I'm headed down to Galveston today for my first 70.3. I've done several half ironmans, but haven't done a 70.3 yet. All of my halfs have been independents. WTC always runs a great race, so I'm looking forward to it. And with Lance racing, I'm expecting it to be a full on media circus. Should be interesting.
If you've been following my blog for a while, you probably know I'm self-coached. Half the fun of this sport for me is putting together my training plan. I love learning about training - what works, what doesn't and - most importantly - why. It's a fun challenge.
As a self-coached athlete, I wear two hats: Coach Mike and Athlete Mike. I enjoy the challenge, but it can be tough to separate Coach Mike from Athlete Mike sometimes (when I first typed that I accidentally wrote Couch Mike...that's a completely different Mike).
As athletes we sometimes train on emotion and that can be a problem. We don't always follow the plan. We make last minute adjustments based on what our competition is doing (or what we think our competition is doing), what our friends are doing (who may also be our competition) or we may be searching for confidence. Rarely do we make the training easier when we do this.
I'm pretty good about not worrying about what my competition is doing, but searching for confidence sometimes leads to bad decisions. Coach Mike spends a lot of time putting together a training plan. The problem is that Athlete Mike has the login and password to TrainingPeaks.
Cycling is my strongest sport, and it's pretty rare I stray from the plan. I have a lot more confidence in my abilities as a cyclist, so I don't worry about a bad workout here and there. I'm also not afraid to ride easy....and by easy, I mean EASY. I think being willing to go really easy from time to time is a sign of confidence.
My confidence is most easily shattered in the pool, so I find I'm continually searching for reassurance. As I continue to improve, I find that a bad workout here and there doesn't leave me wondering if I somehow forgot how to swim from one day to the next like it used to. And with swimming being more forgiving physically, there isn't as big of a price to pay for straying from the plan and increasing the intensity to give yourself some confidence.
But that doesn't make it right. The plan is there for a reason, and sticking to the plan is where we need to find our confidence. One workout doesn't make or break a season. But one workout does affect another and sometimes an easy workout is there to allow you to recover to set up another workout. Trust your plan and find confidence in executing the plan.
With this knee injury I've been battling for over a year, my running fitness isn't where I want it to be. This is where it's difficult being self-coached sometimes. A few weeks ago Athlete Mike logged into TrainingPeaks and made a few changes. Coach Mike had a running plan that was slowly building volume and intensity (and my knee was feeling great). Athlete Mike needed some confidence and saw that the Crazylegs Classic (one of the biggest 8Ks in the country) was quickly approaching. Suddenly there was a 5x1 mile track workout on the schedule.
Athlete Mike nailed the workout and got his confidence back....and along with that came knee pain. That led to a doctor's appointment and an MRI. The tendon was doing well, but wasn't fully healed (there are small lengthwise tears, so it's not like it's torn across and hanging on by a thread). I did some damage and set my recovery back a bit.
I was training on emotion. The plan was working, but I started searching for confidence and made last minute changes. I always have key workouts in the plan to test my fitness (and build confidence), but I got impatient. One thing that typically helps when I need some confidence is reviewing my overall plan to see where I'm at and where I'm headed. That gives me confidence that I'm where I need to be and that everything is going to come together.
So now I'm headed into my first race of the year, and my game plan is nothing like I had pictured when I registered for this race. I thought an early season half would be great for winter motivation, and it would be fun to be 100% focused on a half ironman for a change. Every other half I've done has been close enough to an Ironman that I haven't been 100% focused on the half.
But with my knee less than 100%, my new game plan looks like this: Athlete Mike gets to swim and bike and Coach Mike is doing the run. This means that in T2 I take off the athlete hat and put on the coaches hat (which looks a lot like a visor). It means I run hard, but don't throw away my season. It means I pay attention to...AND REACT TO....pain. Athlete Mike would ignore the pain and tear his knee to shreds. He's dumb like that. He views pain as a challenge, something to push through and conquer. Coach Mike knows when to pull the plug, to live to fight another day. Coach Mike views the pain as a threat to the training plan and the season's goals.
Ideally, my knee will hold up well and it won't be much of an issue. But I'm not going to throw away the entire season for one race....unless, by a very peculiar set of circumstances I find myself ahead of Lance. All bets are off then.
I don't think we have to worry about that.
In Part I, I defined AP, NP, IF, VI, KJ and TSS. In Part II, I showed how they change from ride to ride. In Part III, it's time to dig a little deeper.
What I gave in Part I were simplified definitions. My goal in Part III and Part IV is to expand on what I wrote in Part I about Normalized Power and TSS, but not get carried away and make your head spin...or my head spin.
So let's talk Normalized Power. It's a little tricky.
