shin angle at the catch

No, ergs don't yet float, but some of us do, and here's where you get to discuss that other form of rowing.
Alex Lumier
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shin angle at the catch

Post by Alex Lumier » December 31st, 2020, 12:18 pm

Hello everyone,

it's been 6 years since I started rowing, and I know that at the catch my shins should be at 90º with the boat. But I would like to know why. Biomechanically speaking, why is that so important? What happens to muscle contraction or recruitment if we don't reach that angle?
It would be great if someone knew the answer and/or know some studies that explain why.

Thank you

jamesg
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Re: shin angle at the catch

Post by jamesg » January 1st, 2021, 8:09 am

The rowing action on the erg is governed by the fact that the flywheel is moving fast, so we too must move fast and also produce force, to do mechanical work on the handle.

For this the posture at the catch must be close to ideal, so that the action too can be ideal: a hefty thrust with the legs at the catch, followed by hips, shoulders and arms, at ever increasing speed.

This ideal posture is reached with a straight back and by using the hands away, then swing, then slide recovery sequence. This sequence ends forward with the shins vertical or slightly short of vertical, and our weight on the feet. This leaves the knee angle open, offering speed and force of action as needed. At high race ratings we may tend to use a shorter posture, but normally in training or race cruise, the stroke will be full length, in order to limit the force needed for any given amount of work.

What must be avoided is bringing the slide too far forward: the knee angle is small, posture weak, legs cannot act fast. Can lead to injury. Afloat it's impossible, but if you suffer this problem on the erg, put a frontstop on the rail about 50 cm from your heels and use the recovery sequence.

If you have problems with the recovery sequence, try the backstop drill: first hands and swing only, then add slide after the swing. All as shown here:

https://www.youtube.com/watch?v=zQ82RYIFLN8
08-1940, 183cm, 84kg. Last seen MHR 158 in 2k = 220 - 77% of age.
2021-2: stroke 6 W-min. ½k 1:55.5; 1k 4:09.2; 2k 8:42.2; 5k 23:15; 30' 6247; 10k 49:36.

MiddleAgeCRISIS
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Re: shin angle at the catch

Post by MiddleAgeCRISIS » January 1st, 2021, 8:29 am

Alex Lumier wrote:
December 31st, 2020, 12:18 pm
Hello everyone,

it's been 6 years since I started rowing, and I know that at the catch my shins should be at 90º with the boat. But I would like to know why. Biomechanically speaking, why is that so important? What happens to muscle contraction or recruitment if we don't reach that angle?
It would be great if someone knew the answer and/or know some studies that explain why.

Thank you
I didnt know this for my first 1m of metres and it caused a lot of pain in my ITBs.

Putting in a front stop worked for me. Although the stroke is shorter - i feel it gets straight to the most powerful part of the drive.

I've not rowed on water but i wonder if you would bounce the boat if you went past this angle? I'd love to know.

Hoping to try rowing on the water in the spring on the severn.

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hjs
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Re: shin angle at the catch

Post by hjs » January 1st, 2021, 8:44 am

MiddleAgeCRISIS wrote:
January 1st, 2021, 8:29 am
Alex Lumier wrote:
December 31st, 2020, 12:18 pm
Hello everyone,

it's been 6 years since I started rowing, and I know that at the catch my shins should be at 90º with the boat. But I would like to know why. Biomechanically speaking, why is that so important? What happens to muscle contraction or recruitment if we don't reach that angle?
It would be great if someone knew the answer and/or know some studies that explain why.

Thank you
I didnt know this for my first 1m of metres and it caused a lot of pain in my ITBs.

Putting in a front stop worked for me. Although the stroke is shorter - i feel it gets straight to the most powerful part of the drive.

I've not rowed on water but i wonder if you would bounce the boat if you went past this angle? I'd love to know.

Hoping to try rowing on the water in the spring on the severn.
Stroke does not need to be shorter. Getting the shins beyond vertical is caused by not rocking over the hips/upperbody enough and leaving a gap between the chest and legs. Doing this makes the first part of the stroke weaker. From a vertical shin and forward placed upperbody everything is ready to fire.

