One of the biggest challenges in ACL rehab is regaining adequate strength in the surgical leg. Even at 1 year post-op, many patients still demonstrate significant strength deficits compared to the non-surgical leg. Traditional early post-op ACL rehab consists of ROM, swelling control, gait training, muscle activation and proprioceptive exercises. Unfortunately the leg continues to atrophy and remain in a state of anabolic resistance caused by the trauma of the surgery and subsequent relative or literal immobilization. Early post-op treatments and exercises, while necessary, do very little to help the muscles hypertrophy. The ACSM recommends that in order for hypertrophy to occur, resistance training needs to be loaded at 70% of 1RM. While in the early stages of rehab, loads in that range are unrealistic and potentially dangerous.
Blood Flow Restriction Therapy can be introduced as early as a few days post-op and can also help stop anabolic resistance by initiating protein synthesis, which leads to muscle hypertrophy even at loads of 20% of 1RM and lower. This is possible because the tourniquet creates a hypoxic environment which forces the recruitment of type 2 muscle fibers, even though the load is more appropriate for type 1. Type 1 muscle fibers require oxygen and are important for endurance and low load exercises. While exercising under BFR the stored oxygen becomes depleted and the remaining reps are carried out by type 2 muscle fibers. Type 2 muscle fibers are responsible for speed and power and their byproduct is lactate. The cuff not only restricts the venous return flow, it also holds the lactate in the limb which initiates a systemic response that causes the pituitary gland to release Growth Hormone. Â Growth hormone is responsible for collagen synthesis which is how muscle, tendon, ligament, cartilage and bone heal.
Equipment
Tourniquets are considered medical devices and their use needs to be monitored, there are inherent dangers to improper use of tourniquets. Currently a few types of BFR tourniquet systems and wraps are available and present on social media, but only one is FDA approved as a medical device. The Delfi Personal Tourniquet System contains a Doppler that can accurately measure the amount of blood flow restriction and can adjust for pressure changes during exercise. The Delfi System comes with 3 cuff sizes, each one is wide and tapered for comfort and safety. When deciding to incorporate BFR into your rehab, look for a certified provider on the Owens Recovery Science website.
Treatment Session
A typical treatment session will usually consist of 3-5 different exercises. Â Each exercise will be performed for 75 reps broken down into 4 sets. Â 1 set of 30 reps and 3 sets of 15 reps. Â There is a 30 second rest period between sets with the cuff inflated. Â The cuff will be deflated for at least 1 minute between exercises. Â You can expect to see swelling, color change and muscle fatigue after each treatment. Â Because loads are very low there is no muscle breakdown and little to no subsequent DOMS.
For more information visit  OwensRecoveryScience.com
 Chris Butler, MPT, CSCS, is the Director of Sports Medicine at Catz Physical Therapy Institute in Pasadena CA.  For more information you can find him via the following:
Website: www.chrisbutlersportspt.com
Instagram: @cbutlersportspt
Facebook: Chris Butler Sports PT
Twitter: @cbutlersportsPT
