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Methodological considerations in assessing countermovement jumps with handheld accentuated eccentric loading
Thomas E Bright1,2, John R Harry3, Jason Lake4
1Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK.
Sports Biomechanics
|July 11, 2024
Summary
Comparing motion capture and vertical ground reaction force (vGRF) for dumbbell (DB) release in countermovement jumps with accentuated eccentric loading (CMJAEL) showed significant variability. The vGRF method is promising for identifying DB release points using force platforms.
Area of Science:
- Biomechanics
- Sports Science
- Human Movement Analysis
Background:
- Accurate identification of key events, like dumbbell release, is crucial for analyzing complex movements such as the countermovement jump with accentuated eccentric loading (CMJAEL).
- Vertical ground reaction force (vGRF) analysis offers a potentially accessible method for kinematic event detection, but its agreement with motion capture and its influence on performance variable reliability require investigation.
Purpose of the Study:
- To compare the agreement between 3D motion capture and vGRF in identifying dumbbell (DB) release during CMJAEL.
- To examine how different vGRF analysis methods affect the reliability and magnitude of CMJAEL variables.
Main Methods:
- Twenty participants (10 male, 10 female) performed five maximal effort CMJAEL at 20% and 30% body mass with dumbbells.
- Dumbbell release timing was identified using both 3D motion capture and four different vGRF analysis methods: forward integration (FI), backward integration (BI), FI adjusted at bottom position (BP), and FI adjusted at DB release point (DR).
Main Results:
- Large variability was observed between 3D motion capture and vGRF methods for DB release timing across both loading conditions (CMJAEL20: -0.22 to 0.07 s; CMJAEL30: -0.29 to 0.14 s).
- The DR method yielded greater absolute reliability (CV% ≤ 7.28) compared to the BP method (CV% ≤ 13.74).
- Relative reliability was superior for the BP method (ICC ≥ 0.781) compared to the DR method (ICC ≥ 0.606).
Conclusions:
- The vGRF method shows potential for determining DB release timing when only force platforms are available.
- A combined approach using both forward and backward integration analyses of vGRF data is recommended for a comprehensive understanding of CMJAEL dynamics.
