[Someone]

Kanu? If you mean kayak, I disagree. Kayaking is good for upper body strength, but (exaggerating) atrophies the legs.

Also, I think there is a difference between 'good on average', and 'good for those who manage to do a lot of it without getting injured'. For example decathlon training is good for overall 'athlete look', but the risk of dropping out with some injury is fairly high.

For that reason, I would rank the impact-free sports such as swimming, cross-country skiing and rowing a bit higher.