Characterization of the frequency and muscle responses of the lumbar and thoracic spines of seated volunteers during sinusoidal whole body vibration.
نویسندگان
چکیده
Whole body vibration has been postulated to contribute to the onset of back pain. However, little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to measure the frequency and corresponding muscle responses of seated male volunteers during whole body vibration exposures along the vertical and anteroposterior directions to define the transmissibility and associated muscle activation responses for relevant whole body vibration exposures. Seated human male volunteers underwent separate whole body vibration exposures in the vertical (Z-direction) and anteroposterior (X-direction) directions using sinusoidal sweeps ranging from 2 to 18 Hz, with a constant amplitude of 0.4 g. For each vibration exposure, the accelerations and displacements of the seat and lumbar and thoracic spines were recorded. In addition, muscle activity in the lumbar and thoracic spines was recorded using electromyography (EMG) and surface electrodes in the lumbar and thoracic region. Transmissibility was determined, and peak transmissibility, displacement, and muscle activity were compared in each of the lumbar and thoracic regions. The peak transmissibility for vertical vibrations occurred at 4 Hz for both the lumbar (1.55 ± 0.34) and thoracic (1.49 ± 0.21) regions. For X-directed seat vibrations, the transmissibility ratio in both spinal regions was highest at 2 Hz but never exceeded a value of 1. The peak muscle response in both spinal regions occurred at frequencies corresponding to the peak transmissibility, regardless of the direction of imposed seat vibration: 4 Hz for the Z-direction and 2-3 Hz for the X-direction. In both vibration directions, spinal displacements occurred primarily in the direction of seat vibration, with little off-axis motion. The occurrence of peak muscle responses at frequencies of peak transmissibility suggests that such frequencies may induce greater muscle activity, leading to muscle fatigue, which could be a contributing mechanism of back pain.
منابع مشابه
Analysis of the dynamic behavior of the car user in the irregular terrain
Many people experience vibration effects on whole-body throughout their lives frequently. Vibrating energy absorbed is exposed all-body caused with vibration hazard in the vertically on body and biodynamic responses from body in speed 2.37 to 5.14 m/s could captivate with car seat on user body, so the vibration energy transferred to a seated people body. In this paper, the human body is modeled...
متن کاملInfluence of support conditions on vertical whole-body vibration of the seated human body.
The vibration transmission to the lumbar and thoracic segments of seated human subjects exposed to whole body vibration of a vehicular nature have been mostly characterised without the back and hand supports, which is not representative of general driving conditions. This non-invasive experimental study investigated the transmission of vertical seat vibration to selected vertebrae and the head ...
متن کاملAdverse effects of whole-body vibration on gastric motility.
To investigate the response of gastric motility to whole-body vibration (WBV) exposure, electrogastrography (EGG) and gastric manometry were performed in 10 healthy male volunteers. Sinusoidal vertical vibration of three different frequencies (4 Hz, 8 Hz, and 16 Hz) with a constant vibration magnitude of 1.0 ms-2 (rms.) was randomly given to the subject seated on the platform of a vibrator for ...
متن کاملImmediate effect of whole body vibration on trunk proprioception in non-specific chronic low back pain
Introduction: The available data indicate that there is a relationship between proprioception deficit and low back pain. For this reason, proprioception exercises are usually part of the rehabilitation protocols for these patients. Previous studies revealed that whole body vibration (WBV) can improve muscle performance and proprioception. The aim of this study was to investigate effect of WBV o...
متن کاملChanges of Nerve - Muscle Performance of Elderly Men in Response to Whole Body Vibration
Background and Aims: Whole body vibration exercise by affecting the neuromuscular system and mechanical mechanisms increase muscles strength. This study investigated the effect of whole body vibration training on neuromuscular function of elderly men. Methods: Based on a randomized controlled trial design, 72 retired elderly men with a mean age of 73.00 ± 2.67 years participated in thisstudy. A...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of biomechanical engineering
دوره 136 10 شماره
صفحات -
تاریخ انتشار 2014