How do I increase intensity of my training?

Try going for lower stances but don't exceed the 90-degree knee angle limit. Try to practice the routines continuously without stopping, eg, increase to 2 sets continuously per session, and then 3, then 4 ... Do power training - these are the punches, but don't exceed one minute at a time. Power training is considered advanced, and should not be attempted by beginners. 

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