## 4 Results and Discussion
### WBVE and Mental Conditions
The repeated application (three times) of WBV presented improvements on cognition. WBV have been correlated with higher intelligence and younger age, but not related to ADHD symptoms. [PERSON] et al., 2014 [94; 95] described a protocol of WBV using 30 Hz (frequency) and 4 mm (vibrating amplitude) in healthy and ADHD individuals. It was pointed out that the WBV improved cognitive performance of healthy and ADHD subjects. WBV can be considered as a type of exercise cheap and easy to be applied. Then, it might be auseful in the clinical practice. Additionally, it was found that the WBV was shown to considerably improve neuropsychological test performance of an adult with ADHD, it remains unknown how long these effects last and to what extent the improvements as measured in neuropsychological tests can be generalized to functioning in daily life (e.g., academic or occupational setting). Improvements in the performance of neuropsychological test after WBV intervention indicate the clinical relevance of this kind of exercise in the management of individuals with neuropsychological commitments, as the ADHD. [PERSON] et al., 2020 [54] investigated the effect of WBV in one session with five sets of 1-min vibration and 30 s of rest between each set and concluded that the WBV has the potential to enhance neurocognition. WBV had positive immediate effects on the reaction time in both groups; however, it had negative effects on anticipatory skill with high speed in women with normal lumbar lordosis; these negative effects appeared to be due to mental fatigue in the participants (Table 8). It is important to take care with the use of WBV exercise in COVID-19 survivors due to the increased thromboembolic risk in these individuals. Thromboembolic risk in COVID-19 survivors is a possible and severe complication. [PERSON] et al. 2020 [96] described a 27% occurrence of venous thromboembolism critically COVID-19 subjects in the ICU. Of these, 81% evolved to an acute pulmonary embolism despite thromboprophylactic medication. Acute thrombosis is a contraindication for WBV and therefore caution is needed and the use of WBV in COVID-19 survivors requires careful evaluation by interdisciplinary teams, pondering the risk-benefit ratios of this intervention. It is well-known that COVID-19 leads to the commitment of the human health due to injuries in the respiratory tract and central nervous and musculoskeletal systems [3; 4], among other specific organs and tissues. Some symptoms observed in the COVID-19 patients are fatigue [97], muscle pain [98], sleep disorders [99; 100], and respiratory symptoms [101], these symptoms being also present in individuals with different diseases, such as metabolic syndrome [49; 53; 73; 79], knee osteoarthritis [63; 64], and COPD patients [57; 80; 86; 87] which have profited by the management with WBV exercise. WBV exercise has been described as a potential intervention/training modality in sport, exercise, health, and rehabilitation. Muscle force and power increase for athletes, the aged, and those with diseases due to WBV exercise are reported. The action mechanism involved in WBV exercise response would be explained through neural factors as tonic vibration reflex, in which the muscle spindle plays a role in activating the muscle. Moreover, effects of the WBV exercise in the central nervous system could lead to neuroendocrinological responses that could justify the effect of this kind of exercise intervention at various organs [102; 103]. These effects would justify the use of WBV exercise in COVID-19 survivors. Although, there are limitations, this narrative review is based on the best available knowledge of the effects of WBV exercise in several clinical contexts that might be extrapolated to post COVID-19 subjects. However, it is relevant to consider that this study is a theoretical approach and lacks validation in the context of COVID-19.