With most dogs, the way to their heart is through the stomach. So, if you need something to keep an active dog that has been injured occupied, a great tool is a stuffed bone (perhaps with peanut butter) or a Kong. These toys are excellent distractions and do not take a lot of movement to enjoy. If it is summer time, you can even freeze the Kong to make whatever goodies are inside last longer. A great combination for a Kong recipe is peanut butter, oats, and banana pieces (just be sure you know what your dog enjoys before feeding it to them, as each individual is different).
No one likes to be injured, and sometimes a good cuddle or pat can really make a big difference. So if you can't come up with anything else to do with your injured doggo (or they are just to sore to care about participating in anything) spend just a bit of time loving on them and letting them know that you are there. This will boost their spirits and hopefully spur them towards a quick and painless recovery.
Toys that stretch your dog's mind while their muscles rest are a great way to entertain an injured dog. These puzzle toys offer quite a bit variety so that you can bump up the amount of activity allowed as your dog recovers. For instance, at the beginning, a toy that simply takes a bit of nuzzling to get the reward out would be excellent for a dog that is just coming out of the initial injury. Later on, as more mobility is available, puzzle toys that require more work will be a great way to get your pet moving in a gentle way. You can find many toys from places like Amazon or PetSmart.