Blood Flow Restriction (BFR) – Blog

The incidence of fractures in DK/year is approx. 80,000, of which 3,000-4,000 are ankle-related.

Most often, the fracture is plastered, which can include marrow sewing, osteosynthesis and rarely external fixation. For the first 3 weeks, load is inhibited, at approx. 3 weeks post op. gradually increased weight bearing is recommended.

Therefore, one should be careful about starting exercising, to avoid compromising the healing mechanisms of the bones. As adjacent to the fracture, muscles, arteries and nerves can be injured due to the sharp surfaces of the fracture or during the operation, which potentially complicates the rehab.

Because of the required immobilization following operation, severe muscle atrophy (muscle loss) will occur. As ankle fractures results in longer periods without weight bearing and local immobility, the rehabilitation options are very limited in the early phase.

Though, it has been proven that atrophy can be reduced by a swift implementation of BFR, in respect to fracture type and possible complications. By reducing the associated loss of muscle mass, one could expect a shorter rehab period and therefor a faster return-to-play.

By combining BFR with conventional low-load resisted knee-extension and knee-flexion exercises you got an effective combo to counter act the atrophy of the thighs, hamstrings and the superficial calf muscles.

Considering the recommendation of high frequency training as 1-2 daily for an effective retention of muscle mass for, elastic bands are being used as a low practical setup for 3 consecutive weeks.

Adjacent to this primary effect, BFR may reduce the fracture associated pain (hypoanalgesic effect) and improve overall functioning which may translate to less long-term disability, which is especially relevant for the elderly.

Source:

Cancio et al. (2019) Blood Flow Restriction Therapy after Closed Treatment of Distal Radius Fractures.

Loenneke et al. (2012) Rehabilitation of an osteochondral fracture using blood flow restricted exercise: A case review.

(3) Bittar et al. (2017) Effects of blood flow restriction exercises on bone metabolism: a systematic review.

Because of the inherent difficulties of a fair comparison, results are varying of wherever BFR-RT is more or less effective. Though, at least 4 meta-analysis has explored the potential effect of BFR-RT vs (C-RT) / (HL-RT).

But even though this has been explored in several metal-analysis, methodological difficulties make the question hard to answer without further clarification.

If we take a look at short term follow-up it seems that BFR-RT can be more effective, but probably only in regards to hypertrophy. For longer follow-up periods (>10 weeks) it seems that C-RT is more effective on most parameters.

But the largest issue for measuring the effect of BFR-RT, is the different group designs, i.e. type of exercise intervention. Therefore, we have tried to pin-point some relevant comparisons and the results extracted from various meta-analysis:

BFR-RT vs C-RT (repetition matched):
Strength, significant in favor of BFR-RT. Hypertrophy, significant in favor of BFR-RT.
Though much higher Ratings of Perceived Exertion for BFR-RT.

BFR-RT vs C-RT (voluntary/repetition failure):
Similar effects, thus in favor of BFR-RT.
Similar Ratings of Perceived Exertion. But anywhere from 30-50% more repetition needed without BFR.

BFR-RT vs HL-RT (relative RM matched or voluntary failure):
Strength, in favor of HL-RT. Hypertrophy, similar effect. Though, longer exercise duration for HL-RT.
Similar Ratings of Perceived Exertion.

Summarized:
Short-term muscle mass: Probably BFR-RT.
Long-term muscle mass: Approximately same.
Short-term muscle strength: Approximately same.
Long-term muscle strength: HL-RT.

Side note: Muscle endurance and anaerobic performance: BFR-RT.
Maximum power development and training to improve running velocity: HL-RT.
But these comparisons have only limited practical importance as BFR-RT is primarily targeted the impaired e.g. injured or just as an adjunct to HL-RT for the majority of athletes and average Joe´s.

Source:

Slysz et al. (2016) The efficacy of blood flow restricted exercise: A systematic review & meta-analysis.

Hughes et al. (2017) Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis.

Centner et al. (2018) Effects of Blood Flow Restriction Training on Muscular Strength and Hypertrophy in Older Individuals: A Systematic Review and Meta‑Analysis.

Lixandrao et al. (2018) Magnitude of Muscle Strength and Mass Adaptations Between High-Load Resistance Training Versus Low-Load Resistance Training Associated with Blood-Flow Restriction: Systematic Review and Meta-Analysis.

In the video, a sub-elite orientation runner suffering from fluctuating PFP is implementing Fit Cuffs (older version) to augment the back squat and lunges. In his case, BFR has proven to be a game changer in regard to less aggravation of pain.

Typically, high-load resistance training focusing on strengthening the quadriceps and hip abductors, subsequently to graduated exposure, has been recommended.

But the results from a RCT comparing BFR training and conventional resistance training, shows that BFR is just as effective to elicit strength, though, superior for people with concurrent knee pain.

Background: BFR may provide low-load quadriceps strengthening method to treat PFP as heavy resistance exercises may aggravate knee pain.

Method: BFR, n=35 vs. conventional resistance training n=34, as 8 weeks of leg press and leg extension, at 70% 1RM vs. BFR group at 30% 1RM. Interventions were compared by Kujala Patellofemoral Score, Visual Analogue Scale and pain with daily activity, isometric knee extensor torque (strength) and quadriceps muscle thickness.

Results: BFR group had a significant 93% greater reduction in pain with activities of daily living. Participants with painful resisted knee extension (n=39) had a significant greater increases in knee strength with BFR. Though, no significant difference was detected at 6 months.

