POSTURAL ALTERATIONS AND DISTRIBUTION OF PODALIC LOAD IN AGONISTIC ASYMMETRIC SPORT ACTIVITIES

Introduction. Asymmetric sports are characterized by a non-symmetric muscular activity of kinetic chains of two hemisoma. The aim of our case-control study is to evaluate the interference of non-symmetric muscular activity on the postural asset. In particular boxe and kick-boxing fighters were evaluated because of their asymmetric guard. Materials and methods. From January to May 2012, 35 subjects were recruited; 15 were playing asymmetric sports (8 boxers and 7 kick-boxers), 10 symmetric sports (5 football players and 5 basket players), 10 no sport. Inclusion criteria were: age between 18 and 35 years, male gender, BMI range 20-25 kg/m², right hand preference, middle- high agonistic level (at least 4 training for week, duration of the session≥ 1 hour), absence of pain or of muscle-skeletal injuries in the last 12 mounths. All subjects underwent clinic and biopostural (including baropodometric static and dynamic examination, stabilometric examination and podoscananalyzer) examination. Results. Our results show that players of asymmetric sports present alterations in weight distribution beetwen the 2 lower limbs (left 44.86%, right 55.14%), an average alteration of the hindfoot/forefoot ratio on the left (hf= 60.54%- ff = 39.49%) and invertion of this ratio on the right (hf= 46.95%- ff= 53.05%) with PMP (pressure maximum points) localized on the right forefoot in the 80% of the patients. Moreover mean values of COF (center of foot) angle (5.6°) show a rotation in an anticlockwise direction of the over-segmentary structures in all the athletes. At stabilometric examination, mean values of ellipse surface were respectively of 71.09 mm² with OE (opened eyes) and of 36.15 mm² with CE (closed eyes). Players of simmetric sports present: weight distribution (left 48.16 – right 51.84%), hindfoot- forefoot ratio on the left (hf=59.1%- ff= 40.9%) and on the right (hf=59.06%- ff=40.94%) with PMP localized on the right forefoot in only the 10% of the patients; moreover mean value of COF angle (0.46°) was normal. At stabilometric examination, mean values of ellipse surface were normal with OE (42.96 mm²) and CE (49.16 mm²). As for those who don’t play any sport: weight distribution (left 49,38%- right 50,62%), hindfoot/forefoot ratio on the left (hf=56.77%- ff 43.23%), on the right (hf=53.78%- ff =46.22%) with PMP localized on the right forefoot in only the 15% of the patients; besides mean value of COF angle was 0.91°. At stabilometric examination, mean values of ellipse surface were normal (respectively of 209.66 mm2 with OE and of 247.08mm2 with CE). Conclusions. Our results seem to confirm the hypothesis that asymmetric sport brings some postural changes such as weight distribuition on the lower limbs, hindfoot/forefoot ratio, COF angle. Moreover in agonistic players (asymmetric and symmetric athletes) the stabilometric examination shows a reduction of ellipse surface with OE compared to CE, suggesting an increase of proprioceptive control on the balance. We took underconsideration the boxe and kickboxing fighters who during the sport practice assume postures that are consisting with our findings; so our results are in agreement with the theory about the plasticity of the tonic-postural system. Bibliography 1. Oyama S, Myers JB, Wassinger CA, Daniel Ricci R, Lephart SM. Asymmetric resting scapular posture in healthy overhead athletes. J Athl Train. 2008 Oct-Dec;43(6):565-70. 2. Leroy D, Polin D, Tourny-Chollet C, Weber J. GRHAL (Research group on gait disorders), CHU Rouen. Spatial and temporal gait variable differences between basketball, swimming and soccer players. Int J Sports Med. 2000 Apr;21(3):158-62. 3. Bressel E, Yonker JC, Kras J, Heath EM. Comparison of static and dynamic balance in female collegiate soccer, basketball, and gymnastics athletes. J Athl Train. 2007 Jan-Mar;42(1):42-6.