Blood Flow Restriction Group Research Articles

The acute and chronic effects of resistance training with blood flow restriction on hormonal responses in untrained young men: A comparison of frequency

The present study aimed to determine the effect of low-intensity training with blood flow restriction (BFR) on the response rate of anabolic hormones. Forty healthy and untrained young men, aged 18 to 25 years old, were randomly divided into five groups: one session of BFR training (BFR1), two sessions of BFR training (BFR2), one session of resistance training without BFR (WBFR1), two sessions of resistance training without BFR (WBFR2), and the control group (without training). BFR groups had three sets of 20 repetitions with 20-30% 1RM, and none-BFR groups had three sets of 10 repetitions with 70-80% 1RM for six weeks. Both BFR1 and WBFR1 groups trained 3day a week (1 session in a day and three sessions a week), BFR2 and WBFR2 groups trained three days a week (but two sessions a day and six sessions in a week) and Control group did not perform any training. The mean changes in growth hormone(GH), testosterone(TS), and vascular endothelial growth factor (VEGF) hormones were determined by ELISA technique before, after a first training session and after six weeks of the training program. To the analysis of data, two way repeated measures ANOVA at a significant level of P<0.05 also were used. The results showed a significant increase in GH levels in each of the four training groups as compared with the pre-test and the control group after a first training session and after six weeks of the training program (P<0.05). There was no significant increase in TS levels in each of the four training groups, as compared with the pre-test and the control group in both acute and chronic TS response (P>0.05). Only the WBFR1 group did not significantly increase in VEGF levels after the first training session (P>0.05). In chronic VEGF response, there were no significant changes observed in all training groups as compared with the control group(P>0.05). Despite the effectiveness of low-intensity BFR training, such as high-intensity resistance training on hormonal responses, two sessions per day training with the same volume does not necessarily result in larger responses in all hormones than one session per day training.

Effects of Blood Flow Restriction Training on Muscle Strength and Architecture.

Korkmaz, E, Dönmez, G, Uzuner, K, BabayevaŞerife Şeyma Torgutalp, N, and Özçakar, L. Effects of blood flow restriction training on muscle strength and architecture. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to compare the effect of the traditional resistance (RES) training and low-intensity resistance training with blood flow restriction (BFR) protocols on quadriceps and hamstring muscle strength, and rectus femoris (RF) and vastus lateralis architecture, in youth team soccer players. Twenty-three young trained soccer team players were divided into 2 groups: the RES group that practiced traditional high-intensity resistance training (80% 1 repetition maximum [1RM], 4 sets, 12 rep.) (n = 12) and the BFR group that performed low-intensity resistance exercise with BFR (30% 1RM, 4 sets, 30-15-15-15 rep) (n = 11)-unilateral knee extension exercise-twice a week for 6 weeks. Muscle strength (isokinetic concentric peak torque of the quadriceps and hamstring muscles) and ultrasonographic parameters (muscle thickness, pennation angle, and fascicle length) were assessed. Bilateral knee flexor and extensor strength was increased in both groups compared with pre-exercise. The increase in dominant side extensor muscle strength (60°·s p = 0.02, ηp = 0.256, 180°·s p = 0.019, ηp = 0.271) and RF thickness (p = 0.002, ηp = 0.361) was statistically higher in the BFR group than in the RES group. These findings support that occlusion training can provide better benefits than traditional strength training to improve muscle hypertrophy. In addition, the novelty of our study is that BFR training may affect the muscle structure measured by ultrasonography.

EFFECT OF AEROBIC EXERCISE TRAINING WITH AND WITHOUT BLOOD FLOW RESTRICTION ON AEROBIC CAPACITY IN HEALTHY YOUNG ADULTS: A SYSTEMATIC REVIEW WITH META-ANALYSIS

