I only have to look out the window to see that running has been taken by storm in Melbourne. I don’t know if it’s because it’s a great stress reliever, or whether people have found time to focus on fitness goals, or simply because it’s one of the only things we can do at the moment. But whatever the reason, it is great and I would love to shed some light on how everyone can continue to keep running once COVID-19 is behind us.
Many people that come through the clinic suffer injuries due to training errors. Often people are either training too much, too inconsistently or not incorporating sufficient rest or recovery into their routines. I use a formula, developed by Gabbett et al, to help assist people in monitoring their training load to reduce risk of injury. This is called the acute chronic workload ratio (ACWLR).
What is the Acute Chronic Workload Ratio?
Ok let’s break this down. Workload refers to how much work our tissues do over a certain period of time. For most runners, this is volume which is measured by kilometres or time of activity. Workload also takes into account how hard the intensity of the work out is, we often measure this variable by a rate of perceived exertion (0-10).
To calculate our acute load we look at how much loading we have completed over a given week of training. Multiply the duration of the run by rate of perceived exertion to receive the workout score. Add each workout for the week together to get your acute load total. For example:
| Day | Duration | Type of activity | Rate of perceived exertion | Score |
| Monday | 30min | Easy run | 5 | 30×5 = 150 |
| Tuesday | 60min | Gym session | 3 | 60×3 = 180 |
| Wednesday | 60min | Run with interval training | 8 | 60×8 = 480 |
| Thursday | 60min | Run | 6 | 60×6 = 360 |
| Friday | 60min | Gym session | 3 | 60×3 = 180 |
| Acute load: 150 + 180 + 480 + 360 + 180 = 1350 |
Our chronic load refers to the average workload over the previous 4 weeks.The important value is the ratio between these two numbers. To work out this value, divide the acute workload by chronic workload. A value between 0.8 – 1.3 keeps us within the ‘sweet spot’ where our injury risk is minimised.
Image reproduced from Gabbett et al. The training-injury prevention paradox: should athletes be training smarter and harder?
We did a recent webinar covering this topic in more detail. Please watch below if you’d like further information on this!
