Physiological responses and competitive performance in elite synchronized swimming

Synchronized swimming (SS) is a sports discipline combining swimming, dancing and gymnastics. Synchronized Swimmers perform a choreography called routine consisting of elaborate moves in the water accompanied by music. Previous research investigating SS from a physiological perspective has mainly used figures or fractionated and/or simulated routine protocols during training, although the nature of sports leads to continuous very demanding exercises (~2-4 minutes) performed at increasingly higher levels of intensity with almost 50% of this time underwater. In addition, different from training, competition is a challenging situation which usually stimulates higher psycho-physiological responses in the participant. Current knowledge is thus limited as regards physiological responses in competitive elite SS. Therefore, the overall aim of this thesis is to study the physiological responses related to performance during the execution of competitive routines both during training and competitive sessions in elite synchronized swimmers. The thesis is based on three studies (Studies I – III); all of them use the same protocol with continuous cardiovascular monitoring during competitive routines, perceived exertion assessment after the executions, and blood lactate measurements (Studies I and III). Study I characterized the physiological responses in relation to performance during an official competition. In Study II the execution of the duets in both conditions –training and competitive session– was used to compare the athletes’ internal load in order to ascertain whether swimmers may achieve the competitive intensity during training sessions, and Study III was performed to investigate how immersion periods, with the concomitant bradycardic events, affect perceived exertion with both physiological (HR) and subjective perceptual markers (RPE). The current thesis demonstrates that cardiovascular responses during competition are characterized by intense anticipatory pre-activation and rapidly developing tachycardia up to maximal levels with interspersed periods of marked bradycardia during the exercise bouts performed in apnea (Studies I­III). Moderate blood lactate accumulation suggested the activation of the glycolytic metabolism in the exercising muscles and an adaptive metabolic response due to the specific training adaptations in this kind of athletes (Studies I and III). Furthermore, competitive routines were perceived as very to extremely intense by all swimmers, likely reflecting not only the absolute exercise demands but also their previous experience and expectations (Studies I – III). In Study II, the internal load (HR and RPE) imposed by SS duets performed during training was virtually identical to that elicited in a real competitive situation due to the effects of automaticity –embodied through the replication of the same movement sequence in practice–, and by the swimmers’ long-term adaptations to specific routine exercise and apnea. There was a strong positive relationship between RPE and the duration and / or frequency of bradycardic events during routines (Studies II – III). In fact, the frequency and duration of immersions, the magnitude of subsequent bradycardic events, the blood lactate concentration, and the HR recovery during competitive SS routines explained 62% RPE variance changes in perceived exertion, with cardiorespiratory factors providing a relatively greater neural input as compared to metabolic factors (Study III). Attending the relationships between physiological parameters and performance, the magnitude of anticipatory heart rate activation and bradycardic response explained 26% of variability in performance (Study I) supporting the concept that an augmented diving response was associated to higher performance in SS. However, in Study III the percentage of variance rose to 53% by adding the blood lactate concentration, the number of immersions and longest immersion time, and the lower mean time immersed during the routine. This could explain that best swimmers show a greater adaptation to breath holding and this would likely translate into a more efficient O2 conservation effect (Study III).