Approach flexibility as nervous system training (via breathing and mental relaxation) to deactivate the stretch reflex, rather than as a simple mechanical stretching of muscle fibers.

noli's read

The concept of approaching flexibility through the lens of the nervous system rather than mere muscle mechanics is well-grounded in modern science. A vast meta-analysis published in 2025 shows that long-term gains in flexibility are largely explained by improved 'stretch tolerance,' an adaptation process where the brain allows a greater range of motion by delaying the discomfort signal. Muscle sensors naturally trigger a protective reflex (the stretch reflex) to prevent the muscle from going too far, and only a progressive approach allows one to habituate to it. Furthermore, a 2023 clinical trial confirms that combining gentle stretches with slow, conscious breathing boosts activity in the parasympathetic nervous system, the body's 'rest and digest' mode. Although the purely physical aspect (such as the lengthening of connective tissues) also plays a role, Huberman is quite right to emphasize the key role of mental relaxation. Practicing stretches in a state of relaxation and respiratory control therefore remains one of the most validated methods for gently reprogramming one's limits.

the sources

1. 1Lauersen JB et al. 2014
2. 2Wang XQ, Zheng JJ, Yu ZW, et al. 2012
3. 3Podcast Notes (podcastnotes.org)