Exercise training (ET) with blood flow restriction (BFR) is becoming increasingly popular, but the majority of BFR ET studies have evaluated skeletal muscle strength and hypertrophy. The favorable effect of BFR ET on skeletal muscle and the vasculature appears to improve aerobic capacity (AC) although conflicting results have been observed.Purpose: The purposes of this systematic review with meta- analysis were to examine the effects of aerobic ET with and without BFR on AC and to compare the effect of low-to-moderate aerobic ET with and without BFR to high-intensity aerobic ET with and without BFR on AC. Systematic Review with Meta-analysis. A comprehensive search for studies examining the effects of aerobic ET with and without BFR on AC was performed. Inclusion criteria were: (a) the study was conducted in healthy individuals, (b) there was random allocation of study participants to training and control groups, (c) BFR was the sole intervention difference between the groups. A total of seven studies (5 low-to-moderate ET and 2 high-intensity ET) were included in the meta-analysis providing data from 121 subjects. There was a significant standardized mean difference (SMD) of 0.38 (95% CI = 0.01, 0.75) in AC between the BFR and non-BFR groups of all seven studies (z = 2.01; p = 0.04). Separate analyses of the five low-to-moderate aerobic ET studies found similar results with aerobic ET with BFR eliciting a significantly greater AC (z = 2.47; p=0.01) than aerobic ET without BFR (SMD of 0.57; 95% CI = 0.12, 1.01). Separate analyses of the two high-intensity aerobic ET studies with and without BFR found no significant difference in AC between the groups (SMD of - 0.01; 95% CI = - 0.67, 0.64). Aerobic ET with BFR elicits a significantly greater AC than aerobic ET without BFR in healthy young adults. However, low-to-moderate intensity aerobic ET with BFR elicited a greater improvement in AC than aerobic ET without BFR while high-intensity aerobic ET with BFR did not elicit an improvement in AC over high-intensity aerobic ET without BFR. 1a.

Effects of whole body vibration training combined with blood flow restriction on muscle adaptation

This study investigated the effects of whole body vibration (WBV) training combined with blood flow restriction (BFR) on muscle fitness. Twenty physically inactive adults were randomly assigned to a WBV + BFR group (8 men and 2 women) and a WBV group (8 men and 2 women). The participants in the WBV group were subjected to 10 sets of intermittent WBV exercise 20 min/day, 3 days/week, for 8 weeks. The participants in the WBV + BFR group received the same WBV treatment, but the proximal portion of their thighs was compressed using inflatable cuffs. Dual-energy X-ray absorptiometry estimated thigh muscle mass, one repetition maximal (1RM) leg press, and muscle endurance were measured before and after the training programme. The results indicated that thigh muscle mass significantly increased (3%) after the 8-week training period only in the WBV + BFR group. Meanwhile, 1RM leg press and muscle endurance significantly increased in both groups after training (p < 0.05). Analysis of covariance revealed that the increase in 1RM leg press and muscle endurance was significantly higher (p < 0.05) in the WBV + BFR group than the WBV group (leg press: 11.1%. vs. 4.37%; muscle endurance: 48.84% vs. 15.19%, respectively). In conclusion, exposure to regular WBV + BFR training can increase thigh muscle mass, maximal strength, and muscle endurance compared with exposure to WBV training alone. WBV + BFR training appears to be a feasible strategy for improving muscle mass, strength, and endurance in previously untrained participants.

Acute Inflammatory Response to a Single Bout of Resistance Exercise with or Without Blood Flow Restriction

Background: The effectiveness of resistance training (RT) with blood flow restriction (BFR) is limited from the health perspective. Objectives: This study aimed to investigate the acute inflammatory response to a single bout of RT with or without BFR. Methods: Twenty-four non-athletic male students were randomly divided into 3 groups (n = 8), including: (1) high intensity (HIRT- 80% of 1-RM: 3 × 10 R), (2) low intensity (40% of 1-RM: 3 × 30 R) with BFR (180 mmHg) (LIRT + BFR) and (3) LIRT. Results: Significant increase for IL1-β (p = 0.001), IL-6 (P = 0.001), TNF-α (P = 0.002), CRP (P = 0.007), ICAM1 (P = 0.016), HCY (P = 0.008) were observed. These responses in the HIRE and LIRT + BFR groups were significantly higher than in the LIRT group respectively (P ≤ 0.05). Conclusions: The LIRT + BFR has similar effects to HIRT and can be used in rehabilitation training. The gradual overload and proper recovery are very important due to the increase in acute inflammatory responses.

