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

Introduction This controlled, nonrandomized, parallel-groups trial investigated the effects on performance, VO² and hemoglobin mass (tHb^mass) 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 (VO^2max) 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). tHb^mass 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 VO^2max or tHb^mass. 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.