RESUMO

The purpose of this study was to investigate whether a tethered-swimming incremental test comprising small increases in resistive force applied every 60 seconds could delineate the isocapnic region during rapidly-incremented exercise. Sixteen competitive swimmers (male, n = 11; female, n = 5) performed: (a) a test to determine highest force during 30 seconds of all-out tethered swimming (Favg) and the ΔF, which represented the difference between Favg and the force required to maintain body alignment (Fbase), and (b) an incremental test beginning with 60 seconds of tethered swimming against a load that exceeded Fbase by 30% of ΔF followed by increments of 5% of ΔF every 60 seconds. This incremental test was continued until the limit of tolerance with pulmonary gas exchange (rates of oxygen uptake and carbon dioxide production) and ventilatory (rate of minute ventilation) data collected breath by breath. These data were subsequently analyzed to determine whether two breakpoints defining the isocapnic region (i.e., gas exchange threshold and respiratory compensation point) were present. We also determined the peak rate of O2 uptake and exercise economy during the incremental test. The gas exchange threshold and respiratory compensation point were observed for each test such that the associated metabolic rates, which bound the heavy-intensity domain during constant-work-rate exercise, could be determined. Significant correlations (Spearman's) were observed for exercise economy along with (a) peak rate of oxygen uptake (ρ = .562; p < 0.025), and (b) metabolic rate at gas exchange threshold (ρ = -.759; p < 0.005). A rapidly-incremented tethered-swimming test allows for determination of the metabolic rates that define zones for domain-specific constant-work-rate training.

RESUMO

RESUMO Introdução: Poucos estudos analisaram a contribuição da composição regional de nadadores para o perfil aeróbio, anaeróbio e o desempenho de nado. Objetivo: Verificar a influência da composição corporal regional e total sobre índices da aptidão aeróbia e anaeróbia em nado atado e livre, bem como sobre o desempenho de curta e média duração. Métodos: Onze nadadores (18,0 ± 4,0 anos) foram submetidos a: (1) teste incremental em nado atado, com coleta de gases respiração-a-respiração (K4b2 associado ao novo-AquaTrainerâ); e (2) tempo limite nos desempenhos de 200, 400 e 800 metros de nado livre. A regressão linear entre distância e tempo (d-tLim) empregou o método dos quadrados mínimos. O coeficiente de Pearson (r) averiguou as correlações da composição corporal regional e total com índices da aptidão aeróbica e anaeróbica em nado atado e livre. Resultados: Os valores da massa isenta de gordura (MIG) foram: 61,7 ± 7,4 kg; 7,5 ± 1,1 kg; 28,3 ± 3,7 kg; 22,1 ± 2,5 kg, respectivamente para corpo todo, membros superiores (MS), tronco (T) e membros inferiores (MI). O consumo máximo de oxigênio (VO2max) foi 52,1 ± 5,3 ml×kg-1×min-1, sendo a carga correspondente (iVO2max) de 93,9 ± 12,2 N. O tempo em 200 (132,2 ± 9,7 s), 400 (296,8 ± 17,2 s) e 800 metros (619,5 ± 26,9 s) forneceu velocidade crítica (VC = 1,23 ± 0,06 m×s-1) e capacidade anaeróbica de nado (CNA = 35,8 ± 15,1 m). Observaram-se correlações de iVO2max, CAN e v200m com MIG para MS (r = 0,64; 0,67 e 0,76), porém a MIG para T, MI e corporal demonstraram correlações apenas com v200m (r = 0,75; 0,69 e 0,75) e CAN (r = 0,71; 0,69 e 0,75). Conclusão: Houve, portanto, influência da MIG regional e corporal sobre o desempenho de curta distância e reservas anaeróbias, sendo a MIG-MS também influente sobre a iVO2max, e assim relacionada ao aprimoramento do desempenho de nado.

