Believe it or not, there's some forms and poses in yoga that will fucking wreck you, in a good way. These hamplanetary objects generally do the most watered down, retardedly simplistic poses out there. Other poses will really work you. Granted, not the same way a 500# deadlift or 300# clean will, but you will know you've exerted yourself at the end of a session, and likely have better balance and flexibility for your efforts as well.