Factor structure of trunk performance data for healthy subjects

Objective. To examine the factor structure of various measurements of trunk muscle performance for healthy subjects. Design. A total of 22 performance scores were collected and their univariate and multi-variate relationships were examined. Background. Extensive literature exists on the measurement of trunk performance data and the relationships between measurements but what needs to be collected to realize a true performance score remains unclear. Methods. Trunk muscle performance scores of 150 subjects (71 males and 79 females) were obtained on an Isostation B-200 Dynamometer. Twenty-two parameters measuring range of motion, isometric strength, velocity, and endurance on all three planes of motion were collected. The factor structures were constructed using Principal Components Analysis. Results. Clear-cut factor patterns (explained 96.3% of the total variance) suggests that the five-factor structure might be valid and appropriate for this population. The major loading on each factor indicated that: Factor 1 could be labeled as a static strength measure; Factor 2 as velocity; Factor 3 as flexibility; and Factors 4 and 5 as fatigue-resistance. Conclusion. No single mode of measurement can provide a good representation of a total trunk muscle performance.