Intradialytic exercise with blood flow restriction is more effective than conventional exercise in improving walking endurance in hemodialysis patients: a randomized controlled trial

Objective: This study aims to compare the effect of intradialytic aerobic exercise with blood flow restriction, without blood flow restriction (conventional) and no exercise (control) on muscle strength and walking endurance among chronic kidney disease patients. Design: Open label and parallel group randomized controlled trial. Subjects: Adult patients with chronic kidney disease on hemodialysis. Intervention: A 12-week intradialytic training with or without blood flow restriction compared with a control group. Main measures: Strength and walking endurance were measured using thoracolumbar dynamometry and a 6-minute walk test, respectively, before and after training. Results: A total of 66 patients were randomized into three groups: blood flow restriction group (n = 22), conventional exercise group (n = 22) and control group (n = 22). There were seven dropouts, and 59 patients were included in the analysis. There was a significant increase in the 6-minute walking distance in the blood flow restriction group (from 412.7 (115.9) to 483.0 (131.0) m, P = 0.007) in comparison with the conventional exercise group (from 426.79 (115.00) to 433.2 (120.42) m, not significant) and the control group (from 428.4 (108.1) to 417.3 (100.2) m, not significant). The change in the walking distance over time was significantly different among groups (intervention group/time, P = 0.02). The simple effects test found a significant time effect only in the blood flow restriction group. There was no significant difference in strength change between the groups. Conclusion: Among chronic kidney disease patients, intradialytic exercise of low/moderate intensity with blood flow restriction was more effective in improving walking endurance than conventional exercise or no exercise.

Effects of Practical Blood Flow Restriction Training on Adolescent Lower-Body Strength.

Luebbers, PE, Witte, EV, and Oshel, JQ. Effects of practical blood flow restriction training on adolescent lower-body strength. J Strength Cond Res 33(10): 2674-2683, 2019-The purpose of this study was to examine the effects of a practical blood flow restriction (BFR) training program on lower-body strength of high school weightlifters. Twenty-five students were divided into 3 groups. For 6 weeks, each group completed the same resistance training program with the exception of the parallel back squat exercise (2 d·wk), which was different for each group. One group (HI) completed a traditional high-load (≥65% 1 repetition maximum [1RM]) back squat protocol with 3 sets of low repetitions (≤10). The LO group completed the squat exercise using a relatively light load (≤30% 1RM) for 1 set of 30 repetitions and 3 sets of 15 with 30 seconds of rest between sets. The LO + BFR group followed the same protocol as LO, but did so with blood flow restricted. One repetition maximum back squat tests were conducted before the start of the program and again on conclusion, the values of which were used as the dependent measure. A 3 × 2 (group × time) repeated-measures analysis of variance revealed a significant interaction (p = 0.043). Follow-up tests were conducted to explore the interaction. Paired-sample t-tests for each group indicated a significant increase in leg strength for the LO + BFR group (p = 0.005) but not for the HI (p = 0.142) or LO groups (p = 1.00). This suggests that a practical BFR training program may be effective in increasing 1RM squat performance of high school students.

Progression of Blood Flow Restricted Resistance Training in Older Adults at Risk of Mobility Limitations.

