Core strengthening is an integral component of any injury prevention, rehabilitation or sports performance program. A strong core provides a dynamic link between the upper and lower body, alleviating excess stress on the peripheral joints.

In athletes, core strength contributes to enhanced athletic performance by providing a solid foundation from which the upper and lower extremities can generate force for running, throwing, rowing and jumping. In patients with low-back pain, core strength is crucial to reduce discomfort, restore movement and return to daily activities. If your patient suffers from a rotator cuff strain, lumbar disc herniation or incontinence, you must address the core muscles to reach full recovery and avoid future relapse.

Pilates is an exercise method that has expanded in the past decade. When applied to a core strengthening program, Pilates can help prevent injury, increase efficiency and get athletes back in the game. Pilates embodies core strength, while addressing motor control, endurance, balance and flexibility. While many core conditioning programs use high-load, high-repetition exercises with little proprioceptive feedback, Pilates focuses on fewer reps of precisely controlled movements.

Staying Centered

The core muscles surrounding the torso include the transversus abdominis, internal/external obliques, rectus abdominis, diaphragm, paraspinals, deep hip musculature and the pelvic floor. Excessive forceful co-activation of muscles surrounding the spine can burden joints with high loads, which causes compression, breakdown and pathology.¹

However, low-level co-activation of the transversus abdominis and multifidi produces a "corset effect" around the lumbar spine that provides joint protection and lumbopelvic stability.^2-4 Recruiting the transversus abdominis is also essential for normal motor control, as the muscle is activated prior to any limb movement in healthy people.^5,6

Recent studies suggest that Pilates-based core strengthening is associated with improved ability to contract the transversus abdominis.^7,8 In fact, a study by Herrington and Davies showed Pilates training to be more effective than abdominal curls in strengthening the transversus abdominis and facilitating lumbopelvic stability in asymptomatic people.⁷ Another study showed Pilates was more beneficial reducing low-back pain than usual treatment.⁹ Popular core exercises, including sit-ups, pelvic tilts and hanging straight-leg and bent-knee raises, exert relatively high forces on the spine while primarily activating the rectus abdominis.¹⁰ Sit-ups exert close to 3,000N of force regardless of leg position or attempts at neural inhibition through hamstring activation.¹⁰ In a study by Nadler et al., women participating in a core conditioning program that included sit-ups, pelvic tilts, squats, lunges, leg presses, dead lifts, hang cleans and Roman chair exercises reported an increase in low-back pain.¹¹ Following injury to the low back, research shows that the muscles supporting the lumbar spine are often weak and inhibited.¹² A cross-sectional area of the multifidus is quickly reduced and activation of the transversus abdominis is impaired.^6,13 Other impairments may include overactivity of the rectus abdominis, psoas and tensor fascia lata, holding the breath, inability to find or maintain a neutral spine, pushing out on the pelvic floor, or asymmetrical recruitment of the associated core musculature.

Breathing is a primary principle of Pilates and a seemingly innate component of exercise. Faulty breath patterns may contribute to core instability, while favorable ones can enhance core strength and stability. Evidence supports using breath patterns to activate the transversus abdominis, particularly during exhalation.¹⁴ In Pilates, a 3-D breath pattern aims to relieve tension in the neck and shoulders without letting go of the core.¹⁵ Research shows that co-contraction of the pelvic floor results in increased transversus abdominis activation, as noted by increased muscle thickness on real-time ultrasound feedback.³ Proprioceptive feedback, such as sitting tipped forward on an exercise ball, may help ensure even pelvic floor activation and symmetry. Anterior pelvic floor activation overflows to the transversus abdominis, while posterior pelvic floor activation overflows to the multifidus in the low back. Theoretically, equal and graded activation of the pelvic floor increases core strength and pelvic stability.

An Effective Approach

Some Pilates companies feature training, programming and equipment that use a contemporary approach. Where traditional Pilates promotes a flat-back posture, contemporary approaches recognize the significance of a neutral position. Neutral spine is commonly referred to as the optimal position to absorb shock, engage the transversus abdominis and maintain pain-free, balanced vertebrae. In a neutral position, the spine relies on dynamic muscular stability instead of the passive osseo-ligamentous structures.¹⁶

Depending on a patient's situation, the neutral position may vary. For instance, a patient with a posterior lumbar disc herniation may work well in a neutral biased-toward-lumbar extension. Conversely, a patient with lumbar stenosis or spondylolisthesis may be biased toward lumbar flexion/posterior pelvic tilt. You may also use this position if a patient is too weak or lacks the proprioception to maintain a neutral position.¹⁵ Once your patient is positioned for success, remember that 10 quality repetitions are more effective than 50 poorly executed reps. In a randomized controlled trial, exercise instruction effectively altered conscious patterns of muscle activation.¹⁷ In addition, verbal and tactile cues can decrease unwanted muscle activity and increase desired activation during exercise.¹⁸ You can use proprioceptive cues to encourage recruitment of local stabilizers, such as the multifidi, transversus abdominis, deep posterior fibers of the psoas and gluteals, diaphragm and pelvic floor. These local muscles are anticipatory, responsive to low loads for longer durations and highly proprioceptive.^13,19,20

Biomechanically, activating the muscles in close proximity to the axis of motion minimizes shear and compression around the joint to reduce injury. Unloaded closed-chain exercises such as pelvic rocking (imprint/release), scapular isolation (arms on ball), cat stretch, breast stroke preps, bent knee fall out, hip rolls and hip release may be appropriate, followed by low-loaded exercises such as essential footwork, bend and stretch, midback series or front/back rowing preps.¹⁵ Once the deepest core musculature is functioning properly, intermediate exercises challenge endurance of these local stabilizers while layering on more global muscles, such as the internal/external obliques, gluteals and quadratus lumborum.

Research suggests that optimal performance requires the muscles surrounding the spine to handle high loads of short durations, low loads of long durations and quick repetitive loads. However, intermediate exercises should challenge the supporting musculature with respect to stress on the joints and non-contractile tissues of the spine.²¹ Appropriate exercises may include intermediate footwork, hundreds, arms pulling straps, reverse expansion, side-twist kneeling, star prep, knee stretches, long stretch and mermaid variations.¹ As you integrate Pilates into your athletes' core rehab programs, be sport-specific and you'll achieve superior results.

For a list of references, go to www.advanceweb.com/PT and click on the magazine section of the home page.

Olivia Webster is a certified STOTT PILATES^® instructor specializing in rehabilitation. She is also on staff at Yoga Works in New York City.