Criterion Validity and Reliability of a New Medicine Ball Rotational Power Test

Area of Science:

• Sports Science
• Biomechanics
• Strength and Conditioning

Background:

• Assessing rotational power is crucial for athletic performance.
• Existing field-based medicine ball tests may lack validity and reliability.
• 3-dimensional motion capture (MoCap) serves as a criterion reference standard.

Purpose of the Study:

• To evaluate the criterion validity and reliability of two medicine ball rotational power tests.
• To compare a novel radar-based velocity test (MB vel) against a traditional distance-based test (MB dis) using MoCap.
• To identify the optimal field-based assessment for rotational power.

Main Methods:

• Fifteen professional female cricketers performed maximal throws with a 2kg medicine ball.
• Measurements included radar velocity (MB vel), tape measure distance (MB dis), and 3D MoCap.
• Statistical analyses involved ICCs, Bland-Altman plots, linear regression, and Pearson's correlation.

Main Results:

• MB vel demonstrated excellent validity (ICC=0.97) and reliability (ICC=0.94) compared to MoCap.
• MB vel showed minimal bias (-0.09%) and high precision (1.49%) for overall and side-specific measurements.
• MB dis exhibited poor validity (ICC=0.38), significant bias (12.43%), and lower reliability (ICC=0.72).

Conclusions:

• The MB vel assessment is a valid and reliable field-based method for measuring rotational power.
• MB vel enables accurate profiling, benchmarking, and quality assessment of rotational power performance.
• The traditional MB dis test is less accurate and reliable for assessing rotational power.