IMU Step Detection

Detect heel-strikes from a vertical-axis accelerometer signal, then read off cadence, step time, gait symmetry, and step length.

Load data

📊 Sample accelerometry

CSV or Excel file

Acceleration column

Sample rate (Hz)

Vertical axis acceleration recommended. Positive = upward for heel-strike detection.

Filter

Low-pass filter before detection

Cutoff frequency (Hz)

Removes high-frequency noise while preserving heel-strike peaks. Typical: 15-25 Hz.

Peak detection

Threshold (% of max)

Fraction of dynamic range above baseline. Higher = stricter. Recommended: 30-50%.

Min gap between steps (ms)

Prevents double-detection. Typical walking: 400-600 ms. Running: 200-350 ms.

Step length estimation

Estimate step length

Leg length (m)

Greater trochanter to floor. Used in Grieve & Gear (1966) model.

Method

Status

Load a file to begin.

References

Step length estimation: Grieve, D.W., & Gear, R.J. (1966). The relationships between length of stride, step frequency, time of swing and speed of walking for children and adults. Ergonomics, 9(5), 379-399. · Weinberg, H. (2002). Using the ADXL202 in pedometer and personal navigation applications. Analog Devices AN-602 application note (step length ∝ ⁴√(a_max−a_min); K is a subject/device tuning constant, here 0.5).

Symmetry index: Robinson, R.O., Herzog, W., & Nigg, B.M. (1987). Use of force platform variables to quantify the effects of chiropractic manipulation on gait symmetry. Journal of Manipulative and Physiological Therapeutics, 10(4), 172-176.

IMU gait analysis: Tao, W., Liu, T., Zheng, R., & Feng, H. (2012). Gait analysis using wearable sensors. Sensors, 12(2), 2255-2283.

IMU Step Detection

Acceleration signal

Step-by-step