Whole body vibration activates the tonic vibration reflex during voluntary contraction.

[Purpose] The beneficial neuromuscular effects of whole-body vibration are explained by the tonic vibration or bone myoregulation reflex. Depending on factors that remain undefined, whole-body vibration may activate the tonic vibration or bone myoregulation reflex. We aimed to examine whether voluntary contraction facilitates activation of the tonic vibration reflex during whole-body vibration. [Participants and Methods] Eleven volunteers were included in this study. Local and whole-body vibrations were applied in a quiet standing (without voluntary contraction) and a semi-squatting (isometric soleus contraction) position. Local vibration was applied to the Achilles tendon. Surface electromyography was obtained from the soleus muscle. The cumulative average method was used to determine soleus reflex latency. [Results] In the quiet standing position, the bone myoregulation reflex latency was 39.9 ± 4.1 milliseconds and the tonic vibration reflex latency was 35.4 ± 3.6 milliseconds. Whole-body vibration application in the semi-squatting position activated the tonic vibration reflex in four participants and the bone myoregulation reflex in seven participants. Local vibration activated the tonic vibration reflex in both positions for all participants. [Conclusion] Simultaneous whole-body vibration application and voluntary contraction may activate the tonic vibration reflex. Determining the spinal mechanisms underlying the whole-body vibration exercises will enable their effective and efficient use in rehabilitation and sports.

High-frequency whole-body vibration activates tonic vibration reflex.

Objectives: The aim of this research was to examine whether high-frequency whole-body vibration activates the tonic vibration reflex (TVR). Patients and methods: The experimental study was conducted with seven volunteers (mean age: 30.8±3.3 years; range, 26 to 35 years) between December 2021 and January 2022. To elicit soleus TVR, high-frequency (100-150 Hz) vibration was applied to the Achilles tendon. High-frequency (100-150 Hz) whole-body vibration and low-frequency (30-40 Hz) whole-body vibration were applied in quiet standing. Whole-body vibration-induced reflexes were recorded from the soleus muscle using surface electromyography. The cumulative average method was used to determine the reflex latencies. Results: Soleus TVR latency was 35.6±5.9 msec, the latency of the reflex activated by high-frequency whole-body vibration was 34.8±6.2 msec, and the latency of the reflex activated by low-frequency whole-body vibration was 42.8±3.4 msec (F(2, 12)=40.07, p=0.0001, ƞ2 =0.87). The low-frequency whole-body vibration-induced reflex latency was significantly longer than high-frequency whole-body vibration-induced reflex latency and TVR latency (p=0.002 and p=0.001, respectively). High-frequency whole-body vibration-induced reflex latency and TVR latency were found to be similar (p=0.526). Conclusion: This study showed that high-frequency whole-body vibration activates TVR.

A Survey Focusing on Lucid Dreaming, Metacognition, and Dream Anxiety in Medical Students.

INTRODUCTION: The aim of this study was to examine the level of lucidity and its relation with metacognitive beliefs and dream anxiety in medical students. METHODS: Nine hundred sixteen medical students were enrolled in the study. The participants were assessed with the Lucidity and Consciousness in Dreams Scale (LuCiD), the Metacognition Questionnaire-30 (MCQ-30), and the Van Dream Anxiety Scale (VDAS). RESULTS: There was no significant difference in mean total lucidity score between females and males, but there were some significant sex differences in subscales of lucidity, and control was significantly higher in male students, while realism, thought, and dissociation were significantly higher in female students. In addition, females had more dream anxiety levels, higher total MCQ-30 scores, and higher cognitive confidence and uncontrollability scores according to Metacognition Questionnaire-30 than males. We also found that the mean lucidity level was positively correlated with the mean total metacognition score and the mean total dream anxiety level. DISCUSSION: Our results suggest that female medical students tend to have more realistic dreams (p=0.018), have more logical thoughts during dreaming (p=0.011), and have a more dissociative experience during dreaming (p=0.028), while male medical students have more controlled dream events (p=0.002). There seem to be differences according to lucidity features between sexes, and the relationship between subdomains of lucidity and metacognition might lead to new therapeutic approaches to several psychiatric disorders such as anxiety disorders.