Once we have maximised the capacity of your aerobic engine, we must then increase the fraction of this capacity that can be maintained over any given duration. To achieve this, we must sufficiently reduce your Anaerobic Capacity (VLamax) to an appropriate level. The level to which your VLamax (Maximum Production Rate of Lactate/Pyruvate) should be reduced, depends upon the specific demands of the race you are competing in. Although VLamax must be high enough to fuel your aerobic metabolism, for endurance events where races will not be decided by fast accelerations or sprint finishes, we are always looking to reduce VLamax as much as possible. This is because (as discussed in 'Capacities & Thresholds'), the lower your VLamax - the greater fraction of your VO2max you can maintain over any given duration.


However, if you are anticipating race dynamics that will require a fast acceleration to determine the winner of a race, then it is important to only reduce the power of your anaerobic engine to an 'optimal level'. The 'optimal' level, is one that is low enough to ensure your aerobic power can get you into a position to contest for the race win - but high enough, so that you are the strongest athlete remaining when the race winning move needs to be made. To clarify, you can only win a sprint finish at the end of an endurance race, if you were aerobically strong enough to make it to the start of the sprint still in contention. So possessing race winning anaerobic power is absolutely useless, if your sustainable aerobic power isn't sufficiently strong enough to put you into a race winning position.


Increasing an athlete's Anaerobic Capacity is typically much harder to do than reducing it. It is much harder to turn an endurance athlete into a relatively good sprinter - than it is to turn a sprinter into a relatively good endurance athlete. Nevertheless, if we were looking to increase an athlete's VLamax, we would first look to reduce their VO2max. This is because the working muscle must always choose how to replenish ATP - either anaerobically or aerobically. The higher the VO2max, the more likely the muscle is to produce energy aerobically. To reduce VO2max, you would reduce (or completely cease) endurance training volume, or only perform very easy Level 1 endurance training. You would then combine this with a significant increase in very high high intensity (THP Level 7 & 8) training, with long passive recoveries. The passive recoveries would ensure that VO2 levels remained as low as possible - as keeping them elevated would stimulate the aerobic system.

Significantly reducing an athlete's VLamax, is much easier to do. As discussed above, increasing VO2max will ensure the that the muscle is more likely to replenish ATP through aerobic pathways. So maximising your aerobic capacity is always the first port of call for endurance training. If VO2max is as high as it can go (training volume and intensity both maximised), the next step to reducing VLamax, is to target the moderate intensities between your Aerobic (AeT) and  Anaerobic Threshold (AnT), with a focus on high torque/force muscle recruitment. By targeting Tempo (THP Level 3) and Sub-Threshold (THP Level 4) intensities, with high force power production (e.g. using paddles while swimming, low cadences while cycling and hill running) - you will be recruiting 'Fast-Twitch' (anaerobic) muscle fibres, but training them to take on more 'Slow-Twitch' (aerobic) characteristics.