Enhancing Digital Video Analysis of Bar Kinematics in Weightlifting: A Case Study

Abstract

Dæhlin, TE, Krosshaug, T, and Chiu, LZF. Enhancing digital video analysis of bar kinematics in weightlifting: a case study. J Strength Cond Res 31(6): 1592–1600, 2017—Weightlifting technique can be objectively assessed from two-dimensional video recordings. Despite its importance, participants' bar trajectories in research involving the snatch or clean exercises are often not reported, potentially due to the time required to digitize video. The purpose of this investigation was to evaluate the use of a light-emitting diode (LED)-based marker, digital video, and open-source software to automatically track the bar end during weightlifting exercises. A former national-level weightlifter was recorded with a digital video camera performing the snatch, clean and jerk, and squat exercises. An LED-based marker was placed on the right end of the bar. This marker was automatically tracked using 2 open-source software programs to obtain vertical and horizontal position coordinates. The LED-based marker was successfully auto-tracked for all videos over a variety of camera settings. Furthermore, the vertical and horizontal bar displacements and vertical bar velocity were consistent between the 2 software programs. This study demonstrates that an LED-based marker can be automatically tracked using open-source software. This combination of an LED-based marker, consumer camera, and open-source software is an accessible, low-cost method to objectively evaluate weightlifting technique.

Survey of Barbell Trajectory and Kinematics of the Snatch Lift from the 2015 World and 2017 Pan-American Weightlifting Championships

“…The methods used in this study demonstrate an inexpensive, time-efficient, and user-friendly method to conduct technique analysis. The error and reliability of the methods herein can be improved by optimizing camera setup and specifications [23,34,58], controlling conditions during data collection (e.g., barbell placement [59] and lighting [60]), and selecting appropriate data smoothing or filtering techniques [60][61][62]. Coaches may also elect to use a uniform calibration factor given consistent camera and platform setup to further improve time-efficiency of video analysis.…”

Concurrent Validity and Reliability of the Load-Velocity Relationship to Predict the One-Repetition Maximum during Three Weightlifting Derivatives

“…Barbell trajectory auto-tracking analyses were carried out by the Kinovea software (Experimental Version 0.8.25-x64) (Daehlin, Krosshaug, & Chiu, 2017;Garhammer & Newton, 2013). Kinovea is an appropriate option as it is easy-to-use, requires no experience to obtain accurate and reliable measurements, is a portable and free tool (i.e.…”

Distribution of lower extremity work during clean variations performed with different effort

“…The optical axis of the camera was positioned 0.80 m above the ground 15 m from the right end of the barbell (Olympic competition bar, Iron Grip, Santa Ana, CA, USA), capturing a sagittal plane view. An LEDmarker was placed on the right end of the barbell (Daehlin, Krosshaug, & Chiu, 2017).…”

“…http://physlets.org/tracker/; accessed October 6, 2015) to examine barbell trajectory, as described by Daehlin et al (2017). Horizontal and vertical position coordinates were smoothed using a 5-point moving arc polynomial (Wood, 1982).…”