1. an update of the theoretical concept
Anaerobic threshold (AT) as determined by VO2max and VLAmax of the working muscle mass of the human body -
an update of the theoretical concept
A. MADER
European Congres Sports Science Rom 1998
Institute for Cardiology and Sports Medicine
German Sport University Cologne,
Cologne Germany

2. Basic assumptions About the 30% of body mass are involved in running.
Therefore the energy metabolism in the working muscles is the main cause for the dynamic changes of the measurable parameters which are related to energy supply from oxidative phosphorylation (VO2ml/min*kg) and glycolysis (VLa mmol/l*s).
Glycolysis and oxidative phosphorylation are activated as a function of the cytosolic phosphorylation state of the high energy phosphate system ([ATP] + [PCr]).
As the mechanical power output of the muscle cell decreases the phosphorylation state this activates the metabolic reactions at different levels of the state dephosphorylation.
The lactate distribution space is less than 50% of the body volume.

3. Human body lactic acid distribution space
in % body volume
VLass
100%
30%
48%
65%
Active
muscle
space
Cla(M)
Passive
lactate
space
Cla(B)
Non
H2O
space I
H2O
space
Lactate elimination
Lactate space
VLass
Non lactate space II
CLass Vol.rel
1) Lactate production in the active space
VLaOXss
2) Elimination of lactate in both spaces

4. Log/lin. steady state activity of oxidative phosphorylation and glycolysis VO2MMK = Michaelis-Menten-Kinetik
Oxidative
steady state
PCr
pH = 7.4
VO2
pH=7,0
Non steady
state
pH=6,8
Proton
leak
pH=6.2
-DGATP
VLass
anaerobic threshold
Stage of
VLa
pH=6,6
Chance
VO2
ATP
VO2
MMK
pH=6,4
exhaustion
rest

5. The steady state assumption
As oxidative phosphorylation and glycolysis are regulated as a function of the cytosolic [ADP] “gross lactate formation” (Vlass) is a function of the relation between VO2max versus VO2ss.
The rate of glycolysis is
VLamax
(1 +ks2((VO2max-VO2ss)/ks1*VO2ss)3/n)
Vlass =
+ VLaRest
ks1  mmol/l [ADP]
ks2  0.2 mmol/l [ADP]

6. VLaOXmax (mmol/l*min) = (0.035)* VO2ss(ml/min*kg)
Measured rate of lactate oxidation, trained and untrained rats (results from DONNOVAN and BROOKS (1983))
(OSS = oxidative steady state)
Necessary fuel for maintaining mitochondrial oxidation:
VLaOXmax (mmol/l*min) = (0.035)* VO2ss(ml/min*kg)
Real carbohydrate (lactate) oxidation is a function of the lactate concentration:
VLaOXss (mmol/l*min) = VLaOXmax/(1+ kel/[CLa]2)
CLa(mmol/l) is the blood lactate concentration
The 50% activity constant kel can be estimated from tracer experiments of DONNOVAN & BROOKS
VLaOXmax= f(VO2ma,x, Cla >> 20 mmol/l)
Best fit
kel = 2.0
kel
Blood lactate(mmol/l)
OSS => VLaOXmax > VLass

7. Consequence V(LackPyr) = VLaOXmax - VLaOXss
The 50% activity constant kel (CLa) reflects the sentivity of the pyruvate dehydrogenase (PDH).
If CLa or CLaSS determines the carbohydrate combustion then “fat combustion” can only take place if there is a “lack of pyruvate production”.
The lack of pyruvate expressed as VLass - equivalent is
V(LackPyr) = VLaOXmax - VLaOXss
In this case the mRQ can be recalculated from CLaSS or Cla(B):
---> %VLaOXss = 100/(1+kel/[CLaSS]2)
---> mRQ = (( %VLaOXss)*0.7 + VLaOXss)/100
---> for CLaSS = 4.0 mmol/l the mRQ is ~ 0.97

8. Way of calculation under the “steady state” assumption
It is assumed that under all conditions included the complete depletion of PCr the the rectangular area from start to peak VO2 (~ VO2ss) is covered by oxygen uptake and PCr-depletion.
This is associated with a certain rate of glycolytic energy sup-ply VLass.
VLAss
CLa
VO2ss
Oxidative +
alactic power
VO2tot(ml/min*kg) = VO2ss * VLass(mmol/l*min)

9. The problem of the diagnostic of an athletes metabolic capacities ?
How can be the aerobic capacity (~ aerobic power related to VO2max (ml/min*kg b.w.)) measured or estimated ?
How can be the glycolytic power - defined as “maximal lactate formation rate” (VLamax (mmol/l*s) - determined or estimated ?
Does the extent of each of the two powers influence the appearance of the other ?
How is the appearance of the so called “anaerobic threshold” (AT) related to the extent of the aerobic and the glycolytic power of an athlete ?

10. Low endurance, female 400/800m runner
2 x 300m
= VO2tot
Energy demand
glycolytic
VO2ss
Measured VO2max
treadmill
max. test
2 min
Alactic
+ oxydat.
energy AT
Low endurance
Glycolytic power ?

11. Low endurance, female 400/800m runner measured VO2max = 58 ml/min
Low endurance, female 400/800m runner measured VO2max = 58 ml/min*kg glycolytic power ?
Calcul.
mRQ
400m
Measured RQ
CLa
measured
VO2max
CLa
2 x 300m
74%VO2max
Max.test
2Min. AT

12. Metabolic Profile: Low endurance, female 400/800m runner estimated VO2max = 62 ml/min*kg; glycolytic power = 0.8 mmol/l*s
Measured RQ
treadmill
600m
VLanet
800m
VLaOXmax
400m
VO2ss
%fat comb
300m
2 x 300m
Class AT

13. Energy demand: Highly endurance trained runner: 4mmol speed = 5
Energy demand: Highly endurance trained runner: 4mmol speed = 5.65 m/s, VO2max measured = 76, estimated = 80 m/min*kg BW
VLass
1500m
Competition
86%VO2max
muscle
Energy demand V4
VO2ss
2 min max. test
Range of Endurance
Next slide will appear

14. Long distance runner, high endurance trained
Measured VO2max
measured
vent. RQ
Calculated
mRQ d V4 AT

15. High endurance trainend: VO2max measured 76 ml/min
High endurance trainend: VO2max measured 76 ml/min*kg estimated: 80 ml/min*kg, VLamax~ 0.25 mmol/s*l
Metabolic RQ
1500m
% Fat combustion
VLaOXmax
Maximum
VO2max
measured
VO2
2Min
2 min
Measured RQ
100m
100m
CLa
VLass
Low anaerobic
Maxtest V4
Extended range of endurance

16. High endurance trained
%Fat oxidation
VO2ss
1500m
Measured RQ
600m
100m
Lack of pyr
Fat
VLass
Extensive endurance
training CLa < 1.25mmol/l AT

17. Conclusions:
- It seems to be possible to recalculate the metabolic pattern according to various test results using spiroergometry and measurement of lactate con-centration after short intensive loads.
- The main variables which characterize the athletes metabolic capacities are the estimated maximal oxygen uptake (VO2max) and the maximal rate lactate production (VLAmax).

18. Thank you for your patience and your attention