Dual-task effects on spatiotemporal, kinematic, and kinetic parameters and their variability during running

Running in real-world environments often requires using cognitive resources simultaneously with the motor task (dual tasking, DT). Limited existing evidence suggests that DT reduces running speed. Movement variability is essential for a healthy, adaptable motor system. DT has been shown to affect movement variability during walking. Nonetheless, it remains unclear how DT affects spatiotemporal, kinematic, and kinetic parameters and their variability during running.

Does DT affect spatiotemporal, kinematic, and kinetic measures and their variability during running? Does running speed influence DT effects?

Thirty-one asymptomatic runners participated in this cross-sectional study. Three-dimensional running biomechanics were recorded while participants ran on a treadmill at three speeds (prefer, slow, and fast) with and without performing easy and hard cognitive tasks. Mean and variability of cadence and step length, as well as peak joint angles and moments in the sagittal, frontal, and transverse planes associated with running injuries, were exported for analysis.

There were significant DT effects on peak knee adduction and pelvis ipsilateral drop angles. Findings also indicated significant DT effects on stride-to-stride variability of peak hip flexion, extension, and adduction, knee flexion and adduction, ankle plantar flexion, and pelvis ipsilateral drop angles, as well as peak knee abductor and ankle plantar flexor moments. Pairwise comparison revealed that runners exhibited lower variability when simultaneously performing a hard cognitive task than running alone. No significant task-by-speed interaction effect was observed, indicating DT effects were not affected by running speeds.

Runners demonstrated lower stride-to-stride variability in joint kinematics and kinetics during DT running. This suggests that runners may be less adaptable and thus more susceptible to running injuries under DT conditions. Future evaluation and intervention programs for runners may consider integrating DT condition, which is commonly missing in current practices.