Para-athletes

Clinical reports exist relating to the safe use of BFR training by Para-athletes with a variety of impairments. The use of BFR training for para-athletes should be considered on an individual and case-by-case basis. Prescription and exercise selection may also need to be modified accordingly.

Due to potential complications relating to various impairments it is recommended that all para-athletes should have a medical review prior to commencing BFR training.

General principles

When BFR training is new to an athlete, such training should commence with a familiarisation session and graded progression.

Athletes should avoid training to exhaustion when using BFR.

Exercise and BFR should stop immediately if the athlete is feeling unwell.

Training environment

Practitioners should exercise a higher degree of caution in hot and humid environments, including reminding athletes to maintain appropriate hydration levels. Dehydration may increase the risk of venous thromboembolism (blood clots), so BFR training should not be conducted when dehydrated.

Individualised Arterial Occlusion Pressures

Arterial Occlusion Pressure (AOP) is the pressure required to cease blood flow to a limb and is a reference point that can be used for the prescription of BFR training. There are a number of factors that can influence the pressure required to reach 100% AOP in an individual. These factors include individual blood pressure, limb characteristics, and the shape, width and length of the pressure cuff.

Accuracy of prescription is important to ensure both safety and training efficacy. It is recommended that practitioners measure and/ or calculate individualised AOPs when prescribing and implementing BFR training. Doppler ultrasound techniques are considered the gold standard for measuring AOP in a limb. However, if not accessible to practitioners, the use of a sphygmomanometer or alternative automated blood pressure measurement device is recommended for this purpose.

It is recommended that an individual athlete’s AOP should be recalculated at the start of any new block of BFR training.

During exercise, practitioners should be aware that factors such as variations in limb position, movement of a pressure cuff, and physiological changes within the athlete may influence the restriction of blood flow. Consequently, the use of automated BFR cuffs that have the ability to hold a desired pressure are recommended for use when they are accessible to an athlete.

Supervision

It is recommended that practitioners provide supervision of an athlete undertaking BFR training. In cases where an athlete is inexperienced in the use of BFR, practitioners must provide supervision of BFR training to ensure correct application and safety.

Where an athlete is competent in the application of BFR, and is in possession of the required equipment, then they may be able to use BFR training in unsupervised settings. These may include the use of BFR as a part of a home-based exercise program or during travel.

Where an athlete who is completing unsupervised BFR experiences a significant change to their medical health or physical condition, such as following injury or surgery, they should make contact with the practitioner who has prescribed their BFR exercise and undergo a reassessment, including the completion of the BFR screening questionnaire (Appendix 1), before recommencing BFR training.

General prescription guidelines

The width of the cuff used to apply pressure to a limb is a major determinant of the % AOP achieved at any given pressure. A wide variety of cuff widths have been studied and it is important to know that setting two cuffs with different widths to the same pressure will result in different amounts of blood-flow restriction. Cuff widths typically range from small (5cm) to medium (10-12cm) to large (17-18cm).

Although a wider cuff will generally require less pressure to achieve a desired % AOP, this does not necessarily equate to a safer stimulus. Ideally individualised AOP is calculated and the athlete should use the same cuff in training as was used during assessment.”

In addition to normal exercise guidelines and precautions, in the case of para-athletes, consideration should be given to the effect of BFR in relation to an athlete’s individual impairment.

As the body of evidence relating to BFR training continues to grow, the intention is to monitor research and clinical practice over time, and update these guidelines accordingly.

Based on current evidence, the following parameters represent safe and effective ranges of BFR prescription that may be prescribed during common modes of BFR training:

Risks of BFR training

BFR training appears to be relatively safe with no definite evidence existing to confirm greater risk compared to other exercise modalities for the majority of athletes. However, high-quality research on the safety of BFR training is limited. Most studies on BFR training do not report on adverse events at all. Certain populations may be at increased risk of complications, and practitioners should have a low threshold for referring participants for a review to a medical doctor prior to commencing BFR training.

In order to obtain informed consent from participants, practitioners must explain what is currently known about risks and complications of BFR training, including limitations in the current knowledge base. Importantly, clinical practice and these AIS Best Practice Guidelines will need to be updated as further research on the safety of BFR training becomes available.

Most complications in BFR training that have been reported are through case reports, and there is an absence of high-quality research on rates of complications. The widest studies on complications have been surveys completed at KAATSU training centres, but the methodological limitations of these studies severely limit conclusions that can be drawn about complication rates. It should also be noted that only limited research on risk has been completed to date in athletic populations. Further evidence and guidelines can be extrapolated from surgical tourniquet use where there has been much more extensive safety research, although it should be acknowledged that there are key differences preventing a direct correlation.

