Journal of Orthopaedic & Sports Physical Therapy - Harry C. Davis, MS

Comparison of Electromyographic Activity in Normal Lumbar Sacrospinalis Musculature during continuous and Intermittent Pelvic Traction

Mon, 22 Sep 2008 00:00:00 EST

Carol Jeanne Hood, Dennis L. Hart, Harold G. Smith, Harry C. Davis
This study investigates whether there is a difference in electromyographic activity in the lumbar sacrospinalis musculature during continuous and intermittent pelvic traction. Twenty-nine normal subjects were randomly assigned to a control group, a continuous traction group, or an intermittent traction group. Electromyographic activity was recorded at specific timed intervals. Myoelectric activity increased with the onset of either type of traction, but by the third recording both groups had returned to their normal initial resting myoelectric recordings. The myoelectric patterns over time were similar for the two treatment groups. No significant difference in electromyographic activity of the lumbar sacrospinalis musculature during intermittent or continuous pelvic traction was found.

J Orthop Sports Phys Ther 1981;2(3):137-141.

Cybex II-Data Acquisition System

Mon, 22 Sep 2008 00:00:00 EST

Dennis L. Hart, David C. Barber, Harry C. Davis
The purpose of this paper was to describe a mechanical system that can be used to accurately and objectively record muscle torque and its reliability. The system includes a Cybex II dynamometer and a simple microprocessor that digitalizes the analog signal from the Cybex II. Therefore, the system eliminates the subjectivity of reading the torque recording from the typical Cybex II paper recording. After digitalizing the analog signal from the Cybex II, the Cybex 11-Data Acquisition System determines the maximum torque in millivoltage and displays the maximum millivoltage recorded over a specified time period. Reliability of the system for dead weights was r = 0.99 (P ≤ 0.05). The data acquisition system in conjunction with the Cybex II dynamometer was confirmed as accurate instrumentation for the measurement of loads applied to the Cybex II.

J Orthop Sports Phys Ther 1981;2(4):177-179.

The Effect of Vertical Dimension on Muscular Strength

Mon, 22 Sep 2008 00:00:00 EST

Dennis L. Hart, Donald O. Lundquist, Harry C. Davis
The purposes of this investigation were to determine 1) if there was a difference in systemic muscular strength as mandibular position was varied in apparently normal subjects, and 2) if muscle strength changed, were these changes related to a history of pain or discomfort associated with the temporomandibular joint or to a clinical examination of certain muscles at the head or neck. Twenty-seven subjects filled out a screening questionnaire designed to determine a history of pain or discomfort associated with the head and neck. All subjects were examined for muscle tenderness to palpation and occlusal discrepancies. Each subject was tested for muscular strength on the Cybex II-Data Acquisition System while their vertical dimension of occlusion was altered. The data did not support either research hypothesis. Twenty-three of 2 7 (85%) subjects had medial pterygoid tenderness and 25 of 2 7 (93%) subjects had lateral pterygoid tenderness. Only one subject was asymptomatic to muscle palpation. It appears that many apparently normal individuals are symptomatic to muscle palpation.

J Orthop Sports Phys Ther 1981;3(2):57-61.