I have found walking to be a great workout as I am still recovering from the broken leg ( rt. Fibula ,fixed with plate and screws) and getting back into running.
Walking creates 1/2 to 1/4 the impact on the feet and lower leg (compared to running) thus allowing a recovering person to get out and burn some calories, pump the blood around the body and build/rebuild stamina.
It also create the “stress” needed for bone growth and in my case the bones have healed pretty well but the new hardware needs to assimilate and settle in for the long haul.
Have also added some short bouts of running in 3-5 mile walks. 100-200 yards of easy jogging have been adding some effort and feeling pretty good so far.