Acceptable maximum effort (AME). A psychophysical measure of strength in back pain patients

A new quantitative method for measuring functional abilities of chronic low-back pain patients is introduced. The method is based upon a psychophysical model referred to as acceptable maximum effort (AME). AME is the highest level of voluntary effort that a person can achieve without inducing unacceptable pain. In the current study, the AME method was applied to strength measurement. By use of a static strength measurement procedure, arm, leg, shoulder, back, and composite strengths were assessed upon admission to and discharge from a 4-week, nonsurgical comprehensive pain treatment program. The reliability of the AME method for each strength measure was assessed. In addition, the method was used to evaluate pre- to post-treatment changes in strength. Results indicate the AME method to be highly reliable and useful in determining treatment outcome. Reliability coefficients for all strength measures were above .90. The results are discussed in terms of their implications for standardized functional ability measurement in the area of chronic pain.