Effects of Resting vs. Continuous Blood-Flow Restriction-Training on Strength, Fatigue Resistance, Muscle Thickness, and Perceived Discomfort

The effects of blood flow restriction training on post activation potentiation and fatigue level: systematic review with meta-analysis

Objective

This study aims to comprehensively explore the effects of blood flow restriction (BFR) training on the post-activation potentiation (PAP) and the rating of perceived exertion (RPE) through meta-analysis, so as to provide a scientific basis for athletes' physical fitness training.

Methods

The PubMed, CNKI, Web of Science and EBSCO databases were searched to look for randomized controlled trials (RCTs) on the effects of BFRT on post-activation potentiation (PAP) and the rating of perceived exertion (RPE). The Cochrane risk of bias tool was used to screen the literature. With the help of Revman 5.4 and Stata 17.0 software, the literature quality assessment and statistical analysis were completed. Meanwhile, sensitivity analysis and funnel plots were utilized to examine the stability of the results and the publication bias.

Results

A total of 31 related studies were included, among which 22 studies focused on the relationship between BFR training and PAP, covering 347 participants. Meta-analysis showed that BFRT could significantly affect PAP [SMD = 0.49, 95% CI (0.20, 0.77), P = 0.0008]. When the testing method was Squat Jump [SMD = 1.35, 95% CI (0.40, 2.30), P < 0.0005], the exercise intensity was 40%-70% 1RM [SMD = 1.21, 95% CI (0.69, 1.73), P < 0.0001], and the compression intensity was ≤50% AOP [SMD = 0.77, 95% CI (0.24, 1.30), P = 0.05], the effects on PAP reached the maximum, respectively, and were statistically significant. In terms of the impact of BFR training on RPE, 18 studies with 238 subjects were included. BFR training could significantly increase the RPE of the subjects [SMD = 1.21, 95% CI (0.69, 1.73), P < 0.0001]. When the exercise mode was Knee flexion [SMD = 0.65, 95% CI (0.18, 1.11), P = 0.0006], the exercise intensity was Mixed oxygen Training [SMD = 1.03, 95% CI (0.50, 1.56), P = 0.0001], and the compressive strength was ≥60% AOP [SMD = 0.75, 95% CI (0.02, 1.48), P = 0.05], a more significant effect size was presented.

Conclusion

Blood flow restriction training can induce the occurrence of post-activation potentiation (PAP). BFR exercises with 40%-70% 1RM and ≤50% AOP are more likely to stimulate PAP. Meanwhile, BFR training will significantly affect the rating of perceived exertion (RPE). BFR training under mixed oxygen training and with a compressive strength of ≥60% AOP has a stronger perception of fatigue. Systematic Review Registration: http://inplasy.com, identifier INPLASY202430008.

Progression and perceptual responses to blood flow restriction resistance training among people with multiple sclerosis

PURPOSE

Resistance exercise can attenuate muscular impairments associated with multiple sclerosis (MS), and blood flow restriction (BFR) may provide a viable alternative to prescribing heavy training loads. The purpose of this investigation was to examine the progression of upper and lower body low-load (30% of one-repetition maximum [1RM]) resistance training (RT) with BFR applied intermittently during the exercise intervals (RT + BFR) versus volume-matched heavy-load (65% of 1RM) RT.

METHODS

Men and women with MS (n = 16) were randomly assigned to low-load RT + BFR (applied intermittently) or heavy-load RT and completed 12 weeks (2 × /week) of RT that consisted of bilateral chest press, seated row, shoulder press, leg press, leg extension, and leg curl exercises. Exercise load, tonnage, and rating of perceived exertion were assessed at baseline and every 6 weeks.

RESULTS

Training load increased to a greater extent and sometimes earlier for RT + BFR (57.7-106.3%) than heavy-load RT (42.3-54.3%) during chest press, seated row, and leg curl exercises, while there were similar increases (63.5-101.1%) for shoulder press, leg extension, and leg press exercises. Exercise tonnage was greater across all exercises for RT + BFR than heavy-load RT, although tonnage only increased during the chest press (70.7-80.0%) and leg extension (89.1%) exercises. Perceptions of exertion (4.8-7.2 au) and compliance (97.9-99.0%) were similar for both interventions.