Blood flow restriction (BFR) resistance training leads to increased muscle mass and strength but the progression leading to adaptations may be different as strength gains are often to a lesser magnitude than high-load (HL) training. The impact of training loads and repetitions on older adults’ muscle mass and strength following BFR or HL training was evaluated. Twenty-one older adults (67–90 years) classified as being at risk of mobility limitations were randomly assigned to HL (n = 11) or BFR (n = 10) knee extension (KE) and flexion (KF) training twice per week for 12 weeks. Strength was measured with 10-repetition maximum (10-RM) tests and isometric contractions. Cross-sectional area (CSA) of the quadriceps and hamstrings was measured. HL and BFR interventions increased 10-RM KF and isometric strength (P < 0.05) and hamstrings CSA increased an average of 4.8 ± 5.9% after HL and BFR training (time main effect P < 0.01). There were no differences between the training groups (time x group interactions P > 0.05). The rate of progression of KF training load and repetitions was comparable (time × group interactions of each variable P > 0.05). The groups averaged an increase of 0.50 ± 25 kg⋅week-1 and 1.8 ± 0.1.7 repetitions⋅week-1 of training (time main effects P < 0.05). The HL training group experienced greater improvements in KE 10-RM strength than the BFR group (60.7 ± 36.0% vs. 35.3 ± 25.5%; P = 0.03). In both groups, isometric KE strength increased 17.3 ± 18.5% (P = 0.001) and there were no differences between groups (P = 0.24). Quadriceps CSA increased (time main effect P < 0.01) and to similar magnitudes (time x group interaction P = 0.62) following HL (6.5 ± 3.1%) and BFR training (7.8 ± 8.2%). The HL group experienced accelerated progression of load when compared to BFR (0.90 ± 0.60 kg⋅week-1 vs. 30 ± 0.21 kg⋅week-1; P = 0.006) but was not different when expressed in relative terms. BFR training progressed at a rate of 3.6 ± 1.3 repetitions⋅week-1 while the HL group progressed at 2.2 ± 0.43 repetitions⋅week-1 (P = 0.003). HL training led to greater increases in KE 10-RM and it may be attributed to the greater load and/or faster rate of progression of the load throughout the 12-week training period and the specificity of the testing modality. Incorporating systematic load progression throughout BFR training periods should be employed to lead to maximal strength gains.

Blood Flow Restriction During Futsal Training Increases Muscle Activation and Strength

The aim of this study was to investigate the effect of leg blood flow restriction (BFR) applied during a 3-a-side futsal game on strength-related parameters. Twelve male futsal players were randomly assigned into two groups (n = 6 for each group) during 10 training sessions either with or without leg BFR. Prior to and post-training sessions, participants completed a series of tests to assess anabolic hormones and leg strength. Pneumatic cuffs were initially inflated to 110% of leg systolic blood pressure and further increased by 10% after every two completed sessions. In comparison with baseline, the resting post-training levels of myostatin (p = 0.002) and IGF-1/MSTN ratio (p = 0.006) in the BFR group changed, whereas no change in the acute level of IGF-1 and myostatin after exercise was observed. Peak torque of knee extension and flexion increased in both groups (p < 0.05). A trend of increased neural activation of all heads of the quadriceps was observed in both groups, however, it was statistically significant only for rectus femoris in BFR (p = 0.02). These findings indicated that the addition of BFR to normal futsal training might induce greater neuromuscular benefits by increasing muscle activation and augmenting the hormonal response.

Blood Flow Restriction Therapy Preserves Whole Limb Bone and Muscle Following ACL Reconstruction

