The Sunday long run is an institution amongst runners, the importance and prominence of which is rarely questioned amongst marathon runners, despite it having been brought into question by legendary coaches such as Jack Daniels and the Hanson Brothers (no, not the MMMBop guys) for over two decades.
Why Do We Do Long Runs?
The physiological reasons:
You can train the body through experience to be more effective at using both sugar and fat to create ATP (Adenosine Triphosphate) which is directly made into energy with the musculature. There are two things which longer training runs do to improve this; reduce the body’s need for sugar by being more efficient at oxidising carbohydrate and creates extra capillaries to move fatty acids into the muscles to be used as fuel (although this latter aspect is somewhat limited).
You’re increasing the size of muscular component of your heart (most of it) – this is more effective at slower speeds because your heart goes faster in the tougher runs but it only beats harder up to a certain point at about 60% of VO2 max.
You increase the size of your muscles, the bigger the muscles, the more glycogen you can store in them (admittedly, the amount of this done by slow running is minimal). The more you use the slow twitch fibres in your legs the more they repair, grow and improve. You can’t change the ratio of fast/slow twitch fibres you have in your body – that ratio will be with you for life but you can improve the fibres you have.
The newest marathon training book by the Hanson brothers advocates for a 16 mile (that’s 25km for those of us who live in the modern world) longest pre-marathon run but to set up this 25km run so that it simulates the final, rather than the first 25km of a race by building up the days prior to the long run.
Those of you who know me could well accuse me of hypocrisy towards this since I regularly run 50 to 60 kilometres on Saturdays just to get between coaching appointments. You would be right to do that if I was running at marathon pace: I’m not, I’m running on average about half a minute per km slower and crucially I’m taking regular breaks to chat to runners, stretch, drink coffee, eat Soreen with jam, pop in to McDonalds to use the toilets and on one memorable occasion, wrestling a friendly but insistent Rottweiler off my poached eggs and avocado toast.
The neglected aspect of this, which I often encounter with athletes is the psychological aspect, people need to know that they can run the marathon, so need to have run a certain distance to be able to know that, this is important and I absolutely accept it. There’s a lot to be gained from understanding the importance of the way athletes feel going into a marathon, confidence is not measurable but it is crucial.
Fatigue is the negative side of long endurance runs. All runs build fatigue to some extent but racing a marathon will create a level of fatigue which takes a month to fully recover from, this means that if you are to run 75% of a marathon at marathon race pace it will render your training for the next couple of weeks meaningless and you will lose fitness as a result. There is also a much greater risk of injury and I think those are what Jack is talking about in the video just below…
My compromise for this is to allow a training run of longer than is advisable physiologically for psychological reasons, at slower than race pace, well back from the event to minimise the cost of fatigue on race-day and to reduce the chance of injury effecting the race prep. I also don’t incrementally increase distance on a linear basis week on week because you’ll get to a point where you’re only just recovering from your last long run in time to run another one, rendering your crucial midweek speedwork pointless and painful. At the very most I’d schedule two very long steady state runs per month (most likely one) alongside shorter runs at race pace and rest weeks.