Autonomic Nervous System Responses to Whole-Body Vibration and Mental Workload: A Pilot Study

Background:

Whole-body vibration (WBV) and mental workload (MWL) are common stressors among drivers who attempt to control numerous variables while driving a car, bus, or train.

Objective:

To examine the individual and combined effects of the WBV and MWL on the autonomic nervous system.

Methods:

ECG of 24 healthy male students was recorded using NeXus-4 while performing two difficulty levels of a computerized dual task and when they were exposing to WBV (intensity 0.5 m/s2; frequency 3–20 Hz). Each condition was examined for 5 min individually and combined. Inter-beat intervals were extracted from ECG records. The time-domain and frequency-domain heart rate variability parameters were then extracted from the inter-beat intervals data.

Results:

A significant (p=0.008) increase was observed in the mean RR interval while the participants were exposed to WBV; there was a significant (p=0.02) reduction in the mean RR interval while the participants were performing the MWL. WBV (p=0.02) and MWL significantly (p<0.001) increased the standard deviation of normal-to-normal intervals with a moderate-to-large effect size. All active periods increased the low-frequency component and low-frequency/high-frequency ratio. However, only the WBV significantly increased the highfrequency component. A significant (p=0.01) interaction was observed between the WBV and MWL on low-frequency component and low-frequency/high-frequency ratio.

Conclusion:

Exposure to WBV and MWL can dysregulate the autonomic nervous system. WBV stimulates both sympathetic and parasympathetic nervous system; MWL largely affects sympathetic nervous system. Both variables imbalance the sympatho-vagal control as well.

Mandible and iliac osteoblasts exhibit different Wnt signaling responses to LMHF vibration

Objective

The jaw bones and long bones have distinct developmental origins and respond differently to mechanical stimuli. This study aimed to compare the Wnt signaling responses of human mandible osteoblasts and long bone osteoblasts to low-magnitude, high-frequency (LMHF) mechanical vibration in vitro.

Methods

Primary human osteoblast cultures were prepared from mandibular bone (n = 3) and iliac bone (n = 3) specimens (six individuals). Osteoblast cell lines were subjected to vibration (0, 30, 60, 90, or 120 Hz) for 30 min. After 24 h, cells were vibrated for 30 min again, then harvested immediately to quantify Wnt10b, Wnt5a and runt-related transcription factor 2 (RUNX2) mRNA expression, β-catenin protein expression and alkaline phosphatase (ALP) activity.

Results

Mandible and iliac osteoblasts responded differently to LMHF vibration: Wnt10b mRNA was upregulated by the frequency range tested; Wnt5a, β-catenin protein expression and RUNX2 mRNA expression were not altered. Furthermore, vibration upregulated ALP activity in mandible osteoblasts, but not in iliac osteoblasts.

Conclusions

This study demonstrates mandible osteoblasts and long bone osteoblasts respond differently to LMHF mechanical vibration in terms of Wnt signaling expression and ALP activity. Therefore, the effects of whole-body vibration on the long bones cannot be generalized to the jaw bones. Furthermore, osteoblast-like cells mediate the cellular responses to vibration, at least in part, by secreting extracellular signaling molecules.

[Evidence-based diagnostic use of VEMPs : From neurophysiological principles to clinical application. German version]

BACKGROUND

Vestibular evoked myogenic potentials (VEMPs) are increasingly being used for testing otolith organ function.

OBJECTIVE

This article provides an overview of the anatomical, biomechanical and neurophysiological principles of an evidence-based clinical application of ocular and cervical VEMPs (oVEMPs and cVEMPs).

MATERIAL AND METHODS

Systematic literature search in PubMed until April 2019.

RESULTS

Sound and vibration at a frequency of 500 Hz represent selective vestibular stimuli for the otolith organs. The predominant specificity of oVEMPs for contralateral utricular function and of cVEMPs for ipsilateral saccular function is defined by the different neuronal projections of the utricle and the saccule. VEMPs are particularly useful in the diagnosis of superior canal dehiscence and otolith organ-specific vestibular dysfunction and as an alternative diagnostic approach in situations when video oculography is not possible or useful.

CONCLUSION

The use of VEMPs is a simple, safe, reliable and selective test of dynamic function of otolith organs.

