Effects of Low-Frequency Whole-Body Vibration on Muscle Activation, Fatigue, and Oxygen Consumption in Healthy Young Adults: A Single-Group Repeated-Measures Controlled Trial

Effects of whole-body vibration exercise on functional capacity, muscle strength, and quality of life in individuals with severe chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Whole body vibration (WBV) exercise is a therapy used for individuals with low tolerance to conventional exercises, such as patients with chronic obstructive pulmonary disease (COPD). This study aimed to assess the impact of WBV exercise on the functional capacity, muscle strength, and health-related quality of life (HRQoL) in severe COPD patients.

METHODS

Studies published until March 2024 were reviewed, encompassing randomized clinical trials (RCTs) without temporal or linguistic constraints, comparing WBV exercise with other interventions. The PubMed/MEDLINE, Scopus, Cochrane Airways Trials Register, and CINAHL databases were queried. The Revised Cochrane risk-of-bias tool for randomized trials 2.0A was employed for quality assessment.

RESULTS

Among 351 screened studies, 7 met the criteria, totaling 356 participants (WBV group, n = 182; control group, n = 174). Meta-analysis revealed a significant mean difference of 41.36 m [95%CI (13.28-69.44); p = .004] in the 6-minute walk test distance favoring the WBV group for functional capacity. Lower limb muscle strength improved in 57.14% of included studies. HRQoL meta-analysis demonstrated a 1.13-point difference [95%CI -1.24-3.51; p = .35] favoring WBV, although group differences were not significant. A mean difference of 2.31 points favored the control group in health condition [95%CI (-1.32-5.94); p = .021].

CONCLUSION

WBV exercise is recognized as a promising therapeutic modality for severe COPD patients, notably enhancing functional capacity. Although heterogeneous study protocols weaken the evidence for clinically relevant outcomes, improvements in lower limb muscle strength and HRQoL were also observed, differences between groups were not significant.

Whole-body vibration protects against chronic high-altitude hypoxic bone loss by regulating the nitric oxide/HIF-1α axis in osteoblasts

The hypobaric hypoxia environment found at high altitudes imposes various reversible and irreversible detrimental effects on living organisms. Accumulating evidence suggests that hypobaric hypoxia negatively impacts skeleton health by diminishing bone quality and disrupting bone microarchitecture. However, therapeutic strategies to counteract this bone loss remain limited. This study investigates the impact of whole-body vibration (WBV) stimulation on skeletal health of rats continuously exposed to simulated hypobaric hypoxia environment at an altitude of 4500 m for 6 weeks. We found that WBV stimulation at 30 Hz and 0.3 g significantly improved femoral bone mass, microarchitecture, and biomechanical properties in rats exposed to chronic hypobaric hypoxia. Additionally, in vitro studies demonstrated that WBV enhanced osteogenic potential and activity in primary osteoblasts under hypoxia conditions. It also reduced levels of hypoxia-inducible factor 1α (HIF-1α), a key transcription factor involved in cellular response to hypoxia. Conversely, overexpression of HIF-1α significantly inhibited cellular differentiation and osteogenesis in osteoblasts exposed to WBV stimulation under hypoxic conditions. Furthermore, WBV stimulation led to a significant increase in nitric oxide (NO) concentrations in osteoblasts during hypoxic exposure. In vitro experiments showed that blocking of NO synthesis with L-NAME impeded WBV-stimulated osteogenic activity in hypoxia-exposed osteoblasts. In vivo studies demonstrated that inhibiting NO synthesis similarly abolished the positive impact of WBV on bone microarchitecture and biomechanical properties under hypobaric hypoxia. Collectivity, our findings indicate that WBV protects against hypobaric hypoxia-induced bone loss by regulating the NO/HIF-1α axis in osteoblasts, and reveal its clinical potential as a promising non-invasive approach.

