Not a tri question, but maybe you can answer it. This year I did the Transalp Challenge, which is an 8-day mountain bike stage race across the Alps. My teammate and I were typically riding for about 4 hours each day, with lots of long (1-2 hour) climbs. After a few days, I was pretty much riding at a ‘survival pace’ every day. On climbs my heart rate was normally around 145 bpm - considerably lower than my LT heart rate, which is about 165 bpm. Even accounting for a decreased exercise HR from fatigue, my pace was therefore distinctly sub-threshold. With different training could I access a higher HR day-after-day? Do I need to do a better job of repleting glycogen stores? What is it that determines my survival pace, and, in this kind of event, what exactly causes fatigue? Is it really just depleted glycogen, or also damaged muscle fibres? Obviously if I get fitter my pace at the survival HR of 145 bpm should improve, but it seems to me that there are spare beats to play with!
You failed to mention what your nutritional guidelines were over the course of the race.
Fitness level AND nutrition could’ve played a part in your "survival pace’ being the only pace you could sustain. You may need to look at how well you replenished your carbo stores.
As for fitness, it’s a combination of things that will get you in better shape. I see the mix as being part aerobic capacity work, hill climbing intervals, and tempo training. Aerobic work will address the length of the race, hill climbing interals will speak to a higher sustained pace while climbing at lower perceived effort, and tempo training will help you maintain a higher overall pace.
Keep in mind, I am not a fitness guru, but from my own experience this recipe will help you. Hopefully, someone with the proper credentials can add or subtract to what I’ve written here.
This is a common concern amongst Stage Racers. There are many elements which lead to success in multi-day events. These include, but are not limited to:
Overall fitness (stage racing takes a different approach to training)
Race pacing (saving energy at every opportunity)
Nutrition (you are always fueling for BOTH your current race and the subsequent days)
You failed to mention what your nutritional guidelines were over the course of the race.
Fitness level AND nutrition could’ve played a part in your "survival pace’ being the only pace you could sustain. You may need to look at how well you replenished your carbo stores.
Nutrition was always on a somewhat ad hoc basis, because we were riding unsupported and so dependant on aid stations and meals from the camps. (Hopefully this will be different next time.) Typically as much breakfast as possible, then 2 litres of energy drink plus water, 1-2 energy bars, maybe a gel or two during a stage, recovery drink after, then whatever we could get to eat post-stage. Apart from the first day, rehydration was always fine, and I sweat relatively little and never cramp so doubt electrolytes were a problem. Getting carbs in probably was - my stomach is my weak link and I don’t enjoy having to eat loads either. Did try to stay off my feet but again, when you’re riding unsupported, that’s not so easy, what with having to sort out bikes, find food etc.
As for training, that emphasized suffering, using a mixture of aerobic, tempo and threshold work, but very little done over threshold. General aim was to make myself into a diesel engine, but being a turbodiesel would be even better! Hill reps would be great, but where I live there really aren’t climbs long enough!
However I’d still like to know more about the physiological basis for this kind of fatigue, and whether it’s just down to glycogen stores and refuelling.