Saw this question asked on reddit biomechanics "How would it affect a persons gait if their tibia was longer than their femur?"

One of the answers was

"I would imagine that the level of internal force capacity in the knee flexors would be alot lower. Simply because the femur acts as a moment arm of effort in the motion, whos muscle insertions move the lower leg. So naturally smaller the area generating the force on an lever, the smaller the net force generated."

This could be a reason for reported decreased ability the more lengthening occurs rather than simply permanent muscle damage.