Develop punching power! With this kettlebell exercise! 

I think you should mention weights & rest times as well. For power/speed development development, it is best to do lower reps with adequate rest times in between (say, 3-5 reps with 2-3 min rest), using lighter weights. However, for power/strength development, one needs to use heavier weights. Other variables remain the same...may even increase the rest period by a minute or so...