Addition of blood flow restriction to a 4-week low-load resistance training program significantly improved isotonic leg press strength (28.3 vs 15.6 kg; P=0.0385) in women at risk for knee OA.
RCT (n=45)
Double-blind
Randomized
Does concurrent blood flow restriction during low-load resistance training improve quadriceps strength and volume in women over 45 with risk factors for symptomatic knee osteoarthritis?
The addition of blood flow restriction to a low-load resistance training program significantly increases leg press and knee extensor strength in women at risk for knee osteoarthritis compared to low-load training alone.
Absolute Event Rate: 28.3% vs 15.6%
p-value: p=0.0385
OBJECTIVE: To assess whether concurrent blood flow restriction (BFR) during low-load resistance training is an efficacious and tolerable means of improving quadriceps strength and volume in women with risk factors for symptomatic knee osteoarthritis (OA). DESIGN: Randomized, double-blinded, controlled trial. SETTING: Exercise training clinical research laboratory. PARTICIPANTS: Women over age 45 years with risk factors for symptomatic knee OA. METHODS: Participants were randomized to either low-load resistance training (30% 1RM) alone (control) or with concurrent BFR and completed 4 weeks of 3 times per week leg-press resistance training. Those randomized to BFR wore a cuff that progressively restricted femoral blood flow over the weeks of training. Intergroup differences in outcome measures were compared using regression methods, while adjusting for BMI. MAIN OUTCOME MEASURES: Isotonic bilateral leg press strength, isokinetic knee extensor strength, and quadriceps volume by magnetic resonance imaging were assessed before and after participation. Secondary measures included lower limb muscle power (leg press and stair climb). Knee pain was assessed to determine tolerance. RESULTS: Of 45 women who consented to study participation, 40 completed the program. There were no significant intergroup differences in baseline characteristics except that body mass index was lower in the BFR group (P = .0223). Isotonic 1RM improved significantly more in the BFR group (28.3 ± 4.8 kg) than in the control group (15.6 ± 4.5 kg) (P = .0385). Isokinetic knee extensor strength scaled to body mass increased significantly more in the BFR group (0.07 ± 0.03 nm/kg) than in the control group (-0.05 ± 0.03 nm/kg) (P = .0048). Changes in quadriceps volume, leg press power, and knee-related pain did not significantly differ between groups. CONCLUSIONS: Addition of BFR to a 30% 1RM resistance training program was effective in increasing leg press and knee extensor strength in women at risk for knee OA, in comparison with the same program without BFR.
Segal et al. (Sun,) conducted a rct in Risk factors for symptomatic knee osteoarthritis (n=45). Concurrent blood flow restriction (BFR) vs. Low-load resistance training (30% 1RM) alone was evaluated on Isotonic bilateral leg press strength (1RM) (p=0.0385). Addition of blood flow restriction to a 4-week low-load resistance training program significantly improved isotonic leg press strength (28.3 vs 15.6 kg; P=0.0385) in women at risk for knee OA.