Saturday, February 13, 2016

Overuse Injuries? Or Is It Related To Your Training Load?

Picture by richseow from Flickr
A pair of physiotherapists from the Australian Institute Of Sport (AIS) has suggested that overuse injuries are not caused by how much you train but rather by how your training load changes.

They found that comparing your total workload in the most recent week to the rolling average of the last four weeks of training could predict how likely you were to get injured. The term they used was acute versus chronic training load ratio. They suggest that a ratio above 1.5 is a risk factor for injury.

Consider another study done on a group of elite Australian Rugby League players (St. George Illawarra Dragons) for two seasons.

The players' training load was measured using GPS to track how far they ran during training sessions and games. Interestingly, more training did not seem to correspond to greater injury risk, even with back to back matches with less than a week of recovery. They actually found that players with a high chronic (four week average) workload of running 18.9-22 kilometres were less likely to get injured compared to those who trained less.

However, when they measured acute : chronic load ratio, players with a ratio above 1.6 (increasing training load by 60 % compared to their weekly average over four weeks) were far more likely to get injured. A ratio above 1.2 also put the players at risk, but less than those above 1.6.

Let's say you run 50 km a week consistently but suddenly this week you bump it up to 75 km (acute : chronic ratio of 1.5). You have just increased the chances of injuring yourself.

Or if you normally run 50 km a week but due to illness, work or travel commitments missed some training for a month or two and then decide to run 50 km a week again. That increase in mileage also increases your acute : chronic load ratio. So that is actually a training load error and not an overuse problem.

So if you had to take some time off training and want to resume training again remember to ease back into your training otherwise your acute : chronic training load increases and so will your chances of getting injured.

References

Drew MK and Purdam C (2016). Time To Bin The Trem 'Overuse Injury': Is 'Training Load Error' A More Accurate Term? BJSM. DOI: 10.1136/bjsports-2015-095543.

Hulin BT, Babbett TJ et al (2016). Low Chronic Workload And The Acute:Chronic Workload Ratio Are More Predictive Of Injury Than Between-match Recovery Time: A Two-season Prospective Cohort Study In Elite Rugby League Players. BJSM. DOI: 10.1136/bjsports-2015-095364.

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