Improve your Stroke – hit the catch

The catch is one of the most critical parts of the rowing stroke cycle. Boat velocity is lowest at the catch, caused by a phase of deceleration when the rower needs to reverse his body’s direction of motion by pushing against the stretcher. This pushing on the stretcher creates a force direct against the boats direction of movement, therefore slowing it down. Last time in “Improve your stroke with Rowing in Motion” we looked at exactly this phenomenon and discussed various strategies to avoid this by adopting a crews motion pattern in the recovery.

Slow catch – “rowing in” the blade

This time, we’re looking at the next part of the rowing stroke, the catch. The key challenge at the catch is to move the blades into the water as fast as possible at the maximum angle. If the hands move up too slow, we see the blade being “rowed in” to the water. The boat loses even more velocity as the rower starts pushing on the stretcher without generating a positive handle force to compensate for that. What’s more important is that a significant part of stroke length is lost that could instead be used to accelerate the boat. In the “Rowing in Motion Video” below you see the blade being rowed in and the corresponding acceleration graph.

Fast catch with “V-splash”

Now, let’s take a look at an example for an optimal catch. The optimal catch is characterised by the typical “v-splash” when the squared blade hits the water right before the maximum angle is reached (creating a backsplash) and is being moved into the water as fast as possible while beginning the stroke (creating a small frontsplash). In the below “Rowing in Motion Video” you can see a better timing at the catch where the blades hit the water earlier and a visible backsplash is created.

Comparing boat acceleration at the catch

For your reference here’s the full video comparing the two different styles at the catch in realtime and slow motion.

From the same video pieces, we have analysed the typical boat acceleration using Rowing in Motion Analytics.The blue graph is from a part of the exercise where the blade has been “rowed in” and the red graph is from a part of the exercise with a better timing at the catch.

CatchComparison

We can clearly see that boat acceleration in the early drive phase of the stroke is greatly improved with an optimal catch. As I have detailed in another post in this series, earlier acceleration is better since it increases average boat velocity over the stroke. You can think about it this way: boat velocity changes during the stroke but at the end and beginning, it’s the same (since negative and positive boat acceleration add to zero and the boat maintains its average velocity). How do you increase this average velocity? When the boat is slowest at the catch you need to accelerate the boat as quickly as possible to be fast for as long as possible during the stroke cycle. That’s how you increase average velocity.

Exercises for achieving a good catch

It’s important you try to develop a good feeling for an optimal catch and when you get it right. A slow rise in boat acceleration after the catch indicates that the blade is being “rowed in”. Using sonification the difference between an optimal and suboptimal catch can be exemplified and the crew can use this realtime feedback to associate the correct “feeling” with a good catch.

As I mentioned previously, a good visual indicator for a good catch is the typical “V-splash” that can be observed when the blade  hits the water in the right moment. Coaches can usually spot the V-splash easily but there’s no harm to use a simple video analysis to confirm an initial impression. To help crews achieve a good catch, focus on the movement of their hands and upper body. The upper body should remain in a fixed forward position while the hands rise slowly towards the catch so the blade hits the water at the right moment. It’s also important that the blades are being squared early enough so some time remains to put them near and into the water. When the blade is squared too late, the hands usually “dip” down a little to make enough room for squaring – while at the same time moving the blade away from the water and making it impossible to hit the right spot.

Here’s some exercises that may help with a good catch:

  • try squaring the blade reeeeaaaally early, best above the knees or ankles
  • work with overreactions, make the crew push the blades into the water so a huge backsplash is created
  • try to convey to your crew that the blades should be completely buried at the maximum catch angle when they get there, not on the way back
  • try split-crew rowing in the four or eight as that increases boat stability and the feeling of traction when the catch was done correctly

If you want to learn more about using boat acceleration to optimize your rowing technique, check out my article “Optimize your Rowing Stroke”.

6 comments

  • physics nerd

    I could not help noticing that the rowing-in boat is travelling at an average of 3.47m/s, while the back-splash boat was travelling at 3.30 m/s.

    speed, not acceleration, is the goal, isn’t it? The grater accelerations over the cycle just means more boat-speed variation over the cycle and that increases the average water drag on the hull over the cycle, doesn’t it?

    • JohannesRudolph

      Hi physics nerd, good catch. Indeed, it is very important to never miss the “big picture” – we want to row fast. In this case, the shown sections may be too short to draw a valid conclusion (we had her row in the blades intentionally and I’m not sure what we did before the video was recorded).

      Your observation regarding average drag is correct in the general case, i.e. given two equal average speeds for a stroke, the stroke with the larger speed variation requires more mechanic work to overcome the drag. However, increased average speed does always increase hull drag too. I doubt that the variance in speed changed significantly between the two pieces to explain the supposed difference in speed.

      Technical detail: the video was recorded with an old version of the RiM App that is no longer available and used a sliding window to average speed measurements and I’m not sure what we did between recording the pieces. Our current Apps use a much more sophisticated and more accurate algorithm. But still, for a reliable analysis you’d need to take 20+ strokes and create an Analysis in Analytics.

  • graham cawood

    Ideally we need to drop the blade quickly into the water at maximum reach. The greater the reach the less the blade needs to speed up to relative water speed for a clean entry. We need the blade to accelerate to water speed very quickly after stopping.
    If we use the commonly coached straight arms any acceleration has to be done with the shoulders and upper body. Since there is a considerable angle between the blade and stretcher at full reach this acceleration will be slow, probably causing the ‘row in’.
    So! Leave the arms comfortably bent in the recovery. As you near the catch and your body gently decelerates, your arms are pulled straight by the blades. You square the blades as this happens, not earlier. At full stretch of the arms drop the spoon into the water,luckily assisted by gravity. Without any muscular effort the arms then rebound and bend as the spoon drops.
    To add to this I would like to explain an early layback plan.
    As the blade enters, your shoulders will be a little ahead of your hips, and will start to move backwards. Now! Instead of moving the seat back, let it continue moving towards the stretcher, pivoting just below the ribs. When your shoulders are a little behind your hips – you are laid back – let your body rebound from it’s cramped position. The commonly coached lean towards the feet until the legs straighten doesn’t make sense, unnecessarily loading the back.
    This combined technique can be practiced on the erg. You should see that tension on the chain is achieved sooner than before.
    The early layback could reduce the load on the back by perhaps 15%

    • Chris

      How can the blade “pull the arms straight”? It’s you that’s moving the blade back towards the catch, so you’re pushing it all the way. Sounds to me like you’re actually saying “keep your arms bent until x, then push them out straight and square and in”. Sounds like allot of last minute movement to me (not that that’s necessarily incorrect), but the blade can’t “pull” your arms straight?! Also i doubt there’s anything to be gained from refraining from having the arms straight until later rather than earlier, would make no impact eitherway?

      You also seem to be suggesting a “body first” style of rowing? Is it really going to reduce the load on the back if you’re taking the load when it’s at it’s heaviest (the catch) on your back, than at the much later and lighter stage (the finish)? I’d imagine you’d have much more people with back problems advocating taking the heaviest part of the stroke exclusively on the back. To make an analogy to lifting (normal objects), or deadlifts/cleans, unless it’s changed since the last time i read up on the science behind it, it’s all about generating the initial force/acceleration through the legs, then only bringing in the back at the last moment to continue the acceleration.

  • David Harralson

    The concept of a “V” splash at the catch is good. However, both splashes should be minimized.

    A bow splash indicates the oar is still moving toward the bow at the catch, slowing the boat until foot pressure on the foot pressure gets transferred to the water.

    A stern splash indicates pressure on the oar exceeds the ability of the oar blade to transfer the pressure to the water (the blade is not deep enough for the pressure applied).

    However “the hands rise slowly towards the catch” is incorrect. The hands should remain at the same level from the time the blade is extracted and feathered until the catch when the rower drops the oar into the water. If the hands change level, this introduces a rocking motion to the boat, which hopefully is minimized if all the rowers change their hand height at the same time. But, the very fact that the hands change their height requires momentum transfer to accomplish which subtracts from the total momentum of the boat system, slowing the boat.

    By the same token, only slow boats square up early. An early Biorow article quantified to a certain extent how much time could be lost squaring early. Basically, this is because the squared blades provide a good fraction of the aerodynamic resistance during the recovery, so keeping them feathered until the last instance minimizes their aerodynamic resistance. When I started Masters rowing, the coaches got after me to “square early”, and this upset my rowing rhythm. Much to my relief, when I started rowing with the director of my club (a World Cup medalist in the USA LM8+), I noticed he squared up just at the catch also. I guess we are fairly efficient together, being faster than our MM4+ at the same regatta.

    And, finally, do no “lift” the hands at the catch. During the recovery, the fingers can be held flat and downward pressure on the oar handle keeps the oar at the right height above the water. At the catch, square up and release downward pressure on the oar. The oar, oar lock, and boat system are designed so that if there is no pressure on the oar handle, it automatically (well, gravity does the work) drops into the water at the right height. If the rower attempts to modify this, it just upsets the boat and slows it down. The advantage here is that the rower can remain relaxed slightly longer, conserving their energy for rowing.

  • graham cawood

    In reply to Chris’s comments.
    1. In moving the blade towards the catch it has to be both accelerated, and then decelerated. Both require force. The acceleration starts as we push the hands away after the release. The deceleration can happen when we slow our body for the catch. Or we can use the force needed to straighten the arms to do the final stopping of the blade. The main reason I do this is because it can give a very quick reversal to the blade – much quicker, cheaper, and less jerky than if I reverse my whole body at that rate. The quick reversal, at full reach, gets the blade to the lower relative water speed and into the water, very quickly.This results in little loss of reach when the blade is ready for work. No use reaching far out of the water if you get the blade submerged slowly.
    Straightening the arm at the release uses energy. Holding it there for the recovery uses more. What for?
    2. Any force by the legs is taken by the back and arms to the blade. Just because the back is not rotating doesn’t mean it is not working. If you lay forward while pulling, the weight of your upper body is ahead of your hips, and ADDS to the rotating load on your hips(and lower back). Layback and the opposite happens. Look at anyone pulling a stable load and they will lean back(tug of war!). The problem is how to do this layback at the catch. Rotating at the hips is too slow. Rotating above the hips – just below the ribs, at a point which is near the centre of gravity is quicker and uses less energy. The fact that this also gives you a longer leg drive is a bonus.
    May I suggest you try these things on both the erg and in a boat.

Leave a Reply

Your email address will not be published. Required fields are marked *