Right from the very foundational levels of sport science, strength and conditioning, and coaching we are taught the importance of progressive overload. We know that to improve we need to continually increase the amount of stress we are putting on the body. However, the important questions are HOW much stress do we need to put on the body and WHEN to do it. When do we push? When do we pull?
There are a few general rules of thumb and a number of ways you can gain a better understanding of how to manage workload, and more importantly, how much to progress / overload. One method that is often talked about is the 5% rule. Progress by 5% each week to gradually overload the body. It makes sense and can work but it's not that in depth!
Another method is to use auto-regulation, something which I have talked about in a previous blog post. While these methods can work well by providing a basic principles, they may not be as good at predicting when you may be pushing TOO far.
In order to gain a greater understanding of whether they are pushing too much or not enough, many coaches lean towards the use of an Acute Chronic Work Ratio (ACWR). So what is an ACWR? How do you use it? Is it valid?
Simply put, the ACWR shows how your current work period (typically 7 days) relates to the previous periods (generally 28 days). In turn, this allows you to understand how much you have pushed (overloaded) and whether it may be safe to continue pushing, or if you need to ease off the following week.
Acute Workload
As mentioned above, the acute workload is the total amount (SUM) of work you have accumulated in the last 7 days. This can be calculated in a number of ways. You may score use an RPE trimp, where you score each session out of 10 for difficulty and multiply it by the length of the session in minutes. For example
Day 1 - 7/10 effort for 60 mins (7x60 = 420)
Day 2 - Rest
Day 3 - 8/10 effort for 45 mins (8x45 = 360)
Day 4 - 5/10 effort for 75 mins (5x75 = 375)
Day 5 - Rest
Day 6 - 7/10 effort for 60 mins (7x60 = 420)
Day 7 - Rest
Total acute workload = SUM of 420 + 360 + 375 + 420
Total acute workload = 1575
How you choose to quantify workload is your choice, you simply need to add them all together and establish your acute load.
Chronic Work
Your chronic workload is the average of the past 28 days (including the current day). To calculate this, you simply need to add up the total workload from every day and then divide them by 4. For example,
The SUM of the last 28 days adds up to 5590.
Divide this by 4 = 1397.5.
Calculating the ACWR
We now have two figures. An acute load (this weeks training) of 1575 and a chronic load (the previous 4 weeks training including this one) of 1397.5. The next step is to simply divide the acute workload by the chronic workload. In our example, it looks like this:
1575 / 1397.5 = 1.1
Essentially, this tells us we have performed 1.1 times the average weekly work. Meaning we have successfully overloaded the body. The research shows that this falls within the "sweet spot" when it comes to training load. Below are the guidlines of what may be defined as too much or too little.
< 0.80 - Under training = higher risk of injury
80 – 1.30 - Sweet spot = Good level of overload with lowest risk of injury
> 1.50 - Risk of overtraining and related injuries
The image below shows how this may look when plotted on a graph including the thresholds. You can see the point in week 4 where the training load has been increased too much and ACWR has risen above the suggested threshold.
Other Things to Consider
Hopefully the post has provided a quick insight into what ACWR is and how to use it. This last paragraph is essentially a few of my own personal extra thoughts on it and how you may use it.
While I like it, it holds its own mathematical issue in the sense that the acute value bears large influence on the chronic.
By calculating and average it assumes that the previous 4 weeks have been identical
How you calculate and measure workload can massively affect the results
Think about whether you are calculating RPE vs Max weight vs Volume Load etc
It MUST be a guide rather than an absolute decider
Used together with other monitoring tools, it can be very useful
Comentários