The effect of lifting protocol on comparisons with isoinertial lifting performance

The purpose of the study was threefold: (1) to determine if protocol constraints affected scores on a box-lifting task; (2) to identify any differences in impact of protocol changes on male and female scores; and (3) to determine if these protocol changes affected correlations between maximal box-lifting scores and maximal scores obtained on isoinertial lifting tests. Two hundred and sixty nine participants (143 males and 126 females) completed maximal isoinertial lifting tests to 1.50 m and 1.80 m using a constrained protocol on an Incremental Lifting Machine (ILM). Participants were divided into three samples for completion of a maximal box-lifting task, with each sample using one of the following task protocols: (1) set style; (2) free style; and (3) ergonomically redesigned. Statistical analyses using general linear models procedures revealed that changes in protocol constraints significantly affected scores on lifting tasks. Removal of protocol constraints resulted in greater percentage increases in task scores for females than for males. Furthermore, disparate patterns between genders in task-test correlations were observed. It was concluded that the ILM was unable to predict female lifting capabilities accurately using any of the three protocols.