Integrated analysis of the inter-arm coordination in aquatic locomotion

Abstract

Following the ecological dynamics, the capacity to adapt movements to dynamic interacting constraints of a performance environment, to achieve specific intentions and make decisions, broadly defines expertise. The purpose of this thesis were twofold: (i) to investigate which are the variables that most influence front crawl swimming coordination and understand its effects on flexibility when manipulating task constraints; and (ii) examine the effect of different coordinative and strength trainings on front crawl coordination and performance in young swimmers. The protocol contained two distinct protocols: (i) 15 x 50 m front crawl (with 5 min interval), five trials at each 100, 90 and 70% of their 50 m maximal swimming speed, randomly at 90, 95, 100, 105 and 110% of their preferred stroke frequency; and (ii) swimmers were assessed for anthropometry and flexibility and performed 30 s maximal effort on tethered swimming, 12 x 25 m on MAD-system and 50 m maximal front crawl bout. Seven aerial and six underwater cameras were used to assess kinematics, with upper limb coordination computed through continuous relative phase (allowing extracting the relative times spent in in-phase, anti-phase and out-of-phase) and index of coordination methodologies. Results pointed out that speed and stroke frequency were the main control parameters, with speed exerting a greater influence. Their manipulation showed that not all the variability is functional, i.e., the patterns nature and appropriately shifting between them seem moreimportant than attain the highest number of changings or pattern. Performance in 50 m seems to vary more with swimmers sex rather than skill level at these ages, with specific training (same environment: the coordinative and the in-water strength trainings) exerting more changes in coordinative variables and the dry-land strength training exerting a greater influence on performance.