Cardiorespiratory fitness and aerobic performance adaptations to a 4-week sprint interval training in young healthy untrained females.

PURPOSE: The aim of this study was to test the effects of sprint interval training (SIT) on cardiorespiratory fitness and aerobic performance measures in young females.

METHODS: Eight healthy, untrained females (age 21 ± 1 years; height 165 ± 5 cm; body mass 63 ± 6 kg) completed cycling peak oxygen uptake ([Formula: see text] peak), 10-km cycling time trial (TT) and critical power (CP) tests pre- and post-SIT. SIT protocol included 4 × 30-s "all-out" cycling efforts against 7 % body mass interspersed with 4 min of active recovery performed twice per week for 4 weeks (eight sessions in total).

RESULTS: There was no significant difference in [Formula: see text] peak following SIT compared to the control period (control period: 31.7 ± 3.0 ml kg(-1) min(-1); post-SIT: 30.9 ± 4.5 ml kg(-1) min(-1); p > 0.05), but SIT significantly improved time to exhaustion (TTE) (control period: 710 ± 101 s; post-SIT: 798 ± 127 s; p = 0.00), 10-km cycling TT (control period: 1055 ± 129 s; post-SIT: 997 ± 110 s; p = 0.004) and CP (control period: 1.8 ± 0.3 W kg(-1); post-SIT: 2.3 ± 0.6 W kg(-1); p = 0.01).

CONCLUSIONS: These results demonstrate that young untrained females are responsive to SIT as measured by TTE, 10-km cycling TT and CP tests. However, eight sessions of SIT over 4 weeks are not enough to provide sufficient training stimulus to increase [Formula: see text] peak.