Quantifying Jump Height Using Markerless Motion Capture with a Single Smartphone

TL;DR

This study demonstrates that a single smartphone can accurately measure countermovement jump height using markerless motion capture, offering a simple and calibration-free alternative to traditional methods.

Contribution

It introduces a method for measuring jump height with a single smartphone using markerless motion capture without manual segmentation or camera calibration.

Findings

ICC between 0.84 and 0.99 for jump height measurement

No manual segmentation or camera calibration needed

Promising accuracy for practical applications

Abstract

Goal: The countermovement jump (CMJ) is commonly used to measure lower-body explosive power. This study evaluates how accurately markerless motion capture (MMC) with a single smartphone can measure bilateral and unilateral CMJ jump height. Methods: First, three repetitions each of bilateral and unilateral CMJ were performed by sixteen healthy adults (mean age: 30.87$\pm$7.24 years; mean BMI: 23.14$\pm$2.55 $kg/m^2$) on force plates and simultaneously captured using optical motion capture (OMC) and one smartphone camera. Next, MMC was performed on the smartphone videos using OpenPose. Then, we evaluated MMC in quantifying jump height using the force plate and OMC as ground truths. Results: MMC quantifies jump heights with ICC between 0.84 and 0.99 without manual segmentation and camera calibration. Conclusions: Our results suggest that using a single smartphone for markerless motion capture is promising. Index Terms - Countermovement jump, Markerless motion capture, Optical motion capture, Jump height. Impact Statement - Countermovement jump height can be accurately quantified using markerless motion capture with a single smartphone, with a simple setup that requires neither camera calibration nor manual segmentation.