used exclusively at low intensities (<2 mmol·L -1 ). V̇ o2 max, PPO, and P2k were examined before, between, and after both intervention periods. Bayesian's credible intervals revealed relevantly increased V̇ o2 max +0.30 L·min -1 (95% credible interval: +0.00 to +0.61 L·min -1 ) adaptations through BFR. By contrast, PPO +14 W (-6 to +34 W) and P2k -5 W (-14 to +3 W) were not noticeably affected by the BFR intervention. This study revealed that 15 sessions of BFR application with a cumulative total BFR load of 5 h over a 5-week macrocycle increased V̇ o2 max remarkably. Thus, pBFR might serve as a promising tool to improve aerobic capacity in highly trained elite rowers.

Short-Term Impact of Low-Intensity Exercise with Blood Flow Restriction on Mild Knee Osteoarthritis in Older Adults: A Pilot Study

This pilot study aimed to investigate the immediate impact of low-intensity exercises with blood flow restriction (BFR) on older adults with knee osteoarthritis (KOA). Fifteen patients with KOA who were over 50 years old, participated and underwent low-intensity resistance knee exercises at 30% of their one-repetition maximum with BFR three times/week for two weeks. Pre- and post-exercise assessments included pain levels, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, isokinetic knee strength, lower extremity muscle volume (via leg circumference and muscle thickness), functional performance tests (timed up-and-go [TUG] and sit-to-stand [STS]), skeletal muscle index (SMI) using bioelectrical impedance analysis, and handgrip strength (HGS). Post-exercise, there was a significant reduction in pain. WOMAC scores showed significant improvements across all three domains: pain, stiffness, and physical function. In the TUG and STS tests, completion times were significantly reduced. Thigh and calf circumferences, as well as thigh muscle thickness significantly increased after exercise. Post-exercise SMI and HGS also significantly increased. However, isokinetic knee strength did not show significant changes. In conclusion, low-intensity BFR exercises provide immediate benefits in symptoms and physical performance for patients with KOA, potentially inducing local and systemic muscle mass increase, even after a short-term intervention.

Elevating athletic performance: Maximizing strength and power in long jumpers through combined low-intensity blood flow restriction and high-intensity resistance training

PurposeThis study aimed to evaluate the effects of low-intensity blood flow restriction (BFR) training and high-intensity resistance training (HI-RT) on the leaping performance of long-jumpers. Materials and methodsLong jump players were divided into two groups; one group (group A) receiving HI-RT (n = 8) and the other group (group B) receiving combined low-intensity BFR training plus HI-RT (n = 8). Muscle power and knee muscle strength was assessed at baseline, 3 weeks and 6 weeks of intervention. Results1-RM was found to be significantly different between Group A and Group B at 3 and 6 weeks. Further, IKDQR, IKDHR and IKDQL was significantly improved in group B as compared to group A both at 3 and 6 weeks. There was significant time effect, group effect and time-group interaction in the strength of quadriceps and hamstring of both left and right leg measured through isokinetic device. Post-hoc analysis for 1-RM in group B showed a significant improvement at baseline and 6 weeks and the broad jump was significant at baseline and 3 weeks and at baseline and 6 weeks. ConclusionThe combined effects of low-intensity BFR training and HI-RT is effective in improving the muscle strength and power of lower limbs in long jumpers.

Poster 328: Pre-Operative Low-Intensity Blood Flow Restriction Training Does Not Improve Quadriceps Strength or Hypertrophy After Anterior Cruciate Ligament Reconstruction

Objectives: The purpose of this study is to evaluate the effect of low-intensity blood flow restriction (LI- BFR) training utilized in a pre-rehabilitative setting for patients undergoing anterior cruciate ligament reconstruction (ACLR) on postoperative outcomes by minimizing postoperative atrophy and impairment of the quadriceps. We hypothesize that postoperative strength and hypertrophy of the quadriceps will be greater in a population that undergoes preoperative LI-BFR training than that of a population that undergoes low-intensity sham control (LI-SHAM) training. Methods: Twenty-eight subjects undergoing primary ACLR underwent 2 weeks of either a BFR intervention or a SHAM intervention at a rate of 2 sessions per week before surgery. Quadriceps strength and cross-sectional area were measured as well as other exploratory outcomes were measured before and after the intervention before surgery and at 5 different time points after surgery, through 6 months postoperative. Quadriceps strength was assessed through handheld dynamometry and a leg press test and quadriceps cross-sectional area was assessed using musculoskeletal ultrasound imaging. Results: Adjusting for sex, time, and strength/hypertrophy at baseline, there were no significant differences found between treatment groups for the primary endpoints. Compared to 24-48 hours pre- op, this suggests that the post-op average hypertrophy remains significantly lower through 24 weeks post-op, while leg strength is similar at 24 weeks post-op as measured by handheld dynamometer and even significantly larger at 24 weeks as measured by the leg press test. Conclusions: A 2-week preoperative program of LI-BFR training may not be effective to improve postoperative quadriceps strength and hypertrophy after ACLR.

