"Rick Donnelly" wrote in message
m...

...stuff deleted

Paul is onto the basic idea. Muscles fatigue for two reasons:
- overuse from repetitions at a high rate of speed
- overuse from few repetitions against force at low speeds

You can replicate these by doing the following:
- open and close your hand as fast as you can (no resistance)
- climb a steep hill (10 % + grade) on a bicycle

In both cases, you will fatigue within a couple of minutes. Depending upon
conditioning, you may be able to continue to climb the hill, but it is
unlikely that you can continue to open and close your hand after about 2
minutes. After climbing the hill, however, you will need more time to
recover from the cycling than you will from the hand exercise, so there is
a difference in the two types of fatigue (i.e. hard work against low
resistance tends to produce soreness, while fast repetitions do not).

Thus, there is an obvious mid-point of optimal performance before fatigue
sets in. Surprisingly, however, the physical studies suggest that this
optimal performance point results (for most) in a cadence that is too slow
(not a universal truth - I know a few distance cyclists who prefer a
cadence closer to 60, but most, like me, prefer a rate closer to 90).
Cyclists and paddlers will (tend to) find a cadence that is a tad faster
than that optimal performance point. The last study I read suggested that
this is because at the optimal performance point, the muscles fatigue from
both methods of overuse.

Paddlers can adjust cadence by shortening the shaft and narrowing the
paddle blade, with the short shaft having a more drastic effect (a fat
blade is similar to a high gear in that it increases resistance, and
weight, making each stroke a tad more difficult to do). In any case, the
right cadence is fully dependant upon the choice/comfort of the paddler.

Hope this helps (rather than muddies) understanding.

Rick


Rick, I once played the role of a "trained athlete" (all together now...
many moons ago) in which I and a "sedentary" individual were compared in
terms of physiologic responses to increases in exercise rate (this to a
class of med students doing a course on exercise physiology). We both rode
stationary bikes, and were hooked into an ECG machine, ventilator and gas
analyzer. The protocol was for us to both ride the bikes for five minute
intervals, first at no resistance, then at successively increasing
resistance levels. The machines measured the work output, the heart rate,
the amount of air being breathed in and out, and the gas composition (c02
and O2 ratios). While the levels at which I and the other individual
"topped out" were different, the physiologic responses were similar.

In essence, the exercise demonstrated that as the amount of work increases,
the body adapts by increasing heart rate (oxygen delivery), ventilation
volume (oxygen uptake and carbon dioxide exhaust), and oxygen consumption up
to a certain level (which, if I remember correctly was termed VO2max).
Energy consumption up to this point is purely aerobic. As the effort level
increases past this point, the muscles start producing energy anaerobically
(accumulating lactic acid as a by-product). Anaerobic work cannot be
carried out for long as the accumulation of lactic acid starts becoming very
painful, and the breathing pattern collapses into gasps.

If the work is spread out over a number of muscle groups, then the overall
work level is increased (up to the limit of maximum ability of the
heart/lungs to deliver the oxygen). How this applies to kayaking is to use
technique to balance the paddling workload over the maximum number of
muscles, so that no one group gets overloaded. So in essence, that is what
I am trying to figure out - how to achieve maximum output (without crossing
into the anaerobic territory) and which combination of techniques to use.

How this relates to your defining the two types of exercises (high
resistance & low cadence, vs. low resistance & high cadence), is that the
soreness caused by the high resistance exercise is due to lactic acid
accumulation. Recovery is also slower because the lactic acid is an
intermediate oxidation product, and must be oxidized to CO2 to be
eliminated, and the "oxygen debt" that is incurred while producing lactic
acid is then repaid during recovery. Increasing cadence (while reducing the
load) works to a certain point, but as the cadence increases more we get
into neuro-muscular control issues - it becomes harder and harder to
coordinate smooth muscle motion and the motions become more "ballistic",
until you cannot keep the motions coordinated and it all falls apart. The
sweet spot I'm looking for is where the cadence is high enough that the work
level is within the aerobic capacity of my system.

Now, do the maximal exercise long enough, and you run into another
limitation - that of your liver's ability to deliver glucose to the
bloodstream at a sufficient level to support both work generation and brain
function. Once your liver depletes its stores of glycogen, the blood sugar
level drops rapidly, and you get the infamous "bonk" where the athlete runs
out of energy and becomes sluggish and uncoordinated. I've had that happen
to me twice during my cycling phase - and it is not a pleasant experience.
Fortunately, I haven't yet reached that level in paddling.

Regards,

Paul