## 7 Conclusions
These vibration limits are established through standardization, which means having benchmarks for comparison so that human subjects are not exposed to vibrations around these thresholds, which are considered dangerous from the point of view of health deterioration. This does not guarantee that, with repeated exposure to vibrations at values below these limits, the state of health of the exposed person will not be affected over time [1; 4]. It can be observed that the protection of people exposed daily to vibrations in the workplace is evaluated under strict standards regarding the duration of exposure [1; 5; 6; 7; 8; 10], the acceleration amplitude, protective equipment, and periodic checks of the health of the individual exposed to them. There are three standard directions regarding the exposure of a person to vibration, developed by the European Committee for Standardization (CEN) [1], which have been applied since the 1990s. They are concerned with the response of the human body to the action of vibration and are continuously improving [23] by, for instance, establishing general protection limits and safety limit values for devices and work tools and taking individual measures to protect the worker (e.g., using gloves). Gloves are important work protection equipment for vibration reduction. Research however should aim to gather existing results for the various fingers, including the index finger's mechanical properties and anatomical structure, which could be used to evaluate and validate experimental and in silico models in the future [33]. It has been estimated by studies that a daily vibration exposure of 4-8 h/day \"weighted energy\" will develop a symptom latency period of 10-20 years before the appearance of the first symptoms of the condition in question. A study was carried out on a group of people in whom the appearance of the first symptoms of the condition (10%) was observed after these years, in conformity with [1]. Anticipation of the latency period in 30%, 40%, and 50% of subjects exposed to vibration led to the appearance of the first symptoms of finger whitening after a period of daily vibration exposure to only 4 h/day \"_weighted energy_\" [1]. For an easier understanding of the results expressed by other researchers in this field, they have been presented in Figure 15.  
Figure 15 shows a comparison between the probability of the occurrence of ailments caused by a one-week exposure of people to vibrations [%] for different workplaces over ten years (1991-2000). There is an increase in symptoms of professional illness for builders as the construction industry gains momentum. Figure 16 represents a comparison between measurements taken 10 years apart of the vibrations that are transmitted to the hand in an industrial environment, for a common frequency scale of 15-30 Hz. It can be observed that, at frequencies lower than 15 Hz, the vibration, either due to absorption or impedance, is high, which also validates the studies carried out in the 1990s by [PERSON] [1]. Figure 16: Comparison results of absorption power or impedance of the hand between older and newer research: (**a**). non-linear biodynamic models of the hand–arm system and parameter identification using the vibration transmissibility or the driving-point mechanical impedance [56]; and (**b**). estimation of vibration power absorption density in human fingers [16]. Figure 15: A summary of paper results concerning the probability [%] of symptom occurrence, depending on occupation, when subjects are exposed to vibrations for five working days (studies from 1991 are from reference [1] and those from 2000 are in accordance with reference [66]). The higher the gripping force [36; 55], the higher the absorption; the results are in accordance with [PERSON]. (2013) [17] and the data presented in Table 7.  
All countries have legislative measures to prevent illness among professionals working with vibration sources [5; 62; 67; 7; 88; 5; 6; 8]. Also, measures are provided to reduce vibrations in work machines starting from the design phase.