Effects of vibration on anammox-enriched biofilm in a high-loaded upflow reactor

An upflow biofilm reactor was operated for 211 days to investigate the effects of vibration on anammox treatment performance. With vibration, the highest nitrogen removal rates (20 kg-N·m^-3·d^-1) were obtained on day 180. Since the vibration could directly applied on the biofilm, it could release the dinitrogen gas accumulated in the biofilm timely and reduce the internal mass transfer resistance sharply. The specific anammox activity increased by more than 3 times with a higher vibration intensity. Meanwhile, the unique random motion caused by mechanical vibration promotes the production of extracellular proteins. Moreover, the VSS reached 20.97 g·L^-1 which was 1.6 times higher than the control reactor. Such enrichment method resulted in a hard and thick anammox biofilm with a special granular morphology, and the nitrite tolerance concentration could reach 500 mg-N·L^-1. Operated with an adequate vibration intensity could maintain the biofilm thickness and conducive to improve the stability of the reactor. In addition, this technique also allowed the microorganisms inside the biofilm and those on the surface to reach the same culture conditions. Base on the batch experiments, intermittent vibration caused a decrease in energy consumption from about 7.757 (kW·h)·(kg-N)^-1 in group 0-Lv7(60-60) to 0.912 (kW·h)·(kg-N)^-1 in group 0-Lv7(5-60). Compared to the internal recycle without vibration, the energy consumption fell by a slice over 65%. Furthermore, the high-throughput sequencing results showed that the relative abundance of Candidatus Kuenenia in reactor 1 increased from 13.2% to 43.9%.

Central Nervous System Correlates of "Objective" Neuropathy in Alcohol Use Disorder

BACKGROUND

Among the neurological consequences of alcoholism is peripheral neuropathy. Relative to human immunodeficiency virus (HIV) or diabetes-related neuropathies, neuropathy associated with alcohol use disorders (AUD) is understudied. In both the diabetes and HIV literature, emerging evidence supports a central nervous system (CNS) component to peripheral neuropathy.

METHODS

In seeking a central substrate for AUD-related neuropathy, the current study was conducted in 154 individuals with AUD (43 women, age 21 to 74 years) and 99 healthy controls (41 women, age 21 to 77 years) and explored subjective symptoms (self-report) and objective signs (perception of vibration, deep tendon ankle reflex, position sense, 2-point discrimination) of neuropathy separately. In addition to regional brain volumes, risk factors for AUD-related neuropathy, including age, sex, total lifetime ethanol consumed, nutritional indices (i.e., thiamine, folate), and measures of liver integrity (i.e., γ-glutamyltransferase), were evaluated.

RESULTS

The AUD group described more subjective symptoms of neuropathy and was more frequently impaired on bilateral perception of vibration. From 5 correlates, the number of AUD-related seizures was most significantly associated with subjective symptoms of neuropathy. There were 15 correlates of impaired perception of vibration among the AUD participants: Of these, age and volume of frontal precentral cortex were the most robust predictors.

CONCLUSIONS

This study supports CNS involvement in objective signs of neuropathy in AUD.

Dissociable Contributions of Precuneus and Cerebellum to Subjective and Objective Neuropathy in HIV

Neuropathy, typically diagnosed by the presence of either symptoms or signs of peripheral nerve dysfunction, remains a frequently reported complication in the antiretroviral (ART)-treated HIV population. This study was conducted in 109 healthy controls and 57 HIV-infected individuals to investigate CNS regions associated with neuropathy. An index of objective neuropathy was computed based on 4 measures: deep tendon ankle reflex, vibration sense (great toes), position sense (great toes), and 2-point discrimination (feet). Subjective neuropathy (self-report of pain, aching, or burning; pins and needles; or numbness in legs or feet) was also evaluated. Structural MRI data were available for 126/166 cases. The HIV relative to the healthy control group was impaired on all 4 signs of neuropathy. Within the HIV group, an objective neuropathy index of 1 (bilateral impairment on 1 measure) or 2 (bilateral impairment on at least 2/4 measures) was associated with older age and a smaller volume of the cerebellar vermis. Moderate to severe symptoms of neuropathy were associated with more depressive symptoms, reduced quality of life, and a smaller volume of the parietal precuneus. This study is consistent with the recent contention that ART-treated HIV-related neuropathy has a CNS component. Distinguishing subjective symptoms from objective signs of neuropathy allowed for a dissociation between the precuneus, a brain region involved in conscious information processing and the vermis, involved in fine tuning of limb movements. Graphical Abstract In HIV patients, objective signs of neuropathy correlated with smaller cerebellar vermis (red) volumes whereas subjective symptoms of neuropathy were associated with smaller precuneus (blue) volumes.

