Drag Forces in Paralympic Swimming

The present work focuses on the problems linked to the biomechanical role of the kick, in freestyle or front crawl swimming, in category S7 paralympic swimmers. These are swimmers with limited movement of the arms, trunk, and legs at a low to moderate level. The category also groups swimmers with moderate unilateral disability, short stature, or absence of limbs. The focus of the discussion is to clarify whether the front crawl kick, in these swimmers, generates efficient propulsive forces, or only fulfills a stabilizing role of the trunk, thus increasing the forces of resistance to advance [1, 5, 8]. Based on the biomechanical assessments carried out, the sustained hypothesis of this work for swimmers of the S7 category is that the kick is not only not propulsive, but it also lacks efficiency and generates greater resistance to advance. To analyze the role of drag and propulsion forces generated during the execution of the swimming technique, a personalized kinematic study was carried out in a 25-year-old paralympic swimmer with lumbosacral myelomeningocele. The studies were carried out with a 16 Mpx Panasonic® Lumix DMC-FH5 Mega OIS (Optical Image Stabilizer) digital camera, HD format, fixed in the Olympic pool of the Jeanette Campbell swimming complex of the National Center for High Performance Sports (CENARD) from the Autonomous City of Buenos Aires (CABA) and a GoPro Hero 4® camera to study the swimming technique from the sagittal and frontal plane. Both cameras were synchronized. The processing was carried out with the Kinovea ® software version 0.8.27. A protocol was defined and 3 relevant variables were measured: segmental body alignment, left and right hip flexion angle, and kick level. The results of the underwater observations are presented in a qualitative/quantitative way and possible biomechanical strategies to optimize swimming are discussed. This work is considered to be a pioneer in the study of the biomechanics of Argentine paralympic swimmers.