I’m 70 years old and am still an active rock climber (150 plus days a year). I do sets of weighted chin-ups with 30 pounds attached. Just a tip about wind sprints with injuries: If you have back or hip problems, try to find a steep grade. Sprinting up a steep hill will provide a much lower impact work-out than running on flat ground. Although my back problem prevents me from running, or even walking, far on flat ground, I have no problem doing sprints up the hill behind my house.