It's a beautiful day for a ride, and you've gone quite a bit further than
your usual casual spin. As you grind up the last hill, your back begins to
burn and ache. Determined not to be a wuss and stop the climb, you fight
onward, the pain in your back increasing steadily. You have Biker's
Back pain can be an occasional nuisance, or it can be a sign of a serious
disabling problem. In this article, I'm not talking about osteomyelitis (bone
infection), spinal column tumors, herniated discs, trapped nerves, compression
fractures, or arthritis. What I'm writing here applies only to the occasional
exercise-related backache that hits as you struggle along on your faithful
two-wheeled steed. If you have any reason to think your back pain might be
something serious, it probably is: Go see a doctor!
What is Biker's Backache? Typically, back pain from mountain biking is an attention-getting ache felt at waist level, deep inside and wide-spread. It's caused by stress on the back while it's bent in a position that poorly tolerates loading.
It usually originates in the psoas muscles, located alongside the front edge of
the spine. Vertical stress comes down through the spine while it's bent forward. Factors include The Bike, The Pack, The Riding Style,
The Muscles, and Torture.
The Bike: Biker's backache is more likely to occur with a big guy on a smallish-frame bike. Mountain bikes aren't made to ride while hunched over like a roadie. Spacers to raise the front end, a longer front shock, or riser handlebars may help.
If raising the handlebars doesn't help, try lowering them, so you're putting
more of your weight on your hands. This works for roadies -- although it makes
hard-core downhill tech rock riding tougher.
The Pack: To increase the anterior stress on the spine, there's nothing like a heavy Camelbak right up between your shoulder blades, loaded with water, bike tools, powerbars, and tubes, while you're riding hunched over.
Extra weight increases the amount of work your back muscles must do, so they
fatigue more quickly, and it puts more pressure into the joints of your back. Try transferring the tools to an underseat pack, put the water in a bottle on the frame, and stick the powerbar in your jersey. If you can't "ride bare", it helps to let out the straps, so the weight is further down on your back.
The Riding Style: Hillclimbs, sprints, and speed drills will tweak your back. To deliver maximum downstroke power to the pedals, you're pulling up on the handlebars. This puts compression forces through your bent spine. Work on psoas strength with "core" exercises. Limit power-burst work to twice a week to prevent inflammatory responses. When climbing, alternate power-attack with "spinning," where you sit back and "pedal squares" (delivering power to the cranks in all positions) at a higher cadence. Occasionally shift higher, stand on the pedals and ride 30-50 feet standing up.
The Muscles: Muscles need balance. Normally, as you strengthen a
muscle, the muscle that moves the joint in the opposite direction also
strengthens -- automatically. But as you overtrain, trying to get better
strength and performance, you may override this balance. Running (particularly
sprinting) may overdevelop and tighten the hamstrings. The pull of these muscles
on the pelvis as you ride passes stresses along to the spine. You need to
develop the muscles along the front of the spine -- the "tenderloin"
psoas muscles in front of the spine and the abdominal muscles. Power crunches,
done on a consistent basis, will strengthen and tighten these anterior muscles.
To relieve tension in the posterior muscles, stretch the hamstrings for at least
30 seconds after physical activity (knee straight, hip forward with ankle
resting on a bench or rail, then bend your body forward over your leg).
Torture: As you tire on a long ride, your back muscles fatigue. And as the rest of you tires, your riding style changes in a way that actually puts more stress on the back. (In addition to other changes, a tired rider often leans to the side of the downstroke, so the weight of the body can help the tired leg muscles.) After 15-20 miles wearing a Camelbak, I can count on a brutal backache developing around 1 mile into a steady climb. Take a break, fuel up, look at the scenery -- riding is supposed to be fun.
Aerobic exercise that involves the trunk muscles will give your back greater
staying power. This can be fun stuff like tennis and basketball, which involve
lateral tilting as well as forward-and-back motion of the back.
A back conditioning program takes a month or two before you see any benefits, so start slow, be consistent, and be reasonable in what you ask your lumbar spine to tolerate.