Objectives: Patients often experience atrophy and bone loss immediately following anterior cruciate ligament (ACL) reconstruction. Rehabilitation (rehab) combined with blood flow restriction (BFR) therapy have been shown to mitigate muscle atrophy and reduce timelines for earlier return to function. Little is known about how BFR may impact bone loss. The objectives this study were to determine if BFR provides additional benefits when added to standard rehab in young active patients following ACL reconstruction with regards to preserving bone, recovering muscle, and regaining physical function. Methods: Fourteen active young adults (M=8, F=6; 23±7 yr; 170±10 cm, 75±14 kg) undergoing ACL repair via patellar tendon autograft were recruited, provided informed consent, and were randomized into two groups (CONTROL, n=7 &amp; BFR, n=7) who performed 12wks of rehab beginning at 10 days post-surgery (2/wk). Both groups performed the same rehab protocol. However, during select exercises [quadriceps contractions wks1-3, bilateral leg press wk3-12, eccentric leg press wk4-12, hamstring curl wk4-6, eccentric hamstring curl wk7-12.], the BFR group exercised with 80% arterial limb occlusion using an automated tourniquet around the proximal thigh outfitted with Doppler (Delfi®). Exercise resistance was set at 20% of predicted 1-repetition maximum assessed in the contralateral limb. Exercises were performed for 4 sets of 30-15-15-15 repetitions separated by 30 s of rest. Functional assessments were performed at wk8 and wk12 post-surgery. Bone mineral density (BMD), bone mass, and lean muscle mass (LM) were measured using DEXA (Figure 1, GE®) at pre-surgery as well as wk6 and wk12 of rehab. Statistical Analysis: A 2(group) x 3(time) ANCOVA (co-varied on pre-surgery measures) was used to detect and compare changes in muscle and bone measures from pre-surgery at wk6 and wk12. A 2(group) x 2(time) ANOVA was used to detect and compare changes in functional outcomes tested at wk8 and wk12 between groups. Significant interactions were followed with a Tukey’s post hoc test for pairwise comparisons. Type I error was set at α=0.05. Results: Results are shown in Table 1. Both groups experienced similar decreases from pre-surgery measures in total LM at wk6 (p&lt;0.05) with total lean mass in only the CONTROL group remaining diminished at wk12 (p&lt;0.05). Whole leg LM in the injured limb was decreased in the CONTROL group, but not the BFR group, at both wk6 and wk12 (p&lt;0.05). Thigh LM was found to be decreased in both groups at wk6 but to a greater extent in the CONTROL compared to the BFR group and remained decreased in only the CONTROL group at wk12. Whole leg bone mass was decreased in the control group at wk6 and in both groups wk12 (p&lt;0.05). The CONTROL group was observed to have a decrease in BMD at the distal femur and proximal tibia as wk12 as well as the proximal fibula at wk6 and wk12 (p&lt;0.05). Both groups demonstrated similar improvements in single leg squat distance, Y-balance, leg curl, and leg press from wk8 to wk12 of rehab (p&lt;0.05). (Completed Data, N=32 anticipated by time of conference). Conclusion: In addition to recovering muscle to a greater extent than standard rehab alone, the addition of BFR to ACL rehab exercises appears to have a protective effect on bone. This effect also appears to not be limited to the site of cuff compression. Future studies are needed to examine the biochemical and mechanical mechanisms by which BFR may simultaneously act on bone and muscle. [Table: see text]

Proximal, Distal, and Contralateral Effects of Blood Flow Restriction Training on the Lower Extremities: A Randomized Controlled Trial.

Background:Blood flow restriction (BFR) training involves low-weight exercises performed under vascular occlusion via an inflatable cuff. For patients who cannot tolerate high-load exercises, BFR training reportedly provides the benefits of high-load regimens, with the advantage of less tissue and joint stress.Hypothesis:Low-load BFR training is safe and efficacious for strengthening muscle groups proximal, distal, and contralateral to tourniquet placement in the lower extremities.Study Design:Randomized controlled trial.Level of Evidence:Level 1.Methods:This was a randomized controlled trial of healthy participants completing a standardized 6-week course of BFR training. Patients were randomized to BFR training on 1 extremity or to a control group. Patients were excluded for cardiac, pulmonary, or hematologic disease; pregnancy; or previous surgery in the extremity. Data collected at baseline and completion included limb circumferences and strength testing.Results:The protocol was completed by 26 patients, providing 16 BFR and 10 control patients (mean patient age, 27 years; 62% female). A statistically greater increase in strength was seen proximal and distal to the BFR tourniquet when compared with both the nontourniquet extremity and the control group (P < 0.05). Approximately twice the improvement was seen in the BFR group compared with controls. Isokinetic testing showed greater increases in knee extension peak torque (3% vs 11%), total work (6% vs 15%), and average power (4% vs 12%) for the BFR group (P < 0.04). Limb circumference significantly increased in both the thigh (0.8% vs 3.5%) and the leg (0.4% vs 2.8%) compared with the control group (P < 0.01). Additionally, a significant increase occurred in thigh girth (0.8% vs 2.3%) and knee extension strength (3% vs 8%) in the nontourniquet BFR extremity compared with the control group (P < 0.05). There were no reported adverse events.Conclusion:Low-load BFR training led to a greater increase in muscle strength and limb circumference. BFR training had similar strengthening effects on both proximal and distal muscle groups. Gains in the contralateral extremity may corroborate a systemic or crossover effect.Clinical Relevance:BFR training strengthens muscle groups proximal, distal, and contralateral to cuff placement. Patients undergoing therapy for various orthopaedic conditions may benefit from low-load BFR training with the advantage of less tissue stress.

Electromyostimulation with blood flow restriction enhances activation of mTOR and MAPK signaling pathways in rat gastrocnemius muscles.

