Originally Posted by
cny-bikeman
1. Feet may be too far forward on the pedals, but hard to tell. Ball of the foot should be slightly forward of the pedal axle, though, especially for someone who has a flatter (rather than pointed down) foot position. No, folks that is not a typo - I did say ball of the foot forward of pedal axle.
2. Google KOPS (knee over pedal axle). It's a starting point only, nothing magical, let alone biomechanical about it.
3. It took me a while to figure out what made you look cramped in and your back a bit beyond what I consider acceptable/comfortable curvature but it appears to me you have too large a drop to the bars and too little forward extension. Again very hard to evaluate from a static photo, but a longer stem with a slight rise may allow better pull on the bars.
Note that even minor fit changes should be followed by a good amount of miles of sub-max cycling before pushing the limit, to allow accommodation to the new position by the body, as well as to properly judge the effect.
The reason he looks cramped is because he has long legs. Hid body angles are perfect. Not too much drop and not too little reach. Just the right amount of both. Although if he were to reduce the drop he would need more reach.
Lower back pain can result from tight hamstrings and especially tight glutes. Stretch them regularly. Front of knee pain can result from too low a saddle (not a problem according to the pictures) or the saddle being too forward. This something where the whole kops mumbo jumbo can really hurt you. If you need to have your knee a few cm behind the pedal axle then that's what needs to be done.