CONCLUSION

The training-induced increases in load, high compliance, and moderate levels of exertion suggested that RT + BFR and heavy-load RT are viable interventions among people with MS. RT + BFR may be a preferred modality if heavy loads are not well tolerated and/or to promote early-phase training responses.

Individual muscle hypertrophy in high-load resistance training with and without blood flow restriction: A near-infrared spectroscopy approach

We aimed to compare individual hypertrophic responses to high-load resistance training (HL-RT) or high-load with blood flow restriction (HL-BFR). Furthermore, we investigated whether greater responsiveness to one of the protocols could be explained by acute changes in blood deoxyhemoglobin concentration (HHb) and total hemoglobin concentration (tHb) (proxy markers of metabolic stress). Ten untrained participants had their legs randomized into both HL-RT and HL-BFR and underwent 10 weeks of training. Muscle cross-sectional area (mCSA) was measured at baseline and post training, while HHb and tHb during the final session. Using a threshold of 2 × typical errors (3.24%) to compare protocols, five participants showed greater mCSA increases after HL-RT (16.44 ± 7.90%) compared to HL-BFR (10.74 ± 7.12%, p = 0.0054) and five did not respond better to HL-RT (8.95 ± 10.83%) compared to HL-BFR (13.33 ± 8.59%) (p = 0.3105). Additionally, HL-RT induced lower HHb (5855.78 ± 12905.99; p = 0.0101) and tHb (-43169.70 ± 37793.17; p = 0.0030) AUC values compared to HL-BFR (HHb: 39254.80 ± 27020.15; tHb: 46309.40 ± 31613.97). In conclusion, despite the higher levels of metabolic stress markers, most participants did not present greater muscle hypertrophy by combining blood flow restriction with HL-RT.

Blood Flow Restricted Resistance Exercise in Well-Trained Men: Salivary Biomarker Responses and Oxygen Saturation Kinetics

ABSTRACT

Eserhaut, DA, DeLeo, JM, and Fry, AC. Blood flow restricted resistance exercise in well-trained men: Salivary biomarker responses and oxygen saturation kinetics. J Strength Cond Res 38(12): e716-e726, 2024-Resistance exercise with continuous lower-limb blood flow restriction (BFR) may provide supplementary benefit to highly resistance-trained men. Thus, the purpose of this study was to compare cardiovascular and salivary biomarker responses, along with skeletal muscle oxygen saturation (SmO2) during passive lower-limb BFR (pBFR), BFR resistance exercise performed to task failure (BFR+RE), and volume-matched resistance exercise (RE). A within-subjects, repeated measures design was used. Nineteen men (x̄±SD: relative squat 1RM: 1.9 ± 0.3 kg·bw-1) reported for 3 visits. First, body composition, blood pressure, back squat, and leg extension 1 repetition maximums (1RM) were assessed. Resting systolic blood pressure and proximal thigh circumferences were used to estimate arterial occlusion pressures (eAOP). Visit 1 involved pBFR, where BFR cuffs were inflated to 80% eAOP around the proximal thighs for 10 minutes while subjects were seated in a leg extension machine. Then, 24-120 hours later, 4 sets of bilateral seated leg extensions at 30% 1RM were performed to momentary task failure with 1-minute rest at the same 80% eAOP. After 72-120 hours rest, subjects matched the repetition performances from BFR+RE at 30% 1RM for the RE condition. BFR+RE elicited greater (p ≤ 0.05) heart rates, systolic, and diastolic blood pressures relative to pBFR and RE. Significantly elevated (p ≤ 0.05) blood lactate, salivary cortisol concentrations, and α-amylase activity occurred following BFR+RE relative to pBFR and RE. BFR+RE also induced blunted (p < 0.001) SmO2 interset resaturation rates compared with RE. In trained men, continuous BFR+RE seems to significantly alter acute physiological responses to a greater degree than either pBFR alone or volume-matched RE.

Enhancing lower limb and core muscle activation with blood flow restriction training: a randomized crossover study on high-intensity squat exercises

Objective

The primary objective of this study was to assess the impact of high-intensity deep squat training integrated with various blood flow restriction (BFR) modalities on the activation of lower limb and core muscles.

