Smart training: find your sweet spot!

Find your sweet spot and stay there.

I have been reading about smart training. As I am now slowly increasing my mileage on flat runs,  I have been looking into ways of training smarter both to recover from my hamstrings injury completely, and to avoid injuries in the future. But to be honest, the main reason why I have become so interested in sweet spot training is because I have been finding it hard to get my running speed back. When I focus on speed runs, I get exhausted and disappointed, and I now realize that this kind of training is not helping me at all to increase my speed and endurance. Instead I find it much easier to focus on heart rate, and heart rate turns out to be the key to smart training. But don't be mistaken; although sweet spot sounds incredibly nice, it is a completely different place than comfort zone.

Of course I do not come up with these things by myself. Being surrounded by a lot of much faster and more experienced running friends, I try to learn from them what they are doing right. Several of my friends have told me that they never train for a long time at their threshold heart rate. They stay about 10 beats lower than that. To me this has been difficult to understand and follow. I thought that by training at your threshold you increase your threshold speed. This is true in some sense, but I now realize that it is true for intervals and shorter efforts like that. In fact, as I understand it, your sweet spot is around 10 beats lower than your threshold heart rate. When I heard about sweet spot training for the first time from my friend Lars, all previous advice finally made perfect sense to me.

Most probably you do not know your threshold heart rate. I took a lactate and oxygen volume test last year and found out that my threshold heart rate was 162. At that time this corresponded to running flat at a speed of 11.4 km/h. I am afraid the speed is much much lower now, but I think the threshold heart rate is still correct. It is the heart rate at which you can go for about an hour before you start getting stiff by too much lactic acid in your muscles, and it worked for me during the uphill races of this fall. At shorter competitions (like Stoltzekleiven) or at the end of long competitions (if I have any power left) I can go all the way up to 169-172. You could calculate your threshold heart rate from your maximum heart rate, you could take a lactate test (It is really a lot of fun!), or you can for example look at the following chart and try to match it to your values:

From this I conclude that my sweet spot corresponds to about 154 in heart rate. It fits with how I feel during training. When I try to run at the speed I could run before my injury, I very quickly go up to my threshold and beyond, and thus get tired. Instead, if I run at my sweet spot, I can go for much longer time. So why is this spot sweet? The next chart explains it. If you train at a heart rate that is above your threshold, you don't improve that much. In fact training too hard has exactly the same effect as training not hard enough! I have been thinking that since I have participated in a lot of competitions this fall, I have got a lot of good training. And then I have been wondering why I have not noticed a more significant increase in my endurance and speed. And now I finally understand it: competitions are not training! Competitions do not build our form, they tear us down. And if we always train at competition heart rate and speed, the improvement will be minor.

The line "Training effect" shows that the optimal effect is achieved at your sweet spot, which is a little bit below your lactate threshold heart rate. What we normally do is to push it as hard as we can at every training. When you are completely a new beginner, this is fine. Your form is anyway far below your limitations and as long as you are not training too often, you will gain a lot from pushing yourself hard. However, as you get faster and in better shape, you might experience that although you are training hard you are not improving anymore. And the reason is most probably because you are training too hard. Just watch your heart rate, stay below your threshold on the longer sessions, and most probably you will see an improvement pretty soon.

So this is now my training regimen for the next couple of months: Two interval training sessions per week, where I go up to lactate threshold during the intervals. One or two tempo runs where I try to stay in the sweet spot for 30-50 minutes. A long and slow run, where I do not care about the heart rate, the distance or the speed, but just run for a couple of hours. A recovery run at zone 1 (for me: heart rate between 120-130) for about 40 minutes. It will be an interesting experience to see whether this will bring me back to my old speed within a couple of months. And I will be strict about one or two complete rest days a week; no running or strength training on those days. Restitution is a very important part of building form! If my form does improve, I am wondering how it will affect my heart rate zones and sweet spot. I assume that I will be able to run faster at the current heart rate zones. But will my zones stay constant, or will I have to go up to higher heart rates?

Stay tuned and we will find it out altogether!