MiddleAgeCRISIS
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Re: shin angle at the catch

Post by MiddleAgeCRISIS » January 1st, 2021, 9:11 am

hjs wrote:
January 1st, 2021, 8:44 am
MiddleAgeCRISIS wrote:
January 1st, 2021, 8:29 am
Alex Lumier wrote:
December 31st, 2020, 12:18 pm
Hello everyone,

it's been 6 years since I started rowing, and I know that at the catch my shins should be at 90º with the boat. But I would like to know why. Biomechanically speaking, why is that so important? What happens to muscle contraction or recruitment if we don't reach that angle?
It would be great if someone knew the answer and/or know some studies that explain why.

Thank you
I didnt know this for my first 1m of metres and it caused a lot of pain in my ITBs.

Putting in a front stop worked for me. Although the stroke is shorter - i feel it gets straight to the most powerful part of the drive.

I've not rowed on water but i wonder if you would bounce the boat if you went past this angle? I'd love to know.

Hoping to try rowing on the water in the spring on the severn.
Stroke does not need to be shorter. Getting the shins beyond vertical is caused by not rocking over the hips/upperbody enough and leaving a gap between the chest and legs. Doing this makes the first part of the stroke weaker. From a vertical shin and forward placed upperbody everything is ready to fire.

I will take a look at this tonight. Thinking it through presently. My logic was that i lost the gap created by the front stop.

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hjs
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Re: shin angle at the catch

Post by hjs » January 1st, 2021, 10:59 am

MiddleAgeCRISIS wrote:
January 1st, 2021, 9:11 am



I will take a look at this tonight. Thinking it through presently. My logic was that i lost the gap created by the front stop.
Its almost always different angles. More leg bend and less folding, or just the other way around.

MiddleAgeCRISIS
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Re: shin angle at the catch

Post by MiddleAgeCRISIS » January 1st, 2021, 12:27 pm

hjs wrote:
January 1st, 2021, 10:59 am
MiddleAgeCRISIS wrote:
January 1st, 2021, 9:11 am



I will take a look at this tonight. Thinking it through presently. My logic was that i lost the gap created by the front stop.
Its almost always different angles. More leg bend and less folding, or just the other way around.
Think I get it, shins and femurs dictate the pelvis position and then the folding or not. Ish.

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Re: shin angle at the catch

Post by Nomath » January 1st, 2021, 2:23 pm

There is quite a difference between rowing in a boat and rowing on a static C2 ergometer. I cannot comment on the optimal posture in a boat, but there are several studies on the internet.

On a static C2, after the catch you first have to accelerate your body to a speed that matches the momentary speed of the flywheel before you can apply any power to the flywheel. Your posture at the catch should optimize this initial launch in which all force is applied to the foot stretchers. The shin angle will depend on the height of the foot stretchers. As the stretcher height is increased, the shins will be less than vertical.
You can find more details in the article The influence of stretcher height on posture in ergometer rowing, in European J. of Sport Science, 2010.

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hjs
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Re: shin angle at the catch

Post by hjs » January 1st, 2021, 3:23 pm

Nomath wrote:
January 1st, 2021, 2:23 pm
There is quite a difference between rowing in a boat and rowing on a static C2 ergometer. I cannot comment on the optimal posture in a boat, but there are several studies on the internet.

On a static C2, after the catch you first have to accelerate your body to a speed that matches the momentary speed of the flywheel before you can apply any power to the flywheel. Your posture at the catch should optimize this initial launch in which all force is applied to the foot stretchers. The shin angle will depend on the height of the foot stretchers. As the stretcher height is increased, the shins will be less than vertical.
You can find more details in the article The influence of stretcher height on posture in ergometer rowing, in European J. of Sport Science, 2010.
Otw, the water needs to be “caught” the speed of the flywheel is now the speed of the boat versus the water.

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Re: shin angle at the catch

Post by Alex Lumier » January 2nd, 2021, 1:00 pm

Nomath wrote:
January 1st, 2021, 2:23 pm
There is quite a difference between rowing in a boat and rowing on a static C2 ergometer. I cannot comment on the optimal posture in a boat, but there are several studies on the internet.

On a static C2, after the catch you first have to accelerate your body to a speed that matches the momentary speed of the flywheel before you can apply any power to the flywheel. Your posture at the catch should optimize this initial launch in which all force is applied to the foot stretchers. The shin angle will depend on the height of the foot stretchers. As the stretcher height is increased, the shins will be less than vertical.
You can find more details in the article The influence of stretcher height on posture in ergometer rowing, in European J. of Sport Science, 2010.

