Reliability of manual marker placement in twodimensional kinematic analysis of single-leg landing, countermovement jump, and broad jump movement techniques

Abstract

Purpose: Manual two-dimensional (2D) kinematic analysis is widely used in research settings to evaluate jump techniques.
However, a gap remains in the literature regarding the reliability and validity of analyzing single-leg jumps. This study
examines a previously overlooked source of variability in manual 2D kinematic analysis, specifically: (a) the impact of manual
marker placement on anatomical landmarks and (b) the precision of visually identifying key movement time points in singleleg
countermovement jumps, single-leg broad jump push-off and landing phases, and single-leg drop landings.
Methods: Eighty professional handball players (age: 21.8±3.9 years; mass: 92.0±9.6 kg; stature: 1.90±.06 m) were video
recorded from lateral and frontal planes, and the analysis was manually performed using Kinovea software. The study
examined 2D kinematic variables, including the inclinations of the shin, thigh, and trunk segments relative to a vertical
reference line, as well as the joint angles between these segments during single-leg jumps. Reliability was assessed by
comparing (a) three repetitions of manual marker placement (MP) on anatomical landmarks and (b) three repetitions of
visual identification of key movement positions (KPs) during single-leg countermovement jumps, broad jump push-offs and
landings, and drop landings. KPs were defined by two criteria, based on either the lowest vertical position of the greater
trochanter (subjective) or peak vertical ground reaction force data (objective).
Results: The main findings of our study indicate that the reliability of marker placement and key position determination,
regardless of the test, plane of motion, leg, and criteria of key position determination is acceptable (ICC= .883–.999; CV<10
%).
Conclusions: These findings confirm that manual 2D kinematic analysis reliably evaluates movement techniques during
jumps and landings across different KP definitions and variable conditions.