Estimates of weight that subjects can lift frequently in functional capacity evaluations

Background and Purpose. This study was designed to determine whether the maximum weight that can be lifted during 33% to 67% of a workday (weight lifted frequently) can be accurately predicted from other data gathered during a functional capacity evaluation (FCE). The best equations for estimating weight lifted frequently were also identified, and the interrater reliability for measurements obtained during a 6-day FCE was calculated. Subjects. A retrospective chart audit was conducted of clients (36 female, 93 male) who completed 22-hour FCEs during a 6-day period. Ninety subjects had spinal problems, and 39 subjects had injuries not involving the spine. Subjects were randomly assigned to a model estimation group (n=109) or a cross-validation group (n=20). Method. A stepwise multiple regression analysis identified the best predictors of weight lifted frequently, with subjects lifting from four different heights. The resulting equations were used to predict the weight for the cross-validation group, and predicted weights were compared with observed weights using t tests and correlation coefficients. Results. Regression equations explained between 27.3% and 93.0% of the variance in weight, with standard errors of estimation between 1.09 and 5.72. No differences between the mean observed and predicted scores were found when estimates were based on weight only occasionally lifted (maximum weight that could be lifted up to 33% of a workday). Conclusion and Discussion. Estimates of weight lifted frequently based on weight lifted occasionally can be made, but the usefulness of these estimates is questionable. Clinicians should use caution when using estimations of weight lifted for return-to-work recommendations.