Comparative analysis of postural control and vertical jump performance between three different measurement devices

Area of Science:

• Biomechanics
• Kinesiology
• Sports Science

Background:

• Accurate assessment of postural control (PC) and vertical jump performance (VJP) is crucial in sports science and rehabilitation.
• Portable balance assessment systems offer convenience but require validation against laboratory-grade equipment.
• The HUMAC Balance System (HBS) and Balance Trainer BTG4 (BTG) are such systems, necessitating comparison with a force platform (FP).

Purpose of the Study:

• To evaluate the concurrent validity of the HBS and BTG against a laboratory-grade FP for PC and VJP.
• To assess the test-retest reliability of the HBS and BTG for PC measurements.

Main Methods:

• Twenty-two participants performed double and single leg balance tests (eyes open/closed) and countermovement jumps (CMJ) on two occasions.
• Measurements were taken using the HBS, BTG, and a laboratory-grade FP.
• Intraclass correlation coefficients (ICC), Bland-Altman plots (BAP), standard error of measurement (SEM), and minimum detectable change (MDC) were used for analysis.

Main Results:

• Both HBS and BTG demonstrated good to excellent test-retest reliability for center of pressure (COP) path length (ICC = 0.80-0.95).
• The BTG showed good to excellent concurrent validity (ICC = 0.76-0.93) for PC and excellent validity for VJP (ICC = 1.0).
• The HBS exhibited moderate to good PC validity (ICC = 0.49-0.83) but poor VJP validity (ICC = 0.34), with systematic biases noted for both devices.

Conclusions:

• The BTG is a reliable and valid tool for assessing PC and VJP compared to a laboratory FP.
• The HBS is reliable for PC but has limitations in validity, particularly for dynamic movements like jumping.
• Due to significant differences and biases, the HBS and BTG should not be used interchangeably with each other or the FP.