Very recently, I seriously injured my left knee. My current diagnosis is MCL (Medial Collateral Ligament) tear. This means up to 12 weeks recovery time until I can return to any sports activities.
I have been doing plenty of cardio by running (12-16 km 3 times a week). With this injury I (obviously) cannot do that and I'm afraid I'll start losing cardio fitness.
Either way I will lose plenty of muscle tone in my both legs. But I am wondering what exercises involving only upper body can replace a cardio workout?