Effect of alendronate or 8-prenylnaringenin applied as a single therapy or in combination with vibration on muscle structure and bone healing in ovariectomized rats

Bisphosphonate alendronate (ALN), phytoestrogen 8-prenylnaringenin (8-PN) and the whole body vibration exert a favorable effect on osteoporotic bone. However, the impact of these treatments and the combination of pharmacological therapies with biomechanical stimulation on muscle and bone has not yet been explored in detail. The effect of ALN and 8-PN and their combination with the vibration (Vib) on skeletal muscle and bone healing was investigated in ovariectomized (Ovx) rats.

Three-month old rats were Ovx (n = 78), or left intact (Non-Ovx; n = 12). Five weeks after Ovx, all rats were treated according to the group assignment (n = 12/13): 1) Non-Ovx; 2) Ovx; 3) Ovx + Vib; 4) Ovx + ALN; 5) Ovx + ALN + Vib; 6): Ovx + 8-PN; 7) Ovx + 8-PN + Vib. Treatments with ALN (0.58 mg/kg BW, in food), 8-PN (1.77 mg/kg BW, daily s.c. injections) and/or with vertical vibration (0.5 mm, 35 Hz, 1 g, 15 min, 2×/day, 5×/week) were conducted for ten weeks. Nine weeks after Ovx, all rats underwent bilateral tibia osteotomy with plate osteosynthesis and were sacrificed six weeks later.

Vibration increased fiber size and capillary density in muscle, enlarged callus area and width, and decreased callus density in tibia, and elevated alkaline phosphatase in serum. ALN and ALN + Vib enhanced capillarization and lactate dehydrogenase activity in muscle. In tibia, ALN slowed bone healing, ALN + Vib increased callus width and density, enhanced callus formation rate and expression of osteogenic genes. 8-PN and 8-PN + Vib decreased fiber size and increased capillary density in muscle; callus density and cortical width were reduced in tibia. Vibration worsened 8-PN effect on bone healing decreasing the callus width and area.

Our data suggest that Vib, ALN, 8-PN, or 8-PN + Vib do not appear to aid bone healing. ALN + Vib improved bone healing; however application is questionable since single treatments impaired bone healing. Muscle responds to the anti-osteoporosis treatments and should be included in the evaluation of the drugs.

•

Vibration (Vib) was beneficial for muscle structure, it tended to interfere with early bone healing.

•

Alendronate (ALN) enhanced capillary density and metabolism in muscle, slowed bone healing.

•

8-Prenylnaringenin (8-PN) had favorable effects on muscle, for bone healing it was disadvantageous.

•

8PN + Vib further worsened 8-PN effect on bone, ALN + Vib improved bone healing.

•

Muscles respond to anti-osteoporosis treatments, their analysis should be included in the evaluation of drugs.

The effects of muscle vibration on gait control: a review

Background: The purpose of the review is to summarize the literature surrounding the use of muscle vibration as it relates to modifying human gait. Methods: After a brief introduction concerning historical uses and early research identifying the effect of vibration on muscle activation, we reviewed 32 articles that used muscle vibration during walking. The review is structured to address the literature within four broad categories: the effect of vibration to 'trigger' gait-like lower limb motions, the effect of vibration on gait control of healthy individuals and individuals with clinical conditions in which gait disorders are a prominent feature, and the effect of vibration training protocols on gait. Results: The acute effects of vibration during gait involving healthy participants is varied. Some authors reported differences in segmental kinematic and spatiotemporal measures while other authors reported no differences in these outcome measures. The literature involving participants with clinical conditions revealed that vibration consistently had a significant impact on gait, suggesting vibration may be an effective rehabilitation tool. All of the studies that used vibration therapy over time reported significant improvement in gait performance. Conclusions: This review highlights the difficulties in drawing definitive conclusions as to the impact of vibration on gait control, partly because of differences in walking protocols, site of vibration application, and outcome measures used across different investigative teams. It is suggested that the development of common investigative methodologies and outcome measures would accelerate the identification of techniques that may provide optimal rehabilitation protocols for individuals experiencing disordered gait control.

Two-degrees-of-freedom PI2D controller for precise nanopositioning in the presence of hardware-induced constant time delay

