Load Management For Injury Prevention
Managing training load is crucial in injury prevention and treatment. A graphic in Tom Goon’s recent blog visualises how training load outweighs all other factors.
Historically we have advised that training loads shouldn’t increase by more than 10% a week. I’m not sure where this figure comes from. I’ve got no problem with it, it seems reasonable, and I’ve quoted it hundreds of times.
There’s a recent BJSM podcast interview with Tim Gabbett on load management for injury prevention. Specifically Tim talks about this paper:
Spikes in acute workload are associated with increased injury risk in elite cricket fast bowlers
- Billy T Hulin, Tim J Gabbett, Peter Blanch, Paul Chapman, David Bailey, John W Orchard, 2013.
It is research into fast bowlers but I think the principles apply just as well to any athlete.
They measured the acute workload of the last 7 days (and call it “fatigue”) and compare that to the chronic workload of the previous 4 weeks (which they call “fitness”).
Measuring Training Load
For runners, if the training is reasonably homogenous, we could most simply measure the workload as the total kms/week.
Or we could be more accurate and account for a mixed training program that may include a variety of hills / sprints / cross training etc, by giving each session a rate of perceived exertion (RPE) out of 10, and multiply that score by the number of training minutes:
Training load = session RPE x duration (minutes)
This is called a Foster’s Score, and provides a simple method for quantifying training loads from a variety of different training modalities.
The research subtracted the current 1-week average from the previous 4-week average and called this number the “training-stress balance”.
A negative training-stress balance increases the risk of injury 4 times.
[Last 7 days’ session RPE x duration (minutes)] - ([Last 4 weeks’ session RPE x duration (minutes)] / 4) = TRAINING-STRESS BALANCE
Negative balance = 4 times risk of injury
Essentially this formula means you shouldn’t increase your training load by more than 25% a week.
For people that may be more vulnerable to injury I would change the 4-week average to a 6-week average, therefore, bringing the increase in load each week down from 25% to 16%.
This more cautious group could include:
4/9/2015 10:51:20 pm
Great summary of the research and training stress balance. It's an important topic - but not well understood. Well done on getting the message out there. Tim
5/9/2015 07:10:27 am
Thank you for your work Tim : ) It's great to have the research behind what we say.
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