12-10-2010, 11:34 AM
Join Date: Dec 2007
Location: Johannesburg, South Africa
Originally Posted by Steven Low
This is not exactly correct.
Glycolysis turns on maximally above lactate threshold.
Below lac threshold you're using oxidative phosphorylation as the main energy source.
So if you jog for 3 minutes after 100m sprint, glycolysis is turned on somewhat (but not maximally) while mitochondria are replacing the oxygen debt + providing energy for the jog.
The delusion of the energy curves is that each of the contributions of energy are used in that specific order. It's actually almost a reverse order in which they are used.
Aerobic is the prominent resource used during any low intensity activity.
Current ATP stores, PCr, and a bit of glycolysis accounts for some of the lag time between ramping up activity and distribution of oxygen/CO2 to/from the cardiovascular system to the muscles.
Glycolysis is never maximally stimulated unless above lac threshold; thus, the majority of energy contributions below lac threshold are always from aerobic sources (e.g. oxidative phosphorylation in mitochondria).
The energy curves look drastically different for maximal intensity exercise vs. lac threshold vs. walking/slow jogging.
This is also why a lot of Clyde Hart's stuff for 400m utilizes multiple repeats of sub-lac 200m which ramp up intensity building up into the track season. At first you're building primarily aerobic base with them. As the intensity during starts to ramp up during teh season, you still get the aerobic base component + some lac training. Then nearer to major competition you're maintaining the aerobic base + developing the lactate endurance you need to finish strong.
Building up aerobic base (for races longer than 25-30s) especially 400m which is 60/40 anaerobic/aerobic (50/50 for women) is important because aerobic can easily accomodate more adaptation and thus more energy to power running (2 ATP vs 34 ATP). The higher the energy storage in muscles via myoglobin + cardiorespiratory adaptations you don't get as much from as from sprinting alone encourages a broader aerobic base upon which to build a foundation for the more intense lactic training needed to finish off a 400m sprint.
In other words, the greater percentage of your Vo2max that you can go without going above lac threshold, the faster you can run 400m or beyond. Elite endurance athletes can go up around 80-85% VO2max without going above lac threshold.
Thus, why 400m is primarily a combination of 3 types of training:
~Increasing strength and application of through plyometrics
~Increasing maximal sprinting speed through training form and short sprints (0-80m)
~Building aerobic base (off season/preseason) and then adapting into training lac threshold (in season)
This translates to....
1. Increase speed (via sprinting mechanics + strength/plyo).
2. Increase % of Vo2max you can run at without going above lac thresh = increased speed endurance (aerobic base... slower 200m repeats in Hart's coaching)
3. Develop lac threshold tolerance to finish race (supra lac threshold training via usually increased intensity of HIIT -- faster 200m repeats in Hart's coaching)