Análisis comparativo de la actividad electromiográfica en miembro inferior entre técnicas de antepié y retropié, en corredores amateur (Comparative analysis of the electromyographic activity in lower limbs between forefoot and hindfoot techniques in amat

Un importante porcentaje de las lesiones de miembros inferiores ha sido vinculado a la tecnica de carrera, en particular, al contacto inicial con retropie (RP) o antepie (AP). Sin embargo, existe limitada evidencia de la actividad electromiografica (EMG) para ambas condiciones. El objetivo de este estudio fue comparar la amplitud EMG en miembros inferiores al utilizar tecnicas de RP vs AP durante la carrera. Trece corredores fueron evaluado a una velocidad de trote autoseleccionada en dos condiciones: contacto inicial con RP y AP. Se registro la actividad mioelectrica del recto femoral (RF), biceps femoral (BF), tibial anterior (TA), gastrocnemio medial (GM) y lateral (GL). Se considero la amplitud promedio de la EMG en 10 ciclos de carrera, normalizados a la contraccion voluntaria maxima. Los resultados destacan una mayor activacion significativa de los musculos GM y GL en el contacto AP durante la fase de apoyo, balanceo y en todo el ciclo de carrera. Adicionalmente, el TA presento una mayor activacion durante la fase de vuelo y el 100% del ciclo de carrera para la condicion RP. No se encontraron otras diferencias significativas. En conclusion, el uso de la tecnica AP incrementa la actividad muscular de GM y GL, posiblemente asociado a una mayor absorcion del impacto durante la fase de apoyo. Por otro lado, el TA incrementa su actividad con RP, lo que podria implicar un mayor control previo al contacto inicial. La tecnica de carrera se presenta como una condicion modificable segun situaciones de rendimiento o patologia. Abstract. Running technique has an impact on lower limb injuries, particularly the initial contact pattern such as rearfoot (RF) or forefoot (FF). However, there is limited evidence of the electromyographic (EMG) activity for both conditions. The aim of this study was to compare the lower limb muscles EMG amplitude between RF and FF techniques during running. Thirteen runners were evaluated at a self-selected running speed under two conditions: initial contact with RF and FF. The myoelectric activity of the rectus femoris (RE), biceps femoris (BF), tibialis anterior (TA), medial gastrocnemius (GM) and lateral (GL) were analysed. The EMG amplitudes of 10 running cycles were averaged and normalized to the maximum voluntary contraction. The results included a significantly higher activation of GM and GL muscles for the FF condition during the stance phase, balance and the entire running cycle. In addition, TA showed higher activation during the swing phase and the 100% running cycle for the RP condition. No other significant differences were found. In conclusion, FF technique increases GM and GL myoelectric activity, possibly associated with a higher impact absorption during the stance phase. On the other hand, TA increases its activity for RF condition which may imply a greater neuromuscular control prior to initial contact. Finally, the running technique is presented as a modifiable condition which can be changed to enhance performance or in pathologic circumstances.