The Challenging Case of Training at Threshold

January 21, 2017

Our ability to be fast in racing, whether it is cycling or running, is limited by an almost magic upper ceiling. Right below this ceiling, we are able to push ourselves for a long time at a comfortable heart rate, as the body is able to bring fuel to the muscles and recycle toxins. But push above this ceiling, and things quickly fall apart. This limit is our lactate threshold, and although it is mainly determined by genetic factors and it can only be determined exactly in the lab, it is possible to train the body to raise this threshold. Training for threshold will allow sustaining more power for longer periods of time, and at a slightly higher heart rate that will then feel more comfortable.

Theoretically, threshold training requires riding at the race pace we can sustain for an hour. If we go harder than this, we will quickly slow down. If we go slower, we will not be pushing the ceiling up. Training threshold is taxing and the body will usually take up to 48 hours to recover from this session, so although this is not something we want to be doing on consecutive days, we can repeat it quite often and see the training benefits. Let’s also remember that in a well-balanced pro-style training plan, there is space for long endurance miles, some hard SPRINTervals, jumps/pulls, anaerobic intervals, and, critically, structured threshold work.

The standard threshold training specifies holding a steady TT effort for 20 to 30 minutes at the max power or heart rate we can sustain for that period (well, in theory the duration is 60 mins, but only pro or elite level riders can realistically achieve that). There are variants to the steady session, for example over-unders, where you train a few mins slightly higher than threshold and then a few mins slightly lower, to train the body to recover quicker from power surges. As an anecdotal side note, in my endurance, tempo and VO2Max training sessions I guide myself with power, whereas for threshold training I prefer using heart rate. Now, I am not a coach, so please do not read too much into this.

Which brings us to training threshold on Zwift. There are a few options in the workouts module that we could use for this purpose. Or we could go up the EPIC KOM in Watopia. And although I have done these things myself quite a few times, I struggled repeating it week in and week out, so I would skip threshold training. I really prefer to suffer in company, sharing the pain can be a huge motivation.

Races on Zwift can be a good way to train for threshold, but only if you are disciplined. Unfortunately, most races on Zwift are relatively short and have huge power surges at VO2Max for a few mins, so you are either way over threshold or way under. There are exceptions to this though like the longer Asia 100 or KISS 100 races.

So since we tend to avoid threshold training individually, could we design a group ride on Zwift that would motivate us to train at threshold more? I think we do! The only issue is that our threshold levels in a group can be very different, so unless we handicap everybody’s threshold power, the group ride would quickly break.

This is why we created the WBR TT Threshold Training Challenge: this is a handicapped event, you change your bike, your weight and your height so that all riders are equally leveled for power and aerodynamics. The ride is a 40km TT, and since we level rider’s FTP to 4.0 w/kg, it should last about 60 minutes. Most of us won’t be able to hold threshold power for 60 minutes anyway, more like 20 to 30 mins. So depending on your existing level of fitness, you can play with how long you stay at threshold power (or heart rate). For example, you could do two blocks of 20min with 10 mins of high tempo in between, or one block of 30 mins, etc. You can also do some quick surges for a couple of minutes at VO2Max, and then slightly under threshold, i.e. Over-Unders, which will help you train your body to recover during attacks in races.

This WBR ride is happening right now on Tuesday and Friday mornings UTC, with alternate flat vs hilly courses. Usually all riders end up within 2 minutes of each other, and right about 4.0 w/kg average. A small variance is normal, since we are all subject to changes in stress, sleep, etc. and our stamina is also a key factor in these sessions. Messaging inside the event is not only possible but highly encouraged, and there is also obviously a competitive edge to doing a 40km TT.

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