Relationship between quadriceps angle (Q) and plantar pressure distribution in football players Relação entre o ângulo quadriciptal (ÂQ) e a distribuição da pressão plantar em jogadores de futebol

Objectives: To determine whether there is an association between the Q-angle (Q) and the distribution of plantar pressure in football players, and to compare the characteristics of these athletes with non-practitioners of this sport. Methods: 121 male participants were selected: 50 football practitioners (FP) and 71 non-practitioners (NP). We concurrently evaluated the Q-angle and the plantar pressure through the software of postural assessment (SPA) and the F-Mat System, respectively. To verify the correlation between the Q-angle and peak pressure values in four segments of the foot (medial and lateral forefoot, medium-foot and hind-foot), the Pearson coefficient (r) for parametric analysis was used. The independent t-test was used to compare these variables between the groups. Data normality was verified by the skewness values, adopting a significance level of 5%. Results: A negative and weak correlation was found (r=-0.32) between the Q-angle and the plantar pressure in the right medium-foot. The groups differed with regards to the right Q-angle (11.36° in FP versus 13.80° in NP) and the left Q-angle (11.03° in FP versus 13.96° in NP). Plantar pressure was also different between the groups, with FP showing higher mean values for the right side and for the left side of the forefoot (0.77 kg/cm2 in FP versus 0.63 kg/cm2 in NP, and 0.65 kg/cm2 in FP versus 0.54 kg/cm2 in NP, respectively). However, mean peak pressure values for the left medium-foot were higher among NP (0.37 kg/cm2 in FP versus 0.46 kg/cm2 in NP). Conclusions: There was no evidence of an association between the Q-angle and the distribution of plantar pressure in FP. The athletes showed reduced Q-angle values and higher mean peak pressure values for the right and left aspects of the forefoot, suggesting a varus malalignment and a supine distribution of plantar bases.