Neuromuscular electrical stimulation (NMES) combined with blood flow restriction (BFR) induces muscle hypertrophy. However, cellular mechanisms underlying the muscle hypertrophy induced by NMES combined with BFR remain unclear. We tested the hypothesis that NMES combined with BFR would enhance the mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signaling pathways. Age-matched male Wistar rats (6 months old, n = 7 per group) were assigned randomly to control, BFR alone (BFR), NMES alone (NMES), and NMES combined with BFR (NMES/BFR) groups. NMES induced 25 isometric contractions lasting 8 s with 4-s resting periods between contractions in the gastrocnemius muscle. Four sets in total were performed, with 1-min intervals between sets. A latex cuff was placed on the proximal portion of the hind limb and BFR at 200 mm Hg was conducted in 4 sets (each set 5 min) with 1-min rest intervals between sets. Venous blood was collected from the lateral tail vein to determine pH, H+ concentration, and lactate concentration before and immediately after the treatments. Expression levels of proteins related to muscle hypertrophy were determined by Western blot analysis. The application of NMES/BFR promoted muscle fatigue more than NMES alone. NMES/BFR induced greater changes in accumulation of metabolites and increase in gastrocnemius muscle weight. The phosphorylation of mTOR and MAPK signaling-related proteins was also enhanced following NMES/BFR, compared with other conditions. Thus, NMES enhanced the activation of mTOR and MAPK signaling pathways when combined with BFR.

Combinatorial effect of lower extremity blood flow restriction and low intensity endurance exercise on aorta of old male rats: Histomorphological and molecular approach

ObjectiveGiven the importance of knowing the effects of blood flow restriction (BFR) plus exercise training (BFR training) on the cardiovascular system, present study conducted to determine the effect of combination of BFR with low intensity endurance exercise on aorta of old rats. MethodsAnimal groups were control (CTL), sham (Sh), BFR, exercise (Ex), sham + exercise (Sh + Ex), and BFR + exercise (BFR + Ex). BFR induced by partial closing of the bilateral femoral arteries and duration of exercise was 10 weeks. ResultsBFR induced increasing of aorta wall thickness and decreasing its elastin/collagen ratio. Training alone increased the expression of apelin (P < 0.05) and angiotensin AT2 receptor (AT2R) (P < 0.01 versus CTL, Sh and P < 0.05 versus BFR groups) and the elastin/collagen ratio (P < 0.001) but, decreased the expression of angiotensin AT1 receptor (AT1R) (P < 0.01 versus CTL, Sh and BFR groups), the AT1R/AT2R ratio and the wall thickness (P < 0.001) of aorta. In Ex + BFR group, the expression of mentioned receptors increased and reached to more than levels of Ex groups, and the AT1R/AT2R ratio reduced in comparison with CTL, Sh and BFR and was higher than training groups (P < 0.5). Exercise also reversed the negative effect of BFR on elastin/collagen ratio and wall thickness. ConclusionThe beneficial effects of low intensity endurance exercise on aorta of aged male rats are conserved partially in presence of BFR.

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.

Mild exercise along with limb blood-flow restriction modulates the electrocardiogram, angiotensin, and apelin receptors of the heart in aging rats.

Objective(s):Considering the lack of information, the effects of mild endurance exercise plus blood flow restriction (BFR) on electrocardiographic parameters, hypertrophy index, and expression of angiotensin II receptors type 1 (AT1R) and type 2 (AT2R) and apelin receptor (APJ) were assessed in hearts of old male rats.Materials and Methods:Animal were grouped as control (CTL), Sham (Sh), lower extremities blood flow restriction (BFR), exercise (Ex), Sham + exercise (Sh + Ex), and blood flow restriction + exercise (BFR + Ex).Results:Exercise plus BFR significantly decreased the corrected QT (QTc) interval (P<0.01 vs CTL and Sh groups) and increased the heart hypertrophy index (P<0.05 vs CTL and BFR groups). Exercise alone increased expression of the APJ (P<0.01, vs CTL, Sh, and BFR groups) and AT2 receptors (P<0.001, vs Sh, CTL, BFR, and BFR + exercise groups), whereas it reduced expression of AT1R (P<0.01 in comparison with CTL, Sh, and BFR groups). Exercise plus BFR caused a significant increase in APJ (P<0.05 vs Ex, Sh+Ex and P<0.001 vs CTL, Sh, and BFR groups) and also expression of AT1R (P<0.001 vs Ex, Sh + Ex, CTL, Sh, and P<0.01 vs BFR groups). Accompaniment of exercise with BFR destroyed the effect of exercise on the expression of AT2R.Conclusion:Mild endurance exercise plus BFR can alter the expression of angiotensin II and apelin receptors that leads to cardiac hypertrophy and improves the ventricular conductivity of aging rats.

