Hughes, L. and Patterson, S.D, Low intensity blood flow restriction: Rationale for hypoalgesia effect. Medical Hypotheses, 2019. 132: p. 1-7. DOI: 10.1016/j.mehy.2019.109370Natsume, T., et al., Effects of Electrostimulation with Blood Flow Restriction on Muscle Size and Strength. Medicine & Science in Sport & Exercise, 2015. 47(12): p. 2621-2627. DOI: 10.1249/MSS.0000000000000722 Kacin, A., et al., Safety considerations with blood flow restriction training. Annales Kinesiologiae, 2015. 6(1): p. 3-26.
Blood flow restriction (BFR) training, as the name implies, involves partially occluding blood flow to a muscle during resistance or aerobic exercise using a pneumatic cuff or restrictive straps. The training method is a derivative of the Japanese practice of KAATSU training (a term that translates to “added pressure”). When performed at relatively low intensities, BFR has been shown to significantly improve muscle size, strength, and endurance capacities, along with certain cardiovascular parameters, bone health, and tendon structure. These adaptations are typically associated with high-intensity exercise performance. The ability to achieve a significant training stimulus with minimal mechanical loading makes BFR training particularly appealing for low-physical-functioning clinical populations including injury rehabilitation and elderly populations. However, evolving research suggests that BFR may have performance implications for healthy high-performing athletes as well. At Edinburgh Rugby, we have been using BFR training techniques as a part of our daily training routine for the past 3 years. We use the SujiBFR device and one of the primary reasons is that the system allows us to prescribe bespoke occlusion pressures, relative to an individual’s limb occlusion pressure (LOP). LOP is the minimum pressure that is required to completely occlude blood flow to a limb. Using a relative percentage of LOP to prescribe training sessions ensures athletes avoid occlusion pressures that are too high relative to the dimensions of the cuff being used and accounts for the volume and density of the soft-tissue structures under the cuff. We have 3 primary objectives that we are trying to achieve with our training methods at Edinburgh Rugby; pre-training analgesia or pain relief, increasing muscle size and strength in “load intolerant” athletes, and injury rehabilitation. Pre-training pain relief: It is no secret that professional rugby is a physically taxing sport. As a high-performance team, we are required to prepare the squad to train each day which often means managing niggling injuries and ailments. Exercise is known to decrease pain via a mechanism termed exercise-induced hypoalgesia (EIH). However, like most adaptations to exercise, EIH is relative to exercise intensity, such that higher-intensity exercise leads to greater pain relief. BFR has been shown to have a similar pain-relieving effect as high-intensity exercise with a much lower mechanical and metabolic load. For a detailed explanation of this hypoalgesia, effect see Hughes and Patterson, 2019. At Edinburgh, the injuries we have seen the greatest benefit include; patellofemoral joint pain syndrome and lower limb tendon pain. The challenge in using BFR as a pre-training strategy is finding a balance between optimizing pain relief while preventing any fatiguing effect of the exercise intervention. Anecdotally, the most effective protocol we have developed is: • Occlusion pressure – 50% limb occlusion pressure • Volume - 6 sets of 20secs (10x repetitions at a 1:1 tempo) with 10secs of rest – Total occlusion time 3min • Load – self-selected, typically ~20% 1RM • Exercise selection – Individual. Driven by how each athlete tolerates the exercise. Load intolerant athletes: One of the biggest challenges as a high-performance team is developing programmes around injury. The body is a remarkable system of levers and kinetic chains, and in the instance of pain, the body will find alternative strategies to perform the same movement without loading the painful structure. For example, athletes with patella tendon pain will perform a squat or a jump with a hip-dominant movement strategy and a relatively stiff knee. This apprehension to load the knee will lead to a progressive decline in quadricep strength and function if not properly addressed. This can pose a considerable challenge, particularly during a competitive rugby season where maintaining training and game involvements is everyone’s main priority. This is where we use BFR training as a post-training strategy to achieve improvements in muscle size and strength with minimal mechanical load that may exacerbate an athlete’s pain. This intervention is completed as the final part of the athlete’s day, so creating fatigue is no longer a concern, in-fact it is critically important. • Occlusion pressure – 70% limb occlusion pressure • Volume – 4 sets with the following rep scheme – 30, 15, 15, failure. 1min rest – Total occlusion time 5-7min • Load – 30-50% 1RM tested monthly • Exercise selection - Choose an exercise that will most directly load the structure – e.g. knee pain = open kinetic chain leg extension exercise Injury rehabilitation: Perhaps the most obvious example of an individual not capable of tolerating high-intensity training is an injured athlete. The third strategy in which we implement BFR training at Edinburgh is in long-term injured athletes, particularly those likely to suffer an extended period of immobilization. In the early stages of injury rehabilitation (either surgical or conservative management) an athlete’s ability to progress is often limited by muscle wastage, neuromuscular inhibition and a conscious desire to protect the injured limb. With our injured player group, we will use both passive and active BFR strategies to mitigate these responses. Passive intervention – BFR with neuromuscular electrical stimulation (NMES) • Occlusion pressure – 50% limb occlusion pressure (able to progress if well tolerated) • Volume – 5 sets of 4mins of BFR+NMES with 1min rest (during rest BFR cuff is deflated) – Total occlusion time 20mins • Load – 8s of stimulation with a 3s pause. Intensity progressed as tolerated. • Frequency – 2x sessions per day, typically separated by >5 hours. *Protocol derived from Natsume et al. 2015. Active intervention – BFR + low-intensity exercise • Occlusion pressure – 50-70% limb occlusion pressure • Volume - 4 sets of 15 repetitions with a 1min rest period – Total occlusion time 5-10min • Set and rep scheme will progress to the 30, 15, 15, failure used in load-intolerant athletes • Load – 30-40% 1RM tested monthly • Exercise selection – Often multiple exercises selected and determined by impacting functional performance. While BFR is a safe and important component of our long-term rehabilitation strategy, it is imperative that athletes are appropriately screened to establish suitability for a BFR-based intervention. Athletes with significant joint trauma injury that display excessive endothelial disruption or vascular compromise, or those at an increased risk of cardiovascular complication, nerve injury or rhabdomyolysis, may not be suitable candidates. For a comprehensive clinical screening tool for BFR exercise, see Kacin et al., 2015. In summary, at Edinburgh rugby, we find BFR training effective for pre-training pain relief, training load intolerant athletes, and for injury rehabilitation. We use the Suji system provided by SujiBFR because it quickly calculates an individual's LOP, allows our training sessions to be logged and protocols stored, and is cable-free during use.