Thank you for showing me this article, it does a pretty good job at explaining the importance of the shank angle at the catch.

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Re: shin angle at the catch

Post by Tsnor » January 4th, 2021, 3:45 pm

Especially when I am trying to row long/slow and control heart rate, when I get a really good technically correct stroke (shins not past vertical, good forward lean, strong back, lats engaged, heel down leg drive) the split time shoots down at the same perceived effort level.

Suggest you try a few of the suggestions above and try to see the split difference. It's large for me.

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Re: shin angle at the catch

Post by jackarabit » March 25th, 2021, 4:46 pm

jamesg writes:
What must be avoided is bringing the slide too far forward: the knee angle is small, posture weak, legs cannot act fast. Can lead to injury. Afloat it's impossible, but if you suffer this problem on the erg, put a frontstop on the rail about 50 cm from your heels and use the recovery sequence.
I submit that there is not a one size fits all specification of distance from heel to a virtual ‘shin biter’ which either marks or enforces a desirable limit to seat movement on recovery. This measurement is determined empirically and varies directly as total leg length and femur to shin length ratio varies in any population of fitness ergers. Collegiate rowers and competitive ergers may take their stature for granted but we gamba corta types with 29” inseams and <1:1 femur to shin length will need to determine where the seat carriage should stop based on our individual leg geometry.

In my case, I determine the location of this tourniquet and take two turns of hdware store bungee cord around the rail beam, cinched up with a slipped square knot on the underside. I record as a horizontal measurement by leaving shoe in the heel cup, plumbing to the rail surface from intersection heel counter and sole, and measuring to far side of bungee stopper, in my case 26 cm. Sitting with carriage roller @ 50cm distance from heel, the included angle of my shin and femur in profile is much greater than 90°, easily identifiable as quarter stroke per the backstops drill. I row most of my meters @ position #5 on the foot elevator tongue and sometimes sprint at #4.
There are two types of people in this world: Those who can extrapolate from incomplete data

M_74_5'-7"_156lb
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Re: shin angle at the catch

Post by jamesg » March 26th, 2021, 3:48 am

Just 26 cm coupled with high feet must be very uncomfortable. What advantage is there?
08-1940, 183cm, 84kg. Last seen MHR 158 in 2k = 220 - 77% of age.
2021-2: stroke 6 W-min. ½k 1:55.5; 1k 4:09.2; 2k 8:42.2; 5k 23:15; 30' 6247; 10k 49:36.

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jackarabit
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Re: shin angle at the catch

Post by jackarabit » March 26th, 2021, 10:07 am

jamesg wrote:
March 26th, 2021, 3:48 am
Just 26 cm coupled with high feet must be very uncomfortable. What advantage is there?
Buongiorno James

Desiderata:
1) I row in shoes.
2) My shoe size 10 1/2 US, 42.5 metric
3) Six sets of positioning holes in the tongue of heel elevator
4) Top set of holes is unnumbered.
5) Remaining five sets are numbered 5 to 1 top to bottom
6) I row with the tongue in position #5
7) Position #5 puts the heel loop at the very bottom of the foot platform
8) Remaining adjustment for lowering feet is pegs in the unmarked holes at top of tongue
9) Max lowering of heel elevator places strap over knuckles of my big toes
10) Using unmarked position heel elevator and stopping seat roller @ 50 cm, included angle shins/thighs approaches 90°.
11) Assuming this position to be my prescribed catch position, my shins are @ 45° angle to rail surface.

Question: Are you reasonably certain your advice re: location front stops applies to my geometry?
There are two types of people in this world: Those who can extrapolate from incomplete data

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jamesg
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Re: shin angle at the catch

Post by jamesg » March 26th, 2021, 1:31 pm

Sorry to put you to so much trouble, I had it upside down, thinking 1 was at the top. I use the same criterion, strap over toes to allow heel lift and get well forward of the slide to keep the knee angle open.
08-1940, 183cm, 84kg. Last seen MHR 158 in 2k = 220 - 77% of age.
2021-2: stroke 6 W-min. ½k 1:55.5; 1k 4:09.2; 2k 8:42.2; 5k 23:15; 30' 6247; 10k 49:36.

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