Super Slow Motion Form Video - and arrow porpoising?

[bowhunter15]

I had the opportunity this weekend to film with a friend with a camera that can record in 960 frames per second. We took some video that I can use on future videos, and also to check my form and arrow flight.

 https://www.youtube.com/watch?v=sEhdP9g0aK0&feature=youtu.be

It seems to me like the nock of the arrow travels downward a bit after release, then jumps up as it goes over the rest, inducing a vertical flex or porpoising. Is this a simple problem of the nocking point being too low? Or am I doing something in my release that's inducing a vertical flex?

I'm shooting 4 fletch, 90-90. Notice the wear on my calf hair rest. I'm also curious if that is an issue.

I was already planning on hunting with my compound this coming weekend before switching back to the longbow. But if need be I can hunt with the compound until I get this figured out. Then again my groups aren't terrible and I'm shooting very high FOC so I'm not sure how much of an issue it actually is.

[moebow]

bowhunter,

I find it really hard to tell from this video, angles are wrong for form analysis.  That said, what is the weight bias on your fingers at full draw?  It APPEARS that you may have much more weight on your middle and ring finger than on the index finger.  This COULD be causing the problem.

Another "clue" is to watch your string hand after the release.  See how it moves down towards your chest?  Ideally it should move on a straight line from the corner of your mouth to a position in the air right behind the ear.  No downward movement.  I can't really tell from this angle but your string arm elbow MAY be too high, causing this downward movement.

Either/both of these issues MAY be causing the problem.  But, I will admit that this is largely a GUESS at this point.

Try a few shots where you think,"Move horizontally AROUND the spine with the string arm at release."

It also MAY be your nocking point height, but that is an easy experiment to do.  I am one that would suggest that your form/execution is a bigger culprit than your NP.

Arne

[bowhunter15]

Here's a video with more angles for a few weeks ago. It's in regular speed. Two things I did differently since recording that video were slow down and ensure that my string arm comes all the way back before releasing. Any elbow high/low or weight distribution on the fingers would still be the same though. I've never paid attention to which fingers hold more of the weight.

 

[moebow]

Combining the information from the two different videos, if we were working together, we'd look at getting your string arm elbow down for better alignment.  There are 3 things that make me suggest this.

First, The alignment of the forces between you and the bow at full draw.  If you draw a straight line from your bow hand pressure point to your arrow nock,(freeze the video at full draw and place the edge of a piece of paper on the bow hand pressure point and the arrow nock) then extend it back to the elbow, ideally the elbow will be ON or VERY NEAR that line.  Your elbow is significantly above the line. The line is called the draw force line, FYI.

Second, when you release, watch the bow movement.  See how it throws the bottom limb forward? Again, IDEALLY, the entire bow should move straight forward towards the target (no rotation).

And finally, the arrow reaction shown in your first video where the porpoising shows up clearly.  This reinforces my thinking that there is a downward force on the arrow nock when you release.

I BELIEVE, that IF you can get your string elbow down and on the draw force line, much, if not all, of your porpoising will disappear.

Arne

[bowhunter15]

https://www.youtube.com/watch?v=R1RoGxIjyHE&feature=youtu.be  

I did some shooting, really working on pulling the elbow back and down. In fact, I don't think I can hold it any lower than I did in the video.

One thing I noticed, is that if I went frame by frame, the lower limb appears to move faster than the upper limb HOWEVER, I think some of this is an optical illusion. CMOS camera sensors capture data one line at a time, from top to bottom, for each frame of video. So by the time the lower part of the video frame is captured, it's slightly further along in time. That would make the lower limb appear to be more advanced than the upper for any given frame of video.

The bow does still rotate backward after the shot. I think some of this is due to the static balance of the bow and the fact that I shoot with a loose grip. If I hold the bow by the grip and loosen my grasp, the bow naturally cants to the left and tilts backwards toward me. If I remove the quiver, it doesn't cant but still tilts backwards toward me. If it were a compound, I'd add weight to the front stabilizer, but obviously we don't have that kind of ability with trad.

It's really tough for me to say whether or not the arrow is still porpoising. The 120 frames per second just isn't quite fast enough. But, would you say that at the very least my form is better in this video? It will take a little bit of consistent practice to get used to that low elbow. OH, and by the way, the last arrow I shot 3 under just for the heck of it.

[moebow]

That looks better.  It WILL feel strange for a while but the bow moves much better now at the shot release.  Next, when you can, get outside so you can see the arrow in flight.

Arne

[bowhunter15]

Cool, thanks for the help. I'll try to get some outdoor video of arrow flight when I get a chance. Maybe shooting those black arrows towards a target covered in white paper in slow mo.

[BenBow]

I build bows and have found that when you add as much pressure to the grip with the heal of your hand as you appear to do you change the dynamic tiller of your bow. You are over stressing the bottom limb and it does move faster than the top limb which pulls your nocking point down at release. Follow Moe's advise and also put less pressure low on the grip and your arrow flight will improve. For a permanent solution you will have to change the tiller on your bow if you want to continue putting that much pressure low on the grip.
Also if you pause the second video where it is  taken from behind you you can see the bottom limb is bent more than the top limb. The angle isn't perfect but it shows up in the third video as well. There you can see the bottom limb is bending more from the fade through the inner third of the limb.

[slowbowjoe]

FWIW: I've been having a really hard time getting rid of porpoising arrows for some weeks now. Tried all sorts of nock heights, different silencer placements, and spend arrows. Tried different finger pressures on the string.

Changed strike plate and shelf rest to a softer material, did what BenBow describes above, and saw immediate improvement.

Think I was "heeling" the grip too much (had a long layoff due to injury, and forgot some subtleties of my form).

[Roy from Pa]

Your draw arm elbow is way too high as Moe stated above. As you draw, I can see you are actually pulling upward on the bow string. You want your elbow to be straight in line with the arrow.

 

[moebow]

Roy,

Going to respectfully disagree with you here. Ideally, the string elbow to string hand line should point at the bow hand center of pressure.  The forearm pointing on the arrow line is too low.

I know that what you show is popular opinion, but bio-mechanics will show that there is more muscle tension with this approach (on the arrow line) than with the draw force line.

May be a minor distinction  but worth noting IMO.

Arne

[Roy from Pa]

Ok Moe, thanks.

[tracker12]

Arne
I read the draw force explanation before but not quite as simplistic.  Thanks for the moment as always.  I see now that I really need to video my shot to see where my flaws are.