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.

Effect of single and double backpack strap loading on gait and perceived exertion of young adults.

BACKGROUND/AIM: Backpack effect posture, walking and physiological costs but there is dearth of literature on effects of backpack strap (1 versus 2 straps) on gait and perceived exertion among young adults. We determined the influence of type of backpack shoulder strap on gait parameters and perceived exertion of young adults in a free-living normal walking speed. METHODS: Twenty-five young adults with a mean age of 22 years underwent a self-selected normal speed walking for six minutes each under 3 testing conditions: without a backpack; with 1 strap; and with 2 straps. Selected gait parameters and perceived exertion were assessed. RESULTS: There were no significant difference in stride length, stride time, step length, step time, gait speed, and cadence among the three walking conditions. However, perceived exertions were significantly higher when the backpack was carried with 15% irrespective of 1 strap or 2 straps. CONCLUSION: Momentary carriage of a backpack either on 1 strap or 2 straps does not appear to influence gait phases. However, this short bout of normal walking appear to increase perceived exertion in young adults irrespective of whether the backpack is wore on single or double shoulder strap.