With races increasing in popularity, now we have to sign up for races several months before the race. A lot of times life gets in the way, or people think there’s still plenty of time to train. But as we know, time flies and we realize that we only have a couple of months to start training, or some people decrease their training during the holidays and they just want to jump back into their running. By increasing our mileage more than 10% /week will extend the chances of getting injured. Yes, we can get injured by overtraining and not looking after our flexibility, but increasing our training too quickly and intensely will make it challenging to stay injury-free.
There’s a great scientific way to calculate your running ratio to ensure that you keep it balanced between the mileage you are running now, and how much you have run in the last month. This way of calculating is called the “acute-to-chronic” ratio. By tracking your weekly mileage and calculating your ratio will make sure that you are not running too much too quickly or too little. In recent studies, the risk of injuries increased, for runners whose ratio exceeded 1.2, when the ratio reached 1.5 then the injuries increased significantly. A good balance is to aim for under 1.2.
Calculate the ratio:
The acute-to-chronic ratio compares your mileage for the last four weeks. Add your weekly mileage and divide it by four. If you ran 30, 35, 35, 45km, your ratio is 45 (last week’s mileage), then divide it by 36.25 (average of the last four weeks)- That’s 1.24.
Calculate the intensity:
You can use the same acute-to-chronic ratio to calculate your average training intensity. The effort we put into each run also makes a huge difference in the risk of injuries. Rate your effort during your run on a 1-10 scale, then multiply it by the duration of your run in mins. For example, a 45 min run at an effort level of 6 would result in a training score of 270. Do the same calculation as when using mileage. If your training effort for the last four weeks was 260, 260, 265, 280, your ratio is 280 (last week’s effort), then divide it by 266.25 (average of the last four weeks)- That’s 1.05.
You can make this ratio calculator more personalized:
By keeping track of your ratio through the season or the year, you can see which is your personal ratio. You can think of below 1.2 as green, 1.2 yellow and 1.5 as red. Some runners are less prone to injuries so they could increase their average ratio, while others are more prone to running injuries so to keep it under 1.2 is more important. Also, keep track not only of injuries, but also minor aches and pains, that way you can adjust your mileage. If you tend to get nagging pains look back at the pattern to figure out the triggers.
Bottom line is being careful when you increase your mileage and intensity, keeping your ratio within the right range will help you train and progress safely.
Train Hard, Eat Right, Feel Great!