Coming back to our training
About the Author
When we speak of a car, the bigger the capacity of the car engine, the faster the car can go. The engine determines the power that can be developed, and then of course, the weight of the chassis determines the strength-to-weight ratio or effectiveness of the power. Runners are similar: The faster the runner is over one mile, the faster they can go over 20km, 42km or 100km. Of course, two runners with the same mile time can have different strength-to-weight ratios, with a lighter-framed runner likely to have a greater ratio, which affects running efficiency.
However, speed( engine size / capacity) only indicates your potential to go fast over the distance. How far you can actually go depends on the size of the fuel tank. In running, as with a hybrid car, we have two fuel tanks: The first is fat metabolising which we use at low intensity work such as sitting, walking and working at a desk. This is akin to the battery and generator system in the hybrid. As long as we keep the intensity low, we can run on this virtually forever as we convert blood fatty acids into carbohydrate and hence into energy. As long as we convert sufficient amounts of carbohydrate to maintain the pace, we will not run out of fuel. The only additional fuel needed will be minimal and that will be to keep the blood sugar level up, to power the mind.
Now, when we put the foot on the accelerator or hit a hill, the hybrid car brings the petrol engine into play. In runners, this means increasing the amount of carbohydrate from the muscles. However, the muscles have a limited amount of glycogen / carbohydrate( say 400 grams) and once that is gone, we cannot replace it without stopping for a period. This means we are then forced to use the fat metabolising( battery power) for energy until we can refuel. It’ s the same as having to use the battery until we can stop at a garage and fill up with petrol.
By Norrie Williamson
Let’ s Talk Car Engines …
March sees the‘ nights drawing in,’ as the Scots have it in relation to the shortening of daylight hours. It is also a time that many South African runners shift focus for the coming weeks and months to the Two Oceans, Om Die Dam, Loskop and Comrades ultras, and this is the time to think like a car designer.
In effect, we need to share that 400 grams over the full length of the distance( and time) we are covering. If, for instance, you are looking at 10 hours for the Comrades, you can burn only 40 grams per hour. This provides 160 calories per hour, but we need 800 to 880 calories per hour, which means 700 must come from metabolised fat. This is around 75 grams of fat per hour that has to be metabolised. So the more efficiently this can be done, the faster the pace the runner can cruise at.
For this reason, all our long, slow running should be at a very slow pace – normally about one minute slower per kay than our current best marathon pace – or at a heart rate equal to 180-age + 5, which ensures we are in the fat metabolising zone. The more we practise running in this zone, the more efficient our conversion of fat to carbohydrate becomes, and the faster we can run at this pace.
Coming back to our training
When coaching I emphasise the use of short track, hill and quality sessions, because such work improves the size / capacity of the engine. This in turn changes the paces of all our distances, including Comrades and long run pace. The bigger the capacity is, the faster the cruising pace( dictated by heart rate), the bigger the weekly distance, and the greater the racing potential.
Put this all together and in March we can put the emphasis on building over a six-week period until we can do our peak distance for three weeks, then taper to the marathon or Oceans in April, or Comrades later in June. The place that we are in this phase will depend on the goal race. For the runner with a year or more of running experience and now targeting distance and ultra-running, get as fast as you can over the short distance by developing your capacity, then move to making your relevant energy source( fat metabolising) as efficient as possible. Consider yourself similar to that hybrid car and build your battery power so you can develop the energy to go the full distance.
About the Author
Norrie represented Scotland and Great Britain in numerous ultra-distance events, then emigrated and represented South Africa in triathlon. He is an IAAF-accredited coach and course measurer and is the official Old Mutual Virtual Coach. He has authored two books( Everyman’ s Guide to Distance Running and Every Beginner’ s Guide to Walking & Running), and counts 21 Comrades medals amongst his more than 150 ultra-marathon medals. More info at www. coachnorrie. co. za.
Image: Fotolia & Jetline Action Photo
26 ISSUE 92 MARCH 2017 / www. modernathlete. co. za