1. Not using your breathing:
The breathing is often the tricky part for people as it feels back to front! However it really is crucial to breath correctly to get your core really activated. When you breathe in, the diaphragm contracts downward drawing in air. When you exhale, the diaphragm returns pushing air out. The core muscles act as a brace around your spine to support and protect your back. Practise breathing with your core engaged, with every out breath feeling the strength of your core. Generally in Pilates you exhale on the hardest part of the exercise when you need the most core strength.
2. Neutral Pelvis.
Neutral pelvis is when the pubic bone and hipbones are level and in the same plane. This means that the pelvis is not tucked under (bum under, back into the mat) or tilted back (bum stuck out, larger arch in back). If your pelvis is tilted back pressing you lower back right into the mat for exercises such as the hundred, your spine is not being supported securely, your abs will engage but you will not get the same benefits for your back.
3. Neck Strain:
Your upper abdominals should be used when you are doing anything in a curled up position in Pilates. To help you use these properly and not strain your neck you need to get the correct neck alignment. Start with a small chin nod, and then use your upper abs to curl up, never lead with your head or neck when curling up. Always keep enough space for a small orange between your chin and your chest. You shouldn’t feel too much stress in your neck. You can always modify those exercises by keeping your head resting on the mat.
4. Lower abs support your legs.
When lifting your legs (for example knee folds) you need to make sure that the majority of the weight of your legs is supported by your lower abdominals. Your legs should almost feel light as feathers, with your neutral pelvis in place. Practice lying on your back and feeling your pelvis getting heavy and your feet getting light, then bring your knees (one at a time) above your hips, keeping neutral pelvis.
5. No Momentum.
In Pilates moving slowly and connecting every movement to your breath is key. Using momentum skips over muscles fibers and doesn’t allow you to build strength throughout the entire range of the muscle group needed to eventually accomplish the exercises correctly. One example is the roll up. If done incorrectly, overtime you can actually put more tension in your back and hip flexors. Many people do not have a flexible enough spine to execute the roll up without using momentum. To help build strength and flexibility try bringing the mat to your body, by adding a small pillow or folded towel where your spine is less flexible. Many people think quick moves equals more burn, but slow, steady movements work the deep core muscles to their fullest ability.