Avoiding Repetitive Knee Injuries While Riding a Bike

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by Casey McIlvaine

With the high cost of gas, concern for the environment and obesity at an all time high, bike riding has become the main form of transportation for many commuters. Not only can you cut down on pollution and spend less time sitting in traffic, but you can also help reach your daily fitness goals. However, riding a bicycle can take a toll on your knees, if not done properly. While in a gym working out, you are much more cautious of your form rather then when bicycling outdoors. This article will discuss the importance of your bike being set up appropriately, and will go through the steps of setting up your bike properly to avoid injuries to your knees.

Steps for Perfect Biking Position

How to make sure your seat is in the appropriate position:

  1. Adjust your seat so its level
  2. While on the bike, make pedals parallel to the ground
  3. Use a plumb bob device align knee with pedal shaft and align your knees at either the pedal shaft or just behind the pedal shaft.
  4. While in this position, your knee should make a 90 degree angle

Be sure to check both legs before checking the angles of your knee.

How to accurately measure the angle of your knee:

  1. Sit on your bike to find a comfortable position for your seat
  2. Spin the crank arm until either left or right crank arm is in down stroke with opposing crank aligned up with seat tube angle Take goniometer and place on the outside (lateral side) of knee
  3. Align on arm of the goniometer with the greater trochanter
  4. Align the other arm of goniometer aligned with your shin
  5. Measure the angle of the knee. The recommended knee angle is 25-35 degrees.

If the angle of your knee is lower or higher, raise the height of your seat until you have reached the recommended angles.

How to accurately measure the angle without a goniometer:

  1. Stand with proper posture.
  2. Have a friend measure the height from the bottom of your feet to your hip
  3. Using this measurement, multiply by 96, 98, or 100%. (This number varies by your pedaling mechanics.)
  4. Use these measurement and apply to the bike
  5. Measure the distance from top of bike to the pedal. Make sure that the crank is aligned with seat tube angle.

These measurements will allow you to be within the proper 25-35 degree knee angle for riding.

Trochanteric Height  X 98% = Proper Seat Height

The Importance of a Proper Seat Height

Common amongst many cyclist and tri-athletes is the problem of “overuse-also known as repetitive knee injuries.” Repetitive knee injuries are associated with an improper seat high caused by an improper fitting bike. The best method in find your proper bike fit and avoid overuse injuries is having a knee angle of 25 to 35 degree. The average cyclist produces pedal strokes of 90 revolutions per minute. So if were to be cycling for 40 minutes, you would accumulate 360 pedal strokes over the duration of your ride. In theory, 360 pedal strokes is similar motion to completing 360 squats. When performed incorrectly, the repetitive motion of pedal strokes will lead to overuse and repetitive knee injuries.

Cycling with a seat height that is too low you can leave to anterior (front) pain in the knee. A bike seat that is too low will leave to muscle imbalance and injuries to the patella femoral ligaments.

Likewise, having a bike seat that is too high can lead to injuries to the posterior (behind) knee. Excessive extension of the knee will lead to posterior cruciate ligament or a hamstring tendon strain.

Now that you know how to ride a bike properly to avoid injury, get outside and ride as a form of fun and exercise. Along with cycling, try these fun outdoor workouts before Summer ends.

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