I never did a set of sprints for a running routine/workout until this week. The workout didn't kick my butt as much as the recovery which is still going on, so I'm really looking for reasons to keep doing them. (other than: pain = improvement)
What are the benefits to including a sprint workout as part of a weekly routine which is focused more on running long distances like a marathon?
Basic speed workouts have these benefits:
Fast twitch muscle fiber recruitment: speed work is one of the only ways to recruit fast twitch muscle fibers. If you do sprint training, your body will learn how to recruit those muscle fibers for faster running in workouts and when finishing races.
Puts a large amount of stress on the central nervous system: by stressing your CNS, you learn to deal with high amounts of fatigue.
Encourages better biomechanics: people sprint on their forefeet, so by sprinting you can learn to run slower with better biomechanics.
Improves the body's system for storing and returning elastic energy: when sprinting, you stiffen your leg to prepare for impact as fast and powerfully as possible, so you are teaching your body to store and return that elastic energy as fast as possible. This will carry over to running on flatter ground.
Provides a foundation to build to longer, but still fast, race-specific workouts: a biomechanical and neuromuscular base from sprint workouts early in the season will allow you to move to longer, but still fast, workouts as the season progresses. You will be able to move from basic speed to speed endurance to anaerobic speed endurance much more effectively than if you didn't have that foundation.
With the exception of a track event, most everything else will have hills. I've heard hill repeats referred to as "speed work in disguise".
What they have in common is rather than the steady-state output you can build up on the flats, you need the ability to generate a lot more output, and then recover quickly back to your steady-state maintainable race place.
Runners will talk about "cresting", which is that once you get to the top of a hill, rather than slow down and recover, you rapidly resume your faster steady-state race pace.
It's all interval training (a.k.a. fartlek), and deals with the fact that real world running requires shifting power outputs and rapid recovery.
Not directly answering your question, but another reason to have "fast" days (not necessarily sprinting and shorter distances/time) is simply to learn what a race pace is.
If you are running long-slower a lot, you won't get a lot of experience at your race pace. Boiled down, I think these are the main components of training for a distance runner:
You're right though. Running fast is hard on the body, although as any sprinter can attest to, you will get used to it.
Nowadays, most training plans for Marathons, includes both lots of LSR and later a fair bit of speed work. The common idea is to first build up your ability to run long distances on fat and later add speed. As the first part will inevitably slow you pace a bit over time, the later part is needed to get the speed back into the run.
E.g.
Your "steady" pace will get faster : the aim is to run faster for a longer time. It also makes running "slow" easy in comparison.
I ran my first half last year and only did 40-90 min steady runs for training. This year I included more intervals and hills, with one long run per week. I definitely feel faster on my long runs ! The important fact is that I don't feel myself slowing down at the end of the long run.
I guess the important thing during long-distance events is to have a "fast" steady pace that you can hold for a long time and not slowing down in the last 3-4 miles.
That's what the speedwork is for. Running long doesn't necessarily mean running slow. Enjoy !
