This is an excerpt from Physiology of Yoga, The by Andrew McGonigle & Matthew Peter Huy.
While the power of adaptation can make our tissues less susceptible to injury, everyone still has the potential to become injured, of course. What causes injury in one person, however, might cause no harm to another.
Quite simply, injury occurs when a mechanical load exceeds the strength and tolerance strength of a tissue. Thus, the Goldilocks principle is in effect: Too little mechanical stimulation leads to the weakening of muscles, bones, and other tissues, while too much can lead to injury. But if the stimulus is enough to challenge a person progressively (just right), then adaptations are favorable.
Though injury through yoga is possible (as it is with any physical activity), it is important to remember that yoga is a low-load, low-risk activity that is considered at least as safe as regular exercise (Cramer et al. 2015), and most yoga injuries are mild and transient (Cramer, Ostermann, and Dobos 2018). Furthermore, yoga is performed at a slow pace, and participants are regularly encouraged to move at their own pace and modify as needed. So, while a conversation around yoga-incurred injuries is worthwhile, we should also remember that it is a safe practice and potentially very beneficial to our overall health and well-being. A much greater risk to our health is being sedentary, and being too sedentary is known to be connected to cancer, cardiovascular disease, diabetes, and early death (Biswas et al. 2015).
For Goldilocks, finding the porridge of the right temperature was easy. Determining the right level of challenge is not so obvious. It is possible that on a particular day, the loading of a tissue might be too much, and injury occurs. But we can learn from every injury so as to hopefully avoid doing the same in the future.