Heavy power cleans are for advanced lifters only!
There is really no healthy advantage in doing heavy sets of any exercise until you've procured efficiency within that specific movement. If you are new to this movement, consider using your time today learning to improve your power cleaning skill.
Rookies: spend 15-20 minutes today drilling this movement under the supervision of your GPP trainer and other GPP vets. Use a relatively light weight and concentrate on setting up for the movement (neutral spine throughout), pulling through the hips, "jumping" the bar to the racked position, and catching the bar at the rack with soft hands.
There is very little reason to perform more than 30 reps (broken into 4-5 sets) if you are new. Be sure to focus on good form. Get plenty of rest between sets. It may be counterproductive to try and develop new skills while in a fatigued state.
Finding it hard to run due to injury, or other malady? Try running on the bike (pedaling while out of the saddle). Spin bikes and other fixed pedal bikes like the Airdyne are great for simulating running activities. No, fitness gained on the bike won't directly transfer to training for your next marathon, but it still makes for a pretty good workout alt.
Alt = (generally)
1 min hard pedaling for 200 m run
2 min hard pedaling for 400 m run
4 min hard pedaling for 800 m run
8 min hard pedaling for 1600 m run