High Intensity Workouts Sledgehammer Workout • slowly raise the sledgehammer up over your shoulder. Keep your feet firmly planted, engage your core and soften knees and hips. As you swing the sledgehammer down, push your hips back and bend your knees, sliding your upper hand down the shaft. Maintain a strong core to stabilise and support your spine. . #cardio #workout #fitness #training #bodybuilding #followme #gym #lifestyle #weightloss #personaltrainer #coach #nyc #goals #exercise #muscle #abs