ABSTRACT Introduction: There have been few studies analyzing the regional body contribution of swimmers for aerobic and anaerobic profiles and swimming performance. Objective: To verify the influence of regional and whole-body composition on aerobic and anaerobic fitness indices in free and tethered swimming, as well as short- and medium-term performance. Methods: Eleven swimmers (18.0 ± 4.0 years old) were submitted to: (1) an incremental test in tethered swimming, with breath-by-breath gas exchange sampling (K4b2 associated with the new-AquaTrainerâ), and (2) timeout while performing the 200, 400 and 800 meter freestyle. Linear regression analysis between distance and time (d-tLim) was performed using the least squares method. Pearson's coefficient (r) was used to test the correlations between regional and whole-body composition and aerobic and anaerobic fitness indices in freestyle and tethered swimming. Results: Mean values for fat free mass (FFM) were: 61.7±7.4 kg; 7.5±1.1 kg; 28.3±3.7 kg; 22.1±2.5 kg, respectively, for the whole-body, upper-limbs (UL), trunk (T) and lower-limbs (LL). Maximal oxygen uptake (VO2max) was 52.1±5.3 ml×kg-1×min-1, and respective load (iVO2max) was 93.9 ± 12.2 N. The timeout in 200 (132.2±9.7 s), 400 (296.8±17.2 s) and 800 meters (619.5±26.9 s) provided critical velocity (CV = 1.23±0.06 m×s-1) and anaerobic swimming capacity (ASC = 35.8±15.1 m). Correlations were observed for iVO2max, ASC and v200m with FFM for UL (r = 0.64; 0.67 and 0.76), but FFM for T, LL and whole body were related only with v200m (r = 0.75; 0.69 and 0.75) and ASC (r = 0.71; 0.69 and 0.75). Conclusion: Regional and whole-body FFM influenced short-term performance and anaerobic reserves; FFM for UL was also related to iVO2max, and was therefore associated with improved swimming performance.

RESUMEN Introducción: Pocos estudios han examinado la contribución de la composición regional de los nadadores para el perfil aerobio, anaerobio y el rendimiento de nado. Objetivo: Verificar la influencia de la composición corporal regional y total sobre índices de aptitud aerobia y anaerobia en nado estacionario y libre, así como sobre el rendimiento de corta y media duración. Métodos: Once nadadores (18,0 ± 4,0 años) fueron sometidos a: (1) test incremental en nado estacionario, con coleta de gases respiración a respiración (K4b2 asociado al nuevo-AquaTrainerâ); y (2) tiempo límite en el rendimiento de 200, 400 y 800 metros en nado libre. La regresión lineal entre la distancia y el tiempo (d-tLim) utilizó el método de los mínimos cuadrados. Se empleó el coeficiente de Pearson (r) para examinar las correlaciones entre la composición corporal regional y total con los índices de capacidad aerobia y anaerobia en el nado estacionario y en el nado libre. Resultados: Los valores de masa libre de grasa (MLG) fueron: 61,7±7,4 kg; 7,5±1,1 kg; 28,3±3,7 kg; 22,1±2,5 kg, respectivamente, para todo el cuerpo, extremidades superiores (ES), tronco (T) y extremidades inferiores (EI). El consumo máximo de oxígeno (VO2máx) fue 52,1 ± 5,3 ml×kg-1×min-1, y la carga correspondiente (iVO2máx) fue 93,9 ± 12,2 N. El tiempo en 200 (132,2 ± 9,7 s), 400 (296,8 ± 17,2 s) y 800 metros (619,5 ± 26,9 s) estableció la velocidad crítica (VC = 1,23±0,06 m×s-1) y la capacidad del nado anaerobia (CNA = 35,8 ± 15,1 m). Se verificaron correlaciones entre iVO2máx, CNA y v200m con MLG de ES (r = 0,64, 0,67 y 0,76), pero la MLG para T, EI y corporal demostraron correlaciones sólo con la v200m (r = 0,75, 0,69 y 0,75) y la CNA (r = 0,71, 0,69 y 0,75). Conclusión: Por lo tanto, hubo influencia de la MLG regional y total en el rendimiento a corto plazo y en las reservas anaerobias, mientras la MLG-ES influye en la iVO2máx y así en la mejora del rendimiento en la natación.