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Data obtained in primarily Caucