Is speed work for making you faster? No, not really, not for most of us. How can I say that? Well look at it like this; I can already run fast enough to run marathon in two hours, the trouble is I can’t maintain that pace for much distance at all. Well yeah you’re thinking to yourself, of course not. The fastest I can run isn’t going to improve much no matter how much I speed train either so this is why I say speed work won’t make me faster. For some people it will, sure, that’s fine, but still that’s not actually why we as endurance athletes must do our speed work if we wish to maximize our improvement. Actually, just reading this one may take a little endurance. It took up two whole pages when I wrote it but if you don’t know a lot about speed work’s hows and whys this will be worth it and it’s written in a manner that should make sense to everyone, not just you science people.
So why? Well, there is a set percent of my personal maximum pace/heart-rate/endurance-buzz-word that I can run at and be able to sustain it for any particular distance. A whole lot of what determines this is the details of my body’s biochemistry. There are little energy factories inside muscle cells called mitochondria which turn sugar into the stuff your muscles can use to work. There are also transporters that bring raw materials into the cell and enzymes in the cells and mitochondria. Everybody has different amounts of all these different things that are needed to get a muscle to contract. If you don’t have enough of one or all of these things to sustain the pace you are trying to sustain then the system will back up and you will slow down.
Well that seems unfair, right? I mean what, I’m just lucky and have more of all this stuff than you? Well then do your speed work. Your body can adapt to all kinds of demands. Speed work creates the kind of intense demand that will cause your body to make more of all the various ingredients. You may not get any faster as a sprinter and your VO2 max and max heart rate may not change but the percent of that max you can run at without having to slow down will change. It can change a lot and it can make a big difference in your race results, not to mention your comfort level while you are running.
Here’s the thing about doing speed work; it hurts, it sucks, for most of us it’s not fun. You may decide that running is recreation for you and that if it’s not fun then you’re not doing it and that’s okay. So what do we mean when we say speed work and how much should you do? Do not do more than two sessions per week or you will ruin the quality of it and deprive your body of the time it needs to respond to what you did and make all the good stuff that will help you. Once a week is just fine and missing the occasional week especially right before or after a long race, won’t stop you from benefitting. For purposes of brevity and simplicity I’m going to break speed work into two types below and explain them. You should do both types alternating weeks or be hardcore and one of each every week.
1) Tempo runs: For this you warm up 10 min. minimum then run at a pace that is uncomfortable to you but that you can sustain and do it for a set amount of time. You may start with 15 min. but should be able to get up to 45 min. and doing even up to 10 miles can still be tempo if you’re fit enough to keep the pace even. Tempo runs do help make the part of the stuff that is mitochondria and aerobic enzymes which is good for making the ATP which is the stuff that your muscle uses to contract to make you go. If you can make more ATP faster, then you can contract your leg muscle at a higher rate for longer.
2) Intervals: Warm up for 10-20 min.-know your own body. I take 15 min. Run 1-4 mins. as fast as you can go for that time/distance. The newer you are to this the closer to 1 min. this should be. Quarter mile intervals are a good and convenient distance. Rest 2-3 minutes between intervals. 5 repeats is a good start and 10 is a very good workout. If you don’t rest but try to keep jogging in between your intervals then your intensity will go down. If you make your intervals too long then your intensity will go down. Why is that bad? Because short, intense intervals create such a specific and intense demand within the body that they result in real change in the body. This helps with the mitochondria and enzymes like a tempo run BUT also does something else. Remember that there are transporters for getting some of the stuff into the muscle cells? These are proteins in the cell membrane and the number of them you have is not set. Short, intense intervals will cause your body to make more of them so you can get the stuff that gets broken down inside the cell out of your blood and into your cell much faster. This means more muscle contractions sooner. This means you can sustain that pace.
3) I know, I said I would have two types. This is a technique note. Did you know that the cadence, the number of strides per minute while racing is about the same for elite sprinters as for elite marathon runners? Crazy! The sprinters have way more power and therefore, a longer stride length so they cover ground faster. Why do I bring this up? Because amateur distance runners often try to lengthen their stride when doing speed work and often at the cost of cadence. Too long a stride over long distance and especially when it is not backed up by enough strength WILL get you injured. As distance runners seeking to improve we need to pay attention to form which includes cadence so: Instead of only trying to cover the ground as fast as you can when you are running intervals, work on the cadence part. Do not let your steps feel long to you. The point is not a faster quarter mile. The point is to have good form that won’t injure you and to get really, really painfully out of breath.
This is a very simplified explanation. If you are interested in learning more, the break-down of glucose to pyruvate, the conversion of that to lactate when there is a back up in the citric acid cycle, MCT 1 are all things you can google or look up in biochemistry and physiology textbooks. I’ve read them and they’re fascinating and boring all at once.
Here is the take home message; Your body has factories for making energy. If you never demand much of them then they won’t upgrade equipment, they’ll just get slowly run down. If you demand more than they can handle all of the time then machines will break and not get fixed and your workers may stage a walk out. If you make some pretty big demands and you give the factory time to upgrade, then it will.