Whats happening when you improve your anarobic fitness

[big booty]

At the caption says, what actually happens as you increase your anaerobic fitness? What brought this question to mind was that I was lucky enough to be in the stands at the start/finish line on the opening day of the tour down under. This young lad Chris (I think?) won one of the intermediate sprints during the 30 lap race. He broke clear and won the sprint quite easy. Stayed in front for one more lap but as he passed the line you could tell he was in extreme pain brought on by the fact that he was well and truly operating in anaerobic mode. The peloton swallowed him up shortly after. So as your anaerobic fitness increases what is your body doing better/more of?

[Alex Simmons/RST]

Increased muscle high energy phosphate (ATP/PCr) stores, which are needed for rapid release and total supply of energy demand above that which can be met with aerobic metabolism. Depending on the training, you can also improve your neuromuscular (peak) power by better utilisation and hypertrophy of fast twitch muscles fibres.

By the time you saw him "in pain" he would have been well and truly back in aerobic-only mode. Our anaerobic energy capacity is quite limited but is trainable. You might have something in the vicinity of 10-20kJ of such reserves available for short term power demand (some have more, sosme less). That can be chewed up very quickly, in as little as a minute at full gas but can also be used up over the course of many minutes provided the energy demand is not too far above threshold power level. e.g. If you start with a functional reserve (anaerobic) capacity of 15kJ and ride at say 100W above threshold power, you'll be able to sustain that for about 2 and a half minutes before you are forced to slow and ride below threshold again.

Keep in mind that replenishing such ATP/PCr supplies in the muscles is itself a wholly aerobic process, and hence in order to restock them you will necessarily need to ride below threshold, and the further below threshold you ride, the faster the replenishment. That's why high aerobic fitness (threshold power) is so important. When you go hard, you are not as far above threshold as others and so don't tap anaerobic capacity as much, and when riding back in the bunch you are likely to recover more quickly as you have more aerobic capacity to do so, and that enables you to respond to or create attacks more frequently and/or last for longer. That's how track endurance riders deal with the sprinter types in scratch races. Attack, attack and attack again.

[big booty]

Thanks for that. Yeah the guy that won the race was the Australian sprint champion (name escapes me). Basically the team shielded him the entire race and the team had him 4th in line with two laps to go. His last team mate peeled off at the top of the last straight to the finish line. All his team mates were absolutely spent. Sprint on to the line which he won by a bike length. Awesome to watch.

[Derny Driver]

This young lad Chris (I think?) won one of the intermediate sprints during the 30 lap race.

Chris Hamilton

[Derny Driver]

Yeah the guy that won the race was the Australian sprint champion (name escapes me). .

Caleb Ewan ...Australian Criterium champion