Bowing of the legs can be due to various causes, but off the top it might be due to:
- Low vitamin D
- Osteoarthritis of the joint
- Related to particular sports
Long term, there may be a change in your gait, it might cause pain in the knees and ultimately impact your function. In situations where you are concerned, it would be good to consult a MSK/Sports Physician or physiotherapist in the first instance for an assessment, investigations and early treatment.
Hope this helps.