Although ice, heat, rest, and medication all have a role in the treatment of mechanical low back pain, a program of rehabilitative exercise is the linchpin of an effective therapeutic strategy. At the beginning of treatment, electrical and thermal modalities provide transient relief, but their chief purpose at this stage is to effect sufficient pain control to allow the introduction of active reconditioning.1-3
In our article on page 993, we described a focused approach to the evaluation of patients with low back pain and presented an overview of the various treatment options. Here we discuss the elements of an exercise program that is effective in most patients who have low back pain of mechanical origin. We also present a sequenced selection of representative exercises.
GOALS OF EXERCISE THERAPY
The restorative benefit of exercise in patients with low back pain is well documented.4-6 Unfortunately, a targeted approach to rehabilitation is seldom possible. The complexities of lumbar anatomy and kinematics make it difficult to trace pain to a single lesion. However, most patients, regardless of their pathology, benefit from restoration and/or "fine-tuning" of spinal kinematics.
Increasing muscle activity. Muscles contribute significantly to spinal stability and orchestrate movements about the spine. The numerous small intersegmental muscles of the back likely assist with stability and motor control through their proprioceptive capabilities. Persistent low back pain has been associated with deep abdominal and multifidus atrophy and with altered firing patterns. In healthy persons these muscles fire constantly, while in persons with low back pain they fire only sporadically (during gross spinal movements).4,7 Subtle improvements in neuromuscular activity in patients with low back pain can often provide significant relief and enhanced function.
Maintaining stability. A key concern when treating the lumbar spine is to maintain stability during movements in all planes. When selecting therapeutic exercises, strive for a balance between maximizing selective muscle activity and minimizing mechanical stress to the spine. Low-intensity, high-frequency endurance training appears to best address lumbar stability requirements.5,8 Have patients perform their assigned exercises daily.
In addition, educate patients about the importance of maintaining the spine in a neutral position, both during exercise and in activities of daily living. "Neutral spine" has been defined as midway between the loosely packed vertebral position of full flexion and the closely packed position of extension.9 This mid-range position provides balanced capsular stiffness, enhanced joint surface congruency, and advantageous length-tension relationships in the surrounding musculature. As the spine moves away from this position, uniplanar laxity or tautness predominates and can compromise vertebral stability.10-12
A SAMPLE SEQUENCE OF EXERCISES
Exercise can be very effective even when "low-tech" equipment is used and the patient's own body mass is the chief source of resistance.The following exercises are presented in order of difficulty. Advancement through the entire sequence is determined by patient tolerance and proficiency; progression to a more challenging exercise may take days or weeks. Advise patients never to progress to a more complex exercise until they can competently and comfortably perform a less difficult one. If necessary, ice can be used after exercising to prevent muscle spasms and modulate pain.
"Camel's hump." This exercise (Figure 1) can help patients recognize the midway position between flexion (hump formed) and extension (back arched). Although this midway position is assumed while the patient is on all fours, it typically resembles his or her normal resting lordosis when upright.
Flexibility exercises. The goals of stretching early in the rehabilitation process are to inhibit spasm, control pain, and flush the muscles of irritating metabolites. Exercises such as the single knee-to-chest stretch (Figure 2) and supine hamstring stretches help lessen a patient's splinting response. Advise patients to keep their inactive leg fully extended during these exercises to help preserve normal lumbar lordosis.
Abdominal exercises. Strengthening the abdominal muscles can enhance lumbar stability. Select activities that combine good muscle activation with a minimal compressive load on the spine. Diagonal curl-ups improve the spine's multiplanar stability by activating both the rectus abdominus and oblique muscles.13 The pullover-hip flexion combination movement (Figure 3) involves the latissimus dorsi (as a shoulder extensor), the transverse abdominals, and the psoas. When conditioned, the latissimus dorsi is able to provide a natural "dynamic corset" for the lower back. The transverse abdominals, typically difficult to isolate, are used here to "hollow out" the stomach as the weight is lowered overhead. Hip flexion activates the psoas. Most importantly, this exercise provides an introduction to coordinated upper extremity, trunk, and lower extremity movements, which will form a foundation for future combined movement patterns.
Proximal paraspinal and periscapular exercises. These are usually well tolerated even by patients whose lower back injury is in the subacute stage. The one-arm row (Figure 4) activates the deep intervertebral rotators of the spine that help maintain transverse plane control.8 Advise patients to keep the spine in the neutral position and the head upright throughout the exercise. Seated row exercises, done using rubber exercise tubing wrapped around a pole or furniture leg, improve lumbar control, thoracolumbar conditioning, and postural proprioception (which can be altered by injury14).The intertransversarii musculature, including the multifidus, plays a key role in postural control.
Extensor exercises. As a patient's comfort level improves and mobility is enhanced, it is appropriate to introduce exercises that target specific extensor muscles. Unilateral hip extensions performed in the quadruped position activate the ipsilateral paraspinals while providing a compressive load on the lumbar spine that is within acceptable limits.5 Such exercises also involve rotational control about a sagittal axis. Initially, patients may find it difficult to maintain their spine in the neutral position when they perform movements in the quadruped position. Suggest they use a short stool to support the trunk until adequate control of the spine is achieved.
The "side bridge" (Figure 5) provides an excellent challenge for the ipsilateral paraspinals and obliques. Here, too, the compressive load on the lumbar spine is within acceptable load limits. This exercise also activates the quadratus lumborum, which helps stabilize the upright spine in the sagittal plane.5,8
Exercises to strengthen the legs and stabilize the trunk. Patients cannot perform occupational tasks, activities of daily living, or athletic feats without correct posture and strong lower extremities; the trunk provides a stable foundation while the legs provide power. The last phase of exercise therapy consists of movements performed with 1 or both feet in a fixed posi- tion; these combine lower extremity strengthening with trunk stabilization and upright posture. To increase the level of difficulty, hand weights can be added to both side and forward lunges (Figure 6). With appropriate guarding, these exercises can also be performed with the eyes closed to enhance the proprioceptive and kinesthetic training effect.
Adjunctive treatments. Because of the buoyant effects of water, aquatic aerobics may be useful for patients with acute low back pain. Back schools-in which patients receive instruction in such things as spinal mechanics, pathoetiology of low back pain, and ergonomic strategies for home and work-have been shown to be useful in conjunction with a comprehensive rehabilitation program; they may have limited value on their own.15 Lumbar supports do not reduce the frequency of low back pain episodes16; however, they may have a role as a postural feedback device.