Clients not sitting straight: what to do?

  • February 18, 2018 at 10:55 pm #8096

    We are a young bikefit studio in a country without a big tradition in the area: Portugal.

    We study a lot and we try every day to improve our skills and learn from more experienced bikefitters. We want more than just put the client on some angle intervals (thats what most portuguese bikefitters do!)!

    We follow lots of experienced bikefitters on Instagram, and they seem to solve a problem that we are having frequently on the last weeks, We are receiving lots of costumers that don’t sit straight on the saddle. It’s easy to see from behind and front (one knee moving towards the frame and other going away).

    What could be the main reasons for that and how to solve it?

    We understand that exists several reasons and several solutions, but can someone give us a “list” of reasons and possible solutions?

    Thank you so much!

    February 22, 2018 at 11:03 pm #8129
    Tom Wiseman

    Without much information to go on other than a basic description “sitting crooked” there can be many causes. I might first try a couple of different saddles to verify they are not sitting crooked because of a poor shaped saddle interface. If they can’t find a good “spot ” to sit on the saddle because of discomfort the saddle might be too narrow [not enough sitbone support] or too wide forcing them to slide forward to get around the saddle to reach the pedals. I might also try extreme changes in saddle height to see if knee tracking changes. If they are too high they will drop hip on one side to reach pedal and “sacrifice” one knee to a very poor stroke causing one in one out look in the frontal plane. Too low a saddle might cause them to “crumple up” and have trouble getting over the top of the pedal stroke. Exceeding the range of motion at the top of the hip might cause a crooked look. How is that for starters.

    February 24, 2018 at 2:42 pm #8131

    thats great tom! but could it be possible that bad posture or sleeping habit could affect riders body thereby creating hip rotation that can be seen when they ride the bicycle? thanks

    February 24, 2018 at 3:09 pm #8133
    Tom Wiseman

    I agree Frederick. My thought would be if there was a postural cause it would show up in a standing assessment and if it were muscular (flexibility/strength) asymmetry it would show itself in the subsequent test for these things. If it shows up while riding without being found in the assessment off the bike it would lead me to believe it would be saddle shape/position to start with. Thoughts?

    March 4, 2018 at 5:47 pm #8135
    Steve Hogg

    A client not sitting squarely on the seat is an unconscious compensatory response to a challenge to their position in space over the bicycle. All compensatory responses increase asymmetry. Common reasons for not sitting squarely include:
    1. Insufficient ability to internally rotate one or both hips.
    As the rider’s torso leans down to reach to the bars, the femoral head has to internally rotate within each acetabulum to allow that to happen. If there is insufficient range of hip motion in internal rotation (typically 10 degrees or less) then the client will twist towards one side in an unconscious compensatory response to protect the plane of movement of their ‘preferred side’. Often but not always, this will cause the knee on the ‘sacrificed side’ to move further from the centre line.
    The solution here is to
    A) assess hip internal rotation
    B) if insufficient, find out whether it is structural or functional; i.e.; whether it is the result of an accident of birth (retroverted acetabula / bony lesions in or around the acetabula, etc) or an accident of development. If the latter and it occurs on only on side the most common cause is a misaligned L4/ C2 vertebral pairing.
    C) if structural, fit pedal extenders or longer pedal axles of sufficient length
    D) if developmental, free up L4 / C2 (or occasionally sacrum / occiput or coccyx / sphenoid on one side if they are implicated)

    2. Lack of optimal foot correction or any part of optimal foot correction. 99% of riders need quality arch support insoles as the starting point in fully and unconsciously prioritising proprioceptive feedback from the feet. Lack of clarity in this is a major trigger for on seat asymmetry. Once arch supports of optimal height are fitted, it is likely that some form of forefoot and / or rearfoot wedging will be required on one or both feet. Additionally, approximately 40% of riders need a 3 mm post under the first ray of their more pronating foot. Doing this correctly improves on seat symmetry dramatically for many. The vast majority of clients exhibit a lateral pelvic tilt without an LLD. Walking like this loads the 1st ray of the more pronating foot more than would otherwise be the caseif the pelvis was level. The CNS gets used to receiving the additional feedback from that 1st ray and ‘seeks ‘it in any gait related activity…………like cycling. On the bike the rider, even with optimal arch supports and (if necessary) wedging will drop / rotate forward the hip on the same side of the more pronating foot in a failed attempt to load the 1st ray on the same side..

    3. A functionally or measurably shorter leg.

    4. A million other progressively less likely causes.

    I’m sorry for the brevity of this reply. Only so many hours in a day.

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