Variability is considered critical for motor learning. When skills are practiced in a variable order, mental effort is heightened and learning is often enhanced.
Variability is also important from a movement pattern perspective. For every task in sport, there is always more than one solution for achieving the task goal. And for most tasks it is advantageous to be able to flexibly switch between movement solutions.
Rajiv Ranganathan and Karl Newell proposed a framework to highlight how coaches can induce variability in the movement system during practice.
The authors state: “Our framework is based on the observation that there is redundancy in most motor tasks, that is, there are multiple ways to execute a movement to achieve the same task goal.”
Consequently, the framework proposes two levels in which coaches can induce variability.
- Variability in the task goal
- Variability in execution redundancy
The proposed framework. Extracted from Ranganathan & Newell (2012)
Variability the task goal
Let’s use basketball shooting as an example. A coach can manipulate the task goal by altering the distance of every shot. For instance, if the first shot is from 15 feet, the next shot could be from 10 feet, and the shot after from 12 feet. This would be considered a structured variation as the coach is specifically altering a parameter of shooting (i.e., shooting distance).
The coach could also alter the task goal in an unstructured manner. This would involve changing multiple parameters of shooting randomly. For instance, not only would the distance of every shot change, but the coach might also ask the player to produce an entirely different movement pattern for every shot (also referred to as differential learning).
What will variations in the task goal achieve?
If the task goal is varied in a structured manner, it promotes the ability to generalise movement patterns to new (unpracticed) scenarios (e.g., a distance that has not been practiced).
If the task goal is varied in an unstructured manner, it encourages players to explore new and potentially more optimal solutions to perform the skill. This can be useful for helping players break through a plateau in performance.
An illustration depicting the differences between (a) variations in the task goal and (b) variations in execution redundancy. Extracted from Ranganathan & Newell (2012)
Variability in execution redundancy
Execution redundancy refers to the fact that there are multiple ways to execute a movement to achieve the same task goal.
Using the basketball example again, a coach might ask a player to find different solutions for shooting the ball from the same distance. This means that players will find new solutions for the same task goal.
This type of practice develops movement patterns that can be flexibly adapted to a changing environment. Additionally, it could also lead to the emergence of a more optimal solution for performing the task.
Take home message
Coaches can have a powerful impact on the development of functional and adaptive movement patterns by carefully designing practice tasks. When planning practice, coaches should identify what the main priority is (e.g., develop new movement solutions, develop the ability to adapt one solution to the same task goal) and the design tasks accordingly.
Ranganathan, R., & Newell, K. M. (2013). Changing up the routine: intervention-induced variability in motor learning. Exercise and sport sciences reviews, 41(1), 64-70.