Differential effects of attentional focus strategies during long-term resistance training.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 29533715 · doi:10.1080/17461391.2018.1447020
What was done
Thirty untrained college-aged men were randomized to an internal focus group (n = 15, instructed to focus on contracting the target muscle) or an external focus group (n = 15, instructed to focus on the outcome of the lift). Both groups completed 8 weeks of resistance training (3 sessions per week, 4 sets of 8–12 repetitions per exercise). Outcomes measured included muscle thickness of the elbow flexors and quadriceps via ultrasound, 6-repetition maximum in the biceps curl, and isometric maximal voluntary contraction in knee extension and elbow flexion.
What was found
The internal focus group experienced a significantly greater increase in elbow flexor muscle thickness compared to the external focus group (12.4% vs. 6.9%). Changes in quadriceps thickness were similar between groups. Isometric elbow flexion strength numerically favored the internal focus group, while isometric knee extension strength numerically favored the external focus group, though neither strength difference reached statistical significance.
Why it matters
This study provides evidence that directing attentional focus internally to target muscles ('mind-muscle connection') can selectively enhance hypertrophy in upper-body musculature compared to an external focus during resistance training.
Limits
The sample size was small (n = 30 total, 15 per group) and limited strictly to untrained college-aged men, meaning findings may not generalize to trained lifters, older adults, or females. The hypertrophic advantage was only observed in the elbow flexors, not the quadriceps, and the study was relatively short (8 weeks).
Cited by
- supports Scientific evidence shows that repetition quality—including technique, range of motion, intent, and mind-muscle connection—influences muscle growth and strength gains.