Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength, Knee Pain, and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial.
Kaitlin G Rabe, Hiroo Matsuse, Anthony Jackson and 1 others
PMID 29852286WHAT IT FOUND
Combined electrical stimulation, volitional contractions, and arm exercises did not improve knee extensor strength more than low-load resistance training in women at risk for knee OA.
Both groups reported less knee pain and faster walking, but the two groups did not differ.
Key findings
01The main outcome, knee extensor strength adjusted for body mass, increased by 0.03 ± 0.04 Nm/kg in the control group and 0.06 ± 0.04 Nm/kg in the hybrid group, and neither increase was statistically significant.
02Knee pain improved within each group on a 0-to-100 scale: by 14.1 ± 15.4 points in the control group and 11.9 ± 11.5 points in the hybrid group, both P = .001.
03No outcome measure showed a statistically significant difference between the hybrid and control groups.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Seven participants discontinued, and data from 18 control and 17 hybrid participants were analyzed. The paper notes a 17% dropout rate, while it had anticipated up to 10% dropout. Electrical stimulation was set to each participant's maximum tolerable voltage, so the stimulation dose was not standardized. Maximum voluntary isometric torque during stimulation was not measured, so some participants may have received less than 60% of that torque. The study included only women with at least one risk factor for knee OA. The hybrid group received electrical stimulation, volitional contractions, and arm exercises together, so the trial cannot separate the contribution of any single component. There was no extended follow-up after the programs ended.
The easy way to misread this
Do not read the within-group improvements in pain and walking as evidence that the hybrid device is better than low-load resistance training. The main knee extensor strength result was not significant, and the paper reports no statistically significant between-group differences for any outcome measure.