Training Load, Performance and Injury Risk

Training loud refers to the amount of training related physical stress that is performed by an athlete. Monitoring training load has become a huge topic in strength and conditioning in the last decade or so. It’s also become a huge business. A variety of companies have emerged with products that are designed to either a) provide a training load metric or b) provide a platform for coaches to input their data for visualization and analysis. Advancements in GPS and accelerometer technology have allowed us to track nearly every movement an athlete makes on the field. Heart rate monitors have become more sophisticated with protected proprietary algorithms that quantify load based on time spent in specific heart rate zones. Often still used however, are the traditional and cost-free methods of training load monitoring including session rating of perceived exertion and basic volume metrics (i.e., distance, sets x reps, etc.).

The issue no longer is about how to quantify training load as there are clearly a variety of useful ways to do so. The issue today rather, is what to do with the training load data for decision-making and training modification. In a recent editorial published in the British Journal of Sports Medicine, Dr. Tim Gabbett and colleagues discussed the usefulness of what they term the “acute:chronic workload ratio”. This simply refers to the ratio between the training load of the current week and the rolling average of the last 4 weeks. The authors posit that abrupt increases in workload (>10%) put athletes at a high risk of injury based on their previous investigations. They also discuss how progressively developing a high chronic workload (i.e., building of work capacity and fitness) reduces the risk of injury.

With regards to return to play following injury, the authors suggest that an athletes readiness to return may have do with the workload completed during rehab. Injury may be due to a lack of fitness as a result of low chronic workloads as a consequence of the injury. Developing a high chronic workload before returning to play will thus likely limits fatigue related injuries on the field after return. The take-home message from the editorial is that chronic workloads may reflect the athletes’ overall capacity to handle training and the acute workload may have to do with managing fatigue. Heading into competition with a decrease in acute workload with a high chronic workload is likely optimal for peaking (i.e., decrease in fatigue with realization of fitness). In contrast, a low chronic workload leading into the season when the acute workload spikes may put athletes at risk of injury. Coaches are therefore encouraged to track the acute vs. chronic workload with their training load data for meaningful decision-making and training modification.

Reference:

Gabbett, T. J., Hulin, B. T., Blanch, P., & Whiteley, R. (2016). High training workloads alone do not cause sports injuries: how you get there is the real issue. British Journal of Sports Medicine, bjsports-2015.