How does the acute:chronic workload ratio work?

Managing the training loads in athletes has become a big issue in recent times as it is so important to get right. If an athlete trains too much, they get more injuries and performance suffers as they are overtraining. They are also at risk of increased psychological problems from repeated injury and overtraining. On the other hand, if they do not train enough, then they will not be at their best for competition. It is a fine line between doing too much and too little training and it can be easy to fall off the edge getting it wrong. That is why good coaches are so valuable to guide the athlete, either individual or team, under their care. In recent times the pressure to get the mix right has led to an increased role for sports scientists in the support team for athletes. They play an essential role in monitoring the training loads in athlete, how they respond to the loads and how they recover from a training and competition load. They provide invaluable information and feedback to the athlete, coach and the rest of the support team.

As a part of this it is known that training loads need to be progressively increased to get the best out of the athlete, but not progressed as such a rate that they get an injury. The body has to adapt to an increased training load before that load gets increased. If too much new load is applied before the body has adapted to it, then the risk for an injury is increased. A lot of data is collected by sports scientists to monitor this and keep an eye on the athletes.

One concept that recently became popular is the acute to chronic workload ratio which is used to monitor increasing the load on athlete. The chronic load is what the athlete has done over the previous 4 week and the acute load is what the athlete has done over the previous 1 week. A ratio of the two is tracked on a daily basis. The aim is to increase the training load of the athlete steadily, but to keep this ration within certain predetermined threshold. If those thresholds are exceeded, then there is assumed to be an increased risk for injury and adjustments need to be made to the training load. There is quite a large body of research that has been done that does appear to support this concept of the acute to chronic workload ratio and the concept is widely applied by many individual athletes and sporting teams around the world.

However, all is not quite as it seems as there has been increased recent criticism of the model, especially how the research has been interpreted. This has let to a lot of debates and discussions in a variety of places. A recent episode of PodChatLive had a discussion with Franco Impellizzeri on what he considers to be the problems with the acute:chronic model and how he thinks the research on it has been misinterpreted. Despite this it is still widely used as a training tool.

Craig Payne is a University lecturer, runner, cynic, researcher, skeptic, forum admin, woo basher, clinician, rabble-rouser, blogger and a dad.