Training for a 215km ride

So, perhaps foolishly, I have signed up for my first audax (US rando) at the end of the month. It’s 215km.

I’m currently able to ride c.120km, over undulating terrain, without stopping (other than for a call of nature) in 4hrs 10 - 4hrs 30, depending on wind, exact nature of the route, etc. HR will be pretty steady in the mid 130s (70%) and climb to low 140s by the end (4-5% cardiac drift).

But I do find I start to struggle beyond the 4.5hr mark, both with a stiff back, and with (very generalised) fatigue; I suppose I get the feeling that ‘this is very hard work all of a sudden’, or ‘I can’t be bothered with this any more’.

I’m currently averaging about 550-650 TSS a week, with 1 long Z2 ride, 1 hard interval session, and three to five 90min to 110m rides (depending on time, all z2, 30 min sweetspot push in 1 of them). Currently sitting at 292w for 20 mins, at 73kg (could afford to lose 2-3kg).

I’ve got almost unlimited time to train from this week onwards.

I’d be interested in people’s recommendations for addressing these 2 issues, but I’m wondering if it’s as simple as doing some core strengthening work, pulling out the intervals for a month, and moving to 3x3hr and 1 progressively longer ride a week?

The other suggestion I’ve had is work on ‘chunking’; i.e. ride for 80k, rest for 20m, ride for 70km, rest for 20m, then ride the rest. I’d be intrigued to know if anyone has tried this.

A few points:

  1. That may be going out a little too hard for a 200 - perhaps start with HR in the high 120’s, and let it drift to mid 130s.

  2. Fuelling is critiical for longer rides. You can do 120km on water alone (although not recommended), beyond that you have to refuel. I am guessing the generalized fatigue may be an indicator of inadequate fueling. Start early - I always make a point of eating something after the 1st 20-30 minutes, even if I don’t feel I need it right then. Personally, I burn about 4500 calories doing an audax, and look to eat about 2000 on the bike.

  3. The nature of audax checkpoints leads itself to “chunking” anyway. By the time you refill water bottles, get your brevet card signed, buy something at the cafe/bakery/gas station that is a typical checkpoint, you are probably looking at 10 minutes anyway. With a stiff back, you may want to work in a few stretches at checkpoints as well.

  4. Your training sounds about right - the only thing is that you may want to gradually increase that 1 sweetspot ride per week. Sweetspot really helps with fatigue resistance, Take a look at some of the SS workouts in the Sustained Power Build and Century plans.


That’s helpful, thanks.

Yeah I’m probably not eating enough; I’ll typically eat a bag of jelly babies (so about 150g carbs/600kcal) on a 4hr ride.

I may drop the threshold intervals and bring back in the sweetspot session I was doing in the spring. I’d worked up to 60 mins at 90% and I do think I felt more resilient at the end of longer rides.

I’m training for a similar distance 230km. I’ve had good success doing 2 rides a day. 2 hour interval session in the morning and 2 hour Z2 in the evening.
Or a 4 hour Z2 in the morning and 1-2 hours of Z2 later in the day.

Those seemed to give a good boost to fatigue resistance and lowered the decoupling % on my 4-5 hour rides. I start my long rides low 120s hr or even in the high 110s and end up maybe mid 130s (190 max hr).

Also I feel like I get much more muscular endurance from threshold work or long VO2 intervals than sweet spot.

What % of FTP are you having to drop down to to keep HR there?

2 a days could be a decent option as well :ok_hand:

I do my endurance rides at 65-70% of FTP. Usually whole ride avg ends up middle of that 67-68%.