The fast and accurate tracking of periodic and arbitrary reference trajectories is the principal goal in many nanopositioning applications. Flexure-based piezoelectric stack driven nanopositioners are widely employed in applications where accurate mechanical displacements at these nanometer scales are required. The performance of these nanopositioners is limited by the presence of lightly damped resonances in their dynamic response and actuator nonlinearities. Closed-loop control techniques incorporating both damping and tracking are typically used to address these limitations. However, most tracking schemes employed use a first-order integrator where a triangular trajectory commonly used in nanopositioning applications necessitates a double integral for zero-error tracking. The phase margin of the damped system combined with the hardware-induced delay deem the implementation of a double-integrator unstable. To overcome this limitation, this paper presents the design, analysis and application of a new control scheme based on the structure of the traditional Two-Degrees-of-Freedom PID controller (2DOF-PID). The proposed controller replaces the integral action of the traditional 2DOF-PID with a double integral action (2DOF-PI²D). Despite its simplicity, the proposed controller delivers superior tracking performance compared to traditional combined damping and tracking control schemes based on well-reported designs such as positive position feedback (PPF), Integral resonant control (IRC), and Positive Velocity and Position Feedback (PVPF). The stability of the control system is analyzed in the presence of a time delay in the system. Experimental results validating the efficacy of the proposed chattering-free control of a piezo-driven nanopositioning system are included.

Effects of vibration, vacuum, and material thickness on infrared drying of Cissus quadrangularis Linn

Infrared (IR), vibratory bed assisted infrared (VIR), vacuum infrared (VC-IR), and vibratory bed assisted vacuum infrared (VC-VIR) drying of Cissus quadrangularis Linn. (CQ) were conducted. The objective was to investigate the effects of vibration, vacuum, and material thickness on IR drying of CQ. VC-VIR drying of 5-mm CQ provided the highest maximum drying rate (DR) of 0.258 g water/g dry matter·min. Although the vacuum operation contributed to improved effective moisture diffusivity (D _eff ), it consumed high energy and degraded active compounds of CQ. VIR drying could be a more promising technique. VIR drying of 15-mm CQ produced the greatest total phenolic content (TPC) and quercetin content of 1083.62 mg GAE/100 g dry matter and 3.472 mg/100 g dry matter, respectively. The lowest total color difference (ΔE) of 13.69 was also obtained. It required low specific energy consumption (SEC) of 17.62 kWh/kg and provided maximum DR of 0.112 g water/g dry matter·min.

Effect of vibration during local anesthesia administration on pain, anxiety, and behavior of pediatric patients aged 6-11 years: A crossover split-mouth study

Background

Uncooperative behavior of children due to dental anxiety may interfere with the effective delivery of dental care and compromise the quality of treatment provided. Injection of local anesthesia is one of the most anxiety-inducing stimuli in pediatric dentistry. This study aimed to compare the efficacy of a child-friendly device, having a combined effect of vibration and distraction, with the conventional method of injection on pain, anxiety, and behavior of pediatric patients aged 6–11 years.

Methods

This randomized, crossover, split-mouth study included 30 children requiring a bilateral inferior alveolar nerve block. The children were equally divided into two groups: group 1, aged 6–8 and group 2, aged 9–11 years. All children were injected with anesthesia using the conventional and device method in two separate sessions. They were assessed for anxiety by measuring the pulse rate before and during the administration of local anesthesia. Behavior was assessed using Faces, Legs, Activity, Cry, Consolability (FLACC) scale, and the child's experience while receiving anesthesia was assessed using the Wong Bakers Pain Rating Scale.

Results

Results showed that the children who received local anesthesia using the device method had a lower mean pulse rate, FLACC scores, and pain rating scores than those who received local anesthesia using the conventional method.

Conclusion

The device method was more effective than the conventional method in managing pain, anxiety, and behavior of patients aged 6–11 years. The device is a cost effective, simple, and child-friendly product for administrating local anesthesia in pediatric patients.

Free vibration of a piezoelectric nanobeam resting on nonlinear Winkler-Pasternak foundation by quadrature methods

This work introduces a numerical scheme for free vibration analysis of elastically supported piezoelectric nanobeam. Based on Hamilton principle, governing equations of the problem are derived. The problem is formulated for linear and nonlinear Winkler–Pasternak foundation type. Three differential quadrature techniques are employed to reduce the problem to an Eigen-value problem. The reduced system is solved iteratively. The natural frequencies of the beam are obtained. Numerical analysis is implemented to investigate computational characteristics affecting convergence, accuracy and efficiency of the proposed scheme. The obtained results agreed with the previous analytical and numerical ones. Furthermore, a parametric study is introduced to show influence of supporting conditions, two different electrical boundary conditions, material characteristics, foundation parameters, temperature change, external electric voltage, nonlocal parameter and beam length-to-thickness ratio on the values of natural frequencies and mode shapes of the problem.

Vibration as an adjunct to exercise: its impact on shoulder muscle activation

PURPOSE

There is an interest within elite sport in understanding the impact of a vibrating platform as an adjunct to exercise in the training and rehabilitation of throwing athletes. However, there has been no comprehensive evaluation of its impact on the rotator cuff muscles or its effect on the timing of shoulder muscle recruitment more globally.

