There's a fair bit of evidence now than most of stretching is, indeed, actually about training the body not to reflexively contract to fight the stretch.
> Due to neurological safeguards against injury such as the Golgi tendon reflex, it is normally impossible for adults to stretch most muscle groups to their fullest length without training due to the activation of muscle antagonists as the muscle reaches the limit of its normal range of motion. [1]
> First, they end up mostly agreeing with a body of previous research suggesting that increased range of motion following a prolonged stretching program is mainly the result of increased tolerance to the sensation of stretching, rather than actually loosening the muscle-tendon unit. [2]
> Due to neurological safeguards against injury such as the Golgi tendon reflex, it is normally impossible for adults to stretch most muscle groups to their fullest length without training due to the activation of muscle antagonists as the muscle reaches the limit of its normal range of motion. [1]
> First, they end up mostly agreeing with a body of previous research suggesting that increased range of motion following a prolonged stretching program is mainly the result of increased tolerance to the sensation of stretching, rather than actually loosening the muscle-tendon unit. [2]
[1] https://en.wikipedia.org/wiki/Stretching
[2] https://www.runnersworld.com/health-injuries/a20811349/does-...