Biomedical subjects

H Farfan

Publications and source records attributed to H Farfan.

4 recordsLinked to original sources

PubMed1989

Dynamic EMG analysis of torque transfer in professional baseball pitchers.

Fifteen professional baseball pitchers underwent active pitching motion analysis of the abdominal oblique, rectus abdominis, lumbar paraspinous and gluteus maximus muscles bilaterally via surface electrode evaluation. Baseline resting and isometric maximum values were obtained and active data referenced against these for comparison. The muscle activity then was measured during the pitching sequence and analyzed in each of the five pitching phases. The abdominal oblique, lumbar paraspinous and rectus abdominis contralateral to the pitching arm and the ipsilateral gluteus maximus all had increases in activity level of 75 to 100% during the active pitching motion. Using these data indicating specific muscle group patterns with clinical and performance data, we hope to minimize injuries and maximize pitching performance.

Abdominal Muscles↗

PubMed1985

The abdominal mechanism.

The abdominal mechanism, utilizing intraabdominal pressure, has been described and numericized. Simulations show that the lumbodorsal fascia under control of the abdominal muscles contributes to reduce the stress at the intervertebral joint. The musculature of the lumbar spine is of primary importance in the control of the efficiency of the spinal mechanism. The system of loading, which results in observable physiologic response, maintains the compressive load at virtually 90 degrees at the bisector of the disc for all weights and all angles of forward flexion.

Abdominal Muscles↗

PubMed1984

Tolerance of the human cervical spine to high acceleration: a modelling approach.

A sagittal plane mathematical model for the cervical spine has been used to simulate the neck's response to loads due to high acceleration. The model is capable of simulating the muscular response of the cervical spine and the stress distribution between the joint levels. In order to obtain conservative estimates of the maximum acceleration that the neck can support, the neck was simulated using the assumption that the inertial load is supported primarily by the muscles. It was found that accelerations of up to 30 g can be supported with the appropriate posture and direction of acceleration. Estimates were also obtained using experimental results to approximate the role that the ligaments of the spine play in supporting the load. It was found that accelerations of up to 40 g can be supported for the appropriate posture and acceleration direction.

Acceleration↗

PubMedDate not supplied

The optimum spine.

System theory is used to describe the mechanism of the lumbar spine. The role of the spine in vertebrate evolution is presented. The importance of the intervertebral joint for the survival of the species is shown to be crucial. The mechanical behavior of the joint is derived, and from this the corresponding spinal motion and muscular responses is calculated. It is shown that physiologic behavior implies that the stress at the intervertebral joints is equalized and minimized. From this simple condition, the motion of the spine in the sagittal plane is calculated. From the analysis of sagittal plane motion together with a knowledge of the energy transfer through the intervertebral joint, a new theory of locomotion is derived. This theory of locomotion differs in important respects from current theories, but nevertheless explains available experimental data. This unified theory of the function of the human spine permits the determination of the level of safe loads that can be lifted and transported. It predicts the conditions of load transfer through a joint. It proposes a new approach to the mechanism of arthritis and to the repair of fractures.

Electromyography↗