When you train your core, whether at the playground or elsewhere, try to find exercises that challenge you from head to toe, with load or resistance from all angles. Be certain to properly engage your core muscles, and focus on proximal to distal movement as well as good body alignment. This kind of overall, integrated strength and stability should help you to move more efficiently and avoid issues like back pain.
Always remember to perform a progressive warm-up before training, and get medical approval before beginning a new fitness program, especially if you have a history of lower back pain or injury.
Hanging leg-raise – An excellent activity to work the front side of your body (flexors) is to hang from the monkeybars and raise your legs up in front of you. To do this safely and effectively, take an overhand grip, with your hands roughly shoulder-width apart. Don’t hang from anything that is too high, and be sure that the ground below you is clear. Once you’re suspended, engage your core stabilizers and slowly bring your knees toward your chest. Be sure to stay under control and avoid swinging or using any momentum as you draw your knees up as high as possible. It’s ok to allow your spine to flex as you lift your pelvis forward and upward. Pause at the top, then slowly lower your legs to the start position. To progressively increase the difficulty, raise your legs when they’re bent, extend them slightly at the top, then lower them in the longer position. Further progression will involve raising your legs when they’re straight. You can also raise them slightly to the right or left of center. Always maintain controlled movements and remember to engage your core muscles. Try performing 2-3 sets to fatigue, in good alignment and control.
Bridge with alternating legs – To train the muscles along the length of your spine and the backside of your pelvis and legs, find a level, elevated surface that will be comfortable for the back of your head and shoulders. Lay back, with the lower half of your body supported by your bent legs, with your feet flat on the ground. Ideally your body should be level and straight from your knee joints to your shoulders and ears. Place your fingertips on your abdomen, or on the front of your hip bones, so that you can feel if your pelvis drops or twists as you lift one foot from the ground. As you lift your left foot and extend the leg, think about keeping your knees side by side, and your hips level. If your left hip drops, the muscles in your right hip aren’t doing a good enough job of stabilizing. Perform 2-3 sets of 5 lifts per side.
Side plank – To work the muscles along the side of your body, try performing a side plank on the ground, or on an elevated surface, which should be slightly easier. Most people advance this exercise too quickly, and don’t pay enough attention to their overall spinal alignment and head position during this exercise, so be sure to keep your body long and neutral, without twisting or bending forward. Side planks can be done as a static hold, or you can add movement by sliding the hips up and down against the downward pull of gravity. They can also be made easier by bending your legs and keeping the knees on the ground. Another variation involves raising the top leg up and down off the lower leg, which will challenge your lateral hip muscles. Perform 2 or 3 30-second holds on each side.