Amid the food trucks, farm stands and 175-plus makers of Boston’s beloved Sunday market, SoWa carves out a free 1 PM wellness workout for anyone who wants to move. The rotating lineup runs from yoga and Pilates to cardio, strength and dance, set against the brick mills and string lights of the South End arts district. Sweat it out, then refuel with a beer-garden pour and a wander through the vintage stalls.