Originally Posted by dominikk1985
I have seen that 18 degree number too but I think that is mostly on balls hit on chest Level. on balls below waist the upward swing angle is probably more than 30 degrees.
when fed hits a low ball he will swing up much more. the upward angle is not only to create spin but also trajectory. to hit a ball at the knees with 3 feet net clearance you Need quite a bit of lift.
here is a nadal FH on a low ball with more than 45 degrees upward swing
and here are higher balls with a flatter swing (more like 25 degree I estimate)
and on chest high balls he will swing probably even flatter. swing trajectory has a Lot to do with strike height.
Subtle difference between the low and high balls...
K90, Gosen OG Micro 16, 23 kg.