Stand and step your right foot forward; bend both knees until your left knee nearly touches the floor (a). Quickly jump into the air as you scissor-kick your legs (b) to land with your left leg forward (c). That's one rep. Alternate legs for each rep.

Stand and hold a pair of dumbbells at your sides (a). Step your right foot forward and bend both knees to lower into a lunge as you raise the weights in front of you to shoulder height, keeping your arms straight (b). Press through your right heel to return to start; switch sides. That's one rep.

Loop a resistance band around a stable object in front of you, at chest level; hold one end in each hand, arms straight (a). Step your left foot back and bend both knees to lower into a lunge as you pull the band with you, squeezing your shoulder blades together (b). Stand to return to start. That's one rep. Switch sides.

Anchor a resistance band around a stable object behind you, at chest level; hold one end of the band in each hand (a). Step your left foot slightly in front of your right as you punch forward with your left arm, keeping your right arm still (b). Reverse the movement to return to start. That's one rep. Switch sides.

Stand behind a box or bench and hold a dumbbell in each hand, elbows bent 90 degrees (a). Step your left foot, then your right foot, onto the box as you push the weights overhead (b). Step down to return to start. That's one rep. Switch sides.

Stand with your feet shoulder-width apart, arms bent, and push your hips down and back until your knees are bent to almost 90 degrees (a). Keeping your torso tall, explosively jump your legs outward (b), then immediately inward to bring them back to start. That's one rep.