Analytic Cycling Logo Optimal Seat Height

Moving the seat can change the geometry and range of motion of muscles.  How does this affect power?

Suppose the "seat height" is changed.   

More precisely, suppose the position of the point of rotation of the thigh at the hip, point d in Figure 1 below, is changed by moving the saddle up or down, fore or aft.  How does Power change?  
  
 This following 3D plot shows Power as "seat height" is changed (point d is moved) over a broad range. From this 3D plot it would seem that the maximum power is found at the maximum distance from the center of the bottom bracket.  In the 3D plot below hip position ranges from 50 cm to 83 cm high and from 45 cm back to 20 cm forward. Values for the Thigh and Shin Fit Points are held constant, but ranges of motion for Thigh and Shin Strength Functions change, as they must, with changing geometries.  

3D Plot of Power vs. Seat Position

  
In the following plot, power is plotted against the distance from the point of rotation of the hips to the center of the bottom bracket for feasible distances. This is, in effect, a slice from the 3D plot above.  It would appear that the further away from the bottom bracket, the better. The curve may be different based on your data.  (This takes a long time to calculate.) 

Plot of Power vs. Seat Height

Pedaling Model Nomenclature

© 1997 Tom Compton