Prolonged muscle vibration reduces maximal voluntary knee extension performance in both the ipsilateral and the contralateral limb in man

Previous studies have shown that prolonged vibration of the rectus femoris decreases maximal voluntary knee extension performance in the ipsilateral leg. In the present study, measurements of maximal voluntary isometric knee extension contractions with the ipsilateral (right) leg and the contralateral (left) leg were made immediately before and after vibration treatment. Significant reductions in maximal force and maximum rate of force generation occurred in both the ipsilateral and contralateral legs following 30 minutes of continuous vibration at both 30 Hz and 120 Hz, with 30 Hz causing the greatest ipsilateral effects. However, although the level of neural activation (iEMG) of the vibrated muscle (right rectus femoris) was reduced following 30 Hz vibration (P=0.026), there were no significant changes occurring in a synergistic muscle (right vastus lateralis) or in either contralateral muscle. It was concluded that muscle vibration may act through spinal reflex pathways to influence the homonymous motoneuron pool. The effects on contralateral force but not specific muscle iEMG suggest an effect on heteronymous motoneuron pools or an effect acting on central descending drive to contralateral muscles. These findings may have implications for the rehabilitation of patients with an immobilised limb. Electronic Publication     

Active or passive journeys and low back pain in adolescents

The objective of this cross-sectional study was to study associations between low back pain (LBP) and modes of transport to school and leisure activities among adolescents. The study population included all adolescents in eighth and ninth grade in two geographic areas in eastern Norway. Eighty-eight adolescents participated (mean age 14.7 years), making the response rate 84%. Data concerning active (walking/bicycling) and passive (bus/car) journeys were obtained from lists and maps from local authorities, and from the pupils, using a questionnaire that also included LBP, activities and wellbeing. Distance walked/bicycled to school was slightly shorter among those reporting LBP in bivariate analyses. Walking/bicycling more than 8 km weekly to regular activities was inversely associated with LBP in multivariate analysis (OR 0.3; 95% confidence interval 0.1–1.0). No associations were found between passive journeys and LBP. The results raise the question for future research of whether lack of active transport may be one cause behind the increase in juvenile LBP.     

振动性血管损伤与血管内皮活性物质关系的研究

目的 探讨手传振动对血管内皮活性物质的影响及意义。方法 对不同接振时间的煤矿掘进工进行了血管内皮活性物质的测定，并同对照组比较分析。结果 内皮素、血栓素B2随接振时间的延长有明显增高的趋势（P＜0．05，P＜0．01）。一氧化氮、6－酮－前列腺素F1α随接振时间的延长有明显降低的趋势（P＜0．05，P＜0．01）。结论 手传振动可导致血管内皮活性物质的改变，这种改变可能与振动性血管损伤有一定联系。     

超低浓度灌注共振吸脂的临床研究

目的：探讨一种低创、快速、确切的吸脂方法。方法：将０．０１５～０．０３％利多卡因肿胀液行皮下快速超量灌注，用高频共振吸脂机将充分肿胀的脂肪振碎低负压吸出体外，同时计算术中出血量，累进栖组１３例术中出血量平均的１４ｍｌ，占抽出物的０．８４％，吸脂快速、彻底、术后皮肤表面平滑，皮肤松驰度明显改善。结论：超低浓度利多卡因皮下超量江注行指肪共振吸脂是一种操作更简单、更快速、真正低创的吸脂技术。     

High-frequency vibration training increases muscle power in postmenopausal women

OBJECTIVE: To test whether training on a high-frequency (28Hz) vibrating platform improves muscle power and bone characteristics in postmenopausal women. DESIGN: Randomized controlled trial with 6-month follow-up. SETTING: Outpatient clinic in a general hospital in Italy. PARTICIPANTS: Twenty-nine postmenopausal women (intervention group, n=14; matched controls, n=15). INTERVENTION: Participants stood on a ground-based oscillating platform for three 2-minute sessions for a total of 6 minutes per training session, twice weekly for 6 months. The controls did not receive any training. Both groups were evaluated at baseline and after 6 months. MAIN OUTCOME MEASURES: Muscle power, calculated from ground reaction forces produced by landing after jumping as high as possible on a forceplate, cortical bone density, and biomarkers of bone turnover. RESULTS: Over 6 months, muscle power improved by about 5% in women who received the intervention, and it remained unchanged in controls (P=.004). Muscle force remained stable in both the intervention and control groups. No significant changes were observed in bone characteristics. CONCLUSION: Reflex muscular contractions induced by vibration training improve muscle power in postmenopausal women.     

Use of the Rydel-Seiffer graduated tuning fork in the assessment of vibration threshold in postherpetic neuralgia patients and healthy controls.

