Altitude Training in Elite Swimmers for Sea Level Performance (Altitude Project).

INTRODUCTION: This controlled, nonrandomized, parallel-groups trial investigated the effects on performance, V˙O2 and hemoglobin mass (tHbmass) of four preparatory in-season training interventions: living and training at moderate altitude for 3 and 4 wk (Hi-Hi3, Hi-Hi), living high and training high and low (Hi-HiLo, 4 wk), and living and training at sea level (SL) (Lo-Lo, 4 wk). METHODS: From 61 elite swimmers, 54 met all inclusion criteria and completed time trials over 50- and 400-m crawl (TT50, TT400), and 100 (sprinters) or 200 m (nonsprinters) at best stroke (TT100/TT200). Maximal oxygen uptake (V˙O2max) and HR were measured with an incremental 4 × 200 m test. Training load was estimated using cumulative training impulse method and session RPE. Initial measures (PRE) were repeated immediately (POST) and once weekly on return to SL (PostW1 to PostW4). tHbmass was measured in duplicate at PRE and once weekly during the camp with CO rebreathing. Effects were analyzed using mixed linear modeling. RESULTS: TT100 or TT200 was worse or unchanged immediately at POST, but improved by approximately 3.5% regardless of living or training at SL or altitude after at least 1 wk of SL recovery. Hi-HiLo achieved greater improvement 2 (5.3%) and 4 wk (6.3%) after the camp. Hi-HiLo also improved more in TT400 and TT50 2 (4.2% and 5.2%, respectively) and 4 wk (4.7% and 5.5%) from return. This performance improvement was not linked linearly to changes in V˙O2max or tHbmass. CONCLUSIONS: A well-implemented 3- or 4-wk training camp may impair performance immediately but clearly improves performance even in elite swimmers after a period of SL recovery. Hi-HiLo for 4 wk improves performance in swimming above and beyond altitude and SL controls through complex mechanisms involving altitude living and SL training effects.

El ascenso a una altura moderada mejora la capacidad de producción de fuerza / Ascent to moderate altitude improves force production

El objeto de este trabajo es analizar el efecto del ascenso súbito a una altura moderada sobre la mecánica muscular en distintos niveles de sobrecarga. Para ello, 5 varones deportistas, participaron en este estudio. Utilizando el ejercicio de sentadilla a 900 con barra libre, los participantes ejecutaron una curva de fuerza-velocidad, a partir de la cual se determinó la potencia máxima con un dinamómetro electrónico. En una jornada diferente se realizó una sesión de entrenamiento de fuerza con el método de 10x10, con elmismoejercicio y con la carga asociada a la potencia máxima.Ambos test se ejecutaron en condiciones de normoxia(N) (690m) y de hipoxia (H) súbita moderada(232Om).La potencia desarrollada, la velocidad de desplazamientode la sobrecarga y la percepción de esfuerzo diferenciadafueron registradas. La potencia máxima alcanzaday la carga a la que se obtuvo fueron significativamentesuperiores en H que en N(9l6,64+/-146,14 vs 823,85+/-118,38W y 110,00+/-12,24104,00+/-11,40Kg respectivamente)(p<0,05). La sesión de fuerza no mostró un efecto significativo de la hipoxia en las variables analizadas, a excepción de la percepción de esfuerzo local, la cual se mostró significativamente reducida en altitud (12,98+/-0,44 vs 11,54+/-0,46 para N e H respectivamente)(p<0,05). Por tanto, sobre la base de los resultados obtenidos y, siendo conscientes de las limitaciones ocasionadas por el tamaño de la muestra empleada, podemos concluir que la exposición a una altura moderada parece mejorar la potencia máxima y la carga a la que se localizaron respecto a la generada a nivel del mar. Tanto la hipoxia, como los cambios en la densidad del aire generados con el ascenso, podrían favorecer el reclutamiento selectivo de fibras de perfil mono-funcional anaeróbico en acciones muscularesde corta duración, justificando éste resultado. La fatigagenerada por la acumulación de repeticiones en lasesión podría enmascarar el efecto "facilitador" de la altura en la aplicación de fuerza a gran velocidad, pudiendo ser necesario en tales casos, acortar el volumen de las series

The aim of this study is to analyze the effect of acute ascent to moderate altitude on muscular mechanisms using different levels of resistance. Five healthy athletes participated in this study. Using back squat 90º flexion with free weights, participants executed a force-velocity curve to determine maximum power. On a different day a strength workout (10xl0) was performed with the same exercise using a maximum power load. Both tests were carried out in normoxia (690m) as well as in hypoxia (2320m). Power, speed and the diferenciated Ratings of Perceived Exertion (RPE) were recorded. Maximum power and the maximum power load, were significantly higher in hypoxia than innormoxia (916.64+/-146.14 vs 823.85+/-118.38 W and 110.00+/-12.24 vs 104.00+/-11.40 Kg respectively) (p<0.05).The variables analyzed in the strength workout didn't show any significant difference between normoxia and hypoxia, with the exception of fue local RPE which was reduced in hypoxic conditions (12.98+/-0.44 vs 11.54+/-0.46)( p<0.05). Therefore, based on fuese results, and taking into consideration the limits of the sample size, we can conclude that exposure to moderate alititude seems to improve maximum power and the maximum power load with respect to sea level. Hypoxia, as well as the changes in air density with ascent to a higher altitude, favour the selective recruitment of anaerobic morfo-functional fibers in short muscular action, justifying this result. The fatigue generated after repetitions in the workout could mask the "facilitator" effect of altitude in the application of strength in high speed movements. In fuese cases it could be necessary to reduce the number of sets