Determination and validation of peak fat oxidation in endurance‐trained men using an upper body graded exercise test

Abstract

Peak fat oxidation rate (PFO) and the intensity that elicits PFO (Fat max ) are commonly determined by a validated graded exercise test (GE) on a cycling ergometer with indirect calorimetry. However, for upper body exercise fat oxidation rates are not well elucidated and no protocol has been validated. Thus, our aim was to test validity and inter-method reliability for determination of PFO and Fat max in trained men using a GE protocol applying double poling on a ski-ergometer. PFO and Fat max were assessed during two identical GE tests (GE1 and GE2) and validated against separated short continuous exercise bouts (SCE) at 35%, 50%, and 65% of VȮ 2peak on the ski-ergometer in 10 endurance-trained men (VȮ 2peak : 65.1 ± 1.0 mL·min −1 ·kg −1 , mean ± SEM). Between GE tests no differences were found in PFO (GE1:0.42 ± 0.03; GE2: 0.45 ± 0.03 g·min −1 , P = .256) or Fat max (GE1: 41 ± 2%; GE2: 43 ± 3% of VȮ 2peak , P = .457) and the intra-individual coefficient of variation (CV) was 8 ± 2% and 11 ± 2% for PFO and Fat max , respectively. Between GE and SCE tests, PFO (GE avg : 0.44 ± 0.03; SCE; 0.47 ± 0.06 g·min −1 , P = .510) was not different, whereas a difference in Fat max (GE avg : 42 ± 2%; SCE: 52 ± 4% of VȮ 2peak , P = .030) was observed with a CV of 17 ± 4% and 15 ± 4% for PFO and Fat max , respectively. In conclusion, GE has a high day-to-day reliability in determination of PFO and Fat max in trained men, whereas it is unclear if PFO and Fat max determined by GE reflect continuous exercise in general. K E Y W O R D Sexercise testing, Fat max , lipid metabolism, peak fat oxidation, test reliability, test validity, upper body exercise 1678 |

The relationship between peak fat oxidation and prolonged double‐poling endurance exercise performance

“…The double‐poling protocol applied was adapted from Hansen et al 2019 32 . In brief, participants rested standing on the ski‐ergometer (ThoraxTrainer Pro Cardio, ThoraxTrainer ApS) for 3 minutes, after which double‐poling exercise commenced at 15 W with a magnetic resistance setting at 0 out of 10 levels.…”

“…Day‐to‐day reliability of this protocol has previously been assessed in endurance‐trained men, and the intra‐individual coefficient of variation was reported to be ≤4% for and during all exercise steps, while it was 8% and 11% for PFO and Fat max , respectively 32 …”

“…The double-poling protocol applied was adapted from Hansen et al 2019. 32 In brief, participants rested standing on the ski-ergometer (ThoraxTrainer Pro Cardio, ThoraxTrainer ApS) for 3 minutes, after which double-poling exercise commenced at 15 W with a magnetic resistance setting at 0 out of 10 levels. The exercise intensity and magnetic resistance setting were subsequently increased every 3rd minute by 15 W and 1 resistance level, until the respiratory exchange ratio (RER) exceeded 1.00.…”

“…Day-to-day reliability of this protocol has previously been assessed in endurance-trained men, and the intra-individual coefficient of variation was reported to be ≤4% for V O 2 and V CO 2 during all exercise steps, while it was 8% and 11% for PFO and Fat max , respectively. 32 After a 5-minute break, V O 2peak was determined during a self-paced incremental exercise test to voluntary exhaustion. 32 In brief, V O 2peak was assessed applying a 10-minute self-paced test design, in which participants performed five 2-minute stages at intensities representing RPE of 13,15,17,19, and 20 on Borg's 6-20 scale.…”

“…32 After a 5-minute break, V O 2peak was determined during a self-paced incremental exercise test to voluntary exhaustion. 32 In brief, V O 2peak was assessed applying a 10-minute self-paced test design, in which participants performed five 2-minute stages at intensities representing RPE of 13,15,17,19, and 20 on Borg's 6-20 scale. The participants were instructed to exert an all-out effort from the beginning of the last stage in order to attain a V O 2 plateau.…”