Start in a push-up position and lower onto your forearms. Keep your body in a straight line from head to heels, engaging your core muscles. Hold this position for the desired duration.
Lie on your back with knees bent and feet flat on the floor. Lift your hips off the ground, squeezing your glutes at the top, and then lower your hips back down.
Lie face down with arms extended in front of you. Lift your arms, chest, and legs off the ground simultaneously, squeezing your lower back muscles. Lower back down and repeat.
Start in a plank position and alternate bringing your knees towards your chest in a running motion, while keeping your core engaged.