Evaluating the Haul

[Merlin]

I assume, how quickly the haul hand achieves maximum speed is an important determinant of performance?

Yes it does John. A strong acceleration of the line hand exarbates the risk of tail, but if it is performed late enough, that should allow increasing haul speed in due time.

Merlin

[Merlin]

Hi Paul

IMHO I think that rod arm and line hand stay close to a (different) plane. In that case the underestimation in speed is limited to the distance in between planes which is not taken into account by the 2D projection. I do not think it could have an influence larger than 15% to 20% on results.

Merlin

[Merlin]

Paul

I just studied a back cast record from you (analyzed by Gordy). Peak line hand velocity occurred 33 ms after MAV, but peak haul velocity took place exactly at MAV. It is the same phenomenon than for the forward cast, peak haul velocity occurs before peak line hand velocity.

Delaying the line hand pull further reduced peak haul velocity significantly (e.g. 2 m/s less for a time increment of 29 ms). The difference in time between PHV and peak line hand velocity varies but is still there (from 20 ms to 50 ms for the cases studied).

The stripping guide contributes to more than 60% of peak haul velocity in your BC (17.7 m/s!). In the case of your forward cast, haul velocity follows very closely the line hand to rod butt distance velocity. Nothing comes from the stripper guide action.

Merlin

[Paul Arden]

Hi Merlin,

I guess we will only know for sure if we have two camera angles. I try to haul slowly at first and then very rapidly. I’m really driven by what I see happen with the loop when training carry. The timing is interesting.

The backcast haul is definitely more effective. I think there are several reasons; the stripping guide, biomechanics and body alignment.

I have a better cast when I twist the thumb at the end of the stroke. In the backcast I turn the thumb out, and on the forward cast I twist the thumb in (hauling over the top of the thumb nail). This is timed at the end of the haul. I’ve also taught this to competition casters and they too have found a that their cast appears more dynamic. I don’t know how we measure this or determine the impact.

Thanks, Paul

[John Waters]

I assume, how quickly the haul hand achieves maximum speed is an important determinant of performance?

Yes it does John. A strong acceleration of the line hand exarbates the risk of tail, but if it is performed late enough, that should allow increasing haul speed in due time.

Merlin

Thanks Daniel, the Czech haul technique and performance achieved reflects your conclusions.

John

[gordonjudd]

I do not think it could have an influence larger than 15% to 20% on results.

Merlin,
Assuming the z offset in the stripper guide plane and the haul hand plane is nominally constant and equal to the .5m width of the shoulders, you can get an idea of how that added fixed distance would impact the haul distance between the stripper guide. Taking the derivative of that "more exact" 3D haul distance of Lasse's backcast shows that it reduced the peak haul speed to around 10 m/s compared to the 10.7 m/s value calculated from the 2D distance values.

That is a difference of around 7%.

Gordy

[Merlin]

Gordy

I realize that mathematically speaking, using a 2D representation underestimates the haul distance but overestimates haul speed by comparison to 3D.

Merlin

[Paul Arden]

Hi Merlin,

Wouldn’t it be the case that if it underestimates distance then it also underestimates speed?

I was comparing a hand moving around a 90 degree arc, to the hand being measured from the side in 2D.

Cheers, Paul

[Merlin]

Hi Paul

I considered two parallel planes, one for the rod, one for line hand. A simplification, I know.

Merlin

[Walter]

Merlin,

That is a clever observation. In addition to angle/parallax in 2D views we also have to consider perspective and perspective can make distance and speed look greater as well as smaller.