The Comparisons of Whole Body Vibration Exposures and Supporting Musculature Loading between Single- and Multi-axial Suspension Seats during Agricultural Tractor Operation

Author(s):  
Jeong Ho Kim ◽  
Jack T Dennerlein ◽  
Peter W Johnson

Due to rough terrain, agricultural tractor drivers are likely exposed to a high level of whole body vibration, especially impulsive shocks. These WBV exposures are often predominant in the fore-aft (x) or lateral (y) axis. However, the current industry standard seats are designed to reduce mainly vertical (z) axis WBV exposures, and therefore, may be less effective in reducing tractor drivers’ exposure to WBV. Therefore, in a repeated-measures design with 11 subjects, this study evaluated efficacy of a multi-axial (vertical + lateral) suspension seat in reducing WBV exposure and low back (erector spinae) muscle activity relative to an industry standard single-axial suspension seat. The results showed that while there was no difference in fore-aft (x) and vertical (z) axis WBV exposures between the seats, the multi-axial suspension seat had lower A(8) lateral (y) WBV exposures [median (interquartile range): 0.7 (0.41, 0.83) m/s2] and VDV(8) [13.5 (7.4, 16.4) m/s1.75] WBV exposures than the single-axial suspension seats [ A(8): 0.81 (0.48 0.93) m/s2; VDV(8): 13.5 (8.7, 18.5) m/s1.75] (p = 0.02 and 0.04, respectively). Low back muscle activity was also lower on the multi-axial suspension seats, however this difference was not significantly significant. These results indicate that mu the multi-axial suspension may have potential to reduce the WBV exposures and muscular loading on low back among agricultural vehicle operators.

2020 ◽  
Author(s):  
yulin dong ◽  
huifang wang ◽  
Yan Zhu ◽  
Binlin Chen ◽  
Yili Zheng ◽  
...  

Abstract BackgroundWhole body vibration (WBV) training as an intervention method can cure chronic low back pain (CLBP). Different WBV parameters exert different effects on lumbar-abdominal muscle performance. Currently, there is a lack of study researched the influence of WBV training on patients with CLBP by lumbar–abdominal muscle activity. Therefore, this study aimed to investigate how WBV and exercise and their interactions influence lumbar-abdominal muscle activity in patients with CLBP.Methodsa group of ambulatory patients with chronic low back pain. Muscle activities of the multifidus, erector spinae, abdominal oblique externus muscle and the rectus abdominis muscle were measured by surface electromyography, whereas participants performed 4 different exercises during three whole body vibration conditions and a no-vibration condition in a single experimental session.ResultsCompared with the same exercises without whole body vibration, muscle activity increased when whole body vibration was added to the exercises. The frequency and exercise presented significant effects on the root mean square of multifidus, whereas exercise and frequency also resulted in significant interaction effects.ConclusionAdding whole body vibration to exercise could increase muscle activation of lumbar–abdominal muscle in patients with CLBP. The optimum frequency for lumbar–abdominal muscles is 15 Hz. The best exercises include plank for multifidus and erector spinae, V crunch for rectus abdominis and single bridge for abdominal oblique externus.Trial registration:ChiCTR-TRC-13003708. Registered 19 October 2013, http://www.chictr.org.cn/showproj.aspx?proj=5852


Author(s):  
Kiana Kia ◽  
Peter W Johnson ◽  
Jeong Ho Kim

This study compared whole body vibration (WBV), muscle activity and non-driving task performance between different seat suspension settings in a simulated autonomous passenger car environment. To simulate autonomous vehicle environment, field-measured vibration profiles were recreated on a large-scale 6-degree-of-freedom motion platform. In a repeated-measures laboratory experiment, we measured whole body vibration, muscle activity (neck, shoulder and low back), participants non-driving task performance while participants performed non-driving tasks (pointing task with a laptop trackpad, keyboard typing, web-browsing, and reading) on three different suspension seats mounted on the motion platform: vertical (z-axis) electromagnetic active suspension, multi-axial (lateral (y-axis) and vertical (z-axis)) electromagnetic active suspension, and no suspension (industry standard suspension-less seat for passenger cars). The average weighted vibration [A(8)] and vibration dose value [VDV(8)] showed that the seat measured vibration on both the vertical [A(8) = 0.29 m/s2 and VDV(8) = 10.70 m/s1.75] and multi-axial suspension seats [A(8) = 0.29 m/s2 and VDV(8) = 10.22m/s1.75] were lower than no-suspension seat vibration [A(8) = 0.36 m/s2 and VDV(8) = 12.84 m/s1.75]. Despite the significant differences in WBV between the different suspensions there were no significant differences across three different suspension seats in typing performance (typing speed and accuracy: p’s > 0.83), pointing task performance (movement time and accuracy: p’s > 0.87), web-browsing (number of questions and webpages read: p = 0.42), and reading (number of words read: p = 0.30). The muscle activity in low back (erector spinae) and shoulder (trapezius) muscles also did not show any significant differences (p’s > 0.22). These laboratory study findings indicated that despite the significant reduction in WBV, neither vertical nor multi-axial active suspension seats improve non-driving task performance as compared to the no-suspension seat.


2020 ◽  
Author(s):  
yulin dong ◽  
huifang wang ◽  
Yan Zhu ◽  
Binlin Chen ◽  
Yili Zheng ◽  
...  

