I am going to be getting my rescue certification in the next year or so. I am told this class is quite physically challenging. For the people who've done it recently, how did you prepare your self? I am not a big burly guy by the way... i am 5'9 and about 136lbs. I am wondering if there is any specific thing i should do to prepare my self. I have been going to the gym, lifting weights, and i plan to start doing laps in our local pool. If there is any other recommendations, i would greatly appreciated it. Thanks!