Does blood flow restriction training increase the diameter of forearm vessels in chronic kidney disease patients? A randomized clinical trial.

Blood flow restriction training can be used as an alternative to conventional exercise in chronic kidney disease patients with indication of arteriovenous fistula. Evaluating the efficacy of blood flow restriction training in the diameter and distensibility change of the cephalic vein and the diameter and flow of the radial artery, muscle strength and forearm circumference in chronic kidney disease patients with arteriovenous fistula pre-creation. A blind randomized clinical trial consisting of 26 chronic kidney disease patients allocated into a blood flow restriction training group (blood flow restriction; n = 12) and a group without blood flow restriction training (control group; n = 14). Blood flow restriction was performed at 50% of systolic blood pressure and using 40% of handgrip strength as load for the isometric exercises in both groups. An increase in the diameter of the cephalic vein in the 2 cm (p = 0.008) and 10 cm segments (p = 0.001) was observed in the control group. The diameter of the radial artery increased in all segments in the blood flow restriction group (2, 10 and 20 cm; p = 0.005, p = 0.021 and p = 0.018, respectively) and in the 10 and 20 cm segments (p = 0.017 and p = 0.026) in the control group. Handgrip strength only increased in the control group (p = 0.003). Physical training associated with blood flow restriction increased cephalic vein diameters in both groups and was effective in increasing the diameter of the radial artery; however, it did not demonstrate superiority over the exercise group protocol without blood flow restriction.

Effect of low-intensity eccentric resistance training with blood flow restriction on the activation and proliferation indicators of satellite cells

Introduction: The objective of the present research was to determine the effect of low-intensity eccentric training with blood flow restriction (BFR) on Hepatocyte Growth Factor (HGF) and myogenic factor 5 (Myf5), in non-athletes young men. Methods: In this study, 20 non-athlete young men were allocated to two eccentric training and eccentric training with BFR groups. Eccentric training program includes 75 knee extension repetitions in severity of 30 IRM within three sets by using isokinetic device. BFR was made by using air pressure meter and a muscular biopsy was taken from the vastus lateralis muscle of active leg, 48 hours before and 24 hours after the training program. The data were analyzed using independent and paired t-tests. Results: The results of analysis showed that HGF serum levels and mRNA Myf5 expression in both eccentric resistance training and without BFR groups had a significant increase compared to pre-test levels (Pl0.05). Moreover, it was observed that HGF serum levels and mRNA Myf5 expression in training group with BFR had a significant increase of 6.39 and 4.05, respectively, compared to training group without BFR (Pl0.05). Conclusion: The results of this research showed that eccentric training with and without BFR may improve the activation and proliferation indicators of satellite cells. But, in spite of this matter, it seems that eccentric resistance training with BFR may have a more significant effect on activation and reproduction of satellite cells. n

Electromyostimulation with Blood Flow Restriction Enhances Activation of mTOR and MAPK Signalling Pathways in Rat Gastrocnemius Muscles