Abstract Background: Whole body vibration (WBV) training as an intervention method can cure chronic low back pain (CLBP). Different WBV parameters exert different effects on lumbar-abdominal muscle performance. Currently, there is a lack of study researched the influence of WBV training on patients with CLBP by lumbar–abdominal muscle activity. Therefore, this study aimed to investigate how WBV and exercise and their interactions influence lumbar-abdominal muscle activity in patients with CLBP.Methods: a group of ambulatory patients with chronic low back pain. Muscle activities of the multifidus (MF), erector spinae (ES), abdominal oblique externus muscle (AOE) and the rectus abdominis muscle (RA) were measured by surface electromyography, whereas participants performed 4 different exercises (single bridge, plank, side stay and V crunch) during three whole body vibration conditions and a no-vibration condition in a single experimental session. Results: Compared with the same exercises without whole body vibration, muscle activity increased when whole body vibration was added to the exercises. MF;the WBV frequency (P=0.002,) and exercise (P<0.001) presented significant effects on the root mean square of MF, whereas exercise * frequency (P=0.044) also resulted in significant interaction effects. ES: the significant differences were detected at WBV frequency (P<0.001), exercise (P<0.001), the interaction effect of exercise and frequency (P=0.225) was no significant. RA: the significant difference was detected at WBV frequency (P=0.018), the effect of exercise (P=0.590) and the exercise * frequency interaction (P=0.572) were no significant. AOE: the significant difference was detected at WBV frequency (P<0.001), the effect of exercise (P=0.152) and the exercise * frequency interaction (P=0.380) were no significant.Conclusion: Adding whole body vibration to exercise could increase muscle activation of lumbar–abdominal muscle in patients with CLBP. The optimum frequency for lumbar–abdominal muscles is 15 Hz. The best exercises include plank for multifidus and erector spinae, V crunch for rectus abdominis and single bridge for abdominal oblique externus.


2020 ◽  
Author(s):  
yulin dong ◽  
huifang wang ◽  
Yan Zhu ◽  
Binlin Chen ◽  
Yili Zheng ◽  
...  

Abstract Background: Whole body vibration (WBV) training as an intervention method can cure chronic low back pain (CLBP). Different WBV parameters exert different effects on lumbar-abdominal muscle performance. Currently, there is a lack of study researched the influence of WBV training on patients with CLBP by lumbar–abdominal muscle activity. Therefore, this study aimed to investigate how WBV and exercise and their interactions influence lumbar-abdominal muscle activity in patients with CLBP.Methods: a group of ambulatory patients with chronic low back pain. Muscle activities of the multifidus (MF), erector spinae (ES), abdominal oblique externus muscle (AOE) and the rectus abdominis muscle (RA) were measured by surface electromyography, whereas participants performed 4 different exercises (single bridge, plank, side stay and V crunch) during three whole body vibration conditions and a no-vibration condition in a single experimental session. Results: Compared with the same exercises without whole body vibration, muscle activity increased when whole body vibration was added to the exercises. MF;the WBV frequency (P=0.002,) and exercise (P<0.001) presented significant effects on the root mean square of MF, whereas exercise * frequency (P=0.044) also resulted in significant interaction effects. ES: the significant differences were detected at WBV frequency (P<0.001), exercise (P<0.001), the interaction effect of exercise and frequency (P=0.225) was no significant. RA: the significant difference was detected at WBV frequency (P=0.018), the effect of exercise (P=0.590) and the exercise * frequency interaction (P=0.572) were no significant. AOE: the significant difference was detected at WBV frequency (P<0.001), the effect of exercise (P=0.152) and the exercise * frequency interaction (P=0.380) were no significant.Conclusion: Adding whole body vibration to exercise could increase muscle activation of lumbar–abdominal muscle in patients with CLBP. The optimum frequency for lumbar–abdominal muscles is 15 Hz. The best exercises include plank for multifidus and erector spinae, V crunch for rectus abdominis and single bridge for abdominal oblique externus.


Author(s):  
Yulin Dong ◽  
Huifang Wang ◽  
Yan Zhu ◽  
Binglin Chen ◽  
Yili Zheng ◽  
...  

Abstract Background Whole body vibration (WBV) training as an intervention method can cure chronic low back pain (CLBP). Different WBV parameters exert different effects on lumbar-abdominal muscle performance. Currently, there is a lack of study researched the influence of WBV training on patients with CLBP by lumbar–abdominal muscle activity. Therefore, this study aimed to investigate how WBV and exercise and their interactions influence lumbar-abdominal muscle activity in patients with CLBP. Methods a group of ambulatory patients with chronic low back pain. Muscle activities of the multifidus (MF), erector spinae (ES), abdominal oblique externus muscle (AOE) and the rectus abdominis muscle (RA) were measured by surface electromyography, whereas participants performed 4 different exercises (single bridge, plank, side stay and V crunch) during three whole body vibration conditions and a no-vibration condition in a single experimental session. Results Compared with the same exercises without whole body vibration, muscle activity increased when whole body vibration was added to the exercises. MF; the WBV frequency (P = 0.002,) and exercise (P < 0.001) presented significant effects on the root mean square of MF, whereas exercise * frequency (P = 0.044) also resulted in significant interaction effects. ES: the significant differences were detected at WBV frequency (P < 0.001), exercise (P < 0.001), the interaction effect of exercise and frequency (P = 0.225) was no significant. RA: the significant difference was detected at WBV frequency (P = 0.018), the effect of exercise (P = 0.590) and the exercise * frequency interaction (P = 0.572) were no significant. AOE: the significant difference was detected at WBV frequency (P < 0.001), the effect of exercise (P = 0.152) and the exercise * frequency interaction (P = 0.380) were no significant. Conclusion Adding whole body vibration to exercise could increase muscle activation of lumbar–abdominal muscle in patients with CLBP. The optimum frequency for lumbar–abdominal muscles is 15 Hz. The best exercises include plank for multifidus and erector spinae, V crunch for rectus abdominis and single bridge for abdominal oblique externus. Clinical registration Trial registration: ChiCTR-TRC-13003708. Registered 19 October 2013. The code of ethical approval 2014008.


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