132. Avoiding the Danger Zone: How to Use Chronic Workload Ratios for Smart Load Progression

Hey everyone. Welcome to PTs Snacks podcast. This is Kasey, your host, and if you are tuning in for the very first time, what you need to know is that this podcast is meant for physical therapists and physical therapist students who are looking to grow their fundamentals

and bite-size segments of time. Now, before we get into today's topic, which I'm really excited about, if you have listened to this show more than three times and you found it to be beneficial. If you wouldn't mind leaving a review wherever you listen to this podcast, that would mean the world to me because those really do help. But now that's aside, let's dive into today's topic, which is chronic workload ratio.

And if this is a new term to you it is probably gonna be more commonly utilized in maybe strength and conditioning, athletic training, sports and orthopedic physical therapy. But essentially let's cover. It's essentially a tool for us to be able to avoid rapid spikes in an athlete's activity to help manage injury risk.

Sometimes injuries just happen, but the more tools that we have in our toolbox to calculate the amount of stress that we're adding to an athlete, the more we can be productive with that stress and have productive adaptations, meaning they're getting stronger, they're able to tolerate more and more. Rather than, holy cow, we just flare them up and we've gotta take a few weeks or maybe even more to back it down again. We don't really want that.

So that is essentially what this ratio is used for, the concept. If you want more information, I'll go over a few resources. But Tim GT's research especially the training, injury Prevention Paradox is a great resource to dive further into this topic. Now, I already mentioned injury risk. We wanna avoid rapid spikes in stress levels with our physical stress that we're adding in during someone's rehab. But this is also an important concept to educate your patients with.

Let's empower them to be able to understand why after a quote unquote easy physical therapy session. That maybe they perceived as too easy and they're worried about losing their gains is important to stick to. Rather than go them going to the gym after and doing a two hour workout 'cause they're worried about it getting too weak and then they flare themselves up. Or let's say, hey, they want to sign up for a marathon someday, and they need to understand that they probably should have

a good training program leading up to it, rather than the month before looking at the calendar and being like, oh crap. I should probably start running and then they hurt themselves. So two points it's for us to use in a rehab and it's for patients to understand on why we do slow ramp up. Got it.

Okay. So in this episode, we are going to cover how to calculate it, what the ideal ratio is for us to aim for, and how to use it with things like running, lifting, and even rate of perceived exertion or RPE. So what is chronic workload ratio? The basic formula is essentially acute load, which is what your athlete did in the last week or seven days, divided by chronic load, which is their 28 day rolling average that they've done. So you would divide the acute load.

Over the chronic load and this, basically, this ratio gives you a snapshot of how much stress that they're under right now compared to what they've been prepared for. So examples of numbers that you would chug into this formula could be mileage. It could be tonnage for like strain training. It could be a

lot of things or average RPE over a week versus a month. All those sorts of things. And we'll give examples here in a little bit. But this is important for us, as I mentioned before, to avoid workload spikes so that we can try our best to reduce our risk for injury or re-injury. That the load, acute load divided by chronic load, let's cover what the ideal zones are. So where should you be?

If we are calculating this and we find that someone's chronic workload ratio is less than 0.8, we are in the under training zone. So there is a risk from deconditioning. Now, let's say we are doing this ratio and their score comes out to be somewhere between 1.3 and 1.5. This is also the caution zone. We want to monitor this pretty closely. 'cause while it may not be a high risk they're pushing it a little bit. The danger zone is more than 1.5.

That is a high risk of overload injury, and the sweet spot is 0.8 to 1.3. That is the best balance of challenge and recovery. I'm gonna say that again. 0.8 to 1.3 is the sweet spot. So if we're gonna cover examples of how to plug and chug. One example, and this is probably a little bit more commonly used in research, would be with mileage. So let's take a runner for instance, and say our athlete usually runs 20 miles a week for, and that's been the case for the last four weeks.

That's their chronic load is 20. This week they decided to ramp it up to 40 miles. So if we do our chronic workload ratio, it's gonna be 40 divided by 20, which equals 2.0. And if you remember, that is a major red flag. Anything over 1.5 is a danger zone, so we want to really make sure that we're nipping this in the butt a little bit and bring their. Mileage back down to something that's in that 0.8 to 1.3 ratio for strain training. You would be tracking total tonnage.

So to calculate tonnage, it is sets times, reps, times a weight. So let's say someone's in the gym. They last week, in the last four weeks, they averaged 5,000 pounds per week. That would be the chronic load, but this week it jumps up to 7,000 pounds. That would be their acute load. So if we're calculating our ratio, it is 7,000 divided by 5,000, which is 1.4. That would be right on the edge of caution. So we just keep an eye on this.

Then let's say in our last example, so this one we're measuring session RPE times time. So in this scenario, RPE is outta 10. So you would calculate what their rating was times time. So if let's say Monday they scored it as a six outta 10 RPE for 60 minutes, we would multiply six times 60 and get 360. Tuesday, let's say it was a seven outta 10 for 50 minutes. Calculating three times 50 is three 50. Thursday, it's an eight outta 10 for 45 minutes.

That brings us to 360 Friday, a six outta 10 for 70 minutes. That's a four 20. That weekly acute load for their RPE is gonna be 1,490. If your chronic average is 1,200 of the last four weeks, remember, if we're calculating their chronic work ratio. That is gonna be 1,490

divided by 1,200, which equals 1.24, and that is still in the sweet spot. So those are three examples. Mileage or distance kilometers, et cetera. Strain training and RPE is that, that is how you would use it in a clinic setting. So again, why this matters for PTs, whether you're in the clinic, the gym, or the training room, or maybe you're just using this for your own workouts. This helps you to quantify safe progressions, so whether you need it for your.

Whether it's for your own programming or educating your patient to make sure they are on board with your plan, it keeps you from guessing when an athlete is ready for more. Granted, we do have other tools in our toolbox typically for return to sport testing, et cetera, but it just depends on where your patient is at. And then it also helps to manage in season fatigue, travel, stress, practice spikes, et cetera. And it's just a good way to spot danger before symptoms show up.

Not saying that people who are in that higher ratio, 1.5, et cetera, are bound to get an injury, but we do want to just reduce the likelihood. Don't forget that workload is only half the picture. You still have to think about recovery.

If your athlete is dealing with poor sleep, high stress, poor nutrition, then even a normal load can feel like a spike. So you need to consider this in context, not just by their numbers. As I mentioned, some more research. If you wanna take a deeper dive into this concept, there's some other resource resources you can use. I already mentioned Tim GT's research. He's written that article, the Training, injury Prevention Paradox, which is a pretty good one on this concept. Science for Sport.

I'm not sponsored, affiliated with them by any means, but they do have some pretty cool stuff on their website and they have free breakdowns on chronic workload ratio. So check out Science for Sport and let me know what you think about it now. If you are looking to continue to grow your fundamentals you need to get some CEUs in a way where you can do it online, you're busy, et cetera.

Bed Bridge is actually a sponsor of this podcast and they are offering listeners over a hundred dollars off their year subscription. So if you wanna take advantage of that, if you use the promo code down below in the show notes you can take full advantage of that. They have tons of webinars courses. Specialty prep exam courses. I use them to help prep me for my OCS exam all sorts of stuff. And students, you get an even better discount. So again, it's in the show notes. Go check that out.

But if you guys have any questions, feel free to reach out at pt. PT Snacks podcast@gmail.com. And beyond that, I hope you guys have a great rest of your day. Try this out. See, test it out with one of your athletes and just see how, what your load has been like compares to this concept. But that's it for today, guys, and until next time.