Blood Flow Restriction
Historical efforts to restore human muscle strength of soft tissue injuries relied on repetitive exercises (reps) at 75–85% of optimal strength over a 12–16-week period. Not only is this procedure painful, but it has proved ineffective for improving muscle strength and many older patients can’t tolerate it. Stephania Bell, PT, OCS Emeritus, CSCS described current non-surgical strategies used for elite human athletes in professional sports. Sherry Johnson, DVM, MS, DACVSMR of Colorado State University discussed the potential incorporation of these strategies that may help with recovery in equine athletes.
Japanese research 20 years ago looked at a method of altered blood flow as a means of improving muscle function. Human rehabilitation programs starting using “blood flow restriction” (BFR) therapy as a critical non-surgical strategy. For veterans with blast trauma of the limbs, this technique was attempted in an effort to avoid amputation.
It works like this: A cuff on the upper part of a limb is inflated to the point of reducing arterial blood flow by 80% and venous blood flow by 100%. While the cuff is in place, the patient performs 30 reps of a particular exercise. Vascular occlusion for this period of time “wrings” out remaining oxygen from the muscles so that fast-twitch muscles fibers—important components of muscle strength output—are recruited. The person performs the reps at a very low load, i.e. 20–30% of optimal effort.
Even within 2–3 weeks, dramatic improvements in muscle force are realized. There are other benefits as well: Vascular occlusion results in trapping lactate in the muscles, and this triggers the brain to release growth hormone 290% above baseline—that is not a typo! Such growth hormone increases enhance muscle strengthening. Another benefit from lactate trapping is increased release of B-endorphins, which is important because a painful muscle is not able to generate strength.
Johnson reported on the use of the BFR technique in horses and happily there were no adverse effects on blood flow or development of laminitis following blood occlusion in horse legs. Muscle margins rounded, blood vessels remained engorged for hours after a BFR session, and muscle tissue density improved as seen on ultrasound. BFR improved bone healing in addition to muscle, and also improved superficial digital flexor tendinopathy when used for three weeks, even with no walking.
Pre-Rehabilitation Strategies for Post-Operative Care
Lauren Schnabel, DVM, PhD, DACVS, DACVSMR of North Carolina State University has considered the application of pre-rehabilitation practices to the equine athlete in preparation for surgery. First steps involve setting up expectations and a template for success, she says. The environment a horse recovers in is important for inducing a calm state. A comfortable confinement area may even include a small porch turnout. Prior to surgery, the horse is acclimated to stall rest, bandages, equipment, and exercises. An appropriate diet is fed, mental stimulation is provided with toys, and compatible barn mates are housed nearby. Confident handlers improve a horse’s confidence.
It is beneficial to accustom the horse to hand or tack-walking in the location where post-op rehab will be done, and to start exercises with the handler who will be managing the horse post-op. An appropriate handler who is compliant with instructions is hugely instrumental in a horse’s recovery, stresses Schnabel. Accustom the horse to specific exercises, range-of-motion (ROM) procedures of the limbs, bandaging, icing, compression, and other equipment uses prior to surgery.
Various techniques help with strengthening, such as lateral neck exercises and dynamic mobilization exercises to activate and strengthen core muscles, especially the multifidus muscles of the back and other core muscle groups. Resistance bands (Equiband) improve proprioception and engagement of the hindlimbs. Functional electrical stimulation (FES) is useful to improve multifidus symmetry and movement of the lumbo-sacral area.
For neuromuscular control, tactile stimulations around the coronary band and pastern encourages higher pickup of the limb, as does ground pole work. Working a horse on varied surfaces also improves such control. Balance pads (Sure Foot Equine) improve a horse’s postural stability and paraspinal muscle adaptation to amplify the effects of a rehabilitation program. This is achieved through “perturbation training” that improves stabilizing muscle contractions while negotiating uneven surfaces.
Psychosocial influences are relevant for horses, as well, with pain control mitigating negative associations by a horse when performing specific exercises. The use of the Pain Ethogram is useful to identify the level of pain a horse may be tolerating. Education of caretakers and riders helps to manage hesitation or fears that could have substantial negative effects on a horse.
Foot balancing and shoeing of both front and hindlimbs are critical parts of pre- and rehabilitation, particularly when addressing flexor tendon injuries of the distal limb. Nutrition is adjusted to provide nutrients that optimize healing without making a horse too energetic and active. Stall toys and slow feeder hay nets decrease boredom while windows in the stall add some mental stimulation. Handlers should lavish a horse undergoing rehab with attention, affection, and grooming, and maintain a routine schedule, which is calming to a horse