Ian Stephen has a few thoughts on protecting our knees from injury. This article appeared originally in the December/January 2002 issue of Momentum magazine.
When It's Cool Out,
Consider the cyclist's leg. Above, the sensuous curves of a smooth, powerful thigh. Below, a strong, defined calf. Both meaty, warm parts that can withstand plenty of hard use and might get a massage after! These two are joined by that ugly-duckling, the knee. An ugly-duckling without which the whole works would be useless so far as propelling a bicycle is concerned. That knee, so crucial to our cycling joy, is made up largely of bone, cartilage, tendon and ligament. Tissues that are tough, but slow healing. For the knees, prevention of injury is key.
Common perils to cycling knees can be described as the yin and yang of bike fit, riding and weather. In each of these things balance must be found or harm may result. Most important from a knee's point of view are saddle height and position, cadence, distance changes and cold. Novice riders tend to ride with too low a saddle in too high a gear at too low a cadence. Riders of all levels commonly disregard cold unless it is very cold out.
Saddle Height and Position
A good guide to saddle height is to stand in the shoes you ride in and have someone measure the distance from your crotch to the floor. Guys may be intimidated by someone being there with a tape measure, but it really is easier to do this with the help of a friend. Multiply the measurement (the one to the floor!) by 0.883 to get the distance from the centre of your bike's cranks to the top of the saddle. For horizontal position, sit on the bike with the pedals at 3 and 9 o'clock. The bump at the front of your forward knee should be vertically over the pedal axle.
Ninety rpm is a good cruising cadence. Lugging along in a big gear strains the knee simply because you are pushing harder with each pedal stroke. The same speed in an easier gear at a higher cadence means you don't have to push as hard on the pedals. Most people climb hills at a lower cadence, but as a rule don't go below about 70 rpm. Standing will open the angle of your knee and take some of the strain off. You should stand from time to time anyway just to keep things loose. Too static a position will lead to aches and pains.
Be Careful When Changing Your Distance
If you are riding more than before, good for you! The common guide is to increase by no more than 10% weekly. As a randonneur, I would have to go back in time to prepare for some long rides by this rule, but it is a good guide. Less intuitive is the other end of this yin/yang equation, riding less. A large drop in activity can lead to knee pain just as surely as a large increase. Try to taper down or dabble in other activities if you find yourself riding a lot less than normal.
When it's cool out, for goodness sake cover your knees! Sure it feels good on a warm, sunny day to glide along on one's personal freedom machine with the air flowing over bare skin. When warm, your parts are most elastic. The muscles around the knee relax more between contractions, contributing to a limber feel. Warm synovial fluid, your knee's lubricant, is also less viscous. Lubricants work best when warm (and chocolate flavoured, but that's another story).
Why on cool, sometimes foggy, sometimes rainy mornings is it common to see riders pedaling stoically along with helmet cover, Gortex jacket and shorts!? When you cycle in adverse weather your knees are right out in the worst of it. Western theory recognizes that working connective tissues cold can cause micro-tears. Cartilage in particular has very little blood flow and heals slowly. Once roughened, cartilage tends to get worse rather than better and surgery to cut away the roughened portion may only provide temporary relief. Traditional Chinese medicine describes the effect of cold, damp and wind as "pernicious chi", a description that to my experience feels right. The insidious harm that may result can lead to chronic conditions of the sort we generalize as tendonitis and arthritis.
How cold is too cold? The only person brash enough to put a figure on it has been Noel O'hagan who told me years ago never to cycle with bare knees below 20 celcius. This is pretty warm, but keep in mind that on even a small descent your knees may be subject to a 50 kmh wind. I think it better to err on the side of caution and wear at least light tights when it's below 20 out. If I'm going to out ride the Four Horsemen I'll need my knees.
© Ian Stephen, 2001
Thanks to Dr. Eric Posen DC, ND, RAcc, Dr. David Bayley, BScK, ND, Steve Lund of InternationalCyclingCoaches.com and Noel O'Hagan of Cloverdale Cycles.
Here's the rest of the photo at the top of this page: Ian Stephen battling the flat monster on the 2000 Rocky Mountain 1200. Ian writes frequently for Momentum mag, and was the 2002 BC Randonneurs Cycling Club. Photo: Bob Boonstra.