A comparison of the characteristics of preferred low-back motion of normal subjects and low-back-pain patients.

The purpose of this study was to compare the preferred low-back motion of normal subjects and low-back-pain patients. Each subject performed a maximum isometric flexion trial followed by repeated flexion and extension against a relative resistance set at 50% of the recorded maximum flexion isometric torque. The subjects were instructed to move at their own pace through their preferred movement range until either exhaustion or for 120s. The results showed that the groups differed significantly in their preferred motion characteristics, although the performances were equally consistent.

Reliability of reciprocal isokinetic testing of the knee extensors and flexors.

This study was conducted to assess the reliability of torque measurements across different trials and different test sessions. Each trial consisted of three maximal, reciprocal contractions of the knee extensors and flexors at test velocities of 60 and 180 degrees /sec. Three trials were conducted on each of three test sessions, with each session separated by 48 hours. Results indicate that reliability of reciprocal isokinetic testing of the knee can be improved by 1) testing in more than one occasion, 2) testing more than three trials during a single session if testing during more than one session is impossible, and 3) allowing the subject to become familiar with the isokinetic test procedure and to warm up adequately. Data obtained in this study indicated performance variability was predominantly associated with between subject differences and secondarily related to within subject changes over trials and days. Dynamometer calibration remained stable across all test sessions, indicating that the method was reliable for recording torque output during all testing procedures. J Orthop Sports Phys Ther 1991;14(3):121-127.

The characteristics of preferred low-back motion.

The purposes of this study were to identify the loading effects on preferred low-back motion and to determine the consistency of preferred low-back motion. Fifteen male and female volunteers served as subjects. Each subject performed four trials of repeated flexion and extension until either the subject became exhausted or for 120s. Each trial corresponded to a relative load of 0, 25, 50, and 75% of the subject's prerecorded maximum torque in isometric flexion. The subjects were instructed to perform the movements at their own pace and through their preferred movement range. The results showed that above the 25% resistance level, the increased loads were accompanied by decreased velocities, with the changes due to the cycle temporal characteristics. The increased loads also resulted in decreased cycle excursions, with these changes due to reductions in the extension endpoints. With increased resistances the descriptive parameters became more variable, with a trend of increased variability toward the latter portion of a trial.

Trends in isodynamic and isometric trunk testing on the Isostation B200.

A total of 200 men and 100 women with no prior history of low back pain were evaluated by a series of 6 different tests on the Isostation B200 (Isotechnologies, Hillsborough, NC, U.S.A.) to obtain normative data on the functional performance of the low back. The data collected in this descriptive study were analyzed for significant patterns and differences between an asymptomatic male and female population. In the range of motion test, male subjects demonstrated greater range of motion in all planes; however, values for women showed greater standard deviations. In the maximum isometric test, male torque values exceeded female values, but male values showed greater standard deviations. A rank order of parameter values was made from values recorded during repetitive tests for both men and women. Coupling patterns observed during single-plane repetitive tests allowed secondary and tertiary axes to be identified. Torque values generated over the set resistance were calculated for the repetitive tests conducted in three different planes. A positive curvilinear, concave downward relationship was observed when these values were plotted against the predetermined resistance settings. Future research will study the effect resistance settings on maximum torque output and the role of velocity as a key discriminator between normal and abnormal populations.

Abnormal patient data for the isostation b100.

The purpose of this study was to document the torque and range of motion parameters generated on the lsostation B100 by subacute low back pain patients 2-7 days postinjury. Abnormal values found in this study were compared to normal values found in a previous study. One hundred and forty-three males and 29 females were evaluated in a predetermined combination of three tests. These included: a) range of motion in each plane, b) repetitive flexion/extension, and c) a modified maximum lift. The results of the investigation indicate significant differences (p = 0.01) in parameters generated by the lsostation B100 between normals and abnormals in each test. Discrepancies between normals and abnormals were greater for females than males. Torque output was most significantly affected (p = 0.01) in the axis of flexion/extension for both males and females. Range of motion was most significantly affected (p = 0.01) in extension for both males and females. In test b (the flexion/extension repetitive test), the most significant (p = 0.01) percent reduction in torque and range of motion values occurred in the secondary axis of rotation and lateral flexion rather than flexion/extension. This reduced crossover activity, crosstalk, may be an indicator of guarded effort, poor effort or both. The lsostation B100 is a valuable tool as it provides objective information on torque output and range of motion for the low back.J Orthop Sports Phys Ther 1988;10(4):121-133.

Normative Data for lsostation B100.

The purpose of this study was the gathering of normative data on the low back for normal males and females utilizing the lsostation BlOO (Isotechnologies, Hillsborough, NC). Included in the study were 110 males and 50 females who were evaluated in a series of four tests. Data were gathered three-dimensionally for the following: a) range of motion with light resistance in flexion/extension, rotation to right and left, and lateral flexion to right and left; b) repetitive flexion/extension for a 20-second time period at a light resistance; c) repetitive flexion/extension for 20 seconds with a heavy resistance; and d) a modified maximum lift. In all tests, males had higher values than females; however, females had greater standard deviations than males in all tests. Thus, there were some females who had higher values than some males. There were weak correlations between peak torque output in the flexion/extension axes in relation to height and body weight in tests a and b where light resistance was used. For tests c and d the correlation improved. Also of interest, consistent activity was noted on the torque and range of motion graphs of rotation and lateral flexion during repetitive flexion/extension tests. These patterned torques and ranges of motion noted in rotation and lateral flexion coincide with the graph patterns of flexion/extension. This accessory motion may be indicative of effort or pathology. Crossover activity needs to be researched further as a possible determinant of effort levels and three-dimensional reproducibility. J Orthop Sports Phys Ther 1987;9(4):141-155.