You've probably read definitions very similar to one I wrote in Part I before. So you know NP is a better indicator of intensity and tells you the ride you just did was the equivalent of riding at ___ watts if you had ridden steady on flat terrain. Let's dig a little into the why and how.
Average Power (AP) is pretty straightforward. For AP, you take every data point from your ride, add them up, and divide by the number of data points. I think most people understand the concept of AP. As I mentioned in my earlier posts, AP can be deceiving because two rides that were very different can have the same average power.
The problem is that the relationship between power and physiological stress is not linear, meaning 400w is not twice as stressful or difficult as 200w. It's much, much more difficult and creates a lot more stress on the body.
Say you're riding at threshold, your one-hour power. If you increase your effort by 10%, the physiological stress increases by a lot more than 10% and you will only be able to hold that effort for a fraction of the time you can hold threshold. Normalized Power gives those harder efforts more weight in the calculation to account for that stress and gives you a better idea of the intensity of your ride. Average Power gives all efforts equal weight and that's why it can be deceiving and isn't the best indicator of the intensity of the ride.
Another thing that's helpful to know about NP is that it's calculated off of a rolling 30-second average. The reason for this is because the physiological reactions to higher intensities aren't instant. They take a little time, so a 30s average was used. Using 30 seconds wasn't random, it has to do with half-lives of physiological responses. I don't know all the details; I just know it's not a random number and it's based on science and our physiological responses to exercise intensities.
So if you've ever done some short intervals and uploaded your data and got n/a for NP power for that effort, it most likely has to do with NP using a rolling 30-second average and your interval being too short for the calculation to work.
Sidenote: Does your bike computer have the option to display a rolling 30-second average? My Garmin does, and I can't say for sure they went with 30 seconds over other options because NP is calculated on a 30s average, but I bet it is.
So Normalized Power takes a rolling 30 second average and then everything is raised to the 4th power. Again, not random. The 4th power was based on studies that compared blood lactate levels to power output. Raising everything to the 4th power is how the larger numbers get more weight in the calculation.
Then everything is averaged, and then they take the 4th root to bring it back down to normal numbers.
So it looks like this:
- take a rolling 30-second average
- raise to the 4th power
- average everything
- take the 4th root
See? It's a little tricky. The main takeaway is that it's a weighted average giving harder efforts more weight, so in the end you have a number that gives you a better indicator of the intensity of your workout.
And because NP is a better indicator of intensity than AP, it's used in the calculation for Intensity Factor (IF). That calculation is pretty simple. It's just NP/FTP. Notice it uses your FTP. That's because it's taking your current fitness into account whereas NP is not.
NP is also used in the calculation for Training Stress Score, which I'll get into in my next post.
In Part I, I defined 6 terms/variables you can use to compare rides. In part II I want to compare 3 rides to show you how these variables differ and hopefully give you a better understanding on how you can use them to compare rides and your fitness throughout the season or from season to season.
Ride One: It's spring and you do an easy hour on the trainer at a very steady wattage - 150w. Since there wasn't any variability in your power, your Normalized Power will be the same as your Average Power. At this point in the season, your threshold (FTP) is 250w.
Here are the numbers from this ride:
Duration: 1:00
AP: 150w
NP: 150w
IF: .60
VI: 1.0
KJ: 540
TSS: 36
Ride Two: A few days later, the weather warms up so you head out and do some intervals. It's a one hour ride, just like your last ride on the trainer. The difference is that this ride has a lot of variability - some hard efforts followed by easy riding for recovery. Your threshold is still 250w.
The numbers:
Duration: 1:00
AP: 150w
NP: 200w
IF: .80
VI: 1.33
KJ: 540
TSS: 64
Notice the average power is the same as ride one. If you only looked at that, you might think these rides were identical. But if you look at the Normalized Power of ride two, you notice this ride was much tougher than ride one. The NP of ride two tells us this ride had the physiological cost of riding steady for one hour at 200w. Much more intense than ride one.
The IF (Intensity Factor) of ride one and two also shows us the difference in the two rides, .80 for ride two versus .60 for ride one. The VI (Variability Index) tells us ride two had a lot more variability. The KJs are the same for both rides showing you did the same amount of "work," but like Average Power KJ doesn't always tell the whole story. That's where TSS comes in. You'll notice the TSS is higher showing that the physiological stress of ride two was higher than ride one.
Ride Three: It's fall and you decide to head out one day and repeat that interval ride you did early in the spring, Ride Two. You repeat it exactly. The only real difference is that you've had an entire summer of riding and you're fitter than you were in the spring. Your threshold is now 275w. Since you repeated the ride exactly, nearly all of the metrics are the same.
