PT 412 Blood Flow Restriction

proximal

BFR is used around the proximal or distal end of an extremity?

maintain arterial flow, restrict venous return

Once BFR is inflated, what is the goal?

Dr. Yoshiaki Soto, 1970

Inventor of BFR, and year it was produced

1998

First study on BFR was published when?

KAATSU bands

bands for blood flow restriction training

Delfi BFR system

Gold standard in use today for BFR, which is easy, battery powered, and comes with a sleeve; Tourniquet and microprocessor

manual BFR cuff

BFR device in which you must figure out the appropriate pressure yourself and may not be ideal for use when working out

metabolite accumulation, cellular swelling, blood pool

once venous return is restricted with BFR, what happens in the extremity?

oxygen

Reduction of blood flow reduces the supply of what to the tissue?

volitional failure

with a reduction in oxygen delivery, local energy metabolism must work harder. This reduces the time to reach what?

muscle hypertrophy

The anaerobic environment of BFR promotes what process?

False

True or False. Muscle size correlates to strength

20-50%

Resistance training with BFR set at what % of 1RM can result in muscle hypertrophy similar to that of traditional strength training protocols (70% 1RM)

Metabolite-induced accelerated fatigue, cellular swelling

Processes which explain hypertrophy via BFR

RPE

Instead of using 1RM, what other parameter could we use to measure exercise intensity?

lactate, hydrogen ions (H+), ATP, and inorganic phosphates

By products of muscular contractions which are accumulated in an BFR limb

Type 2 muscle fibers

Metabolic accumulation interferes with the excitation-contraction mechanism causing earlier recruitment of what muscle fibers?

H+ build up w/ impaired calcium binding sites (stresses type 1)

According to the Metabolic Induced Fatigue theory, what should explain type 1 fiber hypertrophy with BFR and exercise>

cell swelling

acute increase in muscle thickness that results from accumulation o fluid in the limb due to a lack of venous return

disuse atrophy

Longer term passive cell swelling applications have been shown to attenuate or completely prevent what process?

acute swelling, pain with exercise

What could be some indications of using BFR passively?

1. Is my patient like the participants in the BFRT studies?
2. Does BFRT have a clinically relevant benefit that outweighs the potential risks of application?
3. Is another tx or method available that could provided similar results with less risk than BFRT

General safety consideration questions for BFR

Thrombosis risk
pregnancy/postpartum
May Thurner syndrome
Hypertension
Cardiovascular issues
CVI, lymphedema

BFR contraindications

thrombosis risk, 50% reduced venous return

Why can we not perform BFR on pregnant/postpartum women?

May Thurner syndrome

Compression of left iliac vein by crossing right iliac artery. This is normal anatomy. Arterial pressure on vein results in wall thickening, narrowing, and thrombosis.

Hypertension

BFR creates potential endothelial dysregulation, by increasing DBP and mean arterial pressure response after a chronic low load BFRT protocol. This is a concern for what population?

∼5-10 mmHg

How much does BFR add to usual blood pressure responses during resistance traing?

sympathetic nervous system

BFRT generates exaggerated increases in the activity of what part of our nervous system?

Yes - eat carbs before and after tx, monitor BP

When working with a hypoglycemic patient, is BFR allowed?

10% ↓ in SBP and DBP
10% ↓ in HbA1c
8% ↓ in LDL cholesterol
10% weight loss

Theoretical benefits of BFR, especially for those with diabetes, that typically occurs with normal exercise as well

Autoimmune diseases

Prevalence of hypertension, cardiovascular disease, myocardial dysfunction may be higher for individuals with what diagnoses?

NSAIDS
Cyclo-oxygenase II inhibitors
Glucocorticoids
Some modifying antirheumatic drugs 9
DMARDS)

When screening to determine if BFR is appropriate, what should you screen for?

Electrolyte abnormalities
Extreme diet restriction
Anabolic Steroid Use
Post Surgery (risk of DVT)
Muscle Damage ( not beneficial if can't contract)
Nerve Conduction
Covid-19

What are other consideration s when determining if BFR is appropriate?

as low as 20% 1 RM

With low-load BFR resistance training, resistance can be set where?

High Volume (30/15/15/15)

Volume used with low-load BFR resistance training

30 sec btw sets

rests with low-load BFR resistance training

4-6 weeks

Timeline for low-load BFR resistance training in order to see neuromuscular changes

8-12 weeks

Timeline for low-load BFR resistance training in order to see hypertrophy and strength

6 months

Timeline for low-load BFR resistance training in order to see restored symmetry

2-3 days per week

How many times a week can we do BFR?

30% Heart rate reserve

When using BFR with Low Load-BFR Aerobic Training, what is the resistance?

10-15 min

How long do we train with Low Load-BFR Aerobic Training during a session

60-80%

LOP for LE

40-50%

LOP for UE

pain, ROM, effusion, muscle strength

What are some things BFR can help with?

sel-reported function, Y-balance performance

In a study comparing high load resistance training with BFR, BFR-RT resulted in greater and clinically important improvements in what measures? (self-reported improvements)

BFR-RT

In the study comparing high load resistance training with BFR, which one resulted in a greater reduction in knee joint pain, swelling, and range of motion following ACLR rehabilitation

Fatigue, tiredness

What is one of the most inhibiting factors that prevents individuals from working out?

20-50% 1 RM

BFR RT, at what intensity, seems to elicit similar benefits in muscle hypertrophy when directly compared with moderate-load (70% 1RM) and heavy-load (80% 1RM)

greater increases in dynamic muscle strength, central activation (neural drive), greater muscle retention in detraining

In what ways my heavy resistance training be more beneficial for those who are able to exercise at that capacity, than BFR?

False

True or False? BFR can replace heavy-load RT in a long-term periodized program for athletes

adding 1-2 exercises per target muscle for additional stress, only use in deload phase

If you do not recommend BFR to a patient, yet they insist on it, what should you recommend to the patient

2-3x/wk, for > 3wks or 1-2x/day for <3wks

BFR resistance training frequency

30-15-15-15 OR failure

Typical repetition scheme for BFR resistance training

10-20 minutes

Maximum cuff wear time for BFR resistance training (only includes work time, not rest time)

20-50% 1RM, 2-5 RPE

Loads for BFR resistance training