Re: FIELD SPORTS & ANAEROBICS
- To add to the debate about contributions of the energy systems to different
sports I very very strongly recommend my students to rip out the page cited
by Mel Siff - my copy is from Fox and Mathews textbook "Essential of
Exercise Physiology" that contains the table "The predominant energy
systems of different sports" (in fact I do not recommend this text at all).
I my opinion its energy table is bizarre in the extreme. I must
acknowledge that Dr Siff states that more recent texts have modified these
figures - but it is a lot more than "somewhat" as he suggests! A far more
sensible and intuitively correct table is found in "Better Coaching:
Advanced coaches manual" 1991, Australian Coaching Council, ISBN
0958985030. It's values really show to me how silly some of Fox and
Mathews values are and why I think the F & M table should not be cited.
Fox and Mathews claim a 1-mile running race is only 25% aerobic!! - whilst
Better Coachings has the 1500m at 85% aerobic - a far more sensible figure
(my understanding of the research on the time constant of oxygen uptake
kinetics suggests that at the end of even 60s of vigorous exercise,
potentially about 50% of the energy is derived aerobically - let's not get
sidetracked on the details of this point as I only use it to show how rapid
the kinetics of oxygen uptake are). In addition - F & M suggest Basketball
and Volleyball have NO aerobic component at all!! (how they justified this
is mindboggling to me) - whilst Better Coaching suggests 50% and 40%
respectively, also, F & M suggest soccer is 20% aerobic, whilst Better
Coaching suggests 50%. I think a large number of coaches and scientists
would agree the Better Coaching table is far more sensible and in my
opinion, one of the best I have come across.
Although I provide only one example to counter some of the bizarre values
cited by F & M, I really think their table is wildly inaccurate (but has
unfortunately been replicated in other texts), and it is so far out that
should not be used by coaches; I also agree with Evan Stilwell that
accurate energy system figures are needed when making deductions about
PE and Sports Science
University of Hong Kong
Mel Siff commented:
>Evan Stilwell commented:
>If you consult Fox and Matthews 'Interval Training for Sports & General
>Fitness', you will note that the 'aerobic' system contributes some 20% to the
>energy needs of soccer. More recent texts may have modified those figures
>somewhat, but 20% is still a long way off the 50% for offering a contribution
>which is even equal to the two 'anaerobic' systems.
>>>I think it is responsible to at least get the correct energy system of a
>sport if you are going to use that sport as an example to argue against
>altitude training whether good or bad.
- Perhaps I could ask for some important advice that my also help other
members - that is, what is the best on-line metabolic gas analysis system
currently available? We want to replace our ageing Quinton Q-Plex system
and to purchase an accurate, reliable, user-friendly system that has low
maintenance and other on-going costs.
About 10 years ago (pre-Web era) I did went through a very lengthy
exercise and found the Sensormedics 2900 system was considered the best
available (great O2 & CO2 analysers, stable, probably the most vital part
was its excellent ventilation measurement system, low maintenance, provided
B x B and mixing chamber modes, automatic calibration, etc - its only
downfall was the cardiac output system using CO2 rebreathing was hopeless
as the curve-fitting programme was rather inept).
I know its replacement model - Sensormedics Vmax system - has given
persistent problems to some people - so that is out. We are currently
impressed by the Jaeger Oxycon Champion system (as it suits adults and
children - we must have paediatric-sized valves, and has a nice automated
CO2 rebreathing system for cardiac output) - but we need feedback from
users on this Jaeger system or whether other metabolic carts are better -
eg. what about the current Quinton model or MedGraphics system?? Others??
Can readers please send comments either to me or post them to this list -
especially why any current models have either impressed them, or have
provided major problems (please give reasons) or what model you would buy
if you could. I will happily try and post a summary of the comments. I
look forward to your responses.
Dr Duncan Macfarlane
PE and Sports Science Unit
University of Hong Kong