The mind-muscle connection, the intentional focus on contracting a target muscle during weight training, has been a topic of debate among bodybuilders and scientists. Bodybuilders have long advocated for its importance in isolating and activating muscles for optimal growth, while some academics argue that focusing on proper movement execution is sufficient, as the muscles will naturally fire to lift the weight. Historically, scientific data has leaned towards external cueing (focusing on movement execution) over internal cueing (the mind-muscle connection). Studies on attentional focus in areas like stability, balance, and force production generally show external focus to be superior. However, a groundbreaking 2018 study challenges this notion, offering new insights into the role of the mind-muscle connection in hypertrophy.
This study, conducted by Dr. Brad Schoenfeld’s lab, investigated the impact of internal and external focus on muscle growth. Twenty-seven college-aged men were randomly assigned to either an internal focus group (instructed to squeeze the muscle) or an external focus group (instructed to focus on lifting the weight). Both groups trained for eight weeks, performing four sets of eight to twelve repetitions of standing barbell curls and leg extensions to concentric failure. Progressive overload was implemented each week.
The results revealed a significant difference in biceps growth between the two groups, with the internal focus group experiencing over 5% more biceps hypertrophy. Intriguingly, no significant difference was found in quadriceps growth. This disparity raises questions about the effectiveness of the mind-muscle connection in different muscle groups. The researchers suggest that individuals generally have better control and coordination in their upper extremities compared to their lower extremities, potentially explaining the difference in results. This suggests that finer motor control may play a role in the efficacy of the mind-muscle connection.
While the study’s findings are compelling, some limitations warrant consideration. Firstly, the study focused solely on single-joint isolation exercises in a moderate rep range. Therefore, the results may not directly apply to heavier compound exercises like squats, presses, and deadlifts. In fact, previous research suggests that an external focus might be more beneficial for strength gains in these compound movements. Furthermore, the study used an isometric strength test, which might not accurately reflect the benefits of external focus on dynamic motor performance.
Despite these limitations, the study provides compelling evidence supporting the mind-muscle connection for muscle growth, especially in isolation exercises. It reinforces the importance of considering both internal and external cues in training, depending on the exercise and individual goals. For heavy compound lifts, an external focus on proper movement mechanics remains crucial. However, for isolation exercises targeting specific muscles, such as bicep curls, cable flyes, leg extensions, and leg curls, incorporating the mind-muscle connection can enhance hypertrophy.
Moreover, some compound exercises like hip thrusts and Romanian deadlifts, where individuals may struggle to activate the glutes and hamstrings, can also benefit from a mind-muscle connection. This focused approach can help prevent the lower back or quads from taking over during these movements. More research is needed to fully understand the complexities of the mind-muscle connection, but current evidence supports its use as a valuable tool for maximizing muscle growth.
