Effects of carrying asymmetric bilateral loads on dynamic balance control during locomotion in young adults

• Grant number: 25/15356-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Renato de Moraes
• Grantee: Julia da Rocha Piazentin
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Walking is an essential motor activity that requires dynamic stability and the ability to makepostural adjustments based on the environment and task characteristics. Carrying loads alterswalking biomechanics by shifting the center of mass and demanding compensatory adaptations, which vary depending on the weight and position of the load. Asymmetrical bilateral loads, common in daily life, necessitate bodily adjustments to maintain dynamic balance, affecting biomechanics and arm-leg coordination during gait. Although studies have shown that unilateral loads impact postural stability, data on the effects of asymmetrical bilateral loads are limited, constraining our understanding of gait adaptations under these conditions. Investigating such scenarios may provide valuable insights into safer load-carrying strategies to enhance dynamic balance. Therefore, the aim of this study is to investigate the effects of carrying asymmetrical bilateral loads on dynamic balance during walking in young adults. Fifteen young adults (aged 18 to 30 years) will be recruited. After assessing upper limb dominance, 39 retroreflective markers will be placed on anatomical landmarks for kinematicanalysis. Movements will be captured using nine Vicon motion analysis cameras at a samplingfrequency of 200 Hz. Participants will walk at their preferred speed along a 9-meter walkwayunder four experimental conditions: (A) no load (control), (B) a 5 kg unilateral load on thedominant hand (unilateral transport), (C) a bilateral asymmetrical load with a light weight onthe non-dominant hand (light bilateral asymmetric transport - 5.4 kg on the dominant hand and0.4 kg on the non-dominant hand), and (D) a bilateral asymmetrical load with a heavier weighton the non-dominant hand (heavy bilateral asymmetric transport - 7 kg on the dominant handand 2 kg on the non-dominant hand). Each participant will perform five trials per condition, totaling 20 fully randomized trials. The margin of stability in the anteroposterior andmediolateral directions will be analyzed during the four central steps on the walkway. Statisticalanalysis will be based on the mean values from the five trials in each condition. A one-way repeated-measures analysis of variance (ANOVA) will be conducted across the four experimental conditions, with a significance level set at 0.05.