This week we take a look at a fascinating concept that I was made aware of whilst working in rehabilitation circles, the concept of using imagery to strengthen your muscles & joints – even though you may not be able to move them! I had heard of AFL footballers returning to play after injury much faster by just imagining themselves running and kicking a football. Apparently it extends beyond injury and is a valid method for improving general strength and no doubt sporting performance as this recent systematic review into the technique will explain.
Effects of mental imagery on muscular strength in healthy and patient participants: a systematic review, by Slimani, Tod, Chaabene, Miarka & Chamari, in Journal of Sports Science and Medicine (2016)
Background Mental imagery is often explained as a way of creating an experience in the mind of a particular event. It can be performed either with an external perspective, in which the individual imagines watching themselves as if they are an outside observer, or it can be performed with an internal perspective, in which the individual imagines themselves as if actually performing the movement there and then. In the context of strength training or sports, mental imagery usually involves the recreation of performing either an exercise (such as a squat or deadlift) or a sporting movement (such as a sprinting effort or jump). Mental imagery has often been used immediately prior to a real attempt, in order to prepare an athlete for optimal performance. It may be the case that mental imagery improves performance by enhancing motivation, self-efficacy, self-confidence and reducing competitive anxiety. Even so, the long-term effects of mental imagery have been less well-described. Some investigations have reported that mental imagery performed during rehabilitation can enhance the speed of functional recovery, especially after limb immobilization.
Overall, there was evidence that mental imagery can increase strength gains. Moreover, it seemed that the internal type of imagery was more beneficial for closed skills than external imagery, whereas the external type of imagery might be more helpful for open skills. Open skills are those that require more coordination in response to a changing environment, while closed skills are those involving a much more predictable set of circumstances. The internal type of imagery was also found to produce higher levels of EMG activity than the external type of imagery. In addition, there was evidence that self-efficacy, motivation, and imagery ability were responsible for the effectiveness of the imagery programs.
The researchers concluded that mental imagery is able to induce an increase in maximal strength tests, in a similar way to actual strength training. This is of course likely to be caused by neural mechanisms, and possibly in a similar way to the cross-education effect where the contralateral limb increases strength even while the ipsilateral limb is trained unilaterally.
So the take home messages are:
1. If you want to maximise a simple exercise or rehabilitation use internal imagery, ie. imagine yourself doing it.
2. If you want to maximise a complex skill use external imagery, ie. watch others doing it
3. This will only improve the accuracy of your nervous system – it won’t bring about all of the other health benefits such as improved metabolism that come from the real exercise!