Comparison of Values Generated During Testing of the Knee Using the Cybex II Plus^®and Biodex Model B-2000^®Isokinetic Dynamometers

Abstract

Forty-eight, healthy, adult, volunteer subjects (20 males, 28 females) who ranged in age from 21-46 years were studied during isokinetic testing of the knee joint. The same knee of each subject was tested at speeds of 60, 180, and 240°/sec on both the Biodex Model 8-2000" and the Cybex I 1 Plus' isokinetic dynamometers. The following variables were compared: peak torques, angle of peak torques, peak torque to body weight ratios, and flexion to extension ratios. Analysis of correlation coefficients showed statistically significant (p < 0.05) relationships between several pairs of values. However, results of paired t-tests revealed many statistically significant (p < 0.05) and nonuniform differences. The nonuniform differences between data generated by the two brands of isokinetic dynamometers indicated that clinicians should exercise caution when attempting to extrapolate test data from one machine to another.Isokinetics, a concept introduced in 1967 (36, 59), has gained popularity in a variety of clinical applications. lsokinetic technology is used to strengthen muscle and to assess dysfunction (19,20,29,39,42,43,56,60). Other uses for isokinetic dynamometers include passive stretching, preemployment screening, industrial rehabilitation, determining return to competition status, and research (1 1, 24, 45, 46 0190-601

Learning effect of isokinetic measurements in healthy subjects, and reliability and comparability of Biodex and Lido dynamometers

“…The highest reproducibility for measured isokinetic muscle strength is achieved at velocities below 100°s )1 (Baltzopoulos & Brodie, 1989;Thompson et al, 1989;Gross et al, 1991). When comparing the total work (in Watt), no significant difference was observed for knee or elbow, or for flexion or extension (data not presented).…”

“…Earlier studies comparing different isokinetic devices indicate difficulties in extrapolating results from one device to another (Thompson et al, 1989;Gross et al, 1991). A comparison of different isokinetic devices seems necessary since good intermachine reliability may reflect the validity of each instrument.…”

Eccentric and concentric isokinetic knee flexion and extension: a reliability study using the Cybex 6000 dynamometer.

“…2 [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Harding et al studied test-retest reliability of concentric peak and average torques of the knee extensor and flexor muscles using the Kin-Com. '3 Feiring el at measured peak torque and total work output of knee extensor and flexor muscles using the Biodex dynamo-meter.30 In both studies, high test-retest reliability interclass correlation coefficients (ICCs) were shown (ICCs 0-936 and 0-952, respectively).…”

Intramachine and Intermachine Reliability of the Biodex and Cybex®II for Knee Flexion and Extension Peak Torque and Angular Work

“…No statistical difference in peak torque was found for knee flexion and extension at 60°/sec and for knee flexion at 180°/sec. Thompson et al (13) reported that the intermachine reliability between Cybex and Biodex measurements of knee flexion and extension torque using the Pearson correlation coefficient ranged between 0.80 and 0.90, but that Cybex and Biodex measurements differed significantly for some variables as assessed by paired t-testing.…”