The Impact of Lower Limb Dominance on Side-to-Side Symmetry in Daily Living and Sports-related Tasks

Evaluating side-to-side symmetry in the lower extremity has been significant in assessing injury risk and the success of rehabilitation programs. Considering limb dominance in the lower limbs is also important as limb dominance could influence symmetry measures. There is a need to assess symmetry, particularly in healthy populations, in tasks other than walking and running and establish how the dominant limb can impact symmetry. By evaluating symmetry in healthy adults, how the limbs function with respect to one another can be determined. Therefore, the first purpose of this study was to investigate the impact of lower limb dominance on walking and sitting-to-standing. Data was collected from 49 healthy older adults, aged 50-89 years old. Using loadsol® sensors (Novel, St. Paul, MN, USA), plantar loading data such as peak impact force and loading rate was calculated. Participants completed one sit-to-stand trial and three 10-meter walking trials, as these serve as prime examples of daily activities. The secondary purpose of this study was to assess the impact of lower limb dominance on athletic tasks like running and agility. The pedar-X® pressure insoles (Novel, St. Paul, MN, USA) were used to collect plantar loading data such as peak force, contact area, and contact time, from 10 athletes. Participants completed five t-drill trials and five agility ladder drill trials. The acceleration phase of the t-drill served as standard running. A mixed effects model was used to test if differences existed in various plantar loading outcome measures based on limb dominance. Non-parametric tests were used for non-normally distributed data. The statistical analysis determined that no significant differences existed between the dominant limb and non-dominant limb for the 10-meter walking trials peak impact force (p=0.245) or average loading rate (p=0.943). During the sit-to-stand trial, no significant differences existed in peak impact force (p=0.317) or average loading rate (p=0.943). For the agility ladder drill, the maximum force (p=0.427), contact area (p=0.517), or contact time (p=0.734) showed no significant differences. In the T-drill, the maximum force (p=0.385), contact area (p=0.571), or contact time (p=0.571) had no significant differences. These drive the conclusion that limb dominance does not need to be considered when assessing side-to-side symmetry.