The impact of recovery interval duration and intensity on the acute physiological responses to interval training during cycling exercise

The current thesis aimed to investigate the impact of the recovery interval duration and intensity on the acute physiological and perceptual responses to high intensity interval training (HIIT) during cycling exercise. Two studies were completed to examine the effects of the recovery interval duration and intensity in isolation. In Study One, sixteen participants completed a 6 x 4-min and 3 x 8-min HIIT session twice, with a standardised (STD) and individualised (IND) recovery duration based upon a resolution of muscle oxygen consumption (mV̇O2) to pre-exercise levels. In Study Two, fourteen participants completed a 6 x 4-min and 3 x 8-min HIIT session three times, with a passive (PA) and two active (ACT) recovery intensities. Results of Study One found there were no significant differences between the IND and STD recovery durations for any of the physiological or performance parameters assessed. Study Two results demonstrated that ACT recovery intensities increased the overall accumulation of central and peripheral physiological stress, without increasing the total training time commitment of the HIIT session, when compared to PA recovery intensity. Recovery intensity did not affect the time spent above 90 and 95% of V̇O2max during the HIIT sessions. In conclusion, full recovery of mV̇O2 and a return of the exercising muscle to metabolic homeostasis may not be required to maintain work interval performance and to generate the desired acute physiological responses during HIIT. Moreover, evidence within this thesis highlights the importance of the optimisation of the recovery interval components to the specific individual and HIIT protocol when seeking to maximising the training stimulus, and time efficiency of the training session. However, at present, the 2:1 work recovery ratio and a moderate ACT recovery intensity appear to be the most practical recovery component prescription when programming the recovery intervals during long work interval HIIT across a broad range of individuals.