Effect of backpack strap patterns on gait parameters in young adults at self-selected normal and fast walking speeds

Background The effects of backpack load on young adults’ gait parameters have received little attention. We previously reported that with a backpack load within 15% body weight (BW), young adults maintain their gait parameters at the expense of increased exertion during a 6-minute walk at self-selected normal walking speed. However, the effect of backpack strap pattern on gait parameters during faster walking or longer stride length has not been evaluated. Objective To determine the effect of different backpack strap patterns on gait parameters during a 12-minute walk test in young adults at self-selected normal and fast walking speeds. Design A crossover, self-controlled experimental study with repeated measures. Setting Department of Medical Rehabilitation, University of Nigeria. Participants A convenience sample of 24 healthy young adults (21.29 ± 1.20 years) who voluntarily signed an informed consent form, were able to wear a backpack on 1 and on both shoulders, were able to walk independently, and passed the physical activity readiness screening participated in this study. Methods Using a validated method of an observational gait analysis, each participant carried out a 12-minute walk test at self-determined normal and fast walking speeds, respectively. The effect of the following test conditions on the selected gait parameters was evaluated: normal and fast walking without load, and normal and fast walking with 10% and 20% BW backpack carried each on 1 and both shoulders. Main Outcome Measurement Stride length, stride time, velocity, cadence, and base of support were assessed by the equation definitions method of the velocity field diagram. Results At self-selected fast walking speed with 10% BW backpack load, stride time (P = .004) and cadence (P = .006) were significantly decreased when participants wore a double-strap backpack. At self-selected normal walking speed with 20% BW backpack load, cadence was significantly decreased with double-strap backpack carriage (P = .008). Cadence (P <.001), velocity (P <.001), and stride time (P <.001)were also significantly decreased at both conditions of single and double-strap backpack carriage of 20% BW respectively at fast walking speed. Conclusion Backpack strap patterns do not affect the gait parameters of young adults in a 12-minute bout of normal walking speed, provided that the load is less than 20% BW. However, a load up to 10% BW carried on a double strap causes a decrease in stride time and cadence when these individuals walk fast. Level of Evidence Not applicable.