We are teaching/trying to use "pull the boat towards you" technique for a year now- (after this video was published)- works amazingly well on start ups of any age and ability to slow down on a slide, more experienced to speed up boat at least 1/km per hour at any stroke rate (tried and measured on devices and app available to anyone of public, easy for anyone to test it on themselves). Slides and curves on this video worked well to get curious to try not spending pressures time on a details and other data, we have progressed on simple ways for rowers to feel it before getting in a boat. Resuming above- thank you so much for this video (and others too), and all you do for us to enjoy rowing more :)

There is a big difference between the two acceleration peaks you talk about. The one during the drive has both boat and rower moving forward, hence the rower and boat are both gaining momentum. The peak at the catch has the rower moving backward and the boat moving forward, so all that is happening is the momentum is being transferred from rower to boat. As you said, most of the mass is in the rower, so we should care more about making the rowers mass move quickly. You get weird analysis results like this when you only measure how the 15kg boat is moving and not the 90kg rower. I think if you were to measure the rowers movement you would get a very different story.

@willshaffer9951

Жыл бұрын

I was wondering about something similar as well. I know it can be somewhat inferred from this graph (or even calculated with the raw data), but I figured seeing cumulative meters graphed against time would be enlightening as well (for some number of strokes/time depending on whether stroke rate is consistent or not). Or perhaps seeing boat speed graphed against time for an entire 2k piece would be good to see how well speed can be maintained (some form of measuring energy exhaustion).

I know that you would probably use professional athletes for your videos, but to my eye, there looks like there is acceleration up the slide on the recovery? I would love to hear back as it will help me...

Interesting comparison. Is it possible to get more data? Stroke lengths/ angles, heart rates and lactate levels? Also, how would such an approach fare in a headwind condition when the system (boat and athlete) are going slower? Is it difficult to coordinate? How is Joel pulling the boat towards him- what reference points is he focusing on? Pulling his feet so they pull against the straps of his shoes? Or his heels? Calves? Hamstrings? Does the pulling motion and higher rate affect the athlete's ability to achieve a forward angle to return to the catch position? Or does it enhance the bracing of the spine once the blades are loaded?

At last you are beginning to talk sense. However the graphs are very poor and you need a much better traducer to measure the fine accelerations. One of the great problems of our modern age are instruments that pretend to measure but give only very rounded readings that impart very little real information. The graphs if they are accurate are for a very average club oarsman and not an elite oarsman. It is Newton's third law that comes into play when the oarsman moves is mass up and down the slide. It is this that affects the boat speed not the pulling or pushing on the stretcher. The oarsman must use his body mass wisely. A slow (and slow is essential) acceleration of the body mass from the finish to the catch provides enough force to counteract the drag on the boat hull, to keep the boat speed constant. On the other hand a quick thrust of the body forward out of the finish (FISA's style for decades to prevent bum shoving off the catch) accelerates the boat greatly after the stroke to well above the average speed but the long slowing down approach to the catch, aided by hull drag, slows the boat well below the average speed as well as making the boat very heavy at the catch. Equally flying up the slide and crashing into front stops slows down a boat. The boat mass moves at a relatively constant pace. The less variation the higher the average speed. The movement of the rower's mass is constantly changing backwards and forward. almost like the wave of alternating electricity. Some say that it does not matter how it moves as Newton's laws will keep it constant. However how the mass moves is very important as it can be used to accelerate and then slow the boat greatly above and greatly below its average speed, thus reducing the average, or used to keep the boat speed constant thus increasing the average speed. The speed of the catch is vital. The body mass when it changes direction at the catch, accelerates towards the bows causing the boat mass to accelerate backwards at a faster pace as it has a lower mass. How do we counteract this? Kleshnev advocates a trampoline like bounce off the stretcher and slippage (bum shove) of 1 cm on the slide to provide enough momentum and speed when the blades are buried to lift the boat at the catch and thus counteracting the force stopping the boat without putting undue strain on the lower back. The initial smaller curve is not produced by power output but by the clever use of the body mass. Great power at the catch, advocated by Mike Spracklen using the analogy of a square wave, is the surest way to blow up a crew. All their power is given when the boat is heaviest, when their bodies are in their weakest position being third degree levers, and where the weight on the blade is over twice as much as it is in the middle of the stroke. Muscles overpowered at the catch are seize up and will not work for the rest of the stroke. Fairbairn was the first to realize the importance of momentum. Harry Mahon used it to great effect. Kleshnev has discovered it through his very fine measurements. Tony O'Connor who coached the KIWi's Olympic gold had an incredibly fast catch and was very intelligently coached by John Holland for over 8 years. Unlike your curves which show the power curve at the finish, Kleshnev shows the power curve reaching its second and much more substantial peak slightly before the middle of the stroke. The larger the boat the earlier the curve. This power is produced by the big muscles in the legs, the quads, the hamstrings and glutes. Your curves show the curve at its height just before the finish produced by leaning back when the legs are spent and useless. Again I think it is a faulty traducer and not the rowing style that has produced this inefficient curve. When a crew develops the Kleshnev rhythm then in a boat I cox at a stroke rate of 23 spm, it gradually gets faster by about 6 seconds in the 500m splits with less apparent effort. On the other hand if they rush the slides , crash into front stops, slow down on the last half of the slide. or hang at the catch the splits increase by 2 or 3 seconds in one stroke.

@turbokeene

Жыл бұрын

I found this breakdown very interesting. Thanks

@joevdb9232

Жыл бұрын

The curves in this video show the acceleration of the boat only, not the acceleration of the whole mass system of rower and boat. Therefore, they do not show us the real power being exerted on the water. Perhaps this explains why they appear faulty when compared to Kleshnev's.

@VMVarga-yf6eg

Жыл бұрын

James with all respect go back and watch the New Zealand men’s pair row from 2009 to 2016. The sport has progressed. Their stroke is extremely front end loaded. The weight of the blade at the catch reflects the efficiency of the blade at a time when it is moving forward in the water and away from the hull. This is where the blade is more effective and this is why in Paris you will a lot of Gold medal winning crews with a front end loaded stroke

The recovery you recommend is not mutually exclusive to the front end loaded stroke that produces the most effective in stroke acceleration. If you want to go really fast combine both. Also if you really want to analyse rhythm in a relevant way do all of the simulations at race rate. Anything less is completely irrelevant For Joel 40 spm is clearly not going to be sustainable for 2k as he is simply not skilled enough to be efficient at this rate at this time. He would maintain more even splits at a slightly lower rate and this would produce the fastest 2k outcome for him