1. Lunge run
Stand with your feet hip-width apart, arms at your sides (a). Step back and lower into a reverse lunge, then pump your arms like you're running for 3-5 seconds, keeping your core tight (b). Press through your front heel to return to standing, then quickly repeat on the other side, continuing alternating.
Do each exercise as a 1-minute interval: do as many reps as you can in 30 seconds, then rest for 30 seconds before continuing to the next move. Rest 1 minute at the end, then repeat the circuit 2 more times. If you're not time-crunched, perform up to 6 intervals for a 30-minute workout.
2. Low-box burpee
Stand facing a box or step with your feet hip-width apart (a). Sit your hips back, bend your knees and place your hands on the step (b), then jump both feet behind you so that your body forms a straight line from head to heels (c). Quickly reverse the movement to return to standing.
3. Skier swing
Stand with your feet hip-width apart, knees slightly bent; hinge forward at the waist to lower your chest towards the ground, extending your arms straight behind you (a). In one explosive movement, push your hips forward and swing your arms overhead, rising onto your toes (b). Reverse the movement to return to start. Continue in a quick, rhythmic pattern.
4. Primal Push-up
Start in a push-up position (a), then bend your knees and sit your hips back as far as you can, arms straight (b). In one motion, shift your weight onto your hands and drive your right foot forward into a lunge position, raising your right hand off the ground (c). Reverse the movement to return to start, and repeat on the other side; continue alternating.