Most people have either had an over-use injury or know someone that has had one and likely know how frustrating they can be to rehab back to normal. Luckily, Shaun is here to explain how these injuries are prevented in the sports medicine and elite sport world.
A few common examples of Sports-related overuse injuries are:
Foot stress fractures in runners
Rib stress fractures in rowers
And much, much more!
I bet at least one of those sound far too familiar to you!
So, the big thing for us sports physios is firstly to rehab these injuries back to normal through hands-on treatment, strengthening and gradual reloading and then secondly and most importantly, to work out an ideal training plan with you long term so that it doesn’t happen again.
To do that, we first need to know how these injuries occur, because they certainly aren’t just random bad luck –they are due to training error. So, here is the run-down, of how they happen:
It is all about the Acute/Chronic workload ratio.
What does this mean?
Well, the chronic workload is what your body is used to. For example, say you have been playing one game per week or running 20km per week for the last month – that is the chronic workload and what your body is used to.
Whereas your acute workload is the change. The new load you have added onto this regular workload.
That makes sense so far right?
So if we build on that, sports-related overuse injuries (as well as work-related overuse injuries) occur when that ratio gets too high. When we are adding in too much new/acute load on top of what our body is used to without enough rest to adapt and get stronger.
Here is a good graph to illustrate where the “danger zone” is:
So here is an example of how to work out the Acute/Chronic workload ratio, which is typically worked out over a 28 day period:
Over the last 4 weeks (28 days) I have run a total of 85km, making that an average of 21.25km per week, giving me my chronic workload.
Over the last week, I ran 25km in total, giving me my acute workload
So, my acute/Chronic ration is 25/21.25. giving me a ratio of 1.2
Phew, which puts me in that sweet spot!
But if I had increased by 10km in the last week, I would be into that danger zone and at risk of tissue overload, injury and a long and frustrating time away from the sport I enjoy. This way of understanding workload and injury can be translated into any sport – bowlers in cricket would count balls bowled to avoid stress fractures in their low back, team sports players measure the metres covered during games and training, and tennis players the number of balls hit just for a few examples.
This way of understanding workload and injury can be translated into almost any sport – bowlers in cricket would count balls bowled to avoid stress fractures in their low back, team sports players measure the metres covered during games and training, tennis players the number of balls hit to avoid tennis elbow and rugby or netball players would keep a rough record of metres run each week. The below graph shows a team sports training load and injury rate through a season with a very high injury rate in the first half of their season where their load peaks.
Relationship between training load and injury rate in team sport athletes
To avoid training-load error, you need to train smart. It’s not about training less – in fact, having a moderate chronic load is protective of injury – it is about training smart and not having large spikes in training load and gradually building up.
The acute:chronic workload ratio has been proven to be a great predictor of injury and better than just measuring acute or chronic load by themselves. It is used throughout elite and international sporting teams now and would be hugely beneficial to be used on the and applied throughout all sports to help prevent injury and therefore increase player availability and performance – When it comes to non-elite team-sport where it is tricky to be accurate with load, player estimates can give you a rough guide.