Human Postural Adaptation to Earthly and Atypical Gravitational Environments. Effects of Sport Training on Stabilometric Parameters.

Earthly gravitational environment conditioned organisms evolutional transformations. Mankind evolution in acquiring the upright posture changed functional anatomical characteristics behaved in an almost stable environment (g= 9.81 m/s). Technological environment, up to the microgravity conditions, faces peculiar gravitational conditions that may affect locomotion, working capabilities and living situation. To understand human adapting capacities some systematic knowledge may come from the study of trained persons such as those practising sports in different postures and environments. The aims of this study is to investigate whether long term practice of a physical activity, in which body attitude and postural regulation are organized in different ways, can influence postural control and generate a “postural memory”. Three groups of male athletes (average age: 22±3 years, weight: 69±9 kg, height: 179.6±5.5 cm) were studied in 26 athletes (runners, bikers and swimmers). The protocol consisted of balance tests with eyes open (EO) and closed (EC) in bipodalic and monopodalic conditions. Bikers showed a mean velocity lower than swimmers both in EO (p=.004) and EC condition (p=.03). Also for mean velocity in M-L plane (p=.02) and for perimeter length (p=.003) during EO condition, bikers showed lower results. Moreover, bikers showed a more posterior position of the centre of pressure when compared to runners with EO (p=.02) and with EC (p=.03). These findings suggested that sport-specific physical training induced postural modifications on upright stance. Within the main results concerning the gravitational aspects appears paramount that swimming, the most 0g sport (water is the best terrestrial 0g simulator environment) gives the smallest postural memory conditioning. The studies about human postural control in normal condition, about postural modifications and memory induced by specific physical training in normal versus atypical gravitation setting, open new perspective in anthropological studies on postural adaptations, ability and performance in extreme environments.