Duration: 1:00
AP: 150w
NP: 200w
IF: .73 *****
VI: 1.33
KJ: 540
TSS: 53 *****
I put asterisks by the variables that differ between ride two and three. Notice the AP, NP, VI and KJ are exactly the same as ride two. That tells you this ride was indeed the same. You did a great job replicating ride two.
You might remember from Part I that the difference between IF and TSS and the other terms is that IF and TSS are relative to your FTP (they take your current fitness into account). That's why those two variables are different between ride two and ride three. Your threshold was higher when you did ride three so the ride wasn't as intense compared to your current fitness and it didn't create as much physiological stress even though the total workload (KJ) was the same. You were fitter for ride three, and IF and TSS illustrate.
The difference in IF and TSS between ride two and three also highlight how important it is to do periodic threshold testing. If you had never retested your threshold and changed your threshold in whatever software you use (I use WKO+ 3.0 and TrainingPeaks.com), the IF and TSS for ride three would have been incorrect leading you to believe the ride was exactly the same as ride two.
Obviously, this is a simplified example and you're not going to end up with rides quite this easy to compare, but I hope this showed you how the variables change and gave you a better understanding of how they work.
This was originally going to be a two part post, but I decided it needs a little more. In Part III, I'm going to go a little more in depth on Normalized Power. In Part IV, I'm going to dig a little deeper into TSS. There is a lot you can do with TSS and having a better understanding of it (and how it's calculated) can help you take your training and racing to the next level.
Monday evening I led a workshop on power file analysis at SBR Coaching. After spending years geeking out and obsessing over power data, it was really fun to get out and show others how I look at power files and maybe give them some new ideas on how they can better utilize their power meter.
I decided I would share part of the talk here on my blog. There are a lot of terms to know, but I focused on 6 main terms/variables you need to understand if you're training with power. And if you don't train with power but are considering it, knowing these terms may give you a better understanding of the benefits of training with power.
Before I get into those, you need to know what FTP is (yes, a 7th term). FTP stands for Functional Threshold Power (aka Threshold) and is the most power you can hold for 60 minutes.
If you're training with power, you absolutely must have a good estimate of your FTP. A few variables are calculated off your FTP so if you don't know your FTP some of the data in your power files will be wrong. And that means you must continue to retest your FTP as your fitness changes, or your data is wrong. You paid a lot for a power meter so it only makes sense to make sure you have good data.
Plus, there are the training zones which are calculated off your FTP, but I'm not going to get into those right now.
Here are the terms/variables I focused on:
1. Average Power (AP) - This is an easy one. It's your average power over the duration of the ride. I think most people understand this one.
2. Normalized Power (NP) - This one is a little more confusing than Average Power. Normalized Power is what you could have averaged for the same physiological cost had you ridden steady on flat ground for the entire ride. It gives you a better gauge of intensity than Average Power. A ride with some hard efforts and easy efforts might give you an AP of 150 watts, but a NP of 200 watts. The NP tells you that ride had the same physiological stress as riding steady at 200 watts. The formula is complicated, but I think the main takeaway is that it's a better measure of intensity than Average Power.
3. Intensity Factor (IF) - This is the ratio of Normalized Power to your FTP. IF = NP/FTP. An example: A ride with a NP of 200w for a rider with an FTP of 250w would be .8.
I know what you're thinking.....wait a minute. You just said Normalized Power was a better gauge of intensity than average power, but now you're defining Intensity Factor. If we have Intensity Factor, why do we need Normalized Power? NP is a great way to compare rides, but it doesn't take fitness into account. Notice that the formula for Intensity Factor has your FTP in it. Intensity Factor takes your current FTP into account, meaning it takes fitness into account. A ride that gives you a NP of 200w won't always give you the same IF. Intensity Factor allows you to compare your fitness throughout the season or from year to year. It also lets you compare fitness among different riders. 200w NP will not be the same intensity for everyone.
4. Variability Index (VI) - This shows you how much variability there was in your power. It's the ratio of Normalized Power to Average Power. The bigger the gap between those two numbers, the more variability and the higher the VI. A time trial typically has almost no variability and will give you a VI of 1.0.
5. Kilojoules (KJ) - This is the total work you did over the course of the ride. 1 KJ = 1 Calorie burned. You can use KJ to estimate your caloric needs (I went into detail on this at the workshop and may post some of that here - this can do a lot to help you nail down your nutrition and discover mistakes).
6. Training Stress Score (TSS) - This is a number that uses intensity and duration to measure the training load or physiological stress placed on your body by that training session. It's similar to KJ, except TSS is calculated off your FTP so it takes fitness into account. KJ does not.
So you have NP and IF, both measures of intensity. The difference is that Intensity Factor takes fitness into account.
And you have KJ and TSS, both measures of workload. The difference is that TSS takes fitness into account.
In part II of this post I'll compare 3 rides to show you how you can use these variables to compare rides and fitness.