METHODS

Twenty healthy participants were recruited with EMG recorded from 15 shoulder girdle muscles. Isometric shoulder flexion at 25% maximal voluntary contraction was performed in three testing scenarios [no vibration; whole body vibration (WBV); and arm vibration (AV)]. A press up and triceps dips with and without vibration were also performed. Muscular recruitment was assessed pre- and post-vibration exposure as participants initiated forward flexion.

RESULTS

Activation of the anterior deltoid (p = 0.002), serratus anterior (p = 0.004), and rotator cuff muscles (p = 0.004-0.022) occurred significantly earlier following exposure to vibration. Significantly greater activation was seen in the anterior, middle and posterior deltoid, upper, middle and lower trapezius, serratus anterior, teres major, latissimus dorsi, supraspinatus, and infraspinatus when the isometric contraction was performed with either WBV and/or AV (p =  < 0.001-0.040). Similarly, increased activation was also demonstrated during the press up and triceps dips when performed with vibration.

CONCLUSION

The use of vibration as an adjunct to exercise provokes a near global increase in shoulder muscle activation level. Furthermore, exposure to vibration alters muscular recruitment improving readiness for movement. This has potential implications within elite sport for both training and game preparation; however, further longitudinal work is required.

Forced vibration of a heated wire subjected to nucleate boiling

Vapor bubble nucleation during subcooled boiling on thin strip wire heaters and the resultant vibrations are studied experimentally. The results show how the subcooled boiling-induced vibrations (SBIV) are intrinsically related to the hydrodynamic flow induced near the heated wires. It is shown that the dominant force responsible for the vibrations in this case is imposed by a localized strong hydrodynamic flow rather than by the vapor recoil force. The dominant frequency of SBIV is the fundamental frequency of the wire, regardless of the individual departure frequencies of the nucleating vapor bubbles. The recorded wire vibrations are used to quantify the hydrodynamic flow. It is shown experimentally and theoretically that the flow fades exponentially with distance from the wire.

Vibration enhances osteoclastogenesis by inducing RANKL expression via NF-κB signaling in osteocytes

To shorten the duration of orthodontic treatment it is important not only to reduce risks such as dental caries, periodontal disease, and root resorption, but also to decrease pain and discomfort caused by a fixed appliance. Several studies have investigated the effect of vibration applied to fixed appliances to accelerate tooth movement. Although it was reported that vibration accelerates orthodontic tooth movement by enhancing alveolar bone resorption, the underlying cellular and molecular mechanisms remain unclear. In this study, we investigated the effects of vibration on osteoclastogenesis in vitro and in vivo. Vibration applied to pre-osteoclast cell line RAW264.7 cells enhanced cell proliferation but did not affect their differentiation into osteoclasts. Osteocytes in bone are known to be mechanosensitive and to act as receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL). Therefore, in the present study, vibration was applied to cells from the osteocyte-like cell line MLO-Y4. In MLO-Y4 cells, vibration induced phosphorylation of the inhibitor of NF-κB (IκB) and caused nuclear localization of NF-κB p65. Additionally, vibration increased RANKL mRNA expression, but did not affect osteoprotegerin (OPG) mRNA expression in MLO-Y4 cells, thus resulting in an increased RANKL/OPG ratio. Consistent with these findings, vibration applied during experimental tooth movement increased NF-κB activation and RANKL expression in osteocytes on the compression side of alveolar bone in vivo, whereas vibration had no such effects on the tension side. Furthermore, in a co-culture of MLO-Y4 cells and RAW264.7 cells, vibration applied to MLO-Y4 cells enhanced osteoclastogenesis. These findings suggest that vibration could accelerate orthodontic tooth movement by enhancing osteoclastogenesis through increasing the number of pre-osteoclasts and up-regulating RANKL expression in osteocytes on the compression side of alveolar bone via NF-κB activation.

A single whole body vibration session influences quadriceps muscle strength, functional mobility and balance of elderly with osteopenia and/or osteoporosis? Pragmatic clinical trial

BACKGROUND

The purpose of this study verify the immediate effect of whole body vibration (WBV) on quadriceps muscle strength, functional mobility and balance in elderly patients with Osteopenia and/or Osteoporosis.

METHODS

This was a randomized pragmatic clinical trial with 34 elderly (32 women) randomly assigned to two groups: the experimental group (EG; n = 17) who underwent low-frequency (16 Hz) WBV and the control group (CG; n = 17) who performed the walk. Outcome measures were: quadriceps muscle strength measured by a maximal repetition test (1RM); functional mobility assessed by the Timed Up and Go (TUG) test and balance assessed by the Berg Balance Scale (BBS).

