Seated Knee Raise
Sit at the very end of a bench. Lean back slightly. Round your lower back slightly. Lift both feet two inches off floor. Pull one knee towards your chest then extend back to start. Alternate legs. Keep your core contracted and do not let your back arch.
Dumbbell Side Bend
Stand with a dumbbell in your right hand. Lower dumbbell down thigh as far as you can without leaning forward or back. Return to upright.
Lie on your back with your legs straight and arms extended overhead. Exhale as you begin to roll up. Lift your arms, then head, then shoulders. Continue to roll up articulating your spine one vertebrae at a time up and forward. Inhale as you stretch forward keeping your belly button pressed to your spine. Exhale and roll back down slowly with control, exhaling throughout the whole movement. Stretch tall, inhale. Exhale and roll back up.
Think of curling yourself forward, stretching then slowly uncurling back down to the mat. Move with a smooth fluid motion at a constant speed. Avoid throwing your body up, or allowing it to flop down. Keep your heels on the floor at all times.
Lie on your back with your arms by your sides and legs held up towards the ceiling. Inhale to prepare. Exhale slowly, contract your lower abs and peel your spine off the mat one vertebra at a time from your tailbone. Inhale when you have lifted as far as you can. Exhale as you lower to the starting position with your legs straight up towards the ceiling. Control the movement avoiding any throwing or jerking. Move fluidly. Do not roll onto the back of the neck, balance on the shoulders instead. Make sure you are lifting from the back of your hips and not simply allowing the weight of your legs to pull you over. Move with your exhale. Only curl your pelvis up as much as your muscle strength will allow.
Roman Chair Back Extensions
If you have access to a Roman chair, back extensions are great to build strength. Bend all the way forward and when you lift up, do so only to a neutral spine position. Avoid hyper extending (bending back too much) your spine. Start with 3x10 and build up to 3x20. I don't like adding weight to this exercise but prefer adding various rotation movements. As you lift turn your shoulders to the side or try figure of eight rotations with your shoulders.
Lie on stomach, completely outstretched. Reach your fingertips for the wall on front of you. Hold your head in a neutral spin position (don't look up). Pull your belly button up in to your spine to activate your transverse abdominis muscle and then bring right arm and left leg up while simultaneously lifting chest off the mat. Switch arms and legs while holding chest up and transverse abdominis muscle tight (just keep your belly button pulled into your spine to do this). Continue beating arms and legs up and down in opposition while holding core strong and stable. Imagine you are balancing on a rock in the water and need to keep the movements controlled so you don't slip off. Complete 20 beats slowly, 20 beats quickly and another 20 beats slowly with no rest.