Adapted Cycling

To replace running or spin class, use one of several adapted cycling techniques for 30 to 60 minutes to reach an aerobic level of exercise. Put a small arm bicycle on the floor and cycle from a chair. If you don't have access to a small bicycle, then simulate the movement in multiple positions, such as lying down with your pelvis lifted slightly from the floor or while sitting in a sturdy chair and cycling in the air. You may even find these adapted exercises more challenging and intense than your prior exercise.

Swimming

Swimming can substitute for almost any cardio exercise that would strain your foot. You can opt for swimming laps, kicking your feet while holding onto the wall and even treading water with a weighted band to challenge you. If this is too much strain for your foot, swim laps using only your arms to really exercise your heart. Also, you can "run" in the deep end without putting your feet on the pool floor using the same motion as running and taking advantage of the resistance of the water to really amp up the intensity of your routine.

Water Aerobics

Water aerobics can replace many weight-training exercises and, combined with treading water, can help you reach a higher level of intensity. Avoid any water exercises that require you to keep your feet on the pool floor, as this will place strain on your foot; opt for exercises in the deep end. Using a water aerobics device or any waterproof weighted item such as a gallon jug of water, perform your exercises in the deep end, allowing the buoyancy of the water to take the weight off your feet.

General Physical Preparedness (GPP)

GPP weight training involves using a lower weight to perform the same exercise repeatedly for two to five minutes to tone your muscles and help you reach aerobic intensity. Modify your exercises and perform them sitting in a chair or lying down to reduce the strain on your foot. Avoid any exercises below the ankle and move the weight or resistance band to ankle height or mid-calf height to protect your foot. You can do virtually any arm exercise in this manner and you can use leg exercises such a kicks, knee bends and marches.