A simple method for quantifying jump loads in volleyball athletes.

Area of Science:

• Sports Science
• Biomechanics
• Wearable Technology

Background:

• Accurate measurement of external load is crucial for optimizing training and preventing injury in elite athletes.
• Volleyball involves numerous jumps, making jump count and vertical displacement key performance indicators.
• Existing methods for load quantification can be time-consuming and require specialized equipment.

Purpose of the Study:

• To validate a commercial wearable device, the Vert, for measuring vertical displacement and jump count in volleyball athletes.
• To propose a method for quantifying external training and match load using wearable device data.

Main Methods:

• A validation study comparing the Vert device to laboratory motion analysis for vertical displacement.
• Assessing jump count accuracy using video analysis for precision and recall.
• Proposing a load index (LdIx) algorithm based on jump count and kinetic energy.

Main Results:

• The Vert device showed good to excellent correlation (r=0.83-0.97) with 3D motion analysis for vertical displacement.
• Excellent precision (0.995-1.000) was observed for jump counting, with higher false negatives (lower recall: 0.814-0.930).
• The Vert device offers a practical solution for data collection without extensive analysis.

Conclusions:

• The Vert wearable device is a valid tool for measuring vertical displacement and jump count in elite junior volleyball athletes.
• The device facilitates efficient data collection, enabling better quantification of athlete load.
• The proposed LdIx algorithm can utilize Vert data to quantify external load during training and competition.