The mind-muscle connection is a practice in resistance training to induce muscle hypertrophy – which is increasing the size and volume of muscle fibres (1). This is based on the idea that the activation of a muscle can be improved through focusing and concentrating on the specific muscle during exercise which would allow for hypertrophy. While this type of training has been considered ‘bro science’ by skeptics, recent evidence on this topic has indicated otherwise. In research, the mind-muscle connection is referred to as an attentional focus strategy which relates to what someone is thinking about when doing a particular movement or activity (2). There are two primary types of attentional focus strategies: external and internal (2). An external attentional focus involves imagining the outcome of a movement while performing an activity such as thinking about moving the weight when performing resistance training exercises (3). Conversely, internally focused strategies – which are often thought of as conventional mind-muscle connection training – involve thinking about what your body is doing while you're performing an exercise (3). For example, directing one’s focus to “squeezing” their biceps during arm curls. Despite the similarities in these two strategies concerning attention and focus, research has shown that they have significantly different impacts on performance outcomes. This article will examine the research investigating these attentional focus strategies and how they may be utilized to optimize one’s training.
An external attentional focus involves focusing on the outcome of an action rather than the execution of the movement itself (3). This type of strategy is reported to be favorable for performance-oriented tasks. In a study that reviewed over 50 academic papers, it was found that more than 90% of the studies showed better results in motor learning – the process to allow the acquisition of new skills that depend on movement, such as learning to ride a bike – when using an external focus rather than an internal focus (4,5). Utilizing an external attentional focus has also been shown to be highly beneficial for strength performance. A meta-analysis – which is a type of review that looks at many different published research investigations and combines their results to derive a conclusion (6) – looked at 10 studies and showed that an external focus of attention relative to an internal focus had a positive effect on acute muscular strength but no differences in long-term gains in overall muscular strength (7). It was also found that lower body exercises benefited the most from training with an external focus. Simply put, this study suggests that an external attentional focus strategy can lead to advantages in muscle strength during the short term and lower body. Other research investigating an external attentional focus on muscle hypertrophy has yielded non-favourable outcomes. One novel study showed that using an external attentional focus among 30 untrained young men had fewer increases in muscle thickness in their elbow flexors and quadriceps after 8 weeks of resistance training relative to a group using an internal attentional focus (3). Taken together, directing one's attention toward the outcome of a movement is likely best used for performance-oriented and strength-related tasks. However, training that aims to increase muscle size may benefit more from an internal attentional focus.
As mentioned previously, internal attentional focus emphasizes bodily movements while performing an activity (3). Internal attentional focus is best used during training that aims to stimulate muscle hypertrophy. This has been observed in a study by Karst & Willett (8) which showed that subjects who consciously focused on the respective muscles while performing the curl-up exercise were able to elicit greater activation on the rectus abdominis or obliques relative to those incorporating an external attentional focus as measured by EMG – a device which measures the electrical activity in muscles when they contract (9). Theoretically, greater activation of specific muscle groups during an exercise is thought to reduce the involvement of other muscles which can result in muscle hypertrophy. Evidence for this idea has been shown in a 2-part experiment that had 12 untrained men engage in a triceps training program for 12 weeks (10). These participants showed greater activation in the triceps which correlated with its increase in muscle size after 12 weeks. It is important to note that this study did not involve investigating muscle activation related to attentional focus strategies and does necessarily mean greater muscle hypertrophy due to adopting an internal attentional focus. Although, a study previously discussed seems to validate this theory given that it showed 30 untrained young men using an internal attentional focus were able to achieve greater increases in muscle hypertrophy compared to an external attentional focus (3). These findings suggest that internal attentional focus strategies may have advantages for training related to muscle hypertrophy purposes. This is likely due to the greater muscle activation it elicits when focusing on what your body is doing during a movement.
In conclusion, mind-muscle connection training is one of two attentional focus strategies that can be utilized to have positive effects on results related to training. By adopting an external focus and thinking about the outcome of your movements, it can likely lead to improvements in performance-oriented tasks and strength-related exercises. Comparatively, an internal focus that emphasizes bodily movements during training may produce greater muscle activation and potentially increase muscle hypertrophy. These findings can be used as a tool to optimize your performance and training results.