Isokinetic and functional parameters in patients following reconstruction of the anterior cruciate ligament

Both isokinetic testing and functional tests are commonly used to evaluate patients following reconstruction of the anterior cruciate ligament (ACLR). To determine the relationship of scores on an isokinetic test to scores on a variety of lower extremity functional tests ten healthy subjects and eleven ACLR patients at least six months after surgery performed knee isokinetic test at 60 and 180 deg/sec and three functional tests: leg vertical jump, single hop, and triple cross-over hop for distance. Correlation coefficients of isokinetic peak torque to body weight and functional testing were not significant at the P < 0.05 level in patients or control subjects, whi1e ratio of involved to uninvolved knee quadriceps isokinetics peak torque and Limb Symmetry Index (LSI) of functional test were significant at the P < 0.05 level (r=0.54 to 0.97). These results indicate a significant relationship between the LSI of various functional tests and side-to-side ratio of isokinetic testing just in ACLR patients. © 2005 - IOS Press and the authors. All rights reserved

Functional outcome of lower limb following anterior cruciate ligament reconstruction; a prospective clinical study

Background: Both isokinetic testing and functional tests are commonly used to evaluate anterior cruciate ligament reconstructed (ACLR) patients. The object of this study was to evaluate motor performance of the knee and determine the relationship of isokinetic test scores to scores on a variety of lower extremity functional tests. Methods: Ten healthy subjects and eleven ACLR patients at least six months after surgery performed the following: knee isokinetic tests at 60 and 180 deg/sec; three functional tests including leg vertical jump, single hop, and triple cross-over hop for distance. The International Knee Document Committee Subjective Knee Evaluation Form (IKDCSKEF) was used to score the self-assessment of each study participant. Paired T-test was used to compare the involved and uninvolved knee. Pearson correlation coefficients were used to determine the relationship between the scores on the isokinetic test and functional tests. Significance was determined by P<0.05. Results: IKDCSKEF score was significantly lower in patients than control subjects. Quadriceps peak torque and functional test scores were significantly lower in the involved knee of the ACLR subjects compared to the uninvolved knee. Correlation coefficients of isokinetic peak torque to body weight and functional testing were not significant in patients or control subjects, whi1e the limb symmetry index (LSI) of the quadriceps isokinetics peak torque to body weight and the LSI of the functional tests were significant (r = 0.54 to 0.97). Conclusion: These results indicate a significant relationship between the LSI of various functional tests and the LSI of isokinetic testing among ACLR patients. Thus, in situations where an isokinetic dynamometer is not available, the LSI of functional tests can be used to estimate quadriceps deficiency for ACLR patients. © 2008, Tehran University of Medical Sciences. All rights reserved

Study of the effect of contact force model on the dynamic response of mechanical systems with dry clearance joints : computational and experimental approaches

The main objective of this work is to present a computational and experimental study on the contact forces developed in revolute clearance joints. For this purpose, a well-known slider-crank mechanism with a revolute clearance joint between the connecting rod and slider is utilized. The intra-joint contact forces that generated at this clearance joints are computed by considered several different elastic and dissipative approaches, namely those based on the Hertz contact theory and the ESDU tribology-based for cylindrical contacts, along with a hysteresis-type dissipative damping. The normal contact force is augmented with the dry Coulomb’s friction force. In addition, an experimental apparatus is use to obtained some experimental data in order to verify and validate the computational models. From the outcomes reported in this paper, it is concluded that the selection of the appropriate contact force model with proper dissipative damping plays a significant role in the dynamic response of mechanical systems involving contact events at low or moderate impact velocities.Fundação para a Ciência e a Tecnologia (FCT