Following on last month’s article on the need for finding the optimal center of gravity front to back for a proper bike fit, and its relation to proper cleat position I want to go a bit more into cleat positioning. In the latest newsletter from Bike Fit Systems LLC (www.bikefit.com) they discuss cleat positioning and use of cleat stagger to remedy leg length discrepancy. Cleat stagger is when the cleat on one bike shoe is positioned forward and the other one to the rear rather than symmetrically.
If the cleat is set forward of the ball of the foot then the leg is effectively lengthened, and vice versa, if the cleat is set behind the ball of the foot then leg length is effectively shortened. Bike Fit Systems feels that cleat stagger is rarely a good solution and ask the bike fitter to ask the following:
1. Is the leg length difference is only in the femur?
2. Is optimum cleat Fore/Aft position being sacrificed with cleat stagger?
3. What other aspect(s) of fit related to comfort and efficiency are potential being compromised?
Bike Fit Systems suggests that using a leg length shim between the cleat and shoe is a better solution. In my experience a shim might be just the ticket, but not always. The final test of what is appropriate is feedback from the cyclist while examining pedal stroke. I examine the pedal stroke should be done visually from each side to look at how the knees and ankles are flexing and from the front and rear to look at the path of the knees and heels through the full crank rotation. The aid of analysis tools – a laser level and the Computrainer in Spin Scan mode in conjunction with cyclist feedback and visual observation creates a good picture of the quality of the fit, and provides direction for how it can be improved. I’ll save the use of the Computrainer in optimizing fit for the next article, but here’s a great explanation of how good fit and proper technique will show up on the Spin Scan from coach Marc Evans via YouTube: https://www.youtube.com/watch?v=3Mc5l5m5B9w.
One of the most difficult aspects of a bike fit is checking for leg length difference. There can be a true difference in the length of a portion of the legs, but not always. A twisted pelvis can be the result of leg length discrepancy or it can create the appearance of leg length discrepancy. A twisted pelvis isn’t something that a bike fit can correct. A bike fit should not be used to mask a problem or make a compromise that could cause other physical problems in the future. The article, Twisted Pelvis Check - an extract from 'A Bowen Therapists Notebook' (http://www.timetotreat.co.uk/remedies/pelvischeck.shtml) provides a succinct summation on the possible causes of pelvic twist, “An unbalanced pelvis is a fairly common. The causes are many and varied, muscles in spasm, injury within muscles and the skeletal structure of the pelvic system… The pelvis is a cats’ cradle held in place by muscles, associated skeletal system, and ligaments. It forms a major part of the body and contains within it the reproductive system and parts of the digestive system and is the conduit through which passes the nerves and blood supplies to the lower limbs. It (the pelvis) is the pivot upon which the rest of the body sits. Any unbalance of it (the pelvis), and its parts have far reaching effects upon the person.”
If you are wondering whether you have a leg length discrepancy issue one thing to check is if one knee drifts out during the pedal stroke. Hopefully it is not causing an issue, but the lateral knee drift is a sign that efficiency could be improved through a bike fit that examines if there is a leg length discrepancy.
…this link is a great examination of the pelvic function – let’s rock! https://www.youtube.com/watch?v=HZJTgYzf9FE