Effects of Blood Flow Restriction on Muscle Activation During Dynamic Balance Exercises in Individuals With Chronic Ankle Instability.

CONTEXT: Dynamic balance exercises are commonly utilized during ankle sprain and chronic ankle instability (CAI) rehabilitation. Blood flow restriction (BFR) has been used to enhance muscle activity during exercise and improve outcomes of traditional rehabilitation exercises in clinical populations.

OBJECTIVE

Examine the effects of BFR on lower-extremity muscle activation during dynamic balance exercises in individuals with CAI.

DESIGN

Crossover study design.

SETTING

Laboratory.

PATIENTS OR OTHER

PARTICIPANTS

Twenty-five (N = 25) young adults with a history of CAI.

INTERVENTIONS: Participants performed dynamic balance reaching exercises during 2 randomized order conditions, BFR, and control. For each condition, participants performed 2 trials of balance exercises. Each trial included 4 sets (30 × 15 × 15 × 15) of reaches in anterior, posteromedial, and posterolateral directions. For the BFR condition, the authors placed a cuff around the proximal thigh at 80% of arterial occlusion pressure. For the control condition, no cuff was worn.

MAIN OUTCOME MEASURE(S): The authors recorded normalized electromyography muscle activation of the vastus lateralis, soleus, tibialis anterior, and fibularis longus during balance exercise trials and recorded participants' ratings of perceived postural instability and exertion after each trial of balance exercises.

RESULTS

The authors observed greater vastus lateralis (P < .001, d = 0.86 [0.28 to 1.44]) and soleus (P = .03, d = 0.32 [-0.24 to 0.87]) muscle activation during balance exercises with BFR than control. The authors observed no differences in tibialis anterior (P = .33, d = 0.09 [-0.46 to 0.65]) or fibularis longus (P = .13, d = 0.06 [-0.50 to 0.61]) muscle activation between the conditions. The authors observed greater ratings of perceived postural instability (P = .004) and exertion (P < .001) during balance exercises with BFR than control.

CONCLUSIONS

Individuals with CAI demonstrated large increases in vastus lateralis and small increases in soleus muscle activation during dynamic balance exercises with BFR. The BFR had no effect on fibularis longus and tibialis anterior muscle activation. Individuals with CAI perceived greater postural instability and exertion during dynamic balance exercises with BFR.