by Dr. Timothy J. Maggs, © 2001
In my quest to make biomechanics as commonplace as the daily number or as important as the daily weather report, I'm going to push your limits of tolerance and talk about the all-important Q angle. When looking at the biomechanics of an athlete, one of the more important measurements is that of the Q angle.
The Q angle represents the relationship and alignment between the pelvis, leg and foot. This measurement is extremely important, especially for athletes. Repetitive and continual stress through the lower back, pelvis, hip, knee and ankle can and will produce injuries in athletes, especially those with abnormal Q angles. This type of structural defect must be determined, improved and corrected as much as possible as mere symptomatic care will only produce a false and detrimental sense of security to the athlete.
Measuring the Q Angle
In the standing position, the knee-cap (patella) should be somewhat positioned over the bump at the top of the shin bone (tibial tubercle). The other anatomical landmark of importance is the ASIS, which is the bony protuberance at the very top of the quadricep muscle. This is the bone that sticks out on each side of the body just below the level of the navel.
A normal Q angle will have the patella rotated slightly more towards the mid-line than the tibial tubercle. To get the Q angle, mark a point at the center of the tibial tubercle, and draw a line straight through the center of the patella. This is the first line in the angle. Now draw a line from the center point of the patella up to the ASIS. This will form the second line of the angle.
A normal angle should typically fall between 18°-22°, with males usually at the lower end and females at the upper normal end. An abnormal Q angle will typically be increased from normal. This automatically increases the vulnerability to tracking problems, as well as other low back, pelvis, leg and foot problems. This occurs due to an unleveling of the pelvis with interference to the alignment of the lumbar spine. There will often be a compensatory imbalance in the upper back and neck as well.
An abnormal Q angle becomes further complicated when accompanied by a functional or anatomical short leg. Many people, especially runners, suffer with the short leg syndrome. But, what many don't realize is that the majority of these syndromes are functional short legs rather than anatomical short legs. A functional short leg is the short leg that isn't actually short, it's just the appearance of a short leg due to some structural defect (such as an abnormal Q angle). Too often a lift is recommended for this situation, and the problems now become compounded. Remember, a lift should only be used when the measurement from the outside hip bone to the outside ankle is different on both legs. And the lift should never equal the difference. Lift therapy should begin with 1/3 to 1/2 of the measured leg length difference.
Fixing the Q Angle
It's a daunting task to begin to improve the Q angle. Every structural defect may have some influence on it, and finding the most important defects is somewhat important. Needless to say, a thorough biomechanical exam should be the first step. The evaluation of the feet is the first place to start. Pronation will very often be an underlying contributor to an increased angle. Orthotics or some type of insert is usually recommended.
Standing x-rays of the low back, with measurements of the gravity line and sacral base angle, are also important. You never know if the chicken or the egg came first, and so it goes with these findings. The gravity line and the sacral base angle will greatly benefit from proper treatment and the implementation of corrective exercises, but if they're not included in your quest to correct the Q angle, it will become impossible to efficiently recommend proper treatment or exercises. If that's too confusing, try this---don't ignore your pelvis and low back if you suffer with an increased Q angle. And again, if unable to find someone to help you with this information, feel free to call or e mail me with any questions.
The sports world and sportsmedicine industry has failed greatly (to date anyways) in stressing the importance of the biomechanics of athletes. Bridges are checked for structural flaws each year, kid's teeth are checked for alignment, cars have alignment checks, but who's checking people (runners)? We've accepted getting acute crisis care only after we're injured. Every athlete would do well to begin today to look at their structures and begin to make corrective changes as soon as possible. It's a small price to pay to stay out on the roads. Have a great month.