We all get older and know that in general our running is going to slow down along the way - but by how much and how quickly? This can be worked out using grading factors, which people with a fascination for statistics and sports have been calculating since the late 1970's. These number crunchers look at all of the fastest times achieved for men, women and children over different ages and distances to calculate sets of lookup tables for these factors.
It follows that if you can use the data to figure out how much you can be expected to slow down over time, you can also use these grading factors to figure out how well you did in a race in comparison to everyone else by taking your (and their) ages into account to modify your (and their) times. You can also use the grading factors to figure out a bunch of other things too - running through some simple examples below will make all of this clearer.The history and maths behind these gradings and the various political, sporting statistical arguments that have gone along with this are actually quite interesting in a geeky kind of way - you might want to peruse Professor Howard Grubb's pages and also the Masters Track blog for more information. A more gentle introduction with some interesting real examples on the controversies that have happened when clubs have forced age grading to be applied can be found in a very interesting article by Jonathan Beverly.
The upshot is that most people use what are know as the WAVA / WMA grading factors, the latest ones are from 2006 and it is these figures that are used in the grading calculator on this site.
Let's start with the example of Glenn Hughes-Williams who at 55 in 2006 ran a 10K road race in Fleet. We'll get to the times later on, but to start with we can enter the data for a 55 year old male running a 10K road race in the calculator and this shows us two pieces of information from the WMA tables.
As an aside - to understand why the same distance on track and road have different OC times - have a look hrough Alan Jones' website
The Age Factor is the second piece of information and is in this example .8395 - this is the adjustment that should be applied to times to take Glenn's age into account.
The first thing we can do with the data is to divide the OC time (in seconds) by the age factor. This give us the Age Standard which is a time which, if achieved would mean that Glenn would be setting (or be close to setting) a new world record for his age. The calculator automatically figures out and displays the Age Standard - in this case 1611 / .8395 = 1919 seconds or 31:59 - so old Glenn is some way off picking up the world record for the 10K for a 55 year old. Looking at the World Masters World Records page we can see that the 10K world record for M55 is 32:27 by Mike Hager of Gloucester (it's not clear from this page whether this is a track or road time - I'm guessing track).
OK, so even before we look at an actual time that has been run, we've got 3 important pieces of data, Open Class Time, Age Factor and Age Standard Time.
Glenn ran his race in 40:02 (irrespective of what his watch said), which is 2402 seconds. Multiplying this time by his Age Factor gives us Glenn's Age Adjusted Time - which is the time that he would have realistically got if he'd been in his potential running prime (agewise), which in his case is 2402 * .8395 = 2016 seconds or 33:36 which is pretty impressive. Again, the calculator allows you to optionally enter your time in the format hh:mm:ss and will calculate the Age Adjusted Time for you. If you work out the age adjusted times of everyone in the race you can see who actually did 'best', relatively speaking.
It's important to bear in mind that these factors can also be used to look to the future - so you can take the 5K time of a 12 year old to project forward what they may be able to achieve when they are 20.
Glenn's Performance Level Percentage is calculated from the Age Standard Time / actual time achieved - in this case it is (1919 / 2402) * 100 = 80% (the calculator will show this if you entered the optional actual time run) - so in other words Glenn's time was approximately 80% of the way to achieving a world record time for his age group. The Performance Level Percentages can be compared across distance, age or sex as the grading factors have taken these things into account when they are put together. In fact for the WAVA factors the following PLP values and associated standards are accepted:
100% world record level
90-99% world class
80-89% national class
70-79% regional class
60-69% local class
So according to WAVA, Glenn's performance level percentage puts him at national class for his age. Very impressive indeed.
Alan Bent finished the 2007 London Marathon in a time of 03:28:55 (12535 seconds) coming first in the M65 category. Using the calculator we see Alan's Performance Level Percentage is 77%. A few weeks later Alan completed the Staines 10K in 00:43:46. These figures in the calculator show Alan's performance level Percentage for that race was 80% - so Alan's performance was consistent (and impressive) across these two very different events.
If we wanted to, we could use the calculator to show the times that Alan would need to achieve at these two distances in the future to maintain (or better) his current PLP's.
If you made it this far - well done - grab yourself a drink of whatever you fancy and get playing with the calculator.
What's this got do do with BFR Star / Wicat Ratings? Good question. You can find out here.