Interesting observation by your friend and good of them to bring it up for you. Sometimes these things can be difficult to discuss especially if it raises the question of injury or health concerns.
As mentioned, bowing of the legs is unusual from the activities that you mention. That said, as a caveat, I have noted that people who have played soccer for a number of years can sometimes develop this phenomenon. This is likely to be due to the repeated striking of the ball using the inside of their foot causing tightness of muscles over the inside of the leg and slight bowing of the legs.
One thing to bear in mind is that bowing of legs can be caused by other causes, particularly in younger individuals. The main one to consider is vitamin D deficiency; despite the warm climate and sunny days that we have here in Singapore, I am sure that vitamin D deficiency is quite prevalent given that most people work indoors or they exercise outdoors, in the evening! So it’s worth considering this when discussing bowing of the legs.
In the meantime, keep training, consider your technique and be safe!
Bw
