This study aimed to evaluate the validity and reliability of the BEI under different gait conditions (low-speed [LS], comfortable-speed [CS], high-speed [HS], and comfortable-speed with a cane [CS-C]) in healthy young adults, and to compare the BEI with traditional measures to determine whether the BEI more accurately represents walking efficiency.
Twenty healthy young adults (mean age: 25.9 ± 2.7 years; 11 males, 9 females) participated. Each participant wore an actigraphy device (HJA-750C; OMRON HEALTHCARE, Japan) at the L3 spinous process level and electrocardiogram electrodes. They were assessed while walking for two minutes under four conditions: LS, CS, HS, and CS-C. CS was set as the speed each participant used during their usual social activities. The gait velocities of other conditions were determined using the Global Rating of Change (GRC) scale, a subjective scale ranging from -5 to +5, with CS set as the base at 0. LS and HS were set at -3 and +3, respectively. For CS-C, participants walked with a cane at the same speed as CS. All measurements were repeated on a different day to confirm their reliability. The BEI was calculated as GV / estimated METs (eMETs). The eMETs were derived from a three-axis accelerometer actigraphy device using a proprietary algorithm and have been reported to closely approximate actual METs. The Physical Cost Index (PCI), a traditional measure of walking efficiency, was calculated using GV / ΔHR. One-way ANOVA for normal data and Kruskal-Wallis test for non-normal data were used to assess validity, and Intraclass Correlation Coefficient (ICC) to assess reliability.
The GV values for each condition were: LS, 0.69 ± 0.12m/s; CS, 1.25 ± 0.08m/s; CS-C, 1.18 ± 0.07m/s; and HS, 1.86 ± 0.14m/s, indicating comparability between CS and CS-C. The BEI values were: CS, 20.5 ± 0.8; CS-C, 19.7 ± 0.9; LS, 16.9 ± 1.1; and HS, 18.7 ± 1.1. There were significant differences across all conditions (p 0.01), especially with CS showing the highest value. The PCI values were: LS, 4.1 ± 2.7; CS, 3.8 ± 1.2; CS-C, 3.3 ± 1.1; and HS, 2.3 ± 0.6. There were significant differences only in HS (p 0.05), which was lower than the other conditions. The reliability of BEI was high (ICC: 0.81), whereas PCI had low reliability (ICC: 0.22).
The findings suggest that BEI can differentiate walking efficiency across various gait conditions, particularly showing that CS was the most efficient. Furthermore, the BEI showed high reliability, making it a valuable tool for assessing walking efficiency.
The BEI may allow clinicians to more accurately assess an individual's walking efficiency and guide appropriate rehabilitation treatments for people with various gait disorders.
Walking Efficiency
Gait Conditions
