I recently read an article called "How does V02 evolve during the 800m?" by
Hanon, Thomas, Chevalier, Gajer and Vandawalle. It is in edition 3/4 2002 of
IAAF New Studies in Athletics. The researchers studied many physiological
parameters during 800m race conditions. The athletes used were about 2min
athletes. Their findings make interesting reading. The summary follows:
Phase 1- During about the first 315m or around 45s that VO2 increased.
Phase 2 - The next 215m up until about 535m VO2max was maintained. This was a
total duration of just 33s. The furthest anyone in the study maintained V02max
was 640m.
Phase 3- V02 gradually decreased to reach an average of 83% of VO2max at the
finish line. The average decrease was 20% (range 13-27%)

The explanation for the dramatic change in Phase 3 was suggested to be
hyperventilation, lowered blood pH, fatigue of respiratory muscles and a
decrease in heart stroke volume. All of these factors contributed to result in
the reduction of gas exchange with the blood.

It is apparent that only 33s of 120s in the athletes tested was spent at V02max
which is 27%. However the decline phase lasted an average of 43s which is 36% of
the race.

The 800m race is run at an average pace which is well above the Maximal Aerobic
Speed(MAS). In this study the average pace was 124% of Maximal Aerobic Speed.
Even in the final phase in the last 25m the athletes speed was still an average
of 112% of MAS. This emphasizes that the speed capacity is being provided to a
great extent by the anaerobic system.

In my view it is certainly worth working the V02max and improving it. But it
seems that an athlete could improve VO2max and maybe not be able to sustain it
for very long. It seems more desirable to be able to sustain it for longer or
prolong the distance decline starts to occur. It is also apparent that athletes
also need to fully develop their anaerobic systems since the speed is always
going to be well above MAS even when in the final 25m. It is no point having a
highly developed aerobic system and an under-developed anaerobic system.

Running at any given speed during an 800m race will require the energy to
maintain that speed to come from all of the bodies energy systems. At race pace
mid race the athlete is not accelerating and all they have to do is maintain
momentum, Fundamentally all this required is a certain magnitude of force being
delivered to the ground.

One extremely important aspect to have a long term view about is in developing
the athletes efficiency at race pace. This is because with improved efficiency
there will be a lower energy cost to run at race pace. This way whatever their
energy systems will be able to provide in total will be able to result in a
faster performance. A useful analogy may be it is no point supercharging a race
car at great expense and ignore improving its weight, aerodynamics, tyre
pressure, gearbox etc.

The added problem with running is that training that may optimize energy system
outputs may also have the undesirable effect of decreasing running efficiency.
This can come about as the result of the natural shaping effect on efficiency
that occurs from the athletes practising the running habit in a way that
exhibits bad running form. Bad running form can easily occur in any athlete who
has not worked directly on improving its maintenance. Most athletes when
fatigued can easily lower their centre of gravity by having a more bent support
leg, lowered hips, low knee lift, overstriding in attempts to maintain stride
frequency, excessive rotation of torso, footstrike not straight, etc.
The same session in one athlete may shape improved efficiency where in another
underprepared athlete may impact to decrease efficiency eg Wilson Kipketer doing
20 x 200m in 26s regardless of rest between would tend to hold great form and
make that pace look really easy. He would get slower if super tired because of
loss of prime mover power but it would not be accompanied by overstriding,
wobbling etc. However a common under conditioned athlete may do a similarly
intense session and look like a fun runner after 5 reps and then practise
progressive worsening loss of form for the next 15. They would be typically
overstriding, twisting, low knee lift - obvious long contacts , straining etc.
This athlete may finish the session proud and satisfied because they know that
this speed session wll make them fitter i.e. it will improve their energy system
outputs. The sad part is that performance in races may decrease due to the
negative impact that this session may have on their efficiency. People may argue
that if the athlete improves in each session then the session must therefore be
worthwhile. The flaw in this thinking is that the energy system adaptations that
are happening may be of a short term nature. The improvement in efficiency is
much more longer term. As is the damage to efficiency much more longer term.
This is not the sort of thing that an athlete can detect "this season". However
it is a fault that will have a great impact long term on athletes who train
under coaching regimes that ignore the concept.

No technical training will improve an athletes efficiency "today", try running
on a treadmill a a certain speed and change your technique, you will not be able
to impact on heart rate at all. This is because the effect of running form
changes on efficiency is a very much slower changing adaptation than we used to.
I think coaches & athletes enjoy the quickness of so many of the adaptations
that we can bring about with training that we ignore some of the bigger slower
ones. EFFICIENCY should targetted and underpin our training philosophies because
it is this important area we compromize when we forget about it. The problem is
athletes often try to run with a better technique and feel that it is not
working and this is because it isn't. It is just like the first time someone
shows you how to swing a golf club. It initially starts of feeling really
"fake"and it is. But eventually it becomes the habit and is totally normal, this
happens after much shaping and then it is effective. Efficiency is like this.

Training short term (season by season) in the area of energy systems can be a
long term disaster for the athlete. This is especially true if young athletes do
not have programs that target predominantly the development of efficiency first
so that good habits are in place. They could then later introduce higher levels
of energy system focused training as they improve their tolerance to maintaining
really good form under high levels of fatigue.

regards
Steve Bennett
www.oztrack.com