The upper extremity attenuates intermediate frequency vibrations.
Vibration is related to reports of low back pain; however the biomechanics of vibration transmission through the hand-arm system has not been previously studied. Vibration was recorded on an accelerometer mounted to a pin percutaneously imbedded in the spinous process of L4 of five human subjects. The energy was applied through an impact via a pendulum. The subjects adopted an erect, relaxed or bent knee posture. The first resonance was 4-6 Hz and the second at 9-14 Hz. With the knee bent, the signal was almost completely attenuated. If the impact was applied through a handle and the hand-arm system there was complete attenuation.
Pope
M H
MH
Iowa Spine Research Center, University of Iowa, Iowa City 52242, USA.
Magnusson
M
M
Hansson
T
T
D000054:Acceleration; D000328:Adult; D000703:Analog-Digital Conversion; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D004735:Energy Transfer; D005260:Female; D006225:Hand / Q000502:physiology; D018737:Hand Strength; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology; D017116:Low Back Pain / Q000209:etiology; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D009784:Occupational Diseases / Q000209:etiology; D011187:Posture / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D014159:Transducers; D014732:Vibration / Q000009:adverse effects*