Protein + neuromuscular electrical stimulation for increasing hand muscle size and strength Original paper

In this randomized controlled trial in young men in Japan, whey protein and neuromuscular electrical stimulation increased the strength of a small muscle deep in the hand.

The effect of whey protein and/or neuromuscular electrical stimulation (NMES) on the strength and thickness of the abductor digiti minimi muscle (ADM; a deep muscle on the outer side of the palm that moves the little finger away from the other fingers).

20 young men (ages 20–30) with no known health conditions who were recruited from the Prefectural University of Hiroshima in Japan.

A 6-week randomized controlled trial was conducted, in which the participants were put in one of the following groups:

• Placebo: The participants took a placebo but did not use NMES on either hand.
• Placebo + NMES: The participants took a placebo and also used NMES on one hand.
• Whey protein: The participants took whey protein but did not use NMES on either hand.
• Whey protein + NMES: The participants took whey protein and also used NMES on one hand.

The participants performed the NMES at their home for 20 minutes, 3 times per week.

The participants in the whey protein groups took the whey protein 3 times per week at the dose needed (median of 30 grams/day) to reach an intake of at least 1.6 grams of protein per kg of body weight per day; in the NMES group, the participants took the protein after the NMES session. The participants were instructed to maintain their usual diet and lifestyle but avoid performing tasks and exercises that could fatigue the hand muscles.

The strength of the ADM increased more in the whey protein+NMES group than in the placebo group or the placebo+NMES group.

Because the trial recruited only young men with no known health conditions and examined the effect of NMES specifically on one small muscle of the hand, the findings may not apply to other populations or other muscle groups.