BACKGROUND AND AIMS: Afferent large fibre impairment has been reported as a useful predictor of postherpetic neuralgia (PHN) in patients with acute herpes zoster infection, using an electromechanical device to provide quantitative vibrametry. We aimed to demonstrate a clinically significant increase in vibration threshold in individuals with PHN compared to age-matched controls, using the portable and affordable Rydel-Seiffer graduated tuning fork. METHODS: We studied 45 PHN subjects aged over 55 years, and 45 age-matched controls with no history of herpes zoster infection. We excluded subjects with a history of disorders associated with neuropathy or immunocompromise. Measurements were performed at the ulnar styloid process and the head of the first metatarsal on the right side, in a warm room with the subject seated. Readings were taken in triplicate and the data analysed by a repeated measures design. RESULTS: We observed a significant difference in vibration threshold at both wrist and toe between the PHN and control groups (p < 0.001). Age-stratification of subjects produced an increased and clinically useful difference between the two groups at both sites in subjects between 55 and 70 years (p < 0.0001). CONCLUSIONS: We have shown a statistically significant decrease in vibration sensitivity in individuals with PHN aged 55-70 years compared to age-matched healthy controls, using the Rydel-Seiffer graduated tuning fork. A prospective study of patients with acute zoster infection is needed to determine the sensitivity and specificity of the graduated tuning fork in predicting PHN in patients with acute zoster infection.     

Constrained tibial vibration does not produce an anabolic bone response in adult mice

Osteoporosis is characterized by low bone mass and increased fracture risk. High frequency, low-amplitude whole-body vibration (WBV) has been proposed as a treatment for osteoporosis because it can stimulate new bone formation and prevent trabecular bone loss. We developed constrained tibial vibration (CTV) as a method for controlled vibrational loading of the lower leg of a mouse. We first subjected mice to five weeks of daily CTV loading (0.5 G maximum acceleration) with loading parameters chosen to independently investigate the effects of strain magnitude, loading frequency, and cyclic acceleration on the adaptive response to vibration. We hypothesized that mice subjected to the highest magnitude of dynamic strain would have the largest bone formation response. We observed a slight, local benefit of CTV loading on trabecular bone, as BV/TV was 5.2% higher in the loaded vs. non-loaded tibia of mice loaded with the highest bone strain magnitude. However, despite these positive differences, we observed significantly lower measures of trabecular structure in both loaded and non-loaded tibias from CTV loaded mice compared to Sham and Baseline Control animals, indicating a negative systemic effect of CTV on trabecular bone. Based on this evidence, we conducted a follow-up study wherein mice were subjected to CTV or sham loading, and tibias were scanned at the beginning and end of the study period using in vivo microCT. Consistent with the findings of the first study, trabecular BV/TV in both tibias of CTV loaded and Sham mice was, on average, 36% and 31% lower on day 36 than day 0, respectively, compared to 20% lower in Age-Matched Controls over the same time period. Contrary to the first study, there were no differences between loaded and non-loaded tibias in CTV loaded mice, providing no evidence for a local benefit of CTV. In summary, 5 weeks of daily CTV loading of mice was, at best, weakly anabolic for trabecular bone in the proximal tibia, while daily handling and exposure to anesthesia was associated with significant loss of trabecular and cortical bone. We conclude that direct vibrational loading of bone in anesthetized, adult mice is not anabolic.     

Vibrations produced during erbium:yttrium–aluminum–garnet laser irradiation

The purpose of this study was to evaluate vibrations induced by an erbium:yttrium–aluminum–garnet (Er:YAG) laser in the non-contact mode and compare the vibrations with different pulse durations and energy parameters. The experiment was conducted on an extracted tooth built up in silicone impression material. The vibrations were measured by piezoelectric accelerometer for a super-short pulse (SSP), a very short pulse (VSP), and a short pulse (SP) at a frequency of 5 Hz for 1 s. For VSP and SP, the energy parameters tested were 200 mJ, 300 mJ, and 400 mJ. Measurements were performed 15 times for each individual irradiation energy level. The highest values of vibrations were measured for SP (0.160 ± 0.04 m/s²), and the lowest were measured for VSP mode at the energy parameter 200 mJ (0.05 ± 0.02 m/s²). There was a statistically significant (P < 0.01) difference between the various laser pulse modes (SSP, VSP, SP) at different energy parameters. At energy levels of 300 mJ and 400 mJ, the least amount of vibration during cavity preparations with the non-contact Er:YAG laser was produced by SSP mode.     

Vibrotactile threshold measurement for detecting peripheral neuropathy: defining variability and a normal range for clinical and research use

Aims/hypothesis We aimed to define normal ranges for vibration sense as measured by vibratory perception thresholds (VPTs) using biothesiometry. Methods We performed biothesiometry in a community-dwelling sample of 901 people aged 55 to 85 years who did not have diabetes. We quantitated the variation between repeat measures using analysis of variance and Bland–Altman plots. We also plotted the age- and sex-specific reference ranges. Results We found small but statistically significant differences between repeat measures using the ascending and descending method of limits. Statistically higher vibration thresholds were noted on the right arm and leg compared with the left. Significantly higher vibration thresholds were also seen in men vs women for both lower limbs. We also defined sex-specific reference intervals (normal ranges) for biothesiometry for older persons and quantitated the increase in vibration threshold with increasing age. Conclusions/interpretation For reliability, it may be sufficient to obtain the average of two ascending measures separated by at least 1 min in just the right hand or right foot, since this is usually the one with the higher threshold. Although identical reference ranges can be used for men and women for the upper limb, there are significant differences in the lower limbs. The major determinant of VPT is age: we have established age-specific norms for VPT testing for adults between 55 and 85 years of age.