Athletes with a history, or any suspicion of the following conditions should not undertake BFR training. If unsure, refer for review with a medical doctor to further assess. These absolute contraindications are:

• Peripheral vascular disease
• Previous vascular surgery to the effected limb
• An arteriovenous fistula to the effected limb.

The following are either relative contraindications, or medical conditions that may require individual consideration prior to commencing BFR training. Anyone with a history, or any suspicion of the following conditions must have a review with a medical doctor prior to commencing BFR training to assess whether it is safe for that individual:

• Hypertension
• Venous thromboembolism (including deep vein thrombosis or pulmonary embolus)
• Sickle cell disease
• Haemophilia or other bleeding/clotting disorder
• Cerebral infarction / stroke
• Peripheral neuropathy

Some para athletes may have altered sensation, altered autonomic response including autonomic dysreflexia, be at increased risk of VTE, and be more prone to other side effects such as pressure sores. Therefore, all para athletes should also be medically reviewed prior to commencing BFR training.

More detail about these and other potential complications are explained below. This is not an exhaustive list, so any athlete or practitioners with concerns about any other medical conditions should review or discuss these with a medical doctor prior to commencing BFR training.

Venous thromboembolism

Vascular occlusion could theoretically lead to thrombus formation, and case reports of venous thromboembolism (VTE) in the form of deep vein thrombosis (DVT) and pulmonary embolus (PE) following BFR training have been recorded. In a surgical tourniquet setting, VTE is usually listed as a potential complication but a direct correlation remains unclear. Increased fibrinolytic activity following tourniquet use may contribute to this finding. Those with a history of VTE or risk factors for VTE should be assessed further by a medical doctor prior to commencing BFR training, and it is likely that BFR training will not be appropriate for these athletes.

The oral contraceptive pill (OCP) may increase the risk of VTE in certain individuals. While the risk is small, and OCP usage is not listed as a contraindication to surgical tourniquet use, certain athletes may wish to discuss their own individual risk profile with their doctor before beginning BFR training.

Other cardiovascular considerations

Those with peripheral vascular disease have decreased vessel wall compliance making tourniquet use less effective, and potentially dangerous ischaemic damage could result. A history of hypertension or increased blood pressure (systolic blood pressure >140) on pre-screening should prompt review with a medical doctor prior to commencing BFR training.

One case of cerebral infarction with BFR training has been reported, however no further details are available, and this is not routinely listed as potential complication from surgical tourniquet use. Therefore, the relevance of this case is currently unknown.

Sickle cell disease may be a contraindication to BFR training as localised haemostasis, acidity and hypoxia caused by tourniquet use may provoke sickling of red blood cells. Sickle cell disease is also a risk factor for rhabdomyolysis which can occur with BFR training. Those with a history of sickle cell disease should be medically reviewed before considering BFR training, and it is likely that the risks will outweigh the benefits and preclude BFR training for these individuals.

Rhabdomyolysis

Case reports of rhabdomyolysis after BFR training have been documented. It is proposed that rhabdomyolysis may be more common with BFR training due to the magnified metabolic stress involved, however with the limited data available there is no clear evidence that the incidence is greater than with other risk of training. Anyone with a history of rhabdomyolysis should be reviewed by a medical doctor before commencing BFR training.

Nerve injury

Transient numbness and neuropathy have been reported following BFR training, but with no clear evidence of any long-term damage. Nerve palsies have been reported with surgical tourniquet, but the majority of cases are transient, and severity appears to relate to longer tourniquet times (mainly over 3 hours) which should not be applicable to BFR training. Both direct nerve compression and microvascular ischaemia have been implicated as potential mechanism of action. Symptoms or signs to suggest nerve involvement should be monitored for, with medical review if they persist.

Other considerations

Subcutaneous haemorrhage is not uncommon with BFR training but is self-limiting. However, those with a bleeding disorder such as haemophilia should have a medical review before commencing BFR training, as this group may also be at risk of other bleeding complications.

Pre-syncopal and syncopal episode are also reported and could result in a secondary traumatic injury in the training environment.

This risk can usually be managed, but participants should be informed of these potential complications even if more minor.

These guidelines are an initiative of the Australian High Performance Sport System. The Australian Institute of Sport acknowledges the support of contributors and their organisations;

• Justin Crow, Paralympics Australia
• Brendan Scott, Murdoch University
• Harry Brennan, Victoria Institute of Sport
• Martyn Binnie, Western Australian Institute of Sport
• Alek Saunders, Paralympics Australia/South Australian Sports Institute
• Chris Gaviglio, Queensland Academy of Sport
• Peter Culhane, Australian Institute of Sport/Tasmanian Institute of Sport