AimNeuromuscular electrical stimulation (NMES) combined with blood flow restriction (BFR) can induce muscle hypertrophy. However, cellular mechanisms underlying the muscle hypertrophy induced by NMES combined with BFR remain unclear. Thus, the purpose of this study was to elucidate the signalling pathways involved in NMES with BFR induced muscle hypertrophy.MethodsAge‐matched male Wistar rats (6 months old, n=7 per group) were assigned randomly into control, BFR alone (BFR), NMES alone (NMES) and NMES combined with BFR (NMES/BFR) groups. NMES induced 25 isometric contractions lasting 8 s with a 4 s resting period between each contraction in the gastrocnemius muscle. Four sets in total were performed, with 1‐min intervals between each set. Latex cuff was placed on the proximal portion of hind limb and BFR was conducted in four sets (each set 5 min) with 1‐min rest intervals in between at 200 mmHg. Venous blood was collected from the lateral tail vein to determine pH, H+, lactic acid concentration before and immediately after the treatments. Expression levels of proteins related to muscle hypertrophy were determined by western blot analysis.ResultsThe application of NMES combined with BFR encouraged muscle fatigue more than NMES alone. NMES/BFR induced greater changes in accumulation of metabolites and increase in the weight of gastrocnemius muscle. The phosphorylation of mTOR and MAPK signalling related proteins also enhanced following NMES combined with BFR, compared with other conditions.ConclusionsWe elucidated that NMES enhanced the activation of mTOR and MAPK signalling pathways when combined with BFR.Support or Funding InformationThis work was supported by Japan Society for Promotion of Science (JSPS) KAKENHI Grant No. 16K16564 (T. Natsume) and Grant No. 17K01765 (T. Yoshihara). Grants from the MEXT‐Supported Program for Strategic Research Foundation at Private Universities also supported this research.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Lower body blood flow restriction training may induce remote muscle strength adaptations in an active unrestricted arm.

We examined the concurrent characteristics of the remote development of strength and cross-sectional area (CSA) of upper body skeletal muscle in response to lower body resistance training performed with an applied blood flow restriction (BFR). Males allocated to an experimental BFR group (EXP; n = 12) or a non-BFR control group (CON; n = 12) completed 7-weeks of resistance training comprising three sets of unilateral bicep curls [50% 1-repetition maximum (1-RM)], then four sets of bilateral knee extension and flexion exercises (30% 1-RM). EXP performed leg exercises with an applied BFR (60% limb occlusion pressure). 1-RM strength was measured using bilateral leg exercises and unilateral bicep curls in both trained and untrained arms. Muscle CSA was measured via peripheral quantitative computed tomography in the dominant leg and both arms. 1-RM in the trained arm increased more in EXP (2.5 ± 0.4kg; mean ± SEM) than the contralateral untrained arm (0.8 ± 0.4kg), and the trained arm of CON (0.6 ± 0.3kg, P < 0.05). The increase in knee extension 1-RM was twofold that of CON (P < 0.01). Knee flexion 1-RM, leg CSA, and trained arm CSA increased similarly between groups (P > 0.05), while untrained arm CSA did not change (P > 0.05). Lower limb BFR training increased trained arm strength more than the contralateral untrained arm, and the trained arm of controls. However, there was no additional effect on muscle CSA. These findings support evidence for a BFR training-derived remote strength transfer that may be relevant to populations with localised movement disorders.

Jump training with blood flow restriction has no effect on jump performance.

This study investigated whether jump training with blood flow restriction (BFR) improves jump performance compared to jump training without BFR under similar exercise intensity in healthy young humans. The participants were twenty healthy males who were assigned to either jump training with BFR (n = 10) or jump training without BFR [control (CON); n = 10] groups. All subjects completed five sets of 10 repetitions with one-minute intervals of half-squat jumps (SJ) at maximal effort, four days a week for four weeks. In the BFR group, circulatory occlusion around both thigh muscles was applied at a pressure of 200 mmHg, and physical characteristics, muscle strength and jump performance were evaluated before and after training. A significant main effect of training period on lean body mass, percentage of body fat and leg circumference in both groups was observed (P < 0.05). For jump training with BFR, only knee flexion strength increased (P < 0.05), while in the CON group, both knee extension and flexion strength increased (P < 0.05). BFR training did not improve SJ or counter-movement jumps (CMJ) (P > 0.05), whereas training without BFR (CON) improved the performance of both jumps (SJ: pre 35.7 ± 5.1 vs. post 38.9 ± 4.1 cm, P = 0.002: CMJ: pre 41.6 ± 3.6 vs. post 44.6 ± 3.8 cm, P < 0.001). These results indicate that jump training with BFR may not be an effective strategy for improving jump performance.