There is a low point in the ground of course at the lowest point of the divot.
But there is also a low point in relation to the shoulder joint with regards to the #4 accumulator. Seems to me that once the left arm is directly opposite the left shoulder joint (the in line condition of #4) the left arm is no longer going down . . . but going up. So that would be the low point with regards to the arm swing but maybe not the ground's low point?
Well yeah kinda...
The arm in relation to the shoulder joint will still be swinging down even though that joint is also moving upwards, so yes and you are also correct that the orbit of the left hand will be rising just before it goes directly below the left shoulder.
The incorrect part however is that directly below the shoulder is not the 'inline' condition of accumulator no.4 - the inline condition is when both arms are straight.
Linear Mode
