Comparison between simple neuro-motor reaction time(SNMRT) and relevant speed of movement (VM) in children aged 6 to 11

Introduction The total time of neuromotor reaction (TTRNM) is what exists between appearance of the stimulus, and the beginning of the muscular response. In this study the TTRNM has been evaluated throught the simple neuromotor reaction to a visual stimulus. According to the most recent studies, the simple TTRNM can be initially subdivided at first in: TPM (pre-motor time) that exists between the application of the stimulus to the action and the modifying EMG (electromyography) of the muscles that will then be recruited, and TM or elettro-mechanical delay , represented by the temporal interval that exists between the arrival of the EMG signal and the beginning of the movement. The TTRNM on an average estimate, is therefore attributed in part to the pre-motor time (TPM=76.2%) and in part to the motor time (TEM+TM=23.8%) . Methods In this study we wanted to examine the simple neuromotor response and the initial speed of release in 105 children, aged 6-11, attending an Italian elementary school such to observe the eventual variations according to the age (Tab.1). The instrumentation used for such evaluation has already been published2 and is constituted by 6 elements: - a springboard of departure;- a double series of photocells (the first couple placed in line at 3.5cm distance to the tibial crest of the child legs and the second couple placed in a more advanced position, 10cm far from the previous couple); - a series of six pillars with a bright led to order;- a switchboard, joined output-input to the instrumentation arranged on the field, in a position to manage the starting of the led, to determine the latency between the arrival of the stimulus and neuromotor response of the children and to calculate the speed of the limb passage across the photocells system; - an equipped computer equipped with an appropriate software to distribute the visual stimulus in the moment it is wanted by the tester and to receive the returning signals from the equipment, working them out in real time; -a printer. Results Through this study we have been able to verify a quantitatively noteworthy difference in the simple neuromotor response and in the initial movement speed among the groups A and B (children aged 6 to 9) and the group C (children aged 10 to 11); among the three groups a correlation exists among personal age and speed of simple neuromotor reaction (TRNMS) and the relevant speed of movement (VM). Discussion/Conclusion The reduction of the time of simple neuromotor reaction (TRNMS) and the relating speed of movement (VM) in correspondence with the progress of the age, represent positive indicators of development and maturation of the nervous system in the child. What remains is if such correlation becomes confirmed in the successive age and if it also exists in referring to the times of neuromotor reaction of choice (TRNMdS). References Welford A.T. , Reaction time, Academic Press, London 1980 2 Minelli R.,D’Introno L., et al Metodologia di valutazione del tempo di reazione neuro-motoria e della velocità di movimento nello sportivo. Medicina dello sport , vol 48, n.3, 1995 Schmidt R.A.,Wrisberg C.A., Motor learning and performance, Human Kinetics , Champaign USA 2000 Pirola V. Cinesiologia : Il movimento umano , Edi Ermes , Milano 1998