Study after study has been done (and is being done) looking at running injuries and what contributes or leads to them. From a wide lens and big picture perspective, little is known from all of this research – the really only firm and consistent finding is that if you have had a prior injury, you will likely be injured again. When you start looking at specific injuries, there are a few more specific findings but still minimal to put your finger on.
One thing that is universally accepted (although not proven) is that training factors and workload likely play a large role in running injuries. When prior studies have looked at training workload, conflicting evidence again persists. For instance, multiple studies have shown that training over x amount can potentially lead to injury; however, those same studies or others have also shown that training at higher loads can also be protective for injury. This can be super frustrating for therapists and coaches and runners.
Some relatively recent research from Tim Gabbett has been making some pretty big splashes in sports injury prevention and management. His work has been focused on cricket, rugby, and Aussie rules football primarily; however, his findings and ideas for tracking training workloads can be applied in a wide range of situations. To my knowledge no research using this tracking method has been done on runners. Anecdotally, I have found it to be very useful in my own training and in the training of many athletes I coach.
Gabbett and his team of researchers talk about “acute:chronic workload” management. The idea behind this is that you can monitor your acute (present) training as it compares to your chronic (last several weeks) training. This can present you with a ratio that you can monitor to make sure you don’t get any big spikes in training workload. At a very basic level, if you were only looking at mileage/week, you might run 10 miles this week and compare that to your average over the last 4 weeks. If you averaged 5 miles/week over 4 weeks and ran 10 miles this week, you would have a 2:1 acute:chronic workload.
But Gabbett takes it much further in how he recommends monitoring workload. You can really measure much more than distance or time. You could look at monitoring just how much time was spent at a high effort or sprinting or intervals or any number of other variables. One of the ways Gabbett has monitored intensity is by having athletes rate their workout sessions using an RPE (rating of perceived exertion) scale. Below is an RPE scale modified by Foster et al. in 1996.
|4||Sort of hard|
|9||Really, really hard|
|10||Just like my hardest race|
|Answering the question as if posed from your mother or significant other:||How was your workout, honey?|
The RPE scale and self-rating has actually been shown to correlate very strongly with HR readings in multiple studies on athletes. As long as you honestly rate how you felt (not how you are “supposed to feel”), RPE is just as valid as using HR or other more objective measures of workload.
Using the RPE rating scale, runners can use a simple formula to help track both the workload of running in distance/time and also in intensity, which is really a big part of how the body responds to training. The formula is quite simple:
Training time (mins) x sRPE (session RPE rating) = Workload unit (arbitrary unit)
To give a real life example, let’s say that I went out for a 60 min run and rated the run as moderate. In the formula above, it would look like this:
60 mins x 3 on RPE scale = 180 arbitrary units
Over the course of several weeks of training, I would be able to come up with a weekly “arbitrary unit” total. This would then allow me to start tracking the workload ratio as Gabbett has recommended from his research. For instance, let’s say I have 4 weeks of data using the training time x RPE formula above: 1000 units, 1200 units, 900 units, 1400 units. This would give me an average over the last 4 weeks of 1,125 units. The 1,125 unit number = “chronic workload”. It gives me the average of 4 weeks of data for how long I worked out and how hard I worked during those workouts.
Now let’s say that I run the next week and come up with 1700 units (i.e. I pushed it a little bit this week). This is my “acute workload”. I can get my acute:chronic workload by completing the calculation of 1700 divided by 1125. This equals 1.5 for the acute:chronic workload. So this week’s workout was 1.5x the average over the last 4 weeks when looking at total time and RPE.
In Gabbett’s work with cricket players, rugby players, footballers, etc., he has determined that a ratio of >1.5 is considered a spike in training. He has found that this places athletes at a significantly higher risk of injury in the coming weeks. So, his goal is to keep away from spikes in training load.
One of the big talking points and results of Gabbett’s research is that high levels of volume and intensity are being shown to not necessarily be the problem. If you’ve ever been told that you are “running too much”, his research is indicating that this might not be true. What really seems to matter is whether you are “spiking” in your training or whether you are maintaining a solid “chronic workload” that might actually be protecting you from injury. High training workloads are not necessarily the problem … how you get to those high training workloads might be the problem.
Won’t this take a lot of time and work?
This method of tracking your training is so easy to add in if you are already keeping some form of a training log or training journal. For each run, you simply need to log 1) time and 2) RPE.
At the end of the week, add up your arbitrary units (time x RPE) for the week. Log that number in your training journal.
After you have 4 weeks of data, the easiest way to move forward is to set up a formula in an Excel-like sheet. It looks something like this:
You would just plug in the sRPE from your training journal for each week. Then you would create a formula for “sRPE.4w” that equals sum (row 1-4 of column 2 divided by 4). Then for the “acute:chronic” you would simply take your weekly “sRPE” divided by the “sRPE.4w”
I have been using this method to track my own workouts and multiple clients’ workouts over the last several months, and it has been a big game changer in how I approach weeks and workouts. I have used the above method to “pump the brakes” on runners and also have used it to “loosen the reins”. It is also a great way to measure how you are actually feeling after a prescribed easy run. For instance, if you keep rating your prescribed easy days as “hard”, it is a sign that you need to back down on those days. I’ve also already seen a client go above 1.5 on the acute:chronic ratio two times in 6 months, and injuries have come on within 1-2 weeks of that “spike” each time.
I highly encourage you to give this a try in your own tracking especially if you have a long injury history. This could be what changes that pattern!
Gabbett TJ. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med. 2016;0:1-9.
Blanch P, Gabbett TJ. Has the athlete trained enough to return to play safely? The acute:chronic workload ratio permits clinicians to quantify a player’s risk of subsequent injury. Br J Sports Med. 2016;50:471-475.
Hulin B, Gabbett TJ, Blanch P, et al. Spikes in acute workload are associated with increased injury risk in elite cricket fast bowlers. Br J Sports Med. 2014;48:708-712.
Hulin BT, Gabbett TJ, Lawson DW, et al. The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby players. Br J Sports Med. 2016;50:231-236.
Foster C. Monitoring training in athletes with reference to overtraining syndrome. Med Sci Sports Exerc. 1998;30:1164-1168.
Halson S. Monitoring training load to understand fatigue in athletes. Sports Med. 2014;44:139-147.
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