# Vibration from Electric Hand-Held Harvesters for Olives
## 1 Introduction  
Olive cultivation in Italy produces approximately 2,500,000 tons and the cultivated surface is about 1,160,000 ha [1], mainly concentrated in the centre-south of the peninsula. According to FAO statistics [2], Italy, alongside Spain, Greece, and Turkey, is among the major producers of olive oil in the Mediterranean basin. However, olive cultivation incurs high production costs, mainly during the harvesting phase. A recent study by [PERSON] et al. [3] analyzed several scenarios and reported harvesting costs of around 3300 EUR/ha with manual harvesting, 1720-1980 EUR/ha with the use of hand-held equipment, 920-1350 EUR/ha with the use of trunk-shakers and ground nets, 660-1060 EUR/ha using trunk-shakers equipped with collecting umbrella, and 330-500 EUR/ha using self-propelled straddle harvesters in super-intensive groves. Harvesting costs decrease with the increase in mechanization level. The mechanization of the harvesting of olive groves characterized by low tree density, old trees, irregular spacing, located in marginal areas, in some cases terraced and impracticable, such as that present in many Italian regions, is a very difficult task [4]. The most appropriate level of mechanization should be chosen in a manner closely connected withtechnical-organizational factors such as the structural characteristics of the territory and of the farm [5]. In olive groves where high levels of mechanization are not possible, the use of hand-held vibrating harvesters is quite spread. These machines are approximately capable of increasing by three times the productivity of workers using manual harvesting methods, and they also reduce harvesting costs [6]. The use of vibrating equipment, both portable and self-propelled, is very common in agriculture for harvesting operations of a wide range of products. Unfortunately, the workers, when using these machines, are mainly interested in productivity, and very often they underestimate ergonomics and safety aspects. Vibration of the hand-arm system is probably the most important risk connected with the use of portable harvesters and vibrating tools in general [7; 8; 9; 10; 11; 12]. Exposure to hand-arm vibration may result in several chronic disorders such as sensory, vascular, and musculoskeletal symptoms, recognized by several names: secondary Raynaud's phenomenon, vibration white finger, dead finger, traumatic vasospastic disease, and vibration syndrome, collectively known as Hand-Arm Vibration Syndrome (HAVS) [13; 14; 15; 16; 17; 18]. If detected in the early states, HAVS is reversible by reducing or eliminating further exposure to vibration, but, once in an advanced stage, symptoms are progressive, and treatment is usually ineffective [19]. Moreover, as recently established [20; 21], exposure to vibration leads to the production of reactive oxygen species that, in turn, can cause damage to biomolecules, including DNA. DNA damage is known to lead to carcinogenesis, teratogenesis and premature aging, so vibration risk exposure should be promptly recognized and properly managed. The transmission of the vibration and its propagation in the organism through the hand-arm system is a complex phenomenon that involves several factors, including biodynamic characteristics [22; 23], mechanical impedance of the hand [22; 24; 25], posture [26; 27], muscle tension and hand forces [28; 29], handle size [29], use of isolators [30], which interact with the intensity of the vibration and its transmissibility [31]. Considering the vibration produced by portable harvesters for olives, the kinematics of the harvester head, the rod material, its geometry (length and diameter), and its configuration (fixed length or telescopic) play a key role. Other important aspects to be considered are the working conditions (idling or full-load) and the operator characteristics (weight, grip force, ability), so the assessment of the effective risk requires direct measurement under real working conditions or the definition of standardized procedures able to provide reliable acceleration values [32; 33].