>I have just been reading about this. Kicking for propulsion can quadruple
>oxygen use so it is usually not worth the effort. It is useful for sprint
>races and spring finishes, or I would guess, if you just feel like using more
The above is convention wisdom. It really does miss the point.
For starters, if you don't use oxygen, you don't burn fat. The reason why you
get increased oxygen use is that you are using the oxygen to metabolize both
lactic acid and fat, both of which the upper body does poorly, relative to the
In the second place, there is nothing wrong with "increasing oxygen use."
Ability to supply oxygen to exercising muscle is not limiting to swim
performance. There is no correlation between VO2 max and distance swimming
performance. Janet Evans had a relatively low VO2 max. Chad Carvin remains a
great distance swimmer, despite losing significant cardiac function with his
devastating myocardopathy. VO2 max highly correlates with performance in lower
body sports (running, cycling). But not in swimming Heart evolved to meet the
needs of the lower body musculature, which have vastly more cross-sectional
capillary diameter than does upper body musculature. Therefore, there is
EXCESS capacity to supply oxygen than needed for maximally working upper body
muscles. Also, upper body (higher ratio of anaerobic glycolysis to aerobic
Krebs' cycle metabolism, relative to lower body) burns little fat, which IS
burned along with the "increasing oxygen use" as more and more kicking is
brought into play).
Some of this excess capacity can and should be put into kicking. You want to
kick at an "aerobic" (positive ratio of lactate consumption over lactate
production) level. A good approximation for an aerobic kick is one which can
be maintained continuously for 30 minutes. At this aerobic level, you will
gain the following advantages:
1. Improved propulsion (speed)
2. Improved front to back balance, less drag
3. Increased fat burning (see # 4, immediately below)
4. Net lactate removal from the ***. The upper body
is very poor at utilizing oxygen (fewer capillaries per
unit of muscle, fewer mitochondria, less myoglobin).
The reason behind this is evident from evolution.
Paleolithic humans did use their legs continuously
for hours, but used their upper body for just brief,
instense efforts (spear throwing, tree climbing to
escape saber tooth tigers, etc.). So human upper
body is more like turkey wings (white meat) than
like duck wings (red meat), relative to the lower
body (red meat). So exercising upper body works largely at
a lactate producing level. This increases with
increased speed, as in a race. The lactate enters
the *** and the ability to flush lactate from
the muscle into the *** by moving along
a gradient from high lactate (in the muscle) to
low lactate (in the ***) decreases. Finally,
lactate levels rise in the ***, lactate removal
from the muscle stops, and the swimmer stops.
But if the legs are working aerobically (net lactate
consumption - lactate is actually preferred over
sugar as a fuel for aerobically working muscle),
then the legs act as a "sink" to reduce ***
lactate and allow upper body muscles to work
longer before fatique from terminal lactate
saturation sets in. This is why modern
distance swimmers who maintain a brisk
kick throughout their distance races are
so successful (e.g. Eric Vendt).
What a deal! Kickers win.
- Larry Weisenthal