Low-Intensity Blood Flow Restriction Exercises Modulate Pain Sensitivity in Healthy Adults: A Systematic Review

Low-intensity exercise with blood flow restriction (LIE-BFR) has been proposed as an effective intervention to induce hypoalgesia in both healthy individuals and patients with knee pain. Nevertheless, there is no systematic review reporting the effect of this method on pain threshold. We aimed to evaluate the following: (i) the effect of LIE-BFR on pain threshold compared to other interventions in patients or healthy individuals; and (ii) how different types of applications may influence hypoalgesic response. We included randomized controlled trials assessing the effectiveness of LIE-BFR alone or as an additive intervention compared with controls or other interventions. Pain threshold was the outcome measure. Methodological quality was assessed using the PEDro score. Six studies with 189 healthy adults were included. Five studies were rated with 'moderate' and 'high' methodological quality. Due to substantial clinical heterogeneity, quantitative synthesis could not be performed. All studies used pressure pain thresholds (PPTs) to assess pain sensitivity. LIE-BFR resulted in significant increases in PPTs compared to conventional exercise at local and remote sites 5 min post-intervention. Higher-pressure BFR results in greater exercise-induced hypoalgesia compared to lower pressure, while exercise to failure produces a similar reduction in pain sensitivity with or without BFR. Based on our findings, LIE-BFR can be an effective intervention to increase pain threshold; however, the effect depends on the exercise methodology. Further research is necessary to investigate the effectiveness of this method in reducing pain sensitivity in patients with pain symptomatology.

Blood Flow Restricted Cycling Impairs Subsequent Jumping But Not Balance Performance Slightly More Than Non-Restricted Cycling: An Acute Randomized Controlled Cross-Over Trial.

Chronic blood flow restriction (BFR) training has been shown to improve drop jumping (DJ) and balance performance. However, the acute effects of low intensity BFR cycling on DJ and balance indices have not yet been examined. 28 healthy young adults (9 female; 21.8 ± 2.7years; 1.79 ± 0.08m; 73.9 ± 9.5kg) performed DJ and balance testing before and immediately after 20min low intensity cycling (40% of power at maximal oxygen uptake) with (BFR) and without BFR (noBFR). For DJ related parameters, no significant mode × time interactions were found (p ≥ 0.221, ηp 2 ≤ 0.06). Large time effects for DJ heights and the reactive strength index were observed (p < 0.001, ηp 2 ≥ 0.42). Pairwise comparison revealed notably lower values for both DJ jumping height and reactive strength index at post compared to pre (BFR: -7.4 ± 9.4%, noBFR: -4.2 ± 7.4%). No statistically significant mode × time interactions (p ≥ 0.36; ηp 2 ≤ 0.01) have been observed for balance testing. Low intensity cycling with BFR results in increased (p ≤ 0.01; SMD ≥ 0.72) mean heart rate (+14 ± 8bpm), maximal heart rate (+16 ± 12 bpm), lactate (+0.7 ± 1.2 mmol/L), perceived training intensity (+2.5 ± 1.6au) and pain scores (+4.9 ± 2.2au) compared to noBFR. BFR cycling induced acutely impaired DJ performance, but balance performance was not affected, compared to noBFR cycling. Heart rate, lactate, perceived training intensity, and pain scores were increased during BFR cycling.

Physiological adaptations and myocellular stress in short-term, high-frequency blood flow restriction training: A scoping review.

High frequency (1-2 times per day) low-intensity blood flow restriction (BFR) training has been recommended as a prescription approach for short durations of time to maximize relevant physiological adaptations. However, some studies demonstrate negative physiological changes after short periods of high-frequency BFR training, including prolonged strength decline and muscle fiber atrophy. To provide a comprehensive overview of short-term, high-frequency blood flow restriction training, including main adaptations, myocellular stress, limitations in the literature, and future perspectives. A systematic search of electronic databases (Scopus, PubMed®, and Web of Science) was performed from the earliest record to April 23, 2022. Two independent reviewers selected experimental studies that analyzed physical training protocols (aerobic or resistance) of high weekly frequency (>4 days/week) and short durations (≤3 weeks). In total, 22 studies were included in this review. The samples were composed exclusively of young predominantly male individuals. Muscle strength and hypertrophy were the main outcomes analyzed in the studies. In general, studies have demonstrated increases in strength and muscle size after short term (1-3 weeks), high-frequency low-intensity BFR training, non-failure, but not after control conditions (non-BFR; equalized training volume). Under failure conditions, some studies have demonstrated strength decline and muscle fiber atrophy after BFR conditions, accompanying increases in muscle damage markers. Significant limitations exist in the current HF-BFR literature due to large heterogeneities in methodologies. The synthesis presented indicates that short-term, high-frequency BFR training programs can generate significant neuromuscular adaptations. However, in resistance training to failure, strength declines and muscle fiber atrophy were reported. Currently, there are no studies analyzing low-frequency vs. high-frequency in short-term BFR training. Comparisons between resistance exercises of similar intensities (e.g., combined effort) are lacking, limiting conclusions on whether the effect is a product of proximity to failure or a specific effect of BFR.

