Post
by jamesg » June 27th, 2008, 2:28 am
For what it's worth, I usually warm up at around 10m/stroke @18, and then get into UT1 at 11-11.5 m/stroke, rating 20-21. I'm 67, 6'2 (188cm) and 87-90kg as to season. When sculling too, I like to see the puddles well astern when I take the catch, which probably is the origin of the m/stroke idea; certainly eights like to see a nice chain.
When I raced 2ks, it was 10m/stroke at 27. This is Work of around 10W-minutes per stroke (often called SPI, something of a misleading misnomer, it's Work Done per Stroke, not Power). My net stroke length was around 1.2-1.25m (2/3 of height), and handle force 50kg (2/3 my fit weight); and 1.2 x 50 x g x 27/60 = 270W.
In engineering (i.e real) terms, Work Done = Force x Distance travelled by the point of application of the Force; in our case, average handle force x net handle travel (after engaging the gears). There is no more fundamental nor more important index of what we are doing on the erg (or afloat), and it is what the erg actually measures. Note that this gives equal importance to stroke length and to handle force; an effective stroke must have both, and in particular a zero net length stroke means work (and power) also = zero. Since the erg wastes 20-30cm at the catch, short strokes are heavily penalised.
In the various L4 (for which many thanks to MC) and the older Interactive schedules (Idem TO'N I guess), if we convert the specified paces to Watts, and divide by the ratings, we can see that the work per stroke is effectively constant, from 18 to 26. And so it should be; why should an oarsman change his preferred handle force and length just because he changes the rating? To do so would defeat the object of increasing the rating, which is to go faster.
There is no obligation to use this index, but it's there, like it or not. It's not a training tool, it's a technical index, and there aren't many others (maybe W/kg). When someone neither very old nor very small writes here that he does 2:20/500 (130W?) at 35, this means less than 4W'/stroke; i.e he's very lazy or has no idea what rowing is about, or both.
If I could pull 10W' for 7 minutes @27 with perfectly normal rowing technique at age 63 and with no particular strength, I don't see why someone 20+ years younger and heavier can't do at least as well. And he can, but has to learn how; rowing is a technical sport, and it's the technique that works us hard.
So let's not be afraid of Work or SPI, in itself, or as the erg tells us; it's what gets us fit, if it's high enough.
08-1940, 183cm, 83kg.
2024: stroke 5.5W-min@20-21. ½k 190W, 1k 145W, 2k 120W. Using Wods 4-5days/week. Fading fast.