A Properly Fitted Bicycle Helps Prevent Overuse Injuries

Written by on February 17, 2012 in Coaching, Fitness - No comments

If you are like many cyclists, you may think that spending the money and time on having a bike properly fitted to you is a waste time and money. You might think that having a bike fitted is only needed when you are a pro. As a cycling coach, I tell all my athletes that having a proper fitting bicycle is a must because it prevents injuries.

In the sport of cycling, injuries such as dislocations, contusions, fractures, tears, concussions, and abrasions are usually the result of cashing (Callaghan & Jarvis, 1996) (McLennan, McLennan & Ungersma, 1988) (Kronisch, Meeuwisse, & Chow, 2004). Unfortunately, most crashes occur in the first or last 500 meters of a race, or during close group riding. As such, it is not always possible, or practical to prevent crashes (McLennan, McLennan & Ungersma, 1988). However, through proper bike fitting, it is possible to prevent overuse injuries caused by hours in the saddle with over 4,500 pedal strokes per hour.

The most common overuse injuries reported by cyclists is pain in the lower back and knee (Callaghan & Jarvis, 1996) (McLennan, McLennan & Ungersma, 1988). Most of these can be addressed by the set up of the bike. The two major overuse injuries in cycling are knee injuries (Pevler, Pounders, & Bishop, 2007) and chronic pain in the lower back (Callaghan 7 Jarvis, 1996) with knee injuries making over 25% of all cycling injuries (Ruby & Hull, 1993). Both of these injuries are directly related to the position. When preventing these types of injuries, it is not possible to separate the rider from the bike. They must be considered as an integrated unit (Gregor & Rugg, 1986).

When fitting the bike properly for saddle height there are two rules of thumb. The first is that optimum saddle height for aerobic power is at 109% the rider‚Äôs inseam length. The second is that the least amount of stress on the knee occurs when the knee angle is between 25¬∞ and 35¬∞ (Pevler, Pounders, & Bishop, 2007). The trick is that both conditions are achievable less than half the time. The research conducted by Pevler, Pounders, and Bishop (2007) shows that setting saddle height by the 25˚ and 35˚ rule of thumb is best for the knee, and the power loss is negligible.

Another aspect that effects the knee is the pedal-foot alignment. Two types of pedal systems have been tested. Pedals that allow float in adduction/abduction direction significantly reduced axial and varsus/valgus knee moments as compared to fix pedals (Ruby & Hull, 1993). Whereas, the inversion/eversion pedals only reduces varsus/valgus moments (Gregersen, Hull & Hakansson, 2006).

Bike fitting is a complicated task. Much of it is personalized to the rider. It is clear that in order to minimize the risk of injury, it is important that all riders have their bike fitted prior to extensive training.

Reference

Bompa, T. O., & Haff, G. (2009). Periodization: theory and methodology of training. Champaign, IL: Human Kinetics.

Feingold, M. L. (1986). Chapter 3: Flexibility standards of the U.S. Cycling Team. In E. R. Burke (Ed.), Science of cycling. Champaign, IL: Human Kinetics.

Gregersen, C. S., Hull, M. L., & Hakansson, N. A. (2006). How Changing the Inversion/Eversion Foot Angle Affects the Nondriving Intersegmental Knee Moments and the Relative Activation of the Vastii Muscles in Cycling. Journal of Biomechanical Engineering, 128(3), 391. doi: 10.1115/1.2193543

Gregor, R. J., & Rugg, S. G. (1986). Chapter 4: Effects of saddle height and pedaling cadence on output efficiency. In E. R. Burke (Ed.), Science of cycling. Champaign, IL: Human Kinetics.

Holly, C. (2007). Training Injuries: Natural treatment (3rd ed.). Vancouver, Canada: Cory holly Institute.

Kronisch, R. L., Pfeiffer, R. P., & Chow, T. K. (1996). Acute injuries in cross-country and downhill off-road bicycle racing. Medicine & Science in Sports & Exercise, 28(11), 1351-1355. doi: 10.1097/00005768-199611000-00002

McLennan, J. G., McLennan, J. C., & Ungersma, J. (1988). Accident prevention in competitive cycling. The American Journal of Sports Medicine, 16(3), 266-268. doi: 10.1177/036354658801600312

Peveler, W. W., Pounders, J. D., & Bishop, P. A. (2007). Effects of Saddle Height on Anaerobic Power Production in Cycling. The Journal of Strength and Conditioning Research, 21(4), 1023. doi: 10.1519/R-20316.1

Ruby, P., & Hull, M. L. (1993). Response of intersegmental knee loads to foot/platform degrees of freedom in cycling. Journal of Biomechanics, 26(11), 1327-1340.

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