RESULTS

In within-group interaction, a significant increase was observed in quadriceps muscle strength (EG:p = 0.047) and balance (EG: p = 0,012; CG: p = 0,007). In between-groups interaction, a significant difference was not observed. There was an increase in the muscular strength of the EG and in the balance in both groups.

CONCLUSION

An WBV training session was able to alter the muscular strength of the LQ and the balance of the elderly with Osteopenia and/or Osteoporosis. It is suggested, however, that future studies involving larger sample number and/or populations should be developed to analyze the short-term effects of WBV.

Vibration and bubbles: a systematic review of the effects of helicopter retrieval on injured divers

INTRODUCTION

Vibration from a helicopter during aeromedical retrieval of divers may increase venous gas emboli (VGE) production, evolution or distribution, potentially worsening the patient's condition.

AIM

To review the literature surrounding the helicopter transport of injured divers and establish if vibration contributes to increased VGE.

METHOD

A systematic literature search of key databases was conducted to identify articles investigating vibration and bubbles during helicopter retrieval of divers. Level of evidence was graded using the Oxford Centre for Evidence-Based Medicine guidelines. A modified quality assessment tool for studies with diverse designs (QATSDD) was used to assess the overall quality of evidence.

RESULTS

Seven studies were included in the review. An in vitro research paper provided some evidence of bubble formation with gas supersaturation and vibration. Only one prospective intervention study was identified which examined the effect of vibration on VGE formation. Bubble duration was used to quantify VGE load with no difference found between the vibration and non-vibration time periods. This study was published in 1980 and technological advances since that time suggest cautious interpretation of the results. The remaining studies were retrospective chart reviews of helicopter retrieval of divers. Mode of transport, altitude exposure, oxygen and intravenous fluids use were examined.

CONCLUSION

There is some physical evidence that vibration leads to bubble formation although there is a paucity of research on the specific effects of helicopter vibration and VGE in divers. Technological advances have led to improved assessment of VGE in divers and will aid in further research.

Acute and Long-Term Effects of Mechanotherapy on the Outcome After an Achilles Repair: A Prospective Cohort Study With Historical Controls

OBJECTIVES

To evaluate the effects of vibration on Achilles' tendon microcirculation and characteristics following surgical repair of Achilles' tendon rupture.

DESIGN

Cohort study with historical controls.

SETTING

A university institute.

PARTICIPANTS

Participants (N=32), including 19 (16 men, 3 women; median [range] age: 43.0 [25.0-57.0] years) and 13 (10 men, 3 women; 44.00 [29.0-60.0] years) in the vibration (application to the ball of the foot, 30Hz, 2mm amplitude, 4kg pressure, and self-administration) and control groups, respectively, who underwent unilateral Achilles' tendon repairs were recruited.

INTERVENTION

A 4-week vibration intervention in the vibration group.

MAIN OUTCOME MEASUREMENTS

The tendon microcirculation was measured after the first session of vibration. The participants were evaluated repeatedly with bilateral follow-up measurements of tendon stiffness, 3 functional outcome tests, and a questionnaire survey.

RESULTS

Acute effects of the vibration were observed immediately after the 5-minute vibration (P≤.001). Lower total hemoglobin and oxygen saturation were respectively observed (P=.043) in the repaired legs 3 and 6 months postsurgery in the vibration group as compared with the control group. The vibration group also showed greater tendon stiffness, heel raising height and hopping distance 3 or 6 months postoperation in both the repaired and noninjured legs (all P<.05). The microcirculatory characteristics 2 months postoperation were correlated with the outcomes at 6 months postoperation.

CONCLUSIONS

Differences in microcirculatory characteristics and better rehabilitation outcomes were observed in the legs with an Achilles repair that underwent the early vibration intervention.

Effect of intravaginal vibratory versus electric stimulation on the pelvic floor muscles: A randomized clinical trial

Introduction

According to the International Urogynecological Association and International Continence Society people with normal pelvic floor muscle function should have the ability to voluntarily and involuntarily contract and relax these muscles. However, many women are unaware of their pelvic floor, and it is estimated that about 30–50% do not know how to actively contract these muscles. Within this context, therapeutic strategies to improve pelvic floor muscle strength and function are particularly relevant.

Aims

To compare the use of an intravaginal vibratory stimulus (IVVS) versus intravaginal electrical stimulation (IVES) on pelvic floor muscle functionality in women with pelvic floor dysfunctions who cannot voluntarily contract these muscles.