Methods

A randomized, self-controlled crossover experimental design was employed with 12 participants. The exercise protocol consisted of squat training at 75% of one-repetition maximum (1RM), performed in 3 sets of 8 repetitions with a 2-min inter-set rest period. This was conducted under four distinct BFR conditions: continuous low BFR (T1), intermittent medium BFR (T2), intermittent high BFR (T3), and a non-restricted control (C). Surface electromyography (EMG) was utilized to collect EMG signals from the target muscles during the BFR and squat training sessions. The root mean square (RMS) amplitude standard values were calculated for each squat set to quantify muscle activation levels, with these values expressed as a percentage of the maximum voluntary contraction (%MVC). Rating of Perceived Exertion was evaluated after each squat set, and leg circumference measurements were taken.

Results

1) During the first two sets of deep squats, the %MVC of the vastus lateralis and vastus medialis in all compression groups was significantly higher than that in the control group (p < 0.05). Furthermore, in the first set, the %MVC of the vastus lateralis in Group T3 was significantly higher than in Group T2 (p < 0.05). In the third set, the %MVC of the vastus medialis in Groups T1 and T3 was significantly lower than in the first two sets (p < 0.05). 2) Group T1 showed an increased activation of the biceps femoris and semitendinosus muscles in the second and third sets, with %MVC values significantly greater than in the first set (p < 0.05). Group T2 only showed an increase in biceps femoris activation in the third set (p < 0.05). Group T3 significantly increased the activation of the biceps femoris and semitendinosus muscles only in the first set (p < 0.05). 3) No significant differences were observed in the changes of rectus abdominis %MVC among the groups (p > 0.05). In the first set, Group T3's erector spinae %MVC was significantly higher than the control group's; in the second set, it was significantly higher than both Group T2 and the control group's (p < 0.05). 4) After training, a significant increase in thigh circumference was observed in all groups compared to before training (p < 0.05). 5) For RPE values, Group T2's post-squat values were significantly higher than the control group's after all three sets (p < 0.05). Group T1's RPE values were also significantly higher than the control group's after the third set (p < 0.05). Groups T1, T2, and C all had significantly higher RPE values in the second and third sets compared to the first set (p < 0.05).

Conclusion

All BFR modalities significantly enhanced the activation level of the anterior thigh muscles, with the continuous low BFR mode demonstrating a more stable effect. No significant differences were found in the activation level of the rectus abdominis among the groups. However, the intermittent high BFR mode was the most effective in increasing the activation level of the erector spinae muscles. While BFR did not further augment leg circumference changes, it did elevate subjective fatigue levels. The RPE was lowest during squatting under the intermittent high BFR condition.

Effects of different ischemic pressures on bar velocity during the bench press exercise: A randomized crossover trial

The main objective of this study was to evaluate the effects of different ischemic pressures applied during rest intervals on bar velocity during the bench press exercise. 10 resistance-trained males (age = 23.2 ± 2.7 years; body mass = 83.9 ± 9 kg; body height = 181 ± 5.2 cm; bench press 1 repetition maximum (1RM) = 125 ± 16.4 kg; training experience = 5.4 ± 3.4 years) participated in the study. During 4 experimental sessions, following a randomized crossover design, the subjects performed 5 sets of 3 repetitions of the bench press exercise with a load of 60% 1RM under conditions: with ischemia (50% or 80% of arterial occlusion pressure), with SHAM ischemia (20 mmHg) and without ischemia (control condition). For the ischemic conditions cuffs were applied before each set for 6.5 min and released 30 s before the start of the set as reperfusion (6.5 min ischemia + 0.5 min reperfusion). In the control condition, ischemia was not applied. The two-way repeated measures ANOVA showed no significant condition × set interaction for mean bar velocity (MV; p = 0.17) and peak bar velocity (PV; p = 0.66). There was also no main effect of condition for MV (p = 0.58) and PV (p = 0.61). The results indicate that ischemic or SHAM treatment (6.5 minutes ischemia or SHAM + 30 s reperfusion) does not affect mean and peak bar velocity during the bench press exercise regardless of the applied pressure.

Acute Effects of Sprint Interval Training and Blood Flow Restriction on Neuromuscular and Muscle Function

BFR) applied during sprint interval training (SIT) on performance and neuromuscular function.

