Side plank with twist:

Marching hip raises

Lie on your back with your knees bent, heels near your butt, and arms along your sides with palms facing down. Press into your heels as you lift your hips up so your body forms a line between your knees and shoulders. Without extending your leg, squeeze your butt as you lift your right foot up off the bed and bring your right knee directly over your right hip. Place your right foot back on the bed and repeat on the left side. Continue to alternate.

Target: Butt, abs, and thighs

Lie on your right side and place your right forearm on the bed. Keeping your hips, shoulders, and feet stacked, brace your core as you lift your hips up toward the ceiling as high as you can. Stretch your left arm straight up toward the ceiling. Without touching the bed, slowly lower your hips, then return to starting position. Keeping your core tight, twist from the waist as you bring your left arm down, underneath your body. Return to starting position to complete one rep. Continue for 30 seconds, then repeat on opposite side. Target: Abs, obliques, and triceps

Diamond reverse crunches

Lie on your back with your arms along your sides, palms facing down. Bring your feet together and open your knees out to the sides so the space between your legs resembles a diamond. Press into your palms and brace your core as you raise your feet up over your hips.

From this position, lift your hips up off the bed to drive your feet straight up toward the ceiling. With control, bring your hips back to the bed. (Take care not to drop your feet downwards with a jerk.)

Target: Lower abs and thighs

Scissor legs

Lie on your back with your hands underneath your hips and your palms facing down. Bring both feet straight up into the air and point your toes. Keeping both legs as straight as possible, engage your core as you lower your right leg down toward the bed with control.

Without touching down, bring your leg back up to starting position. Then repeat on the opposite side to complete one rep. You may slowly increase the number of reps.

Target: Lower abs and legs