[Scott Johnston]

AeT can vary depending on grade.  The only way to know is to test.  I’m not sure why this happens.  My theory is that it is combo of femur length and leg strength.  Those with long femurs tend to see a bigger difference as the hill steepens.  They will often be fast up until some critical steepness and then boom, they see a non-linear increase in HR as the grade goes up.  We often test both and I would say we see something like 50% of runners have a pronounced non linear increase in HR to grade at some point.  This happens at lower grades with those with long femurs.

Scott