I try to learn something from any unfortunate experience I go through, both psychologically and physically -- that's just the way I (try to) roll. Tearing my hip flexor, as it turns out, has been a most fascinating experience -- a true crash course in the intricacies of muscular anatomy. I've learned a ton, which I can now share with you...
First, some background: Simplified, we have two kinds of muscles -- ones that mobilize, ones that stabilize. The "mobilizers" are the ones that produce rapid/powerful motion at high force (but lack endurance) -- and over time and with repeated use, they tend to shorten and tighten. The "stabilizers" work against gravity and support the body in a given posture. These "stabilizers" tend to become weak and lengthen (which is bad for "stabilizers") over time. Ideally, "mobilizers" and "stabilizers" work together to both move and stabilize -- which is how they start out. But sometimes, "mobilizers" can actually interfere with "stabilizers" -- and can actually attempt to stabilize on their own. When "mobilizers" start to do all the work (both mobilizing and stabilizing... and perform neither particularly well!), that's how we get muscle imbalances.
How does this play out in cycling? Our tight quads and even-tighter hip flexors pull the pelvis forward (tilting slightly), which sets off a whole slew of other imbalances.
* Pelvic tilt --> increased arching of lower back
* Arched lower back --> overloads muscles of lumbar spine; lengthens/weakens the abdominals
* Weaked abdominals --> can't support our body weight, compensation occurs with upper body and hips (which is how we started this mess in the first place...)
What's compensation, you ask? When the hip flexors, for example, are shortened/tight/inflamed from overuse, some of our other muscles "step up to help" -- and they're not particularly good at doing the original muscles' jobs. Our quads tend to be more developed than the hamstrings -- so instead of pulling up with our hamstrings, we try to push down with the quads... and we get hurt. Our glutes/core tend to be weaker than our hip flexors, so we use our tight hips to stabilize our body over the saddle... rendering them even tighter/shorter.
In my case, for example, when my hip flexor didn't feel like 'coming out to play,' I suddenly started to experience pain and spasms in my quadricep, calf, and even my knee. Compensation injuries, all of them -- and muscle imbalances can result in injuries far more serious than mine!
This can also happen with the upper body, too. When we ride, we have a rounded upper back (we're supposed to, at least...).
*Rounded upper back --> shoulder blades raise and pull back --> chest muscles/upper trapezius get tight
* Tight chest muscles/upper traps --> leave shoulders hiked up/forward (which is why I often coach you more than 10x per class with "shoulders rolled back and down!" -- to counteract that natural tendency!)
and also --> weaken the mid-back/scapula stabilizing muscles and cause neck tension/pain!
If there were ONE posture criticism that I think I'd make for 85% of my 250+ students, it's the head. Head should be in line with your spine -- looking down, but with your chin off the chest. When you tilt the head hanging downwards even a little bit, it shifts the distribution of the head's weight so that the seven vertebrae in the cervical spine are NOT supporting the head evenly; rather, the vertebrae at the base of the neck are rudely taxed with far more force. This leads to calcium deposits and even arthritic symptoms in the spine -- not to mention tightness of the neck flexors and weakening of the neck extensors. Undue stress on the muscles of the back of the neck commonly causes neck pain and headaches!
Get frequent headaches? RIDE NEXT TO A MIRROR AND CHECK YOUR HEAD POSTURE.
So, now that we've covered how we GET muscle imbalances -- how do we prevent them, you ask? Let me introduce the concept of "PREHABILITATION" -- the steps to take to prevent injuries from happening, before they happen. The three things you should keep in mind are as follows:
1) Make sure you are using proper technique in the first place. Sometimes ineffective techniques are obvious -- when I see them, I correct them. Sometimes, however, they are more subtle. If you are in doubt, come talk to me before class and I'll pay very close attention to your technique...
2) STRETCH. STRETCH. STRETCH. STREEEEEEEEEEEEEEEEEEEEEETCH. (Hint: the cool-down stretching at the end of class is totally totally insufficient!)
3) Strength-training! We need to strengthen the glutes (not just the "gluteus maximus" on the backside - but the "gluteus medius" in particular... that's the one on the side, a prime stabilizer that gets long and weak!) and the hamstrings. We need to strengthen the core muscles. Strength-training makes us better cyclists... and keeps us safe!
Email me if you have any questions... firstname.lastname@example.org.
*UPDATE* Psychological Effects of Heart Rate Monitor Use Study
12/21/2010: Preliminary results were reported at Indoor Cycle Instructor in October 2010. Manuscript in preparation. Once published, results will be made available on this site and at ICI.