ACUTE EFFECT OF BLOOD FLOW RESTRICTED RESISTANCE EXERCISE ON IRISIN AND SEX HORMONES

Purpose: The relationship between exercise and irisin and sex hormone release is unclear and is of interest to current research. This study aimed to investigate the acute effect of blood flow restricted (BFR) resistance exercise on irisin and sex hormones.&#x0D; Material and Methods: The study included healthy males over 18 years of age. Participants' physical activity levels were determined using International Physical Activity Questionnaire (IPAQ). Participants underwent body composition analysis and isotonic muscle strength measurement and were randomly divided into 3 groups: low-intensity (20% of 1-RM) resistance exercise with BFR, high-intensity (70% of 1-RM) resistance exercise without BFR, and a control group. Blood samples were obtained 15 minutes post-exercise to assess acute irisin, testosterone, and estrogen responses.&#x0D; Results: The study included 17 healthy males. The average age was 26.1±2.9 years, mean physical activity was 1259.2±1003.1 MET/week, and mean 1-RM max (as measured with isotonic muscle strength test) was 41.1±7.5 kg. The descriptive characteristics of the three groups were statistically similar (p&gt;0.05). The acute post-intervention irisin and sex hormone levels were not statistically different between the groups (p&gt;0.05).&#x0D; Conclusion: Acute changes in irisin and sex hormone levels were not statistically different for low-intensity BFR and high-intensity non-BFR exercise.

Effects of Low Intensity Blood Flow Restriction Training on Muscle Volume, Strength and Power in Healthy Middle-Aged Females

OBJECTIVES The purpose of this study is to investigate the efficacy of weight training with controlled blood flow occlusion compared to conventional resistance training, in the ageing population.METHODS Twenty-three healthy female subjects (aged 40-55) were randomly assigned to one of three groups; low intensity blood flow restriction training (LI-BFRT) (n = 9), conventional resistance training (RT) (n = 7) and control (CON) (n = 7). The RT group trained between 65-70% one repetition maximum (1RM) and the LI-BFRT group trained at 30% 1RM while wearing pressure cuffs inflated to 100-120% of brachial systolic blood pressure (bSBP). Relative appendicular skeletal muscle mass (ASM/weight), isokinetic strength and power were tested pre and post 8 weeks of training.RESULTS Upper limb ASM/weight increased significantly in the LI-BFRT and RT groups (both p &lt; 0.001). Only LI-BFRT showed significant difference compared with the CON group (p &lt; 0.01). Lower limb ASM/weight improved in both the LI-BFRT (p &lt; 0.01) and CON (p &lt; 0.01) groups without group differences. Lower limb flexion strength increased in the LI-BFRT and RT groups (both p &lt; 0.01), with differences between groups (p &lt; 0.01, LI-BFRT &gt; RT &gt; CON). Only RT increased extension muscle strength (p &lt; 0.05). Lower limb flexion and extension power improved following LI-BFRT (p &lt; 0.05 and p &lt; 0.01, respectively), significantly greater than RT in both flexion (p &lt; 0.001) and extension (p &lt; 0.01).CONCLUSIONS LI-BFRT may be as, if not more effective than RT for increasing muscle volume, strength and power in middle-aged women.

The Impact Of Blood Flow Restriction Resistance Training On Pain Modulation In Pain Free Individuals

