Abstract: A non-invasive method for determining the dynamic biomechanical characteristics (frequency response functions and natural frequency) of a musculoskeletal structure is provided. The method generally comprises exciting the musculoskeletal structure over a broad range of frequencies with a low amplitude, high velocity impulsive input force, measuring the input force with a force transducer, detecting the output motion response with an output transducer, processing input force and output response data into time-signal histories with a data acquisition and analysis means or digital computer, transforming the time-signal histories from the time domain to the frequency domain by applying Fourier analysis; and calculating a frequency response function and the natural frequency from the input force and dynamic output response time-signal histories.

Abstract: A non-invasive method and apparatus for determining the dynamic biomechanical characteristics (frequency response functions and natural frequency) of a musculoskeletal structure is provided. The method generally comprises exciting the musculoskeletal structure over a broad range of frequencies with a low amplitude, high velocity impulsive input force, measuring the input force with a force transducer, detecting the output motion response with an output transducer, processing input force and output response data into time-signal histories with a data acquisition and analysis means or digital computer, transforming the time-signal histories from the time domain to the frequency domain by applying Fourier analysis; and calculating a frequency response function and the natural frequency from the input force and dynamic output response time-signal histories.

Abstract: An improved chiropractic adjusting instrument and method is provided for use in spinal manipulative therapy and for exciting a human spine at its natural frequency. The chiropractic adjusting instrument includes a thrust element for delivering an input force, a body contact member removably attached to the thrust element, a spring member for propelling the thrust element and the body contact member outwardly, and an adjustment knob arranged on the thrust element for adjusting the amount of potential energy imposed on the spring member and for controlling the magnitude of the resulting input force. In use, the input force is mechanically tuned to the natural frequency of a musculoskeletal structure (e.g., a human spine) by positioning a shaped mass on the thrust element, by varying the stiffness of the removable body contact member, and/or by varying the stiffness of the spring member. The input force is then delivered to the musculoskeletal structure at its natural frequency.

Abstract: An improved chiropractic adjusting instrument is provided for use in spinal manipulative therapy and for exciting a human spine at its natural frequency. The chiropractic adjusting instrument includes a thrust element for delivering an input force, a body contact member removably attached to the thrust element, a spring means for propelling the thrust element and the body contact member outwardly, and an adjustment knob arranged on the thrust element for adjusting the amount of potential energy imposed on the spring means and for controlling the magnitude of the resulting input force. In use, the input force is mechanically tuned to a desired frequency (e.g., the natural frequency of a human spine) by positioning a shaped mass on the thrust element. By mechanically tuning the chiropractic adjusting instrument in this way, the dynamic output response of the spine is maximized while the requisite impact force is minimized.