Saddle Up: The Basics of Seat Height Adjustments
Riding in comfort is key to a fun and safe ride. There are many components to an optimal bike fit, and one of the most important and easiest adjustments to make is seat height. The height of your seat influences many factors in riding, namely how efficiently you pedal as well as the overall stress on your knees. One of the most common overuse injuries suffered by both road and off-road cyclists is knee pain and/or patella femoral syndrome, commonly referred to as biker’s knee.
Before you go through the processes of saddle adjustments, you first need to ensure you have the right size bike for you. Each brand of bicycle offers sizing guides online. However, consider that not all people 5 foot 10 have the same inseam. Therefore, I recommend finding a local bike shop to determine the proper size bike for you based on your body type and brand of bike you're interested in.
Saddle Height
Once you have the right sized ride, the first adjustment you should make is saddle height. Saddle height has a direct influence over patella-femoral forces, as overall muscle force increases at lower saddle heights. In general, patellofemoral compressive forces are inversely related to saddle height. Saddle height also has a direct effect on the ankle, where greater degrees of dorsiflexion (foot up position) are correlated with a higher likelihood of developing knee pain. Adjust your seat height so when you are at bottom dead center/6 o’ clock (BDC) there is a slight bend at the knee (approximately 25 to 35 degrees).
If at this height you develop pain in the back of your knee while cycling, your seat is probably too high. Lower the seat in small increments, say ¼ inch at a time, until you find a comfortable seat height. If you're not sure how to accurately measure your knee angle at BDC, give the heel - toe method a try. While sitting on your saddle, place your heel on the pedal at the BDC position and adjust the saddle height to where your knee is locked straight in extension. This way, when you move off your heel to your forefoot, you will end up with a slight bend in the knee at the BDC position. Again, this is an important adjustment, so if you are unable to get this adjustment right, seek out a certified bike fitter at your local bike shop.
Saddle Position
Saddle position determines how far forward your knee will travel in relation to your foot, which can have an impact on comfort, performance and injury risk. For reference of crank arm position consider a clock: 12 o'clock is 360d/0d; 3 o'clock is 90d; 6 o'clock is 180d; 9 o'clock is 270d. As mentioned earlier, the 6 o'clock position will be referred to as bottom dead center (BDC). When your crank arm is at the 3 o'clock/90 degree position and your forefoot is on the pedal (the default position you end up in if you're clipped in) your knee should be slightly behind your toe. If your knee is ahead of your toe, you are either sitting too far forward on your saddle or your saddle needs moved back. This is an important adjustment, so if you are unable to get this adjustment right, seek out a certified bike fitter at your local bike shop.
References
Swart, J., & Holliday, W. (2019). Cycling biomechanics optimization-the (r) evolution of bicycle fitting. Current sports medicine reports, 18(12), 490-496.
Leavitt, T. G., & Vincent, H. K. (2016). Simple seat height adjustment in bike fitting can reduce injury risk. Curr. Sports Med. Rep, 15, 130.
Bini, R. R., & Bini, A. F. (2018). Potential factors associated with knee pain in cyclists: a systematic review. Open access journal of sports medicine, 9, 99.
Bini, R., Hume, P. A., & Croft, J. L. (2011). Effects of bicycle saddle height on knee injury risk and cycling performance. Sports medicine, 41(6), 463-476.
