Probably due to its long colonial heritage, Kenya is almost unique among African safari destinations (South Africa is the other) in offering a wide range of sporting activities to complement the basic game viewing experience.
Thus there is golf available in certain destinations (OK - not anywhere near South Africa's standard in this respect), together with quite a range of horse riding opportunities - not to mention camel riding as well.
Quite a few places offer the opportunity to rent a mountain bike for a few hours' leisurely exploration of the local area (where, hopefully, you won't need to discover whether a mountain bike is faster than a lion).
If you're feeling really energetic then there is the annual, and legendary, Safaricom Marathon, set in the fabulous Lewa wildlife conservancy area (yes, but can you run faster than a lion?).
Then there's white water rafting, sky diving and so on, if you're really determined to exert yourself out in Kenya.