Threshold

Threshold session for the squad on the bike tomorrow. 8 x 4 minute threshold efforts which is a pretty common early season session that we do at Front Runner. Should be 32 minutes of gut busting fun.

The most common question I get after this sessions is:

"That was great, but why do we do these sessions?"

Always a great question and one that is understandable as a lot of the people in the squad are training for long, lower intensity races and so often wonder why we do shorter, hard efforts.

As it is a common question, I thought I would put together a bit of an explanation.

These sorts of sessions improve our anaerobic threshold.

Great, so why do we care?

Well we know that anaerobic threshold is a great predictor of performance no matter what the distance. Improving anaerobic threshold will also see increases in performance over longer distance races.

Interesting. But why?

Well, for long distance events most of our energy comes from aerobic sources. Once you have been going for more than 15 minutes 95% of your energy is being supplied aerobically, so in training for an Ironman or Half Ironman our primary concern is increasing the capacity/efficiency of our aerobic system. Our anaerobic threshold is the point at which we go from being sustainable with our aerobic energy demands to unsustainable. If we raise our anaerobic threshold then the point at which our aerobic energy demands become unsustainable also increases. If our aerobic performance ceiling increases then we can go faster while still using our aerobic energy systems, this means our performance over distance will be improved.

Sounds awesome, so how do we improve our anaerobic threshold?

Well, we know that the best way to improve our anaerobic threshold is to train at or slightly below it, not above it. Our body doesn't really like working at its anaerobic threshold, so regularly pushing yourself to that point (but not beyond it) prompts the body to make adaptions to improve aerobic capacity. Over the season we gradually increase the amount of time that we spend at anaerobic threshold in our sessions so that we keep improving aerobic capacity. We do this by increasing both the volume and duration of our efforts and decreasing the amount of rest, until gradually work up to around 2 x 20 minute efforts on the bike. Occasionally we will do 3 x 20 minutes at threshold, but that is a very tough session so we don't do it often and only for experienced athletes. One of the keys to this training is that while it is hard, going harder isn't better. If we go too hard and are working beyond our anaerobic threshold then the adaptions to our aerobic capacity won't be as effective. We will be working hard for less benefit, which never makes sense.

If done right though then this sort of training is a key part of driving improvement for our athletes, no matter what distance they are training for.