Matheson L, Mooney V, Holmes D, Leggett S, Grant J, Negri S. University of California San Diego, 1993.


The measurement of change as a consequence of rehabilitation is a necessary component of the evaluation of program efficacy. There are many measures of change that can be considered, some of which are more closely associated with functional improvement than others. To the degree that a measure is related to improvement in function, it can be utilized as an index of program effectiveness.


Data were collected on 54 patients referred for treatment after low back injury (29 females and 25 males). Treatment occurred in one 60-minute session two times each week over an eight-week period. Each treatment session involved the use of the MedX Lumbar Extension machine and seven variable resistance exercise units, including leg extension, leg flexion, hip extension, hip flexion, lat pull-down, seated row, and overhead press. In addition, each patient underwent 10 minutes to 20 minutes of cardiovascular conditioning using a bicycle ergometer, stairmaster, or exercise treadmill.

Data were collected on several variables prior to and at the conclusion of treatment. Isometric back strength was measured through the use of the MedX Lumbar Extension machine. Lift capacity was measured through the use of the EPIC Lift Capacity test. Self-perception was measured through the use of the Spinal Function Sort and Oswestry Questionnaire. Pain ratings were collected using a 10-point analog scale.

In order to isolate any possible reactivity to the EPIC Lift test, patients were randomly assigned to one of two groups prior to evaluation. The first group underwent lift capacity testing on a pre-treatment and post-treatment basis. The second groups underwent lift capacity testing on only a post-treatment basis.

No significant differences were found between the experimental groups. Thus, in this sample, reactivity of the EPIC Lift Capacity test is not an issue.

A stepwise multiple regression procedure which considered change in lift capacity as the dependent variable and change in isometric back strength, pain rating, Oswestry score, and rating of perceived capacity was undertaken. Two variables entered the equation. Change in rating of perceived capacity accounts for 61% of the variance in change in lift capacity. Change in isometric back strength accounts for an additional 17% of the variance. After these two variables were entered, neither the pain difference score or the Oswestry difference score was able to make a significant contribution to the prediction equation.