Two questions regarding FIST principles:
1.) How do you determine whether the saddle should be foreward or rearward in relation to the bottom bracket? Does the length of the saddle make a difference. I am using the Fizik Arione saddle. I am using a perpendicular line drawn from the tibial tuberosity to bisect the pedal spendle to determine fore and aft position (and well as creating a 90 degree shoudler angle.)
2.) When calculating the hip angle, are you suposed to use the angle between the torso and thigh or the angle between the torso and a line drawn from the greater trochanter of the femur to the lateral malleolus of the ankle?
3.) What is the most powerful knee angle for IM racing? 155, 150, 145??? Why is it better to be at 155 than 145? What happens biomechanically to the pedal stroke?
4.) Is it more comfortable on the lower back if your hip angle is closer to 100 degrees or 90 degrees?
5.) Thanks for your help
Cannondale Kid
Two questions?
Based on what we do which is more or less in line with FIST:
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The perpendicular line (aka KOPS for Knee Over Pedal Spindle) is not relevant. Saddle fore-aft is a function of hip angle. If your hip angle is too compressed you move your saddle forwards, too open backwards. There is a bit of judgment required as to what too open and too closed is. You need to consider what the hip angle is relative to how high or low your bars are. If you hip angle is low but you also have a low position this may be ok, but the same low hip angle with a relatively high front end is not desirable. At the same time you need to consider your weight distribution on the bike. Shoulder angle (which is reach to the aerobars) should really be adjusted by changing stem length not saddle fore-aft.
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Here FIST and Enduro Sport vary a bit, unless Dan E. has changed his mind and he might have; Fiona and I attended the very first FIST and Dan just told me he is sending me updated course materials. We measure femur-torso angle from the joint line at the knee to the greater trochanter to the acromion process at the shoulder. We are actually planning to look into a third way to measure hip angle that may provide more accuracy in determining exactly where your saddle fore-aft (and even crank length) should be.
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This is trickier. We look for a range of knee angles. There is no better-worse here. Where you end up in the range is dependent on how effective your technique is at different saddle heights. Keep in mind that knee angle is also not absolute. You can maintain the same knee angle as your saddle is raised by pointing your toes at the bottom of your pedal stroke. IMHO, saddle height and technique are directly related and you can’t adequately address knee angle without at least a cursory look at technique. This reply is going to be long enough without going into the details…
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I would say 100, but other factors need to be considered. Most significantly, overall extension (shoulder angle). If you reach too far to your bars the muscles in your lower back are required to support your torso rather than it being able to “rest” on your upper arms. A lower hip angle causes a greater stretch from you hamstrings to your lower back and can definitely cause fatigue. Just remember there is a limit to how much raising the bars will make you more comfortable - 100 degrees is probably that limit. This is where you start to bring your saddle back as you rotate upwards to maintain the hip angle range.
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Assuming that all made sense, you’re welcome.
“1) The perpendicular line (aka KOPS for Knee Over Pedal Spindle) is not relevant.”
Interesting article as to the reasons why it may not be relevant
http://sheldonbrown.com/kops.html
“2) We measure femur-torso angle from the joint line at the knee to the greater trochanter to the acromion process at the shoulder.”
Don’t know where Dan measures from but it makes sense to measure from the center of ankle, knee, hip, shoulder and elbow joints since these are the axis of movement and roughly correspond with the anatomical markings that have been mentioned. The difficulty may sometimes be to accurately palpate them or to mark them accurately from a photo/video still. It’s not like you can x-ray every customer while sitting on the bike and then do the markings! The method I’ve used is to palpate the anatomical protuberences and then place a piece of sticky tape/dot over them. When you’ve taken the photo these are the points of reference that you can draw your lines from.