Effects of unilateral load carrying on gait initiation in younger and older adults

• Grant number: 25/11334-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Renato de Moraes
• Grantee: João Pedro Zeoti Silva
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The transition from upright standing to walking is one of the most important postural transitiontasks for maintaining individuals' functional independence. Unilateral load carrying can affect andhinder this task, altering biomechanical properties, such as the displacement of the center ofpressure and center of mass and dynamic balance. Thus, the aim of the present study is toinvestigate the effect of unilateral load carrying on gait initiation in younger and older adults. Thirtyhealthy individuals will be divided into two groups, one of younger individuals (18 to 30 years old)and the other of older individuals (65 to 80 years old), who will participate in the study. They willstand in an orthostatic position on two force platforms (one for each foot) and receive a verbalcommand to start walking and walk for approximately five meters while carrying a unilateral load(dumbbell in the dominant hand) according to two different initial step conditions (left or right) andthree different load conditions (no load; load of 4% of body mass; load of 8% of body mass). Forkinematic analysis, cameras from the motion analysis system will track 39 retroreflective markerspositioned at specific anatomical landmarks. The margin of stability, center of pressure andcenter of mass amplitude displacement, and maximum values of shoulder abduction, trunk andhead inclination toward the contralateral side of the transported load will be analyzed. Thedependent variables will be examined using analysis of variance (ANOVA) for three factors (2groups [younger and older individuals] x 3 load conditions [no load, 4%, and 8%] x 2 initial steps[right and left]) with repeated measures in the last two factors. The significance level will be setat 0.05. (AU)