Endurance training zones 70% is not always 70%

[Robh]

Endurance training zones 70% is not always 70% by Juerg Feldmann

70 % is not always 70%. True mathematically it is always 70 % and that is exactly the problem. Math is not physiology and people have many differences we may see ( even if they are only small ) so how about DNA?

Endurance training, and there are many different ways of endurance training that will change mitochondrial enzyme activity. So we will see 2 - 4 time greater mitochondrial activity in people , who do an endurance training regular compared with people , who do less or none.

This leads to a different situation, where either the type I ( STF ) fibers are much better working or if training is properly done where we see in both (STF Type I as well as in FTFa Typ IIa ) fibers similar mitochondrial respiratory capacity, meaning a good ability for a oxygen dependent energy production . Now as the word is self explaining it is oxygen dependent, so oxygen is always a very important part of the energy production and as more FFA is involved, the longer we could go because we would "save” glucose , but we need more oxygen. There for this a very important part of longer and the same performance the % of FFA in the energy production.

This would mean , that in testing with lactate and Fe O2 ( fit Mate ) we can see by what intensity we have this situation most efficient (for races and relatively inefficient ( for training ).

Now there is a interesting study done by Coyle et al, in cyclist with a VO2max of 67ml/kg/min, the blood lactate response to submaximal exercise was used to divide well-trained cyclists into either low or high lactate responders to cycle exercise.
Endurance performance was markedly different in the two groups. The high lactate responders could only cycle half the time at 88%VO2max compared to the low lactate responders.. Leg muscles were studied for mitochondrial marker enzymes, fiber types and their sizes as well as capillaries, and no difference was found between groups with regard to mitochondrial enzyme activity and capillaries/muscle fibre. Thus neither the lactate response nor the performance could be related to these indices of muscle adaptation. Both variables are easily affected by changes in physical activity level and are proposed as a link to a more efficient muscle metabolism. Two other muscle indices differed: those with a poor performance and a lower lactate threshold had less type I muscle fibres ( 47 % - 67 % ) than the good performers, and had a 15 % larger mean muscle fibre size.

Now the interesting question for me is , that every 5 to 8 years somebody comes up with a 4 - 8 week study , comparing endurance training with high intensity and endurance training with low intensity and always will come up with a clear proof, that fast and hard is better to improve performance (Functional and structural).

Yes over 4 - 8 weeks for sure and it does not need more of these studies to show this over and over again. What would be nice is a study comparing the result by testing the same idea over a time frame of 4 - 8 years. Coyle’s study at least should give for us some thoughts , that the claim is a lactate threshold , which was higher in the SFT group , than the FTF group . So question would be how do we train STF fibers and what energy source do they use ?

I would argue, that there was less of a question on the lactate threshold (because it does not exist) than a question of the ability of the STF fibers to produce oxygen dependent energy to a higher % from FFA and less from glucose. Therefore these athletes had a much better way of performing longer, because they would not run out of glucose as early as the FTF group , who used the glucose much earlier and with a much faster rate. Meaning the higher lactate was not an indication of running anaerobic, but rather an indication of running the energy production in the oxygen dependent zone on a higher % of glucose, and therefore the lactate showed up higher and possibly earlier in the system.

Exactly for that reason it is nice to use a lactate pro during a work out on the street and combine the info of the current HR , the feeling , the breathing frequency together with the lactate trend and adjust the intensity accordingly to your training idea on that given day . U sing wattage is relative meaningless alone , but it can taken in concert with the above physiological ideas.

So back to the start of having a research based on a same % of VO2 max and now we go and read the above info from Coyle et al. and now we may have to start thinking again about the values of the findings in research papers like that ( based on 70 % VO2 max groups and so on ).

On the other hand we may have to perhaps as well reconsider the value of any intensity training system based on % of any maximal values, ( HR /VO2 max / max wattage and so on ).

This is what lead us now nearly 20 years ago to the FaCT idea of using trends and now using besides trends in lactate as well trends in other physiological easy to test parameters.
Summary:
1. Lactate can be used as a trend info on metabolic information , as well as possible involvement of certain muscle fibers and long term ( structural ) changes of this fibers , by testing LBP over a longer period of time.
2. Respiratory frequency in combination with O2 sat as well as sometimes in combination with true O2 extraction can be used to check the pulmonary / metabolic synergy.
3. HR / HRV and change in LLL ( lower linear limit or lower own zone value in combination with HR or breathing can be used to asses the situation of your cardio /pulmonary/ metabolic synergy.
Wattage? well we can see whether by a give wattage some of the physiological values have changed over time. But it is not very good to use max wattage for this info . So we use LBP wattage as a possibility to see relative changes of HR . lactate. breathing frequency and FeO2 extraction and if people like VO2 values to see , which of the system responded to our training and which system did not.

This idea can be very nicely explained with T. Noakes Central governor Model, which we extended to the ECGM ( extended Central governor system. This ECGM is the base line of our FaCT IRIS concept and lot's of questions we had over all this years can nicely be explained and tracked back to this ECGM.