The role of the plantarflexor muscles on the daily life functioning in typically developing children

BACKGROUND: The plantarflexor muscles are important during walking. However, walking is not the only task that is used during daily life, and not much is known about the role of the plantarflexor muscles during other dynamic tasks. Insight into the demand of the plantarflexor muscles during different dynamic tasks might help to establish training or functional assessment for patients who experience plantarflexor weakness.

RESEARCH QUESTION: This study aimed to examine the role of the plantarflexor functioning during dynamic tasks in children of 5-9 years old, by identifying differences in ankle kinetics and plantarflexor muscle forces during dynamic tasks.

METHODS: In this observational cross-sectional study, 28 typically developing children from 5 to 9 years old were included. Three-dimensional movement analysis was performed to extract the peak ankle moment, power and plantarflexor muscle forces during the stance phase of walking, heel walking, toe walking, running and one-leg-hopping. To examine differences in peak ankle moment, ankle power and muscle forces, Friedman tests were used in combination with Wilcoxon signed-rank tests to determine differences in peak ankle moment, power and muscle forces of the various dynamic tasks compared to walking.

RESULTS: Based on the differences in peak ankle moment, power and muscle forces compared to walking, heel walking was the least demanding dynamic task. Running and one-leg-hopping were the most demanding tasks.

SIGNIFICANCE: Dynamic tasks with a high demand on the plantarflexor muscles, such as running and one-leg-hopping could be used to quantify deficits in patient populations with plantarflexor weakness that are not visible during walking. Furthermore, these tasks could be used during functional evaluation or training in these patient populations.