A very interesting study, unfortunately using untrained subjects *sigh*.. but perhaps they use them to show a big enough and significant enough variance in result. The mind-muscle connection or internal contraction focus has always fascinated me... I know Bryan has stated it's not that important and that progression of load is key, but something in all this makes sense if tension/force needed to move the weight is directed primarily into/from the target muscle (or created by). Finding it hard to explain this haha.. And like Bryan said in the other thread, it's more a matter of deactivating other muscle groups so the load is directed a bit more to your target muscle. You can't just contract a muscle like crazy and think it'll grow, but I think contracting it harder against load helps to direct it more to it... Anyways, an interesting study! Take from it what you will! https://www.ncbi.nlm.nih.gov/pubmed/29533715 Differential effects of attentional focus strategies during long-term resistance training. Schoenfeld BJ1, Vigotsky A2, Contreras B3, Golden S1, Alto A1, Larson R4, Winkelman N5, Paoli A6. Author information Abstract The purpose of this study was to investigate the effects of using an internal versus external focus of attention during resistance training on muscular adaptations. Thirty untrained college-aged men were randomly assigned to an internal focus group (INTERNAL) that focused on contracting the target muscle during training (n = 15) or an external focus group (EXTERNAL) that focused on the outcome of the lift (n = 15). Training for both routines consisted of 3 weekly sessions performed on non-consecutive days for 8 weeks. Subjects performed 4 sets of 8-12 repetitions per exercise. Changes in strength were assessed by six repetition maximum in the biceps curl and isometric maximal voluntary contraction in knee extension and elbow flexion. Changes in muscle thickness for the elbow flexors and quadriceps were assessed by ultrasound. Results show significantly greater increases in elbow flexor thickness in INTERNAL versus EXTERNAL (12.4% vs. 6.9%, respectively); similar changes were noted in quadriceps thickness. Isometric elbow flexion strength was greater for INTERNAL while isometric knee extension strength was greater for EXTERNAL, although neither reached statistical significance. The findings lend support to the use of a mind-muscle connection to enhance muscle hypertrophy.