One of the top concerns that many of my students have when they begin their Pilates education is neck strain during abdominal exercises that require you to lift your head above the mat. Many people think they just have to build more neck strength and endurance, but strength is usually a small part of the equation. More subtle adjustments in head position, head tilt, and eye gaze have a lot more to do with neck strain and are more easily accessible than the elusive neck strength and conditioning that students believe they need.
A small discussion of anatomy is necessary to understand the biomechanics of skull and neck position. The average human head weighs somewhere between 10-13 lbs. It sits on top of the cervical spine which consists of eight cervical vertebrae. Suboccipital joints associated with the top two cervical vertebrae, referred to as C1 and C2, are uniquely shaped to facilitate movement including rotation as well as flexion and extension. In fact, C1 and C2 are responsible for about 50% of your cervical rotation and about 50% of your flexion and extension. This also means that the other 6 cervical vertebrae together are responsible for the other 50%. Developing and maintaining suboccipital joint motion is necessary to optimally position the weight of the skull during supine (lying on your back), forward flexion (curling up), abdominal exercises.
There is a group of eight, small, muscles that connect the base of the skull to the upper cervical vertebrae collectively called the suboccipital muscles. There are two pairs of rectus (straight) muscles and two pairs of obliques (oblique) muscles. These eight muscles function to tilt the skull as you walk over uneven ground to keep your gaze stable. They are considered stabilizer or postural muscles and consist of highly innervated, slow twitch muscle fibers. These muscles relax to allow your skull to flex down relative to your cervical spine and contract to extend or tilt your head up relative to the cervical spine. The oblique muscles alternate contraction and relaxation to tilt the skull to the right or to the left.
The most common posture I encounter in the studio is head forward posture, otherwise known as slouching. In head forward posture, the suboccipital muscles tend to be chronically tight. In anatomic terms, head forward posture consists of cervical spine flexion combined with suboccipital extension. The head is brought forward by flexing the neck. However, simple cervical flexion will orient the face (and the eyes) looking downwards towards the floor. In order to restore our forward facing gaze, the suboccipital muscles shorten to point the face and gaze forward. If the client is constantly slouching, the suboccipital muscles never really get a chance to relax contributing to neck tension and strain. In Pilates terms, we will often call this shortening through the back of the neck.
One the the fundamental Pilates skills is restoring normal alignment in the head and neck. The tricks Pilates instructors can use to work with clients with head forward posture include placing a foam pad or pillow under the occiput (back of the skull) to compensate for lower cervical spine flexion which displaces the skull forward of the body. The client can then be coached to flex the suboccipital joints by "lengthening through the back of the neck" or sliding the occiput away from the body which results in a gentle "chin tuck" or head nod downwards which requires suboccipital muscle RELAXATION.
Now apply this to an Ab Prep (Pilates abdominal crunch) or other ab exercise like the Hundred or Roll Up. When the client lengthens through the back of the neck, flexing through their suboccipital joints this naturally lowers their gaze. One habit some of my client have when they do an Ab Prep or the Hundred is directing their gaze on the ceiling. When the gaze is high up on the ceiling, the suboccipital muscles are shortened and tense and the client returns to their head forward, tension generating postural patterns. When the gaze is lower, say on the clients knees or thighs, the suboccipital muscle relax and the skull is tilted so that its center of gravity is directly over the flexed cervical spine.
Only once the client has developed the ability to lengthen through the back of the neck to flex the suboccipital joints and relax the suboccipital muscles does it make sense to introduce "strengthening" and "endurance" exercises to the picture, i.e. the Hundred. The Hundred requires maintaining thoracic and cervical flexion and a lifted head and shoulders for 100 counts which will require deep neck flexor muscle strengthening. However, it makes no sense to attempt the exercise if the client falls back into suboccipital extension and their gaze lifts to the ceiling as their head falls back as this position will reinforce their head forward posture pattern and create unnecessary discomfort and strain.
So try keeping cueing eye gaze away from the ceiling because praying to the sky will not help you in the Hundred......