Optimisation of applied loads when using the two-point method for assessing the force-velocity relationship during...

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• The force-velocity (F-V) relationship is crucial for understanding athletic performance.
• Accurate assessment of F-V parameters is essential for training prescription.
• Existing multi-point methods can be time-consuming and fatiguing.

Purpose of the Study:

• To compare the reliability and validity of different two-point methods for determining F-V parameters.
• To evaluate the acute effects of vertical jump testing on unloaded jump height.
• To identify an optimal, efficient method for assessing the F-V relationship.

Main Methods:

• Eighteen male participants performed squat jump (SJ) and countermovement jump (CMJ) exercises against five external loads (17-75 kg).
• F-V relationships were modeled using five two-point methods (e.g., 0-75 kg) and one multiple-point method (0-75 kg).
• Unloaded jump height was measured pre- and post-testing to assess fatigue.

Main Results:

• The most distant two-point method (0-75 kg) demonstrated comparable reliability (CV < 12.1%, ICC > 0.72) and high validity (r > 0.91) to the multiple-point method.
• Reliability and validity decreased as the distance between loads in two-point methods decreased.
• Unloaded jump height significantly decreased post-testing (p < 0.05), indicating acute fatigue.

Conclusions:

• The two-point method using distant loads (0-75 kg) is a reliable and valid approach for assessing the F-V relationship in vertical jumps.
• This method is more practical and less fatiguing than multi-point assessments.
• The findings support the use of the 0-75 kg two-point method for efficient F-V profiling in athletes.