DISCRIMINATION BETWEEN MAXIMAL AND SUBMAXIMAL EFFORT IN LUMBAR DYNAMOMETRY

Objective. The purpose of this study was to investigate differences in consistency between maximum, preferred and a low level trunk performa nce. It was hypothesized that if maximum effort yielded consistent per formances while submaximal efforts were less consistent, a consistency parameter could be used to detect lack of effort. Design. Survey stud y. Methods. Eleven healthy subjects performed lumbar dynamometry measu rements (Isostation-B200) with maximum, preferred and low effort. A st andard protocol was used and velocity and static torque were measured. Five subjects performed three measurements with low effort and traine d the low effort level in between to determine the impact of training on consistency of submaximal performances. Coefficient of variations ( CV), percentage differences and onset slopes were used to determine co nsistency. Results. Results show that maximum and preferred effort are equally consistent. Maximum and low effort and preferred and low effo rt show small significant differences in CV for some velocity and isom etric torque parameters. No significant differences between the three performance levels were indicated for percentage differences and onset slopes. Training did not improve the consistency of the measurements. Conclusions. Small significant differences in CV were found between m aximal and submaximal effort. However the combination with the relativ ely large standard deviations make it unlikely that this parameter can be used for a reliable discrimination. Relevance To correctly assess performance deficits during lumbar dynamometry measurements, maximal p erformance must be demonstrated. Percentage differences and onset slop e are not useful in estimating maximum effort. The CV show small signi ficant differences between effort levels but large standard deviations make these parameters alone not useful in determining sincerity of ef fort. (C) 1998 Elsevier Science Ltd. All rights reserved.