To compare the effect of dual tasking on postural stability between patients with anterior cruciate ligament reconstruction (ACL-R) and healthy controls.
Single-limb postural stability was assessed in 17 athletes with ACL-R and 17 healthy matched athletes while standing on a Biodex Balance System platform in 4 conditions: stability level of 8 (ie, more-stable support surface) with eyes open, stability level of 8 with eyes closed, stability level of 6 (ie, less-stable support surface) with eyes open, and stability level of 6 with eyes closed. Postural-stability tasks were performed with and without auditory Stroop task. The anteroposterior stability index (APSI), mediolateral stability index (MLSI), and overall stability index (OSI) as measures of postural performance, as well as reaction time and error ratio as measures of cognitive performance, were recorded.
Dual-tasking effect on postural stability was not significantly different between the groups in 3 postural conditions. Only in level 6 with eyes open, for APSI and OSI, patients with ACL-R showed lower postural stability under the dual-task condition. However, patients showed poorer performance on both reaction time and error ratio in all postural conditions.
The patients with ACL-R appeared to sacrifice their cognitive performance to optimize their performance on postural stability. This posture-first strategy was reflected by a more pronounced effect of dual tasking on the auditory Stroop task than the postural-stability task. In situations where maintenance of posture is challenging, giving priority to the postural task at the expense of cognitive performance can ensure safety from balance loss.
Mohammadi-Rad, Salavati, Akhbari, and Sherafat are with the Dept of Physical Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Ebrahimi-Takamjani is with the Dept of Physical Therapy, Iran University of Medical Sciences, Tehran, Iran. Negahban is with the Dept of Physical Therapy, Mashhad University of Medical Sciences, Mashhad, Iran. Lali is with the Dept of Energy Engineering, Amirkabir University of Technology, Tehran, Iran. Mazaheri is with the MOVE Research Inst Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands.