How to avoid overtraining and reduce the likelihood of injury – Applying the Acute vs Chronic Workload Ratio to Combat Sports: Part 1


The Importance of Training Load

In previous posts we have discussed goal setting for the year in advance (, setting up a testing battery to establish baseline levels of performance ( and using the results of these processes to plan out the years training cycles ( Critical to the success of the training programme, both in terms of achieving the desired performance outcome and keeping an athlete healthy, is the application of appropriate training load at the appropriate time. This is where the use of an acute vs chronic workload ratio can be a valuable tool in preventing the training spikes that may lead to impaired performance and/or injury.

The training process as a whole is essentially a series of stimuli, used in order to illicit a response. If the stimulus is appropriate, and applied at an appropriate frequency, the response of the system is to grow stronger over time, and this applies to whichever physiological characteristic we are aiming to improve. If the stimulus is insufficient, or not applied frequently enough, there is inadequate reason for the system to adapt. If the stimulus is too great, or applied too frequently, then the system will be overloaded, and adaptations will stagnate, or regress. The incidence of soft tissue injury is greater when an athlete is experiencing higher than usual amounts of fatigue, as the reserves of body are inadequate to cope with the training stress. The incidence of contact injury is also likely to increase under the influence of fatigue, due to a decrease in technical proficiency and an increase in training errors. Therefore, in the art of achieving progressive improvements in physical function and where possible avoiding injury is strongly linked to the ability get training loads right.

The Acute Vs Chronic Workload Ratio

Previous research in field sports (initially with rugby) suggests that acute spikes in training load (e.g. doubling the amount of training during a certain week) may be harmful, leading to overloading and potential injury. On the other hand, having a high chronic training load (e.g. consistent training volume gradually building over time) can be protective, increasing the body’s capacity to handle load.

Gabbett and colleagues have popularized the acute vs chronic workload ratio, which is essentially a metric used to describe the training load of the current week in comparison to the average of the last 4 weeks. They have found that this metric should ideally fall between 0.85-1.35. to lower the risk of injury217. It has also been shown that training loads outside this ratio may cause injury up to 4 weeks after the training load spike218.

In the next post we discuss the relevance of the acute vs chronic workload ratio to combat sports and how we go about calculating it.


  1. Hulin, B. T., Gabbett, T. J., Lawson, D. W., Caputi, P. & Sampson, J. A. The acute: chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players. Br. J. Sports Med. bjsports–2015 (2015).
  2. Rogalski, B., Dawson, B., Heasman, J. & Gabbett, T. J. Training and game loads and injury risk in elite Australian footballers. J. Sci. Med. Sport 16, 499–503 (2013).

A full framework of training load quantification is featured in the science of striking, available in both hard-copy and kindle formats (

#injuryreduction # trainingload # planning #thescienceofstriking #boxing #kickboxing #karate #shinkyokushin #kyokushin

About the author

Sam Gilbert

Sam Gilbert is a registered physiotherapist with the Australian Physiotherapy Association (APA) and certified strength and conditioning specialist (CSCS) with the National Strength and Conditioning Association (NSCA). He holds a bachelor’s degree in Physiotherapy from Latrobe university (Melbourne, Australia) and a master’s degree in Exercise Science (Strength and Conditioning) from Edith Cowan University (Perth, Australia).

A 3rd Dan black belt in Shinkyokushinkai Karate under the World Karate Organisation (WKO), Sam participated for over 20 years in full contact competition, winning multiple state and national titles, and culminating in a 4th place in the heavyweight division of the Shinkyokushinkai World Cup in 2009.

As the co-founder and clinical director of Club 360, the premier multi-disciplinary health and fitness center in Tokyo, Japan, Sam has combined his practical experience with an in-depth study of sports performance in relation to combat sports, and strives to help other combat athletes reach their full competitive potential, whilst at the same time decreasing injury risk and increasing competition and training potential.

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By Sam Gilbert