METHODS

Fifteen men completed a randomized bout of SIT with CBFR, IBFR, and without BFR (No-BFR), consisting of 2, 30-s maximal sprints on a cycle ergometer with a resistance of 7.5% of body mass. Concentric peak torque (CPT), maximal voluntary isometric contraction (MVIC) torque, and muscle thickness (MT) were measured before and after SIT, including surface electromyography (sEMG) recorded during the strength assessments. Peak and mean revolutions per minute (RPM) were measured during SIT and power output was examined relative to physical working capacity at the fatigue threshold (PWCFT).

RESULTS

CPT and MVIC torque decreased from pre-SIT (220.3±47.6 Nm and 355.1±72.5 Nm, respectively) to post-SIT (147.9±27.7 Nm and 252.2±45.5 Nm, respectively, all P<0.05), while MT increased (1.77±0.31 cm to 1.96±0.30 cm). sEMG mean power frequency decreased during CPT (-12.8±10.5%) and MVIC (-8.7±10.2%) muscle actions. %PWCFT was greater during No-BFR (414.2±121.9%) than CBFR (375.9±121.9%).

CONCLUSION

SIT with or without BFR induced comparable alterations in neuromuscular fatigue and sprint performance across all conditions, without affecting neuromuscular function.

Effects of High-Load Bench Press Training with Different Blood Flow Restriction Pressurization Strategies on the Degree of Muscle Activation in the Upper Limbs of Bodybuilders

Background: The aim of this study was to investigate the effects of different pressurization modes during high-load bench press training on muscle activation and subjective fatigue in bodybuilders. Methods: Ten bodybuilders participated in a randomized, self-controlled crossover experimental design, performing bench press training under three different pressurization modes: T1 (low pressure, high resistance), T2 (high pressure, high resistance), and C (non-pressurized conventional). Surface EMG signals were recorded from the pectoralis major, deltoid, and triceps muscles using a Delsys Trigno wireless surface EMG during bench presses. Subjective fatigue was assessed immediately after the training session. Results: (1) Pectoralis major muscle: The muscle activation degree of the T1 group was significantly higher than that of the blank control group during the bench press (p < 0.05). The muscle activation degree of the T2 group was significantly higher than that of the C group during the bench press (p < 0.05). In addition, the muscle activation degree of the T2 group was significantly higher than that of the T1 group during the first group bench press (p < 0.05). (2) Deltoid muscle: The muscle activation degree of the T2 group during the third group bench press was significantly lower than the index values of the first two groups (p < 0.05). The muscle activation degree in the experimental group was significantly higher than that in the C group (p < 0.05). The degree of muscle activation in the T2 group was significantly higher than that in the T1 group during the first bench press (p < 0.05). (3) Triceps: The muscle activation degree of the T1 group was significantly higher than the index value of the third group during the second group bench press (p < 0.05), while the muscle activation degree of the T2 group was significantly lower than the index value of the first two groups during the third group bench press (p < 0.05). The degree of muscle activation in all experimental groups was significantly higher than that in group C (p < 0.05). (5) RPE index values in all groups were significantly increased (p < 0.05). The RPE value of the T1 group was significantly higher than that of the C group after bench press (p < 0.05). The RPE value of the T1 group was significantly higher than that of the C group after bench press (p < 0.05). In the third group, the RPE value of the T1 group was significantly higher than that of the C and T2 groups (p = 0.002) (p < 0.05). Conclusions: The activation of the pectoralis major, triceps brachii, and deltoid muscles is significantly increased by high-intensity bench press training with either continuous or intermittent pressurization. However, continuous pressurization results in a higher level of perceived fatigue. The training mode involving high pressure and high resistance without pressurization during sets but with 180 mmHg occlusion pressure and pressurization during rest intervals yields the most pronounced overall effect on muscle activation.

Effect of Isokinetic Training with Blood Flow Restriction During Rest Interval Versus Exercise on Muscle Strength, Hypertrophy, and Perception: A Pilot Study

Objectives

This study aimed to determine the effects of high-intensity isokinetic training with blood flow restriction during rest interval between set (rBFR) versus during exercise (eBFR) on muscle hypertrophy and increasing muscle strength and determine whether BFR-induced exercise pain is suppressed by rBFR.

