PART 4 of 4: Inadequate back strength: the main reason for chronic back pain
The final reason most people have not developed an optimal amount of back strength is simple – it takes hard work to build up muscle.
While our ancestors lived a lifestyle that naturally required regular physical activity during their days—bending, lifting, and moving—most of us today experience a more sedentary way of life. If you do not engage in daily activities that naturally load these muscles, they will atrophy. Additionally, if you have back pain, your core muscles further atrophy due to reflex inhibition. So you must actively strengthen them.
In years past, physicians advised patients with back pain to take it easy. But prolonged rest or decreased activity can actually hinder rather than help back pain. Weak back muscles that become deconditioned through further lack of use cause even more problems for patients. In fact, in a newer trend, some physicians including myself are going so far as to prescribe patients to use “aggressive rehabilitation” through intensive exercise to overcome chronic back pain. While it may sound counterintuitive to intentionally stress a bad back, the truth is that building up these muscles can provide what seems like a miracle cure for some patients.
Even if you don’t have a bad back, effective strengthening can help reduce the natural loss of muscle as you age. Between ages 50 to 70, we can lose up to 40 percent of our muscle and 30 percent of our strength, making us more vulnerable to balance problems that can cause falls. Many believe that weakened muscles contribute and in fact may be critical to developing chronic back pain. To begin with, altered motor control and deconditioning of the deep spine stabilizer muscles are some theories suggested in today’s literature.
The recurrence rate of low back pain is most significant in individuals who have suffered at least one episode of low back pain. MacDonald et al. demonstrated a delayed onset of the deep spine multifidus muscle activation in subjects who had a history of LBP (1). This means that the deep spine muscles should activate prior to the actual movement in order to stabilize the spine. Therefore, individuals with a history of low back pain experience this delay in motor control, leaving them vulnerable to injury with activities of daily living.
High-intensity resistance training two to three times per week will also reduce arthritis pain, improve mobility and daily functions (like walking, climbing stairs, or getting out of a chair), and lower your risk of heart disease and stroke.
How Does Exercise Enhance Strength?
So now that we see how important weakness is in developing pain, it becomes apparent that training and exercise are the clear solutions. How does exercise work? There are two main mechanisms at play—one involving the nerves and one involving the muscles.
The neural basis of muscle strengthening involves the ability to recruit more muscle cells in a simultaneous manner. There is a natural response of the nervous system to keep muscles from overworking and possibly ripping apart as it creates a level of force to which it is not accustomed. Training decreases this inhibitory response or “brake” that the nervous system applies. Also, untrained muscles tend not to fire together. As you can imagine, having the muscles fire in unison will increase their function.
Exercise can result in significant gains in strength, even without building new muscle, by training the nerves to stop inhibiting and to synchronize their firing. This nerve response is responsible for much of the strength gains seen in the initial stages of all strength training and in women and adolescents who gain strength without bulking up.
The muscle response to exercise is a much slower process and depends on the creation of new muscle proteins, which results in enlargement, or hypertrophy, of the cells.
To develop more muscle, be prepared for hard work and slow gains. In fact, the body will build muscle only in response to a combination of progressive resistance training, proper diet, and adequate rest. Here’s why: Resistance causes stress, which first breaks down muscles. With appropriate diet and rest, the muscles then grow as an “over-compensation” type of mechanism to protect the body from future stress.
The human body breaks down and rebuilds muscles over a several-day period. In fact, this rebuilding peaks about 24 to 36 hours after training and continues at an increased rate for up to as much as 72 hours. So adequate rest between training sessions is a key ingredient for building muscle. You must first stress the muscles enough to “damage” them and then allow a sufficient amount of time between exercises in order for the muscle to rebuild enough. Otherwise, you will simply continue to break down muscle for poor results.
Applying adequate stress to each of your target muscles is important so that it leads to an increase in the release of hormones and greater flow of nutrients into the muscles. The important thing to understand here is that when you lift a light weight, it doesn’t involve a
slight effort on the part of all of your biceps muscle fibers. Rather, only a few fibers—just the exact number required to perform that particular movement—will be involved and only they will be working to their limit while the other muscles will remain inactive.
During this lighter lifting activity, while the rest of the fibers (the other non-working fibers) may get passively pushed, pulled, or moved about by the movement, they will contribute absolutely nothing to the work being performed. As a result, unless you are working all or at least most of your muscle fibers and breaking them all down, they will not build up as quickly as you would like. The resistance must be heavy enough and throughout the range of motion for all of the muscle fibers to be affected. The exercise must therefore be “high intensity.”
I will discuss high intensity exercise in a future post. While there are different techniques for muscle building, one common agreement is that it is important to measure baseline strength, gradually increase resistance, and assess effectiveness. Also, there is no way to “comfortably” build up muscle; it has to be done with enough intensity to truly stress the muscle. Building up muscle occurs by applying this stress—via exercise—to your muscles, and then allowing your body to adapt to this stress by providing it with adequate nutrition and rest. All said, it is a consistent cycle of stress and adaptation. For chronic spine patients in our SpineZone clinics, when this strengthening is performed safely to not injure the associated joints, I have seen drastic decreases in pain and improvements in function.
1- Rainville, J., C. Hartigan, E. Martinez, J. Limke, C. Jouve, and M. Finno. 2004. “Exercise as a treatment for chronic low back pain.” Spine J 4 (1):106-15.