Blood flow restriction (BFR) resistance training (RT) is beneficial for enhancing muscle size and strength at low intensity and is effective and feasible in musculoskeletal rehabilitation. However, the effects of BFR RT on pain modulation remain unclear. PURPOSE: To evaluate the effects of low-intensity BFR and conventional moderate intensity (MI) RT on pain modulation in pain-free adults METHODS: Nineteen adults without current pain (10 M, mean age = 27 yrs., mean BMI = 23 kg/m2) participated in this study. Participants were screened for contraindications of BFR training (e.g., immobilization) and conditions that may influence pain modulation (e.g., neuropathy).A repeated measures design with counterbalanced order of RT conditions were applied. All participants completed two RT visits (MI or BFR) approximately 9 days apart. At each visit, dominant leg one-repetition maximum (1RM) was determined on a leg press machine after standardized warm-up. For both RT conditions, participants performed a unilateral leg press with the dominant leg. For MI, participants performed the unilateral leg press at 50% 1RM. For BFR RT, a 20-cm width cuff was placed at the proximal thigh during exercise. Participants performed the leg press at 30% 1RM with the cuff inflated to 60% limb occlusion pressure. Participants performed four sets of RT in each visit with a protocol of 30-15-15 repetitions at the first three sets and exercise to failure at the fourth set. Failure was defined as failing to maintain the form. A rate of two seconds per repetition was applied with a 30-second rest between sets. Pressure pain threshold (PPT) was measured over the rectus femoris immediately after exercise using a hand-held algometer. Exercise-induced hypoalgesia (EIH) was calculated as the change in PPT. Statistical Analysis: Paired t-tests (α = 0.05) and Cohen’s d for effect size were used to assess statistical significance. RESULTS: Mean (SD) baseline PPT was 46.6 N (15.2) and 45.2 N (10.4) at Visit 1 and Visit 2, respectively. Greater EIH was found with BFR compared to MI RT (31.23% vs. 14.21%, p = 0.039, d = 0.62) CONCLUSIONS: Low-intensity BFR RT elicited a greater EIH effect compared to MI RT in pain-free adults. Future studies are needed to evaluate mechanisms underlying EIH with RT and to extend this work to clinical populations

Cardiometabolic Disease Risk in Normal Weight Obesity and Exercise Interventions for Proactive Prevention

PURPOSE: Normal weight obesity (NWO) is characterized by a normal body mass index but a high body fat mass percentage and low skeletal muscle mass, thereby increasing the risk of cardiometabolic dysfunction and morbidity. However, the effects of exercise intervention in reducing the risk of cardiometabolic disease in NWO have not been fully elucidated. Therefore, this review aimed to summarize the potential cardiometabolic disease risk and to provide implications of exercise interventions for the proactive prevention of cardiometabolic disease risk in NWO.METHODS: We searched and summarized the literature on the cardiometabolic risk factors in NWO. In addition, we summarized literature investigating the effects of exercise intervention on the cardiometabolic risk factors in NWO. We performed the literature search using PubMed, Web of Science, and Google Scholar databases.RESULTS: NWO was associated with increased visceral fat, ectopic fat, oxidative stress, inflammatory cytokines, insulin resistance, dyslipidemia, and subclinical atherosclerosis compared with normal weight lean. NWO requires exercise interventions that induce alterations in body composition, such as decreased body fat percentage and increased muscle mass. Resistance exercise (RE) and high-intensity interval exercise (HIIE) can improve lipid components and alter body composition in NWO. In addition, low-intensity blood flow restriction resistance exercise (BFR-RE) may enhance muscular strength and anaerobic power in NWO.CONCLUSIONS: The cardiometabolic disease risk is increased in NWO. We suggest that exercise interventions (RE, HIIE, and BFR-RE) may effectively prevent cardiometabolic disease risk and alter body composition in NWO. As this has potential implications for exercise interventions in NWO, further investigations are needed to find the optimal exercise for proactive prevention of cardiometabolic risk in NWO.

Acute and Chronic Bone Marker and Endocrine Responses to Resistance Exercise With and Without Blood Flow Restriction in Young Men.

In this study, we compared acute and chronic bone marker and hormone responses to 6 weeks of low intensity (20% 1RM) blood flow restriction (BFR20) resistance training to high intensity (70% 1RM) traditional resistance training (TR70) and moderate intensity (45% 1RM) traditional resistance training (TR45) in young men (18–35 years). Participants were randomized to one of the training groups or to a control group (CON). The following training programs were performed 3 days per week for 6 weeks for knee extension and knee flexion exercises: BFR20, 20%1RM, 4 sets (30, 15, 15, 15 reps) wearing blood flow restriction cuffs around the proximal thighs; TR70, 70% 1RM 3 sets 10 reps; and TR45, 45% 1RM 3 sets 15 reps. Muscle strength and thigh cross-sectional area were assessed at baseline, between week 3 and 6 of training. Acute bone marker (Bone ALP, CTX-I) and hormone (testosterone, IGF-1, IGFBP-3, cortisol) responses were assessed at weeks 1 and 6, with blood collection done in the morning after an overnight fast. The main findings were that the acute bone formation marker (Bone ALP) showed significant changes for TR70 and BFR20 but there was no difference between weeks 1 and 6. TR70 had acute increases in testosterone, IGF-1, and IGFBP-3 (weeks 1 and 6). BFR20 had significant acute increases in testosterone (weeks 1 and 6) and in IGF-1 at week 6, while TR45 had significant acute increases in testosterone (week 1), IGF-1 (week 6), and IGFBP-3 (week 6). Strength and muscle size gains were similar for the training groups. In conclusion, low intensity BFR resistance training was effective for stimulating acute bone formation marker and hormone responses, although TR70 showed the more consistent hormone responses than the other training groups.