Starting in a plank position, bring the left knee up to the left triceps and hold, lower the knee down to the wrist, then raise it back up to the triceps.
Bring the leg back to plank position.
This completes one rep. Keep going for 25 seconds.
When repeating this circuit, perform this exercise on the right side.
Bicycle Crunch
Lie on your back with the knees bent and feet lifted off the floor.
Place your fingertips behind your head, with your elbows open wide, and being mindful not to pull on your head. Keep your chin off your chest and your eyes on the ceiling.
Bring the right elbow toward the left knee. Switch and bring the left elbow to the right knee. Continue bicycling the knees for 25 seconds.
Inch Worm
Begin standing, bend forward and tiptoe your hands all the way out into an extended position.
Tiptoe your feet all the way back to the hands. Make sure to keep your legs and arms as straight as possible so your core is doing most of the work.
Do as many inchworms as you can in 25 seconds.
Squirm Crunches
Lie face up with your arms extended at your sides and off the floor.
Lift your head and shoulder blades up as you reach your left hand toward the inside of your left ankle.
Then switch to the other side, reaching your right hand toward the right ankle.
Move side to side for 25 seconds.
Mountain Climber
Get in plank position.
Bring the right knee up toward the chest, tapping the foot on the ground.
Jump and switch so the left knee moves toward the chest and the toes tap the floor.
Continue running in place, popping off the balls of the feet, for a total of 25 seconds.