I wobble, barefoot, along a series of two-by-fours, arms straight out to the sides for balance.
Five others in this brand-new fitness class are in front of me. Our next task is to squat, hoist heavy sandbags onto our shoulders and walk across a mat that covers the floor at Aikido of Ashland. Now, we drop the bags and crawl 30 feet, making sure our knees and elbows don't touch the mat. We pair off and throw a 14-pound, leather medicine ball to each other 10 times, finishing the circuit with a standing long jump from a squat position.