Conclusion: BFR group experienced greater reduction in pain with daily living at 8 weeks. Improvements were similar between groups as worst pain and Kujala score. The subgroup analysis showed that those with pain during knee extension had greater strength gains with BFR.

Therefore, BFR can be recommended to treat PFP, especially for athletes with pain during conventional exercise or in periods of high training load, e.g. in-season.

Source: Giles et al. (2017) Quadriceps strengthening with and without blood flow restriction in the treatment of patellofemoral pain: a double-blind randomised trial.

In the video @noor.reno is applying Bulgarian split squat with an elevated front foot for increased range of motion. Though, the most import aspect of this relatively low-load setup, is the augmentation of BFR for contralateral leg gain.

Maintaining or improving muscle mass and strength is imperative for higher-level sports and athletic performance.

But for some individuals into training and rehab, BFR is primarily seen as a tool for the injured or otherwise impaired individuals. Thus, recently the body of research on BFR has expanded enormously and repeatedly shows to be a game changer for rapid improvement of performance. This is a soundly reason why, BFR is currently being programmed into the training routines of high-level athletes all around the world.

A relevant implication of BFR for the impaired or for the high performing athlete, is the use of single leg exercises to improve strength in both the proximal and contralateral limb relative to the cuff, as recently discovered by Bowman et al:

Methods: RCT, conducted on healthy participants by a standardized 6-week BFR protocol. BFR training on 1 extremity compared to a control group, specified as BFR-Limp vs No-BFR-Limp vs. control.

Results: A statistically 2-3 fold greater increase in strength was seen proximal and distal to the cuff (BFR-Limp vs control).

Additionally, a significant increase occurred in the thigh girth and knee extension strength for the No-BFR -Limp compared with the control group as (2.3% vs 0.8%) and (8% vs 3%) respectively.

Conclusion: BFR training led to a 2-3 fold greater increase in muscle strength. BFR training had similar strengthening effects on both proximal and distal muscle groups relative to the cuff. Gains in the contralateral limb may corroborate a systemic or crossover effect.

Source:
Bowman et al. (2019) Proximal, Distal, and Contralateral Effects of Blood Flow Restriction Training on the Lower Extremities: A Randomized Controlled Trial.

In the video an Arm Cuff and Fit Manometer is used in a practical setup to monitor the contractions ≈ 50% MVC.

The joints in the hands are some of the most delicate and just the slightest hand arthritis (HA) complicates various parts of daily living.

1 in about 10 adults suffers from visible or invisible symptoms of HA as either spontaneous or chronic with varying symptoms such as pain, swelling, stiffness and in severe cases deformity and grinding in the joints. Subsequently to chronic HA is the loss of grip strength which aggravates symptoms even further.

The primary grip muscles are extrinsic, i.e. muscles localized to the forearms, as the intrinsic muscles localized to the palm and fingers are primarily focused on more subtle occupations. That is why indirect training of the extrinsic muscles can improve grip strength, i.e. palmar flexion of the wrist.

That is why people that suffers from chronic types of HA often are recommended to strengthen their grip and the rational for doing low-load BFR seems apparent. Especially relevant in situations where conventional grip training are exacerbating symptoms. The use of BFR to improve grip strength has actually been explored in at least two RCT’s:

Two groups (BFR vs. No-BFR) exercised 3d/week for 4 weeks as bilateral handgrip training in 20 min with an intensity of 60% of Maximum Voluntary Contraction (MVC) 15 reps/min. (1)

The BFR-group experienced superior strength gains compared to No-BFR (16.17% vs. 8.32%). But please consider that both groups exercised at the same moderate load (60 % MVC), and these findings could not be replicated in a later study using only 30-40% MVC. (2)

Conclusion: While applying BFR to improve grip strength, consider using more than 40% MVC.

Source:

(1) Credeur et al. (2010) Effects of handgrip training with venous restriction on brachial artery vasodilation.

(2) Velic & Hornswill (2014) KAATSU Training and Handgrip Strength.

Method: Sixteen participants randomized as either BFR or No-BFR for 8 running training sessions. Before and after training, subjects completed an incremental test to determine peak running velocity/maximal running speed maximal oxygen uptake “(VO2max)” and running economy. Followed by a time to exhaustion run performed at peak running velocity.

Running training for both groups consisted of progressively increasing volumes of 30 s. intervals completed at 80% of their peak running velocity.

Results: Running economy only improved in the BFR group.

Peak running velocity improved in both groups with small but significant effect size of 0.31 in favor of BFR.

Incremental test time also increased in both groups with small but significant effect size ~0.3 in the BFR group.

Time to exhaustion run was also observed in both groups (27 ± 9% vs. 17 ± 6%) as a small but significant effect size ~ 0.3 in favor of BFR.

“VO2max” improved in both improved in both groups (6.3 ± 3.5 vs 4.0 ± 3.3%) with a trend for higher gains in the BFR group vs. No-BFR.

Conclusion: Running augmented by BFR seems to improve several parameters of performance. The beneficial adaptations after BFR-running are speculated to be primarily muscular rather than cardiovascular.

In the video @frederiksass has elastic band attached to his thighs for additional activation of the hip muscles, performed at a constant pace i.e. 20-30% of his peak running velocity.

We propose, that elastic band resistance combined with BFR-running to be just as beneficial compared to high velocity running, but evading the rapid fluctuation of pressure under the cuff during forceful strides.

Source: Paton at al. (2017) The effects of muscle blood flow restriction during running training on measures of aerobic capacity and run time to exhaustion.