Foot-Placed Inertial Measurement Units Are Valid Against Shank-Placed Units When Measuring Temporospatial Running...

Running is a popular form of physical activity but can increase an individual's lower-extremity injury risk. Running gait analysis via inertial measurement units (IMUs) is a method for collecting important gait data that is related to developing lower-extremity injuries, such as increased load from low step rate (SR), and long stride length (SL). IMU data can be derived from both foot- and shank-placed IMUs, but foot-placed sensors (RunScribe IMUs) need validation against shank-placed sensors.

Determine criterion validity of RunScribe foot-placed IMUs against MyoMotion shank-placed IMU for SR and SL.

cross-sectional laboratory study.

Nine participants (5 males, 4 females; age: 28.33 [5.78]; height: 1.75 [0.11]; mass: 74.06 [16.24]) volunteered for our study. Following a 5-minute warm-up, participants ran on a treadmill for 5 minutes at a self-selected speed. After ∼2.5 minutes, MyoMotion data were collected for 10 seconds. The RunScribe IMUs collected data throughout the full duration of the run. Criterion validity of SR and SL between the foot- and shank-placed IMUs was determined using bivariate Pearson correlations, intraclass correlation coefficients (3,1), and Bland-Altman plots with 95% limits of agreement analysis.

A very strong correlation for SR (r = .90, N = 9, P ≤ .001), and a strong correlation for SL (r = .80, N = 9, P < .001) were found between the foot and shank-placed IMUs. Excellent reliability was found for SR (intraclass correlation coefficient = .91, P ≤ .001, 95% CI, .639-.978), and good reliability was found for SL (intraclass correlation coefficient = .800, P = .003, 95% CI, .340-.951) between the foot and shank-placed IMUs. The mean difference of SR and SL was -2.111 and -0.142, respectively, indicating good agreement between the foot and shank-placed IMUs.

Foot-placed RunScribe IMUs are a valid alternative for measuring SR and SL compared with shank-placed IMUs.