An Evaluation of Symmetries in Ground Reaction Forces during Self-Paced Single- and Dual-Task Treadmill Walking in the Able-Bodied Men

Abstract

Gait is a complex autonomous activity that has long been viewed as a symmetrical locomotion, even when it adapts to secondary concurrent attention-demanding tasks. This study aimed to evaluate the symmetry of the three ground reaction forces (GRFs) in able-bodied individuals during self-paced treadmill walking with and without concurrent cognitive demands. Twenty-five male participants (age: 34.00 ± 4.44 years) completed two gait assessment sessions, each of whom were familiarized with the walking trials during their first session. Both sessions involved six-minute self-paced treadmill walking under three conditions: single-task walking and walking while concurrently responding to auditory 1-back and 2-back memory tasks. The symmetry of the GRFs was estimated using a nonlinear approach. Changes in the symmetry and walking speed across conditions in both sessions were assessed using inferential statistics. Results demonstrated that the three GRFs deviated from perfect symmetry by ≥10%. Engaging working memory during walking significantly reduced the symmetry of the vertical GRF (p = 0.003), and its detrimental effects on walking speed were significantly reduced in the second session with respect to the first session (p < 0.05). The findings indicate imperfect gait symmetry in able-bodied individuals, suggesting that common perceptions of gait symmetry should be reconsidered to reflect its objective importance in clinical settings.

Does treadmill workstation use affect user’s kinematic gait symmetry?

“…In our study, typing speed, a cognitive performance measure, was reduced during treadmill walking. Walking while performing a computer typing task corresponds to a dual-task scenario that contributes to an increase in workload [ 32 , 36 , 37 ]. However, typing accuracy was not affected during treadmill walking.…”

“…Furthermore, a classical method known as dual-task paradigm has been employed to address the interrelation between walking and cognition [ 36 ]. Recent studies on a dual-task paradigm examining gait asymmetries in able-bodied individuals found that gait asymmetries arise under specific constraints in healthy people as an adaptation to task requirements [ 36 , 37 ]. In addition, asymmetrical behavior of the lower limbs during able-bodied ambulation was found to reflect natural functional differences between the lower extremities [ 38 ].…”

Gait stability characteristics in able-bodied individuals during self-paced inclined treadmill walking

“…Meanwhile, they allow the data collection of hundreds of continuous strides during walking within a virtual reality (VR) environment 17,18,20 . Recent evidence supports that self-paced walking within a VR environment would facilitate a natural walking experience, which in turn enables the collection of valid gait parameters that resemble overground walking [17][18][19][20] . To improve the utilisation of these instrumented treadmills, a Human Body Model (HBM) has been developed and validated to allow the estimation of kinetic and kinematic parameters in real-time 21 .…”

“…Fortunately, technological advancements in instrumented treadmills can be advantageous to overcome many limitations in previous literature. These cutting-edge treadmills are laboratory-based, designed with split belts, and equipped with two embedded force plates 17 . They differ from conventional treadmills as they automatically adjust the belt speed in real-time to match the participant's self-paced walking 18,19 .…”

“…Meanwhile, they allow the data collection of hundreds of continuous strides during walking within a virtual reality (VR) environment 17,18,20 . Recent evidence supports that self-paced walking within a VR environment would facilitate a natural walking experience, which in turn enables the collection of valid gait parameters that resemble overground walking [17][18][19][20] .…”