Materials and Methods

Fourteen arms (7 participants) were recruited for the study. We conducted the following interventions for each arm: eBFR (n=4), rBFR (n=5), and exercise only (CON, n=5). The participants performed elbow flexion training with a BIODEX device twice weekly for 8 weeks. This study training consisted of total four sets; each was performed until <50% peak torque was achieved twice consecutively. BFR pressure was set at 120 mmHg. Elbow flexor peak torque during concentric contraction (CC), isometric contraction (IM), and muscle cross-sectional area (CSA) were measured before and after the intervention. Numerical rating scale scores used to assess pain during exercise were determined during training.

Results

Peak torque at the CC increased in the rBFR (p<0.05) and IM increased in the rBFR and CON (p<0.05), while CSA increased in the rBFR and CON (p<0.001). The pain during exercise was severe in the eBFR and moderate in the rBFR and CON.

Conclusions

This study's showed that high-intensity isokinetic training with rBFR did not have a synergistic effect on increasing muscle strength and muscle size. Additionally, high-intensity isokinetic training with BFR when it may be best not to perform it during exercise, because it was induces severe pain and may inhibit increases in muscle strength.

Effects of muscle fatigue on exercise-induced hamstring muscle damage: a three-armed randomized controlled trial

PURPOSE

Hamstring injuries in soccer reportedly increase towards the end of the matches' halves as well as with increased match frequency in combination with short rest periods, possibly due to acute or residual fatigue. Therefore, this study aimed to investigate the effects of acute and residual muscle fatigue on exercise-induced hamstring muscle damage.

METHODS

A three-armed randomized-controlled trial, including 24 resistance-trained males, was performed allocating subjects to either a training group with acute muscle fatigue + eccentric exercise (AF/ECC); residual muscle fatigue + eccentric exercise (RF/ECC) or a control group with only eccentric exercise (ECC). Muscle stiffness, thickness, contractility, peak torque, range of motion, pain perception, and creatine kinase were assessed as muscle damage markers pre, post, 1 h post, and on the consecutive three days.

RESULTS

Significant group × time interactions were revealed for muscle thickness (p = 0.02) and muscle contractility parameters radial displacement (Dm) and contraction velocity (Vc) (both p = 0.01), with larger changes in the ECC group (partial η2 = 0.4). Peak torque dropped by an average of 22% in all groups; stiffness only changed in the RF/ECC group (p = 0.04). Muscle work during the damage protocol was lower for AF/ECC than for ECC and RF/ECC (p = 0.005).

CONCLUSION

Hamstring muscle damage was comparable between the three groups. However, the AF/ECC group resulted in the same amount of muscle damage while accumulating significantly less muscle work during the protocol of the damage exercise.

TRIAL REGISTRATION

This study was preregistered in the international trial registration platform (WHO; registration number: DRKS00025243).

Acute Effects of Blood Flow Restriction Training on Movement Velocity and Neuromuscular Signal during the Back Squat Exercise

The aim of this study was to verify the effects of blood flow restriction on movement velocity and muscle activity during the back squat exercise.

METHODS

Twenty-four university students participated in this study. In two randomized sessions 72 h apart, participants performed a 4-set protocol consisting of 30-15-15-15 repetitions performed at 30% of their one-repetition maximum in the back squat exercise. In both sessions, neuromuscular function was monitored by surface electromyography (EMG) and movement velocity (mean propulsive velocity (MPV), peak concentric velocity (Vmax), and the effort index (EI)). Blood flow restriction (BFR) was applied during exercise in one of the experimental sessions with 80% of full arterial occlusion pressure over lower limbs.

RESULTS

The BFR condition showed higher (p < 0.05) EI, peak, and rooted mean square normalized EMG in Set 1 compared to Set 2. Similar MPV and Vmax were observed in each set for both the BFR and control conditions. No significant differences were observed between conditions in any set.

CONCLUSIONS

BFR did not imply changes in neuromuscular performance during low-intensity resistance training, but it might induce greater intra-series velocity loss and less excitation of the muscles involved.

Resistance training volume does not influence lean mass preservation during energy restriction in trained males

This study investigated the effects of a relatively high- versus moderate-volume resistance training program on changes in lean mass during caloric restriction. Thirty-eight resistance-trained males were randomized to perform either a high-volume (HVG; 5 sets/exercise) or a moderate-volume (MVG; 3 sets/exercise) resistance training program. Both groups were supervised during lower body training. Participants consumed 30 kcal/kg for 6 weeks after 1 week of weight maintenance (45 kcal/kg), with protein intake fixed at 2.8 g/kg fat-free mass. Muscle thickness of the m. rectus femoris, body composition, contractile properties, stiffness, mood, and sleep status were assessed at pre-, mid-, and post-study. No significant group × time interaction was observed for muscle thickness of the m. rectus femoris at 50% (∆ [post-pre] 0.36 ± 0.93 mm vs. ∆ -0.01 ± 1.59 mm; p = 0.226) and 75% length (∆ -0.32 ± 1.12 mm vs. ∆ 0.08 ± 1.14 mm; p = 0.151), contractility, sleep, and mood in the HVG and MVG, respectively. Body mass (HVG: ∆ -1.69 ± 1.12 kg vs. MVG: ∆ -1.76 ± 1.76 kg) and lean mass (∆ -0.51 ± 2.30 kg vs. ∆ -0.92 ± 1.59 kg) decreased significantly in both groups (p = 0.022), with no between-group difference detected (p = 0.966). High-volume resistance training appears to have neither an advantage nor disadvantage over moderate-volume resistance training in terms of maintaining lean mass or muscle thickness. Given that both groups increased volume load and maintained muscle contractility, sleep quality, and mood, either moderate or higher training volumes conceivably can be employed by resistance-trained individuals to preserve muscle during periods of moderate caloric restriction.

Dose-response relationship of blood flow restriction training on isometric muscle strength, maximum strength and lower limb extensor strength: A meta-analysis

Objective: To perform a meta-analysis on the efficacy and dose-response relationship of blood flow restriction training on muscle strength reported worldwide. Methods: Thirty-four eligible articles with a total sample size of 549 participants were included in the meta-analysis. This study was performed using the method recommended by the Cochrane Handbook (https://training.cochrane.org/handbook), and the effect size was estimated using the standardized mean difference (SMD) and using RevMan 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014). Results: The meta-analysis showed that blood flow restriction training increased the lower limb extensor muscle strength [SMD = 0.72, 95%; confidence interval (CI): 0.43 to 1.00, p < 0.01], knee extensor isokinetic torque SMD = 0.48 [95% CI: 0.24 to 0.73, p < 0.01], knee flexor isokinetic torque SMD = 0.39 [95% CI: 0.11 to 0.67, p < 0.01], and squat one-repetition maximum [SMD = 0.28, 95% CI: 0.01 to 0.55, p < 0.01]. There was no publication bias. Evaluation of dose-response relationship showed that the training load, mode, frequency, duration, and maximum cuff pressure affected the muscle function. Conclusion: blood flow restriction training. 16 significantly improved lower limb muscle strength, and the optimal training conditions consisted of a weight load smaller or equal to 30% of one-repetition maximum, training duration longer than 4 weeks, frequency of more than 3 times/week, and maximum cuff pressure lower than 200 mmHg. Systematic Review Registration: website, identifier registration number.

Acute Effects of Ischemic Intra-Conditioning on 30 m Sprint Performance

The present study aimed to evaluate the effects of ischemic intra-conditioning applied during rest intervals on 30 m sprint performance. Thirty-four trained male (n = 12) and female (n = 22) track and field and rugby athletes volunteered to participate in the study (age = 19.6 ± 4 years; training experience = 5.3 ± 1.9 years). In a randomized and counterbalanced order, participants performed six sets of 30 m sprints under three different testing conditions: without ischemic intra-conditioning, and with ischemic intra-conditioning at 60% or 80% arterial occlusion pressure applied bilaterally before the first trial of the sprint and during the rest periods between all sprint trials. During experimental sessions, subjects perform 6 × 30 m sprints with a 7 min rest interval between attempts. The cuffs were applied following a 1 min rest period and lasted for 5 min before being released at the 6th minute to allow for reperfusion (1 min + 5 min ischemic intra-conditioning + 1 min reperfusion). The two-way repeated measures ANOVA did not show statistically significant condition × set interaction for time of the sprint (p = 0.06; η² = 0.05). There was also no main effect of ischemic intra-conditioning for any condition (p = 0.190; η² = 0.05). This study indicates that ischemic intra-conditioning did not enhance the performance of 30 m sprints performed by athletes. However, ischemic intra-conditioning did not decrease performance either.

