Catapult Fundamentals: What can PlayerLoad tell me about athlete work?


Coaches, analysts and sports scientists are always striving to quantify the performance of their athletes, but vast quantities of information can make it easy to get lost in an avalanche of data without unearthing the most powerful insights.

Measuring Athlete Work

One parameter that empowers time-poor coaches, scientists and analysts alike is Catapult’s PlayerLoad metric. In scientific terms, PlayerLoad is instantaneous rate of change of acceleration divided by a scaling factor. In coaching terms, it is a measure of your athlete’s work.

Developed in conjunction with the Australian Institute of Sport (AIS), PlayerLoad measures work performed independent of distance, however well correlated they may be. This leaves you with a single number – obtainable indoors and outdoors – that provides an objective view of an athlete’s workload at any given time.

PlayerLoad is measured instantaneously (an athlete’s work at that second) and cumulatively (total work over a session). Because heel strike force generates vertical accelerations which feed into the formula, PlayerLoad is influenced by distance for athletes whose sport involves a significant amount of movement.

Additionally, by using PlayerLoad 2D, it is possible to omit the vertical accelerometer from the calculation to enable accurate quantification of athletes covering short distances, or whose sport demands they play in tight areas (e.g. badminton). It is also a great measure of work performed in small sided games within team sports.

Context & Validity

Distance and speed metrics are interesting with the appropriate context, but without that context they can be limiting as they don’t capture movement and impact. Giving a more complete picture of the work an athlete gets through, PlayerLoad enables you to personalise and periodise individual athlete loads.

If a coach is seeking a quick summary of an athlete’s work, then PlayerLoad is able to provide that. The metric can also be used to inform far more detailed analysis, with analysts being able to take the number, integrate it with other metrics, and devise their own custom parameters for deeper investigation.

For example, PlayerLoad (PL) represented per unit distance covered or time worked is an excellent indicator of movement efficiency. More efficient athletes expose themselves to less PL/min than less efficient ones. Monitoring players over time, variations in this metric are reflective of alterations in movement efficiency, or within a session of intensity of different drills.

Validated in many independent research papers, PlayerLoad is an easy-to-use solution for scientifically taking the guesswork out of athlete management, and can form a key reference point in your athlete monitoring process.

Interested in finding out how Catapult can help your team find its competitive edge? Click here to learn more about our range of athlete monitoring technologies.