## Race time predictor

**How can I predict my race time?**

You can predict your race time here from:

### What training do I have to do?

The race time predictions are estimates of what a runner might achieve, if they train appropriately for the distance. It does **not** mean, for example, that if you train for a 5km and achieve a good time, then you will automatically achieve the corresponding time at the marathon distance. It shows what you *could* achieve at that distance, if you train properly, given what you have achieved at another distance.

**How accurate are the predictions?**

They seem to be pretty good predictors of performance. They are, however, based on average reduction of speed as the race distance increases, and this relationship will vary from person to person (as well as on the type of training they do: see above). There is therefore a significant margin of error around the estimates.

The margin of error is bigger if the gap between the distances is large. In other words, a half marathon will typically be a better predictor of marathon performance than a 1 mile race.

### What is the age-grading prediction?

The age grading prediction assumes that that the runner will run the same age-graded performance at every distance. So, for example, if the runner has run a 10km at 62% of the world record speed for his or her age and sex, the calculation assumes that the runner would run 62% of the world record speed at each distance, and calculates what time that implies for each distance.

### What is the VO2 max prediction?

The VO2 max prediction works by estimating your VO2 max, given the performance you have entered, using the Daniels and Gilbert VO2 max formula.

The formula is then used in reverse to estimate your likely speed at the other distances. (The times are found by solving the formula numerically for a given VO2 max.)

### What is the Riegel formula prediction?

Peter Riegel’s formula is: t2 = t1 * (d2 / d1)^1.06

This formula was devised by Pete Riegel and published (in a slightly different form) in Runner’s World. Riegel later refined the formula for other sports. This formula has stood up well over time, and has the merit of simplicity. It says, roughly speaking, that a person’s speed declines by around 6% when the distance

doubles.

### What is the Cameron formula prediction?

Dave Cameron found that doing a regression comparing times and distance was futile; but that a model to predict speed produced a good formula which worked well for world records, US national records and collegiate records. He found that the model does well for post-1945 records at the 800m through the 10000m; and that from 1964 it also worked well for the marathon.

The Cameron model is

a = 13.49681 – 0.048865*olddist + 2.438936/(olddist**0.7905)

b = 13.49681 – 0.048865*newdist + 2.438936/(newdist**0.7905)

newtime = (oldtime/olddist) * (a/b) * newdist

Note that the distances are in miles; the times in seconds.

### What is the Purdy formula prediction?

The Purdy point system is calculated from a table of running performances compiled in 1936 called the “Portuguese Scoring Tables.” These velocity measures were intended to be maximum possible velocity in a straight line. Each of these performances was arbitrarily given a Purdy score of 950. (World record times

in 1970 have about 1035 Purdy points.)

Purdy subsequently estimated an equation for the men’s world record performances (as of 1970). This enabled Purdy points to be estimated using the equation rather than the Portuguese tables.

The Purdy formula is often quite different from the other predictions; and I’ve now excluded it from these calculations.

**See also**

May 16 2008 I had a heart attack at the age of 53. I had and have been active all my life playing basketball with 20 year olds a month before I had the heart attack. In Feb 2009 I completed Cardiac Rehab and felt comfortable enough to start running. The goal was to run 10K in about 50mins. (???) I have now trained (most weeks) approx 3 years, 4-5 times a week running 5kms in approx 30mins and pushing weights and exercising afterward. Most workouts last about an hour. I haven’t been able to acquire the stamina to complete 10kms more than a couple of times always in over an hour. I can usually complete about 8.5km in about an hour. I have no joint issues although I have had countless sprained ankles and even broke the right one once furing my lifetime. I had two stents put in and another blockage that is approx 50% (no stent) at the time of the attack. Today I am off almost all of my medications, or have reduced the dosage to minimal levels. The Cardiologist can’t find any signs of cardic disease anymore and has even cleared me to play basketball again but I can’t find anyone my age to play with. My only complaint is at the end of a week I am very tired and wished I had better energy, usually a couple days off and then I start all over again. So I plan to continue running because I feel it is the best way to stay alive without being dependent on medications, I will be 57 next month and will continue down this path until I find something better.

Henry,

I just stumbled on to your posting. I started running at age 47 after losing about 70 LBS and worked my way up to running various distance events all the way to marathons. At age 50, I experienced a heart attack with a full cardiac arrest. Luckily, their was a trained CPR responder and an AED nearby so I was lucky.

As I went through rehab, I to experienced the fatigue you noted. I think it was mostly attributable to the beta blockers that were part of my medication protocal. My resting heart rate was right around 48 prior to the heart attack and the beta blockers dropped me down to just below 40. After 9 months of being on the more powerful beta blocker (metoprolol), my doctor switched me over to Bystolic. That helped a lot as my resting heart rate is back to the mid 40′s and when excercising, my heart rate is able to go up higher. The beta blockers really do a number on you.

My cardiologist has encouraged me to continue running as he said my conditioning is the only thing (beside my emergency responders) that limited the damage to my heart. I ran my first half marathon only 58 days after my heart attack and ended the year running a full marathon 11 months after my attack.

I’m guessing that a beta blocker is part of your medication portfolio and I had much improved energy levels after changing to a different type.

Good luck as you continue you recovery.

Good luck to you and well done. So many people would have just plonked themselves on the couch.

Dear Henry,

It sounds like you are doing an amazing job of keeping yourself in good health. However given how tired you are at the end of each week you may be doing what is known as “chronic cardio”. What isn’t very well known about exercise is that exercise is actually NOT good for us — it is the body’s response to the exercise that is good for us. Exercise breaks us down, but the repair process we go through each time actually improves our fitness. Yet that system doesn’t work if we exercise beyond what we can recover from.

Please see marksdailyapple.com for fitness and nutrition advice that is far superior to anything you would find in the mainstream. (this is where the term ‘chronic cardio’ comes from; Mark Sisson also has a wonderful book entitled The Primal Blueprint that you should check out)

Cheers

Mike in Winnipeg

Sorry, I am missing something about the predictor, particularly the Riegel component.

I am working on the assumption that the Riegel formula is T2=T1X (D2/D1)X1.06

I put in a 5 minute mile as a base to look at predicted performances. The two mile time predicted by the Riegel formula comes at 10:25. Shouldn’t the time predicted by the Riegel formula for two miles be 10:36 — twice the distance and time (10 minutes or 600 seconds for two miles) + 6% (36 seconds) which would come out to 10:36 rather than 10:25. Sorry if I am being dense.

The Riegel formula calculation is correct. You have misread the hat notation “^” for a multiplication sign “X”. The hat notation signifies “to the power of”. For example, 2 squared would be 2^2, while 2 cubed would be 2^3. As such, entering your example into the equation would give 300 X (600/300)^1.06 or 300 X 2^1.06.

2^1.06 = 2.084932

300 X 2.084932 = 625.4796

or 6:25

Sorry,

10:25 not 6:25

I have taken part in 2 Park Runs over 5km can you confirm the world record time for a 77 year old male.