Influence of seat lumbar support adjustment on muscle fatigue under whole body vibration: An in vivo experimental study

2021 ◽  
pp. 1-13
Author(s):  
Li-Xin Guo ◽  
Rui-Chun Dong ◽  
Sheng Yuan ◽  
Qing-Zhi Feng ◽  
Wei Fan

BACKGROUND: In order to alleviate muscle fatigue and improve ride comfort, many published studies aimed to improve the seat environment or optimize seating posture. However, the effect of lumbar support on the lumbar muscle of seated subjects under whole body vibration is still unclear. OBJECTIVE: This study aimed to investigate the effect of lumbar support magnitude of the seat on lumbar muscle fatigue relief under whole body vibration. METHODS: Twenty healthy volunteers without low back pain participated in the experiment. By measuring surface electromyographic signals of erector spinae muscles under vibration or non-vibration for 30 minutes, the effect of different lumbar support conditions on muscle fatigue was analyzed. The magnitude of lumbar support d is assigned as d1= 0 mm, d2= 20 mm and d3= 40 mm for no support, small support and large support, respectively. RESULTS: The results showed that lumbar muscle activation levels vary under different support conditions. For the small support case (d2= 20 mm), the muscle activation level under vibration and no-vibration was the minimum, 42.3% and 77.7% of that under no support (d1= 0 mm). For all support conditions, the muscle activation level under vibration is higher than that under no-vibration. CONCLUSIONS: The results indicate that the small support yields the minimum muscle contraction (low muscle contraction intensity) under vibration, which is more helpful for relieving lumbar muscle fatigue than no support or large support cases. Therefore, an appropriate lumbar support of seats is necessary for alleviating lumbar muscle fatigue.

Dose-Response ◽  
2018 ◽  
Vol 16 (4) ◽  
pp. 155932581880436 ◽  
Author(s):  
Danielle S Morel ◽  
Pedro J Marín ◽  
Eloá Moreira-Marconi ◽  
Carla F Dionello ◽  
Mario Bernardo-Filho

The aim of this study was to investigate the acute effects of whole-body vibration exercises (WBVE) in different positions on muscular activity of flexor digitorum superficialis (FD), wrist extensor (ED), and handgrip strength (HG) of healthy men. Fifteen participants have performed 5 test sets each one consisting of HG strength measurement and 1-minute WBVE intervention (frequency: 50 Hz, amplitude: 1.53 mm, synchronous tri-planar oscillating/vibratory platform), that could be control (no exposition to vibration), squat (30 seconds of rest and 30 seconds of WBVE in squat position), or push-up (30 seconds of rest, and 30 seconds of WBVE in push-up position). After testing, participants had 2 minutes of rest and then were encouraged to keep themselves on a pull-up bar for 30 seconds. During all procedures, muscular activity of FD and ED was measured by surface electromyography (EMG). Statistical analysis has revealed that the EMG measured in the FD during the static pull-up bar exercise after SQUAT condition was significantly higher ( P = .004) than the CONTROL and PUSH-UP conditions. Whole-body vibration exercises in squat position increase acutely muscle activation of the FD during isometric exercises of longer duration, while muscle activation of ED and HG strength are not affected by WBVE.


2010 ◽  
Vol 109 (6) ◽  
pp. 1801-1811 ◽  
Author(s):  
Daniel L. Belavý ◽  
Gabriele Armbrecht ◽  
Ulf Gast ◽  
Carolyn A. Richardson ◽  
Julie A. Hides ◽  
...  

To evaluate the effect of short-duration, high-load resistive exercise, with and without whole body vibration on lumbar muscle size, intervertebral disk and spinal morphology changes, and low back pain (LBP) incidence during prolonged bed rest, 24 subjects underwent 60 days of head-down tilt bed rest and performed either resistive vibration exercise ( n = 7), resistive exercise only ( n = 8), or no exercise ( n = 9; 2nd Berlin Bed-Rest Study). Discal and spinal shape was measured from sagittal plane magnetic resonance images. Cross-sectional areas (CSAs) of the multifidus, erector spinae, quadratus lumborum, and psoas were measured on para-axial magnetic resonance images. LBP incidence was assessed with questionnaires at regular intervals. The countermeasures reduced CSA loss in the multifidus, lumbar erector spinae and quadratus lumborum muscles, with greater increases in psoas muscle CSA seen in the countermeasure groups ( P ≤ 0.004). There was little statistical evidence for an additional effect of whole body vibration above resistive exercise alone on these muscle changes. Exercise subjects reported LBP more frequently in the first week of bed rest, but this was only significant in resistive exercise only ( P = 0.011 vs. control, resistive vibration exercise vs. control: P = 0.56). No effect of the countermeasures on changes in spinal morphology was seen ( P ≥ 0.22). The results suggest that high-load resistive exercise, with or without whole body vibration, performed 3 days/wk can reduce lumbar muscle atrophy, but further countermeasure optimization is required.


Author(s):  
Shiuan-Yu Tseng ◽  
Chung-Po Ko ◽  
Chin-Yen Tseng ◽  
Wei-Ching Huang ◽  
Chung-Liang Lai ◽  
...  

In recent years, whole-body vibration (WBV) training has been used as a training method in health promotion. This study attempted to use WBV at three different frequencies (20, 30, and 40 Hz) with subjects from different age groups to analyze the activation of the rectus femoris muscle. The subjects included 47 females and 51 males with an average age of 45.1 ± 15.2 years. Results indicated significant differences in subjects from different age groups at 20 Hz WBV. Muscle contraction was greater in the subjects who were older (F(4,93) = 82.448, p < 0.001). However, at 30 Hz WBV, the difference was not significant (F(4,93) = 2.373, p = 0.058). At 40 Hz WBV, muscle contraction was less in the older subjects than in the younger subjects (F(4,93) = 18.025, p < 0.001). The spectrum analysis also indicated that at 40 Hz there was less muscle activity during WBV in the older subjects than in the younger ones. Therefore, age was found to have a significant effect on muscle activation during WBV at different frequencies. If the training is offered to elderly subjects, their neuromuscular responses to 20 Hz WBV will be more suitable than to 40 Hz WBV.


Sign in / Sign up

Export Citation Format

Share Document