SIX BOUTS OF SPRINT INTERVAL TRAINING (SIT) IMPROVES INTENSE AEROBIC CYCLING PERFORMANCE AND PEAK ANAEROBIC POWER

Abstract

Two weeks of SIT increased maximal aerobic power (VO2peak), however maximal anaerobic power (Wmax; 30-sec ‘all out’ Wingate test) was unaffected, possibly due to chronic fatigue induced by 14 daily training bouts (Roads et al. Eur. J. Appl. Physiol. 82:480–86, 2000). The effect of fewer sprint training bouts on these parameters is unknown, and no study has assessed changes in performance or skeletal muscle metabolism during intense aerobic exercise after SIT. PURPOSE We examined whether 6 bouts of SIT, performed over 2 wks with 1–2 d rest between bouts, elicited changes in VO2peak, Wmax, or performance/metabolism during a ‘challenge ride’ to exhaustion @ −80% VO2peak. METHODS 8 recreationally-active subjects [6 men; 23±2 yr (mean±SD)] were studied before and 2–3 d following the SIT protocol (6 bouts × 4–8 Wingate tests with 4 min recovery between tests). RESULTS VO2peak was unchanged by SIT (Post: 45.5±5.0 vs. Pre: 44.6±3.2 ml/kg/min) however Wmax increased by 14% (Post: 1067±234 vs Pre: 934±174 W; p ≤ 0.05). Most strikingly, cycle time to exhaustion increased by 101% after SIT (Post: 51.1±30.8 vs. Pre: 25.4±14.4 min, p ≤ 0.01). Biopsies obtained during the challenge rides revealed that muscle lactate ([La]) was not different at rest or after 1 (Post: 23±9 vs Pre: 22±8 mmol/kg dry wt.) or 15 min of exercise (Post: 53±15 vs Pre: 56±13). Extensive metabolic and cardiovascular analyses are underway in order to elucidate potential mechanisms responsible for the marked changes in aerobic performance. CONCLUSION 6 bouts of SIT (total training time: ∼15 min) dramatically improved intense aerobic cycling performance, however this was unrelated to changes in muscle [La] during exercise. Support: NSERC, Canada (MJG) and a Gatorade Sports Science Institute Award (SCH).