Materials and methods

Randomized clinical trial performed at a tertiary care hospital from June 2016 to September 2017. The sample comprised adult women with pelvic floor dysfunction who were unable to contract their pelvic floor muscles voluntarily. Women with latex allergy or other allergies in the pelvic region, vaginal or urinary tract infection, gynecological cancer, significant pain on palpation, or pelvic floor training over the preceding 6 months were excluded. After baseline assessment, women that met the inclusion criteria were randomized to receive once-weekly 20-minute sessions of IVVS or IVES for 6 weeks.

Results

Twenty-one women were randomly assigned to each group; 18 completed the IVVS and 17 completed the IVES protocols. The IVVS group presented a significant increase in PFM strength in relation to the IVES group (p = 0.026). There was a significant interaction between time and type of intervention for the same variable (p = 0.008) in the IVVS group.

Conclusion

Both techniques were beneficial, but IVVS was significantly superior to IVES in improving pevic floor muscle strength. Additional studies are warranted to consolidate the utility of IVVS as a treatment modality for pelvic floor dysfunction.

Effects of Whole-Body Vibration on Flexibility and Stiffness: A Literature Review

The effects of whole-body vibration (WBV) on flexibility and muscle stiffness are focused areas of research. Many studies have been performed over a large range of vibratory conditions and have reported varied results on effectiveness. When reviewing the published literature, it is difficult to track the vibration parameters that have positive effects and which have negative or no effects. In writing this paper, over 80 articles were evaluated, 24 of which met the inclusion requirements. The data gathered in the articles were used to develop charts that illustrate the vibration conditions that elicit helpful, harmful, and no effects on flexibility and muscle stiffness. A combination of published data shows that acceleration is the best metric to predict the effectiveness of WBV for improving flexibility and muscle stiffness. This review shows that acceleration in the range of 5g to 10g was most effective in increasing flexibility. Published data on muscle and tendon stiffness are limited, but shows that although WBV is generally significantly less effective in increasing stiffness than increasing flexibility, accelerations below 6.4g were the most effective.

Interaction between body composition and impact-related parameters in male and female heel-toe runners

BACKGROUND

Bone fatigue resistance and more generally the ability to dissipate the stress sustained in dynamic tasks are partly affected by tissue properties. Men and women demonstrate substantial differences in body composition.

RESEARCH QUESTION

To assess whether gender, as a function of body composition, affects impact-related parameters in running.

METHODS

A qualitative study has been conducted. Twelve females and eighteen males performed four 2-min running trials at 2.8 m∙s^-1, 3.3 m∙s^-1, 3.9 m∙s^-1, and 4.4 m∙s^-1 while recording axial and transverse tibial acceleration. Peak acceleration and power spectral density within the impact-related frequency range (vibration content) were measured. Bone mineral content, fat mass, lean mass, and muscle mass were assessed using an impedance meter. Two-way (gender × speed) ANOVAs were computed. Multiple linear regressions were then used to assess the magnitude of the effect of body composition indicators on impact-related parameters.

RESULTS

Significant gender and speed effects were observed. Females and high running speeds were associated with greater peak acceleration and vibration content at the tibia. Small interactions were observed between muscle mass and axial peak acceleration and vibration content, and between bone mineral content and transverse peak acceleration and vibration content, and axial vibration content.

SIGNIFICANCE

Women demonstrated greater mechanical stress than men during running. High mechanical stress was associated with low bone mineral content and muscle mass. These findings may have implications in the prevention and management of bone overuse injuries in runners.

Sound perception in plants

Can plants perceive sound? And what sounds are they likely to be "listening" to? The environment of plants includes many informative sounds, produced by biotic and abiotic sources. An ability to respond to these sounds could thus have a significant adaptive value for plants. We suggest the term phytoacoustics to describe the emerging field exploring sound emission and sound detection in plants, and review the recent studies published on these topics. We describe evidence of plant responses to sounds, varying from changes in gene expression to changes in pathogen resistance and nectar composition. The main focus of this review is the effect of airborne sounds on living plants. We also review work on sound emissions by plants, and plant morphological adaptations to sound. Finally, we discuss the ecological contexts where response to sound would be most advantageous to plants.

