Start in a plank position on your side, supporting your bodyweight on one forearm and the side of your foot. Keep your body in a straight line from head to heels, engaging your core muscles.
Sit on the floor with knees bent and feet lifted, holding a dumbbell or medicine ball with both hands. Rotate your torso from side to side, touching the weight to the floor on each side.
Alternate bringing your elbow towards the opposite knee while extending the other leg, mimicking a bicycle pedaling motion.
Combine the Russian twist movement with leg raises by lifting your legs off the ground while performing the twisting motion, engaging your lower abs and obliques.
Crunch to one side, bringing your elbow towards your hip while lifting the same side leg off the ground, then repeat on the other side.
Lie on your side with knees bent and legs stacked. Place one hand behind your head and the other on the floor for support.
Stand with feet shoulder-width apart, holding a dumbbell or medicine ball with both hands. Rotate your torso diagonally, bringing the weight from one shoulder to the opposite hip in a chopping motion.
Start in a plank position with hands shoulder-width apart. Alternate bringing your knees towards your chest in a running motion, keeping your core engaged and hips level.
Lie on your back with hands under your glutes for support. Lift your legs off the ground and alternate kicking them up and down in a fluttering motion, engaging your lower abs.
Stand with feet shoulder-width apart, holding a dumbbell or kettlebell in one hand. Slowly lean to the side, bending at the waist, then return to the starting position and repeat on the other side.