Page 61 - Journal of Special Operations Medicine - Spring 2015

maximum (1RM). Traditionally, loads less than this do improved muscular endurance, and muscle hypertro­
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not achieve type II muscle recruitment, muscle hypertro­ phy. 1,20,30 Both elderly populations and healthy, young
phy and strength, and improvement in endurance dur­ athletes improve ambulation and muscular strength. 2,3,8,19
ing resistance training. 7,11
Patients benefit from BFR who cannot participate in tra­
An issue inherent in the ACSM guidelines, when ap­ ditional strength­training exercises or those with chronic
plied to musculoskeletal injuries, is that some patients muscle weakness. Due to these solid, projected benefits,
are unable to tolerate these high resistance loads due BFR has been incorporated into a supervised physical
to instability, pain, post­traumatic osteoarthritis, neu­ therapy program for patients with chronic muscle weak­
rologic deficits, volumetric muscle loss, or postsurgical ness after trauma at our institution.
restrictions. 12–16 BFR therapy, however, is not hindered
by the same limitations. This modality improves mus­
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cular strength and power with resistance at 20% 1RM, Methods
changes that are typically only seen when exercising at
80% of an individual’s 1RM. 1,17–19 As a result, we be­ Participants
lieve that orthopedic­injured rehabilitation patients who All seven patients were seen at our facility, a rehabilita­
are unable to tolerate heavy mechanical loads may ben­ tion center dedicated to active duty Servicemembers. The
efit from low load BFR training. patients had attended regular physical therapy sessions
for lower extremity rehabilitation for a variety of rea­
This low­intensity exercise paired with restricted muscu­ sons. All had chronic quadriceps and/or hamstring mus­
lar venous blood flow was first developed with the intent cle weakness and were at least 3 months from their last
of restricting venous outflow and thus increasing fatigue surgical procedure, and their strength improvement was
of the affected muscle at low­intensity resistance. 18,20 limited by their inability to successfully use traditional
Early human studies indicate muscle hypertrophy and resistance training. To objectively monitor improve­
strength gains in healthy adults and eldery patients with ments in strength, our patients were tested with a Biodex
sarcopenia. 2,3,8,19 Some studies have also indicated that System 3 isokinetic dynamometer (Biodex Med ical Sys­
BFR maintains these gains for a longer duration after tems, Inc; http://www.biodex.com/). All individuals had
training compared with standard practices. 6 their contralateral extremity measured for comparison,
but some patients also had bilateral rehabilitation needs.
A persistent problem in chronic injuries, especially in the All patients had dynamometer measurements for the af­
extremities, is regaining the required strength and endur­ fected lower extremity on at least two occasions during
ance of atrophied or traumatized musculature. This is their course of treatment and were using BFR therapy as
21
demonstrated repeatedly in the literature where even rela­ part of their rehabilitation routine for a minimum of 2
tively simple lower extremity fractures can leave patients weeks (six treatment sessions).
with strength deficits years after their injury. 22­26 An exam­
ple of the pervasiveness of this problem was demonstrated The BFR therapy resistance training at our facility is the
by Lebrun, who studied patients with patella fractures. same for all lower extremity rehabilitation patients. The
26
Even years after operative treatment and bone healing, equipment used includes a Hokanson AG 101 cuff insu­
patients continued to show functional deficits, including lator air source, E20 rapid cuff inflator, and cc17 thigh
an average 30% deficit in knee extension power. Neu­ cuff (Hokanson, Bellevue, WA 98005). All patients
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romuscular recruitment is the initial step in the rehabilita­ participated in BFR training 3 days a week for 2 weeks
tion process, but once this is achieved further gains must during their physical therapy sessions. Initially, all ex­
be made with muscle hypertrophy as muscle regeneration ercises were performed without BFR to determine the
is limited. 14,15,27 Trauma­induced musculoskeletal injuries individual’s one repetition maximum (1RM). Then, an
are associated with several factors that limit rehabilita­ appropriately sized cuff was selected so that it fit around
tion. 21,27 A common factor is the frequent post­operative the patient’s thigh, as proximal to the groin as comfort­
restriction on strengthening following fixation of frac­ able, and covered approximately one­third of the thigh
tures or reconstruction of soft tissue injuries. 13,15,21 An­ length. The weight for each individual exercise started
other is volumetric muscle loss, which has emerged as a at no more than 20% of the patient’s measured 1RM of
debilitating condition for wounded Servicemembers due the injured limb. With the cuff inflated to 110mmHg for
to associated functional weakness. 21,28,29 There are no the duration of one exercise performance, each exercise
current solutions for functionally addressing volumetric (knee extension, leg press, and reverse leg press) was per­
muscle loss for these patients. 21 formed in four sets, each set to failure, with a 30­second
rest between sets. All sets for the knee extension were
Previous studies have demonstrated that with BFR performed before moving to the leg press and later the
training, individuals obtain significant strength gains, reverse leg press. The time to reach muscle failure was

Blood Flow Restriction Rehabilitation for Extremity Weakness 51