Low-frequency vibration transmission and mechanosensory detection in the legs of cave crickets

Vibrational communication is common in insects and often includes signals with prominent frequency components below 200 Hz, but the sensory adaptations for their detection are scarcely investigated. We performed an integrative study of the subgenual organ complex in Troglophilus cave crickets (Orthoptera: Rhaphidophoridae), a mechanosensory system of three scolopidial organs in the proximal tibia, for mechanical, anatomical and physiological aspects revealing matches to low frequency vibration detection. Microcomputed tomography shows that a part of the subgenual organ sensilla and especially the accessory organ posteriorly in this complex are placed closely underneath the cuticle, a position suited to evoke responses to low-frequency vibration via changes in the cuticular strain. Laser-Doppler vibrometry shows that in a narrow low-frequency range the posterior tibial surface reacts stronger to low frequency sinusoidal vibrations than the anterior tibial surface. This finding suggests that the posterior location of sensilla in tight connection to the cuticle, especially in the accessory organ, is adapted to improve detectability of low-frequency vibration signals. By electrophysiological recordings we identify a scolopidial receptor type tuned to 50-300 Hz vibrations, which projects into the central mechanosensory region specialised for processing low-frequency vibratory inputs, and most likely originates from the accessory organ or the posterior subgenual organ. Our findings contribute to understanding of the mechanical and neuronal basis of low-frequency vibration detection in insect legs and their highly differentiated sensory systems.

Efficacy of Topical Vibratory Stimulation for Reducing Pain During Trigger Point Injection to the Gastrocnemius: A Randomized Controlled Trial

OBJECTIVE

To evaluate the efficacy of topical vibratory stimulation for reducing pain during trigger point injection (TPI).

DESIGN

Double-blind randomized placebo-controlled clinical trial.

SETTING

Tertiary care university hospital.

PARTICIPANTS

A total of 136 participants were randomly recruited from among patients with myofascial pain syndrome who were scheduled for TPI. Of these, 65 were excluded because they met the exclusion criteria, and 11 because they refused to participate. Finally, 60 participants were enrolled. No participants dropped out of the study.

INTERVENTION

Participants were randomly assigned to the vibration group or control group. TPI was performed with 0.5% lidocaine using a 25-gauge needle. A vibrator was applied to the popliteal fossa for 3 to 5 seconds prior to and during TPI to the gastrocnemius; 100-Hz vibration was turned on for the vibration group and turned off for the control group.

MAIN OUTCOME MEASURES

Pain intensity during TPI was assessed using a 100-mm visual analog scale (VAS) as a primary outcome, and participant satisfaction and preference for repeated use were measured using 5-point Likert scales as a secondary outcome. These parameters were evaluated immediately after TPI. The primary outcome was evaluated using analysis of covariance and secondary outcome using the Mann-Whitney U test.

RESULTS

VAS scores for pain during TPI were significantly lower in the vibration group (30.30; 95% confidence interval [CI], 22.65-39.26) compared with the control group (47.58; 95% CI, 38.80-56.52; F=7.74; P< .01). The mean difference in VAS scores between the 2 groups was 17.27 (95% CI, 5.24-29.30). Participant satisfaction and preference for repeated use were significantly higher in the vibration group than in the control group (P<.05). No participant showed any side effects.

CONCLUSION

Topical vibratory stimulation significantly decreased pain during TPI of the gastrocnemius.

Sclerostin and parathyroid hormone responses to acute whole-body vibration and resistance exercise in young women

Whole-body vibration (WBV) has been shown to improve bone mineral density, and muscle strength and power. No studies to date have examined sclerostin and parathyroid hormone (PTH) responses to WBV combined with resistance exercise (RE). This randomized crossover study compared acute serum sclerostin and PTH responses to RE and WBV + RE in young women (n = 9) taking oral contraceptives. Participants were exposed to 5 1-min bouts of vibration (20 Hz, 3.38 peak-peak displacement, separated by 1 min of rest) before high intensity resistance exercise. Fasting blood samples were obtained before (PRE), immediately after WBV (POSTWBV), immediately post RE (IP) and 30 min post RE (30P). Pre-exercise sclerostin and PTH levels were not significantly different between conditions. Sclerostin levels significantly (p < 0.05) increased from PRE to IP for the WBV + RE condition, then decreased back to the pre-exercise level. PTH significantly decreased from PRE to 30P (p < 0.05) and IP to 30P (p < 0.01) for both conditions. Correcting for hemoconcentration eliminated the significant sclerostin responses, but the significant decrease in PTH remained (p < 0.05). There were no significant relationships found between sclerostin and PTH. In conclusion, sclerostin concentrations increased in response to the WBV + RE condition, which may have been mediated by plasma volume shifts. There was no transient PTH increase, but it showed a large decrease at 30P for both conditions. Based on these findings, the addition of WBV exposures prior to high intensity RE did not alter sclerostin and PTH responses to RE in young women.