Biomedical subjects

H J Yack

Publications and source records attributed to H J Yack.

21 records · Page 2Linked to original sources

PubMed1984

Techniques for clinical assessment of human movement.

Conventional, clinically available techniques used in the measurement and analysis of human movement are overviewed in the first part of the article. I examine the data produced by these techniques in terms of information content and potential usefulness in assessing human movement. Consideration is given to the observation process and to specific techniques for determining temporal and spatial, kinematic, and kinetic variables. The techniques examined document the end result of the movement process, which limits the information content to a descriptive level. Of these descriptive variables, the temporal and spatial variables have the advantage of being much easier to obtain and interpret. In the last part of the paper, I review more complex methods of analysis. These methods enable the determination of mechanical energy levels and joint moments, which exposes the underlying biomechanics of the movement. Such information can be related to the causes of the movement disorder and can help to diagnose the abnormal movement pattern.

Acceleration↗

PubMed1981

Electromyographic activity recorded from an unexercised muscle during maximal isometric exercise of the contralateral agonists and antagonists.

The purpose of this study was to determine if integrated electromyographic activity recorded from an unexercised muscle during contralateral exercise was dependent upon the contralateral muscle (agonist or antagonist) being exercised and upon the position of the unexercised limb. Twenty normal subjects participated in the study. Electromyographic activity was recorded, using surface electrodes, from the right rectus femoris and the right vastus lateralis muscles during four experimental conditions. Statistical analysis revealed that 1) integrated electromyographic activity recorded from the rectus femoris muscle during contralateral, isometric exercise was not significantly influenced by the position of the unexercised knee or the exercised contralateral muscle and 2) integrated electromyographic activity recorded from the vastus lateralis muscle during contralateral, isometric exercise was significantly greater when the unexercised knee was initially positioned in 10 degrees of flexion and the contralateral agonists were exercised. Integrated electromyographic activity recorded during contralateral exercise appeared to be related to the associated movement of the unexercised limb.

Adult↗

PubMedDate not supplied

Comparison of closed and open kinetic chain exercise in the anterior cruciate ligament-deficient knee.

The purpose of this study was to quantify the amount of anterior tibial displacement occurring in anterior cruciate ligament-deficient knees during two types of rehabilitation exercises: 1) resisted knee extension, an open kinetic chain exercise; and 2) the parallel squat, a closed kinetic chain exercise. An electrogoniometer system was applied to the anterior cruciate ligament-deficient knee of 11 volunteers and to the uninvolved normal knee in 9 of these volunteers. Anterior tibial displacement and the knee flexion angle were measured during each exercise using matched quadriceps loads and during the Lachman test. The anterior cruciate ligament-deficient knee had significantly greater anterior tibial displacement during extension from 64 degrees to 10 degrees in the knee extension exercise as compared to the parallel squat exercise. In addition, the amount of displacement during the Lachman test was significantly less than in the knee extension exercise, but significantly more than in the parallel squat exercise. No significant differences were found between measurements in the normal knee. We concluded that the stress to the anterior cruciate ligament, as indicated by anterior tibial displacement, is minimized by using the parallel squat, a closed kinetic chain exercise, when compared to the relative anterior tibial displacement during knee extension exercise.

Adolescent↗