Changes in the Second Ventilatory Threshold Following Individualised versus Standardised Exercise Prescription among Physically Inactive Adults: A Randomised Trial.

The second ventilatory threshold (VT2) is established as an important indicator of exercise intensity tolerance. A higher VT2 allows for greater duration of higher intensity exercise participation and subsequently greater reductions in cardiovascular disease (CVD) risk. This study aimed to compare the efficacy of standardised and individualised exercise prescription on VT2 among physically inactive adults. Forty-nine physically inactive male and female participants (48.6 ± 11.5 years) were recruited and randomised into a 12-week standardised (n = 25) or individualised (n = 24) exercise prescription intervention. The exercise intensity for the standardised and individualised groups was prescribed as a percentage of heart rate reserve (HRR) or relative to the first ventilatory threshold (VT1) and VT2, respectively. Participants were required to complete a maximal graded exercise test at pre-and post-intervention to determine VT1 and VT2. Participants were categorised as responders to the intervention if an absolute VT2 change of at least 1.9% was attained. Thirty-eight participants were included in the analysis. A significant difference in VT2 change was found between individualised (pre vs. post: 70.6% vs. 78.7% maximum oxygen uptake (VO2max)) and standardised (pre vs. post: 72.5% vs. 72.3% VO2max) exercise groups. Individualised exercise prescription was significantly more efficacious (p = 0.04) in eliciting a positive response in VT2 (15/19, 79%) when compared to the standardised exercise group (9/19, 47%). Individualised exercise prescription appears to be more efficacious than standardised exercise prescription in eliciting a positive VT2 change among physically inactive adults. Increasing VT2 allows for greater tolerance to higher exercise intensities and therefore greater cardiovascular health outcomes.

Set distance time trials for predicting maximal aerobic speed in female Australian Rules Footballers.

OBJECTIVES: Maximal aerobic speed (MAS) may be predicted from 2.0km time trial (TT) running speed in male Australian Rules football (AF) players. Given the between-sex differences in physiological variables precursory to endurance performance, and the impact of this on MAS distance limit, this study determined running speed across various TT distances best approximating MAS in female AF players. METHOD: 33 female AF players completed assessments of MAS and TT performance separated by at least 48h. In a randomised order, half of the athletes completed TT distances of 1.2, 1.6 and 2.0km, and the other half completed distances of 1.4, 1.8 and 2.2km. Bias, limits of agreement (LOA) and linear mixed modelling determined agreement between TT-derived running speed and MAS. RESULTS: Average speed for all TT distances were different to MAS (bias≥0.59±0.45km·h-1; p≤0.015) with the exception of the 1.4km TT (bias=-0.12±0.26km·h-1; p=0.34). LOA was narrowest for the 1.4km TT (±0.76km·h-1; ±6.1%) compared to other TT distances (±0.82-1.67km·h-1; ±6.7-12.9%). A significant linear association between bias and TT distance (r=-0.73; p<0.001) indicated TT speed would be equal to MAS when a 1.4-1.5km TT was completed, and that MAS may be predicted from any distance between 1.2 and 2.2km. CONCLUSIONS: MAS was best approximated by a 1.4-1.5km TT in female AF players, but may be predicted from TT speed for any distance between 1.2 and 2.2km. TT-derived MAS provides a time and resource efficient method for the quantification of aerobic fitness and prescription of future training intensities.