The article by Ranganathan et al (2004) provides some relevant information.
The authors discuss how it can be increased by two main factors, neural adaptation and muscle growth. They note how the motor skill acquisition literature supports the use of visualisation as an adjunct to actual practice as a means of improving performance:
Research on motor skill acquisition has demonstrated clearly that
mental practice leads to improved performance (Corbin, 1972; Feltz &
Landers, 1983). Thus, the neural events controlling the muscle
parameters for performance (e.g., amplitude, timing) can be improved
through mental practice.
They mention studies that have found no effect of visualisation on strength (e.g., Herbert et al 1998).
However, in their study they did find an effect of visualisation on strength. They attribute this gain to neural adaptation rather than muscle growth.
The key ﬁndings of this study were that mental training increases
voluntary strength of both distal and proximal muscles of human upper
extremities and the strength improvements accompanied elevations of
time-locked (to MVC trials) cortical potential (MRCP). Based on the
MRCP data (Figs. 3–5), we are conﬁdent that the primary mechanism
underlying the strength increase is a mental training-induced
enhancement in the central command to muscle. The data suggest that
repetitive mental attempts of maximal muscle activation trained and
enabled the brain to generate stronger signals to muscle.
greater strength is a consequence of stronger brain activity. A
stronger central command could recruit the motor units that were
otherwise inactive in an untrained state and/or drive the active motor
units to higher intensity (higher discharge rate), leading to greater
- Corbin, C. B. (1972). Mental practice. In W. P. Morgan (Ed.), Ergogenic
aids and muscular performance (pp. 93–118). New York: Academic
- Feltz, D. L., & Landers, D. M. (1983). The effects of mental practice
on motor skill learning and performance: A meta-analysis. Journal of
Sports Psychology, 5, 25–27.
- Herbert, R. D., Dean, C., & Gandevia, S. C. (1998). Effects of real
and imagined training on voluntary muscle activation during maximal
isometric contractions. Acta Physiologica Scandinavica, 163, 361–368.
- Ranganathan, V. K., Siemionow, V., Liu, J. Z., Sahgal, V., & Yue, G. H. (2004). From mental power to muscle power—gaining strength by using the mind. Neuropsychologia, 42(7), 944-956. PDF