Efectos de la potenciación post-activación en el rendimiento del nadador velocista

Abstract

Introduction: In sprint swimming, every instant is critical. Nowadays, is common to see how sprint swimmers prepare for racing by activating themselves on many different ways such as doing ballistic stretching, by increasing their breathing and heart rate, or by strongly clapping their chest or limbs. Whether or not those methods really have an influence is not part of this study. However, it cannot be rejected the fact that sprint swimmers need to create an extra activation on their system in order to race at the best of their capacities. Therefore, a suitable activation protocol able of stimulating the neuromuscular system in the best conditions is needed. Many of those methods have been based on post-activation potentiation (PAP). A procedure which improves muscle contractily both in strength and speed through previously applying maximal o submaximal conditioning exercises on the muscle system. The aim of this thesis was testing different PAP protocols on sprint swimming performance. Methods: 6 protocols testing different PAP applications were applied on trained swimmers. In total, 60 different swimmers participated on this thesis. First, it was assessed the influence of conditioning exercises on producing non-localized presence of PAP on lower limbs by testing two maximal voluntary contractions (squat jump and power push-up) on a force plate. Subsequently, same procedures were studied testing different rest time administration between conditioning exercise and test. Upper limbs assessment through force plate and bilateral surface electromyography (EMG) was also adhered in the study. On the other hand, in order to obtain results related to specific swimming-movements, PAP methods were extrapolated from experimental conditions and tested on a swimming start performance. Free-weight load lifting and maximal eccentric flywheel contractions simulating the movement of a swimming start were tested. Kinetic and kinematic variables of performance were obtained through a dynamometer experimental block start station and by photogrammetry. Individual’s strength index were also discussed and related to the results. Finally, conditioning exercises simulating arm strokes in swimming through free-weight and eccentric flywheel were tested on the variables of competition of a swimming race. Results: It was found that assessing pre-daily performance is important as might condition the magnitude and likelihood of finding PAP. Furthermore, possibly callisthenics are able of stimulating the neuromuscular system and it produces similar potentiation effects on performance. Swimming starts are able of being improved through PAP as velocity at take-off was higher, specially after eccentric warm-up protocols. This improvements would come from improvements on the vertical vectors of force/impulse developed by the lower limbs on the block. In fact, stronger athletes seem to react better to PAP protocols, possibly because myosin phosphorilation (main PAP precursor) is more frequent on type II fibers. The first meters of a swimming race might be improved by using PAP. However, some swimming patterns as stroke length might be deteriorated along the race. Conclussion: Fatigue and potentiation co-exists as responses of PAP, therefore, it generates very individualized responses, specially in males. As the application of this methods to competitive constraints seem unfeasiable, this thesis also proved that callisthenics may also produce similar results. Positive results might be obtained from applying PAP methods on the swimming start impulse although is still needed finding a suitable intensity for the conditioning exercises applied on upper limbs.