Resistance Training with Blood Flow Restriction and Ocular Health: A Brief Review

Despite the many health benefits of resistance training, it has been suggested that high-intensity resistance exercise is associated with acute increases in intraocular pressure which is a significant risk factor for the development of glaucomatous optic nerve damage. Therefore, resistance training using a variety of forms (e.g., resistance bands, free weights, weight machines, and bodyweight) may be harmful to patients with or at risk of glaucoma. An appropriate solution for such people may involve the combination of resistance training and blood flow restriction (BFR). During the last decade, the BFR (a.k.a. occlusion or KAATSU training) method has drawn great interest among health and sports professionals because of the possibility for individuals to improve various areas of fitness and performance at lower exercise intensities. In comparison to studies evaluating the efficiency of BFR in terms of physical performance and body composition changes, there is still a paucity of empirical studies concerning safety, especially regarding ocular health. Although the use of BFR during resistance training seems feasible for glaucoma patients or those at risk of glaucoma, some issues must be investigated and resolved. Therefore, this review provides an overview of the available scientific data describing the influence of resistance training combined with BFR on ocular physiology and points to further directions of research.

Effect of low-intensity exercise with blood flow restriction during rest intervals on muscle function and perception

PURPOSE

We assessed the effects of low-intensity exercise with blood flow restriction (BFR) during rest intervals on recovery of muscle function and pain during exercise and rest intervals.

METHODS

Participants were 10 males, and study arms of the participants were randomly assigned into three conditions; low-intensity exercise with BFR during rest intervals (rBFR), low-intensity exercise with BFR during exercise (eBFR) and low-intensity exercise only (EO). The exercise task was elbow flexion until repetition failure at 30% of 1 RM, and cuff pressure was 120 mmHg. The maximum voluntary isometric contraction (MVIC) and the muscle endurance (ME) were measured pre, post, 1 h, 24 h and 48 h after the exercise. Pain during exercise and rest intervals were evaluated using Numerical Rating Scale.

RESULTS

MVIC and ME significantly decreased after exercise in all conditions. Pain during exercise was lower in rBFR (4.2 ± 2.9) (p = 0.007) and EO (4.4 ± 2.7) (p = 0.014) conditions compared to eBFR condition (6.7 ± 1.7), but the pain during rest intervals was more intense in rBFR condition (5.2 ± 1.6) compared to eBFR (1.5 ± 1.4) and EO (1.7 ± 1.2) conditions (all: p < 0.001).

CONCLUSION

We discovered that recovery of muscle function was the same as BFR during rest intervals and BFR during exercise. Also, our results suggested that BFR itself may cause the perception of pain. Future studies are thus required to investigate the optimal dosage focusing on the pressure volume and intensity used in BFR during intervals. This article is protected by copyright. All rights reserved.

The Effects of Ischemia During Rest Intervals on Bar Velocity in the Bench Press Exercise With Different External Loads

The main aim of the present study was to evaluate the acute effects of ischemia used during rest periods on bar velocity changes during the bench press exercise at progressive loads, from 20 to 90% of 1RM. Ten healthy resistance trained men volunteered for the study (age = 26.3 ± 4.7 years; body mass = 89.8 ± 6.3 kg; bench press 1RM = 142.5 ± 16.9 kg; training experience = 7.8 ± 2.7 years). During the experimental sessions the subjects performed the bench press exercise under two different conditions, in a randomized and counterbalanced order: (a) ischemia condition, with ischemia applied before the first set and during every rest periods between sets, and (b) control condition where no ischemia was applied. During each experimental session eight sets of the bench press exercise were performed, against loads starting from 20 to 90% 1RM, increased progressively by 10% in each subsequent set. A 3-min rest interval between sets was used. For ischemia condition the cuffs was applied 3 min before the first set and during every rest period between sets. Ischemia was released during exercise. The cuff pressure was set to ∼80% of full arterial occlusion pressure. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak bar velocity (p = 0.04) and for mean bar velocity (p = 0.01). There was also a statistically significant main effect of condition for peak bar velocity (p < 0.01) but not for mean bar velocity (p = 0.25). The post hoc analysis for interaction showed significantly higher peak bar velocity for the ischemia condition compared to control at a load of 20% 1RM (p = 0.007) and at a load of 50% 1RM (p = 0.006). The results of the present study indicate that ischemia used before each set even for a brief duration of <3 min, has positive effects on peak bar velocity at light loads, but it is insufficient to induce such effect on higher loads.