Balancing Force and Speed
Posted: April 29th, 2015, 1:42 am
I've yet to master the correct technique after nearly a couple of years - sigh - and I've been thinking lately about the forces applied. I've concluded that technique is not just about the correct sequence of actions but also how the forces are applied. For example, just think simply about the biomechanics: At the catch position (see diagrams at: http://www.clubpiscine.ca/159-tips-and- ... iques.html), the feet do the pushing but I don't think it's just a simple push "backwards". For a start, the footrest is angled so if a force normal to the footrest is applied (if it's not normal your feet would tend to slip - one of the reasons you should practice without straps), the foot force has not only a component opposite to the force pulling the chain but a component tending to lift your backside off the seat (to counteract the torque applied by the chain force). So viewed in that way the foot force is actually not aligned with the chain but one pushing you up off the seat - and backwards as well. In other words, at the catch position you should push so as to try to lift your backside off its seat and not just simply push yourself backwards. Another reason for doing so is that with the legs crunched up in the catch position, you can't push backwards with maximum force, which probably occurs during the drive.
The pudding-proof of this is the force curve illustrated quite nicely by Peter Dreissigacker in his video (https://www.youtube.com/watch?feature=p ... iQ0Mqlk_Lo). With a high damper setting it is hard, particularly for novices and light weight rowers, to get the force curve to rise sharply at the beginning. You would literally have to be "jumping off the seat" to do so. Whereas, the arms, being outstretched, can kick in at any time and so are best left to finish off the stroke and force curve, once the legs and back have done their bit. So with a reduced foot force at the catch, but with speed added in, you can get the force curve to rise (as power is force times velocity). In other words, you can compensate for the reduced force with speed. Well, that's the explanation I have come to, and the conclusions with regard to my training are:
1. To build up muscles, train at the higher damper settings but accept that your times will be slower than the best possible - because you will be lacking speed.
2. To build up speed, train as per suggestions by Peter Dreissigacker at the lower damper settings.
3. Your best times will fit in somewhere between these two extremes as you'll need to combine strength and speed. Lighter (and less muscular) rowers like myself will probably tend to use lower damper settings than those with more muscle.
I hope this all makes sense.
Cheers
The pudding-proof of this is the force curve illustrated quite nicely by Peter Dreissigacker in his video (https://www.youtube.com/watch?feature=p ... iQ0Mqlk_Lo). With a high damper setting it is hard, particularly for novices and light weight rowers, to get the force curve to rise sharply at the beginning. You would literally have to be "jumping off the seat" to do so. Whereas, the arms, being outstretched, can kick in at any time and so are best left to finish off the stroke and force curve, once the legs and back have done their bit. So with a reduced foot force at the catch, but with speed added in, you can get the force curve to rise (as power is force times velocity). In other words, you can compensate for the reduced force with speed. Well, that's the explanation I have come to, and the conclusions with regard to my training are:
1. To build up muscles, train at the higher damper settings but accept that your times will be slower than the best possible - because you will be lacking speed.
2. To build up speed, train as per suggestions by Peter Dreissigacker at the lower damper settings.
3. Your best times will fit in somewhere between these two extremes as you'll need to combine strength and speed. Lighter (and less muscular) rowers like myself will probably tend to use lower damper settings than those with more muscle.
I hope this all makes sense.
Cheers