Get the right fit for the long haul
A proper bike fit is paramount to attain an efficient pedal stroke, balance comfort and power while also insuring responsive bike handling.
Optimum performance is achieved by placing a rider over the pedals to maximize the knee joint’s mechanics, and achieve ideal muscle tension of glutes, hamstrings and quadriceps.
Comfort is attained by disbursing the rider’s weight between the saddle, pedals and handlebars, allowing the skeletal structure to support the weight rather than relying on the musculature system.
The first rule of bike fitting 101 is to fit the bike to the individual. Consider the body type, for example, long femur, short torso - don’t force the body to fit the bike. A bike fit is a work in progress – as a new rider invests time on the bike and develops cycling-specific musculature, suppleness and posture, he/she will attain a more efficient, powerful aerodynamic position. There is not an absolute in bike fitting, but a window of the right fit, relative to each individual.
Saddle height is the most critical aspect of the bike fit followed by saddle fore/aft, saddle tilt and finally handle bar reach and height. An effective bike fit strives for 60/40 weight distribution with 60 percent of the rider’s weight on the back and 40 percent on the front wheel.
The greatest concern with improper saddle height is knee injury. A low saddle produces too much force on the back of the patella and behind the knee. The compacted knee experiences constant pressure.
Too high of a saddle position and the rider is reaching at the bottom of the stroke, placing a strain and stretch on the hamstrings. This high position also has the potential of leading to saddle sores - especially aggravated with long rides, ie, centuries.
There are numerical formulas to reach the ballpark saddle height to achieve ideal leg extension, but the position is ultimately honed by the experienced eye of the bike fitter. Once the cyclist has pedaled steadily and settled in to the saddle, the bike fitter looks for level hips, as well as hip, knee and toe alignment, among other factors, to confirm proper saddle height.
Finally, the bike fitter measures the cyclist’s knee flexion at the bottom of the pedal stroke with acceptable flexion measuring between 25-35 degrees, with neutral considered 30 degrees.
Saddle fore/aft is the next factor to be considered. It is ultimately the rider’s femur length that determines this position, placing the knee’s pivot point over the pedal axle. This is measured when the forward pedal is horizontal – the bike fitter drops a plumb bob from the front of the knee to the crank arm. An ideal neutral position lines the end of the knee over the end of the crank arm.
This neutral position allows the rider to jockey forward and back on the saddle as terrain and intensity dictate. For example on a climb a rider might push to the back of the saddle.
In regards to the saddle height and fore/aft position, the rider’s ankling, ankle position - plantar-flexed, dorsi-flexed, or more neutral must be considered. This variable, dictated by individual pedaling style, terrain and intensity significantly changes the knee flexion around the pedal stroke.
Generally, for the century rider, the saddle should be level to the ground, with no tilt forward or back.
When it comes to handlebar reach and height there is more subjectivity than with saddle positions. For the recreational/century rider – comfort rules the day. As a result, a more upright position is likely most suitable.
The rider’s reach creates an angle with the torso in relation to the ground. The reach is greatly determined by the rider’s core strength as well as lower back and hamstring flexibility. The key to reach is rotating at the hips rather than rounding the back. For the sake of comparison – racers/competitive riders strive for a 45 degree torso angle; avid fit riders a 40-50 degree; and recreational riders a 50-60 degree angle.
Riders may proactively train toward a more aerodynamic, powerful upper body position through a cycling specific movement preparation, core stability, and strength program. As a result, riders improve pillar stability and strength as well as hamstring flexibility. More time in the saddle will also allow muscles to develop and become increasingly cycling-specific, supple and strong.
Final fit ingredient – cleat position – for the century rider, the cleat should be positioned with the ball of the foot placed directly over or slightly in front of the pedal spindle. Placing the foot forward of the pedal axle allows greater distribution of the pedal pressure over a larger area of the forefoot versus pinpointing the ball of the foot. This position also reduces stress on the Achilles tendon.
See you next time for - perfecting the century rider’s pedal technique.
Julie Young was a top U.S. professional cyclist for 12 years and has since transitioned to trail running and cross-country skiing. She is the owner of o2 Fitness and now coaches endurance athletes in the region. Check her out online at www.o2fitness.net.