Effects of 6-Week Whole-Body Vibration Training on Isokinetic Trunk Muscle Strength, Postural Stability, and Jump Performance in Female Adults - A Randomized Controlled Trial

Current evidence regarding the benefits of Whole-Body Vibration (WBV) on postural stability and jump performance remains inconsistent and to the best of our knowledge, there is no study comparing the effectiveness of different vibration frequencies on trunk muscle strength. This study was conducted to determine the effect of whole-body vibration training with different vibration frequency on isokinetic trunk muscle strength, postural stability and jump performance in physically inactive and minimally active healthy female adults. Forty-five females were randomly assigned to 45 hz WBV group (n = 15), 25 hz WBV (n = 15) group and control exercise group without WBV (0 hz group, n = 15). Individuals in each group completed a 6-week trunk-based exercise program at the specified vibration frequency. Concentric and eccentric strength of trunk flexor and extensor muscles, postural stability and jump performance were assessed before and after the training period. There were significant group by time interactions in concentric and eccentric trunk muscle strength. Interaction effects showed no significant differences in postural stability and vertical jump performance. However, post hoc analyses revealed that all three groups significantly improved vertical jump height. These findings suggest that WBV combined with exercise training were effective to enhance the strength of trunk muscles in physically inactive and minimally active women. Nevertheless, WBV exercise training performed in this study had no significant impact on postural stability and jump performance.Clinical Trials Number: NCT05014958 (Pre-registired).

Surface Electromyography in Dentistry-Past, Present and Future

Surface electromyography (sEMG) is a technique for measuring and analyzing the electrical signals of muscle activity using electrodes placed on the skin's surface. The aim of this paper was to outline the history of the development and use of surface electromyography in dentistry, to show where research and technical solutions relating to surface electromyography currently lie, and to make recommendations for further research. sEMG is a diagnostic technique that has found significant application in dentistry. The historical section discusses the evolution of sEMG methods and equipment, highlighting how technological advances have influenced the accuracy and applicability of this method in dentistry. The need for standardization of musculoskeletal testing methodology is highlighted and the needed increased technical capabilities of sEMG equipment and the ability to specify parameters (e.g., sampling rates, bandwidth). A higher sampling rate (the recommended may be 2000 Hz or higher in masticatory muscles) allows more accurate recording of changes in the signal, which is essential for accurate analysis of muscle function. Bandwidth is one of the key parameters in sEMG research. Bandwidth determines the range of frequencies effectively recorded by the sEMG system (the recommended frequency limits are usually between 20 Hz and 500 Hz in masticatory muscles). In addition, the increased technical capabilities of sEMG equipment and the ability to specify electromyographic parameters demonstrate the need for a detailed description of selected parameters in the methodological section. This is necessary to maintain the reproducibility of sEMG testing. More high-quality clinical trials are needed in the future.

Effect of Whole-body Vibration frequency on muscle tensile state during graded plantar flexor isometric contractions

Background

Acute physiological and biomechanical alterations have been reported following whole-body vibration (WBV). Stiffening of muscles has only been anecdotally reported in response to WBV. Accordingly, this study investigated active plantar flexor muscle stiffness in response to a single WBV bout at four mechanical vibration frequencies.

Methods

Thirteen healthy adults (37.1 ± 14.4 years old) randomly received WBV in 4 different frequencies (6, 12, 24, and 0 Hz control) for 5 min. Shear wave speed (SWS) in longitudinal and transverse projections, architecture, and electric muscle activity were recorded in the medial gastrocnemius (MG) and soleus (SOL) muscle during graded plantar flexor contraction. Subjective rating of perceived muscle stiffness was assessed via Likert-scale.

Results

SWS of the MG at rest was enhanced in response to 5 min of 24 Hz WBV (p = 0.025), while a small reduction in SOL SWS was found during contraction (p = 0.005) in the longitudinal view. Subjective stiffness rating was increased following 12 Hz intervention. After 24 Hz WBV, pennation angle for MG was decreased (p = 0.011) during contraction. As a secondary finding, plantar flexor strength was significantly increased with each visit, which, however, did not affect the study's main outcome because of balanced sequence allocation.

Conclusion

SWS effects were solely limited to 24 Hz mechanical vibration and in the longitudinal projection. The observed effects are compatible with an interpretation by post-activation potentiation, warm-up, and force-distribution within the triceps surae muscles following 5 min WBV. The outcome may suggest SWS as a useful tool for assessing acute changes in muscle stiffness.