Heavy regimen for fitness fanatics

“Next station!” yelled Will Harris, trainer at the Riverdale Strength and Fitness Club.

Claire Guilette, a pregnant 34-year-old, picked up a sledgehammer and started pounding on a monster-truck tire. On the other side of the tire Gary Axelbank, 56, jumped in the air, landed on it, then jumped backward to the ground. Jeanne Chartier, 64, removed a harness attached to a tire filled with weights and walked over to an 80-pound beer keg filled with water. She picked it up and walked it across the gym. Samantha Sherwood, 24, put on the abandoned harness and dragged the tire across the gym floor.

Around the room, others rowed, jumped rope, lifted sandbags or kettleballs.

Mr. Harris checked his stopwatch. Time’s up.

“Next station! Next station!”