Leversen et al. (PLoS One 7(6):e38830, 2012) emphasise the importance of understanding the principles of life-long development. In their study of motor control, they found a common tendency towards improved motor performance from childhood to adulthood and a subsequent deterioration. The aim of our study was to examine this issue further by investigating fine motor behaviour (tracing a model line) in 196 participants (age range 12-95 years old) in two sensory conditions-proprioceptive ? visual (PV) and proprioceptive only-in both hands and in two types of movement, frontal and transversal. Regression analyses of line length and task performance speed in relation to age were conducted for the different test conditions. The best performance was found in middle age, and a quadratic function provided the best fit for most of the test conditions. The corresponding inflection points (the age at which graphical analysis showed a change in performance as a peak of maturation before decline due to ageing) showed earlier ages in the proprioceptive condition. For most types of movement analysed, performance speed was slower under the PV condition. Paired correlation analysis showed that the symmetry of precision performance between hands became stronger with age. The results provide information on age-dependent differences in proprioception based on fine motor performance. They may be of use in the design of preventive strategies for preserving proprioceptive function by reducing the risk of falls and accidents or diseases such as Parkinson's.

The differences in fine motor precision over line model in different sensorial conditions (visual-proprioceptive and proprioceptive only) for different movement directions (transverse, frontal, and sagittal) and both hands were measured digitally with use of special software. The observed variables were directional (D) and formal (F) deviations, together with changes of line length (LL) from the base model. Analysis indicated non-significant differences for all measured variables for hand use, while for the remaining factors (sensory test condition and movement direction), the differences were significant for all levels. Both sensory information and movement directions are important for hand-drawing precision, not just the specific hand used.

Rose (1970) showed that women had more symmetrical precision in movements in hands, whereas men performed more asymmetrically (with dominance for right hand). These findings were congruent with Ananiev’s (1968) scheme differentiated for sexes, in which for men there was a need for use of additional adaptive mechanisms (asymmetry) whereas women passed with basic ones (symmetry). Our study aimedto check the hands symmetry/asymmetry and correlations in fine motor precision and speed in both sexes and how they change in different age groups. The results of our study showed that the highest asymmetry in fine motor precision was related (for both sex groups and among all movement types) to the developmental periodof life (12-17 years old) followed by group age of 64-95 due to ageing processes. In our study women performed with less asymmetry between both hands for majority of observable variables compared to men in all age groups. The highest frequency of asymmetrical performance in fine motor precision for both sexes was observed in the Frontal movement type, followed by the Transversal, and least, in the Sagittal. For the speed performance, the highest frequency of asymmetrical performance was shown in the Transversal movement type. Keywords: fine motor precision; speed; sex differences; age-depended differences; Proprioceptive diagnostics; M.K.P.