Functional Vs. Running Low-Volume High-Intensity Interval Training: Effects on VO2max and Muscular Endurance

Abstract

The purpose of the study was to assess if high-intensity interval training (HIIT) using functional exercises is as effective as traditional running HIIT in improving maximum oxygen uptake (VO₂max) and muscular endurance. Fifteen healthy, moderately trained female (n = 11) and male (n= 4) participants (age 25.6 ± 2.6 years) were assigned to either running HIIT (HIIT-R; n = 8, 6 females, 2 males) or functional HIIT (HIIT-F; n = 7, 5 females, 2 males). Over a four-week period, both groups performed 14 exercise sessions of either HIIT-R or, HIIT-F consisting of 3-4 sets of low-volume HIIT (8x 20 s, 10 s rest; set rest: 5 min). Training heart rate (HR) data were collected throughout all training sessions. Mean and peak HR during the training sessions were significantly different (p = 0.018 and p = 0.022, respectively) between training groups, with HIIT-F eliciting lower HR responses than the HIIT-R. However, despite these differences in exercise HR, VO₂max improved similarly (~13% for the HIIT-R versus ~11% for the HIIT-F, p=0.300). Muscular endurance (burpees and toes to bar) significantly improved (p =0.004 and p = 0.001, respectively) independent of training modality. These findings suggest that classic running HIIT and functional HIIT both improve VO₂max and affect muscular endurance to the same extent despite a lower cardiovascular strain in the functional protocol.

Keywords: Functional training; Tabata protocol; body composition; calisthenics; sprint interval training.

Figure 1.

Mean and peak heart rate responses (expressed as %HRmax determined in the VO₂max test) over all training sessions for HIIT-R and HIIT-F. HIIT-R, high-intensity interval training running group; HIIT-F, high-intensity interval training functional group; %HRpeak_HIIT, peak heart rate during the training session, expressed as a % of the HRmax determined by the treadmill test; %HRmean_HIIT, mean heart rate during the training session, expressed as a % of the HRmax determined by the treadmill test; *indicates statistically significant result (between-groups).

Figure 2.

Mean ratings of perceived exertion (BORG) over all training sessions for HIIT-R and HIIT-F. HIIT-R, high-intensity interval training running group; HIIT-F, high-intensity interval training functional group; RPE, ratings of perceived exertion (BORG); *indicates statistically significant result (between-groups)