Some surfer wisdom: If you want to ride inside the tube, first you must lose the spare tire. Let Nalu Fit lead the way. The high-intensity surf training program preps your bod to handle the ever-changing demands of the ocean — and gives you a killer workout. Forget fancy equipment. You’ll use props like wheelbarrows, shovels, driftwood, and maritime ropes on a tough ten-exercise circuit that covers all aspects of fitness: flexibility, balance, coordination, power. Explosive drills like up-and-overs simulate pop-ups on the board, and suspension training developed by Navy Seals strengthens arms for paddling out to meet waves. The classes are held at Ocean Beach on Saturdays starting in April. Beginners and seasoned riders alike are welcome. Come June, look for a three-day surf, safety, and wellness workshop with big kahuna Darrick Doerner. And refrain from using the phrase cowabunga, dude. For more information, go to nalufit.com.