Abstract
The purpose of this study was to investigate concentric quadriceps peak torque value using the Cybex II (Cybex, Ronkonkoma, NY), Biodex B-2000 (Biodex, Shirley, Ny) and Kinetic Communicator (KinCom; Chattex, Hixson, TX) 500H. Fourteen subjects (average age 20.14±0.36 years) were tested on their dominant leg on each of the three devices. This study concentrated on two sets of data: (1) highest peak torque, comparing the highest concentric peak torque value produced on each machine; and (2) clinical peak torque comparing the highest peak torque values produced on the Cybex and Biodex with the mean peak torque for the given number of repetitions performed on the KinCom. Subjects were randomly assigned to begin testing on one of the three machines. At least 72 hours of rest occurred between each of the three testing sessions. Subjects first warmed up on a stationary bike for 5 minutes. Subjects then warmed up on the isokinetic device at approximately 25% maximal effort. Three concentric maximal effort extensions were then performed (60 deg/sec). After a minute of rest, each subject was instructed to perform three more concentric maximal effort extensions which were used in the data collection. The speed was increased to 240 deg/sec and the same procedure was followed. Analysis of variance (AN OVA) and posthoc results comparing raw data showed a significant difference between all devices at 60 deg/sec. At 240 deg/sec a significant difference was only noted between the Cybex and Biodex. ANOVA and posthoc tests comparing clinical data at speeds of 60 and 240 deg/sec showed a significant difference when comparing the Biodex to either of the other two dynamometers. Pearson product-moment correlation coefficient ranged from 0.84 to 0.97. This result indicated a strong relationship between the three dynamometers. The authors concluded that caution should be used when comparing the results from one isokinetic dynamometer to the results of a different model dynamometer.