Like Tepford said, med ball throws should be fine. If you have room, the "throw ball, walk/jog to ball, throw ball, repeat"-workout can be killer.
Boxing is another obvious upper body only option, if you have equipment. Bodyweight stuff like a circuit of push-ups, chins, and planks. Loaded carries. Battle ropes. Barbell or dumbbell complexes.
And, of course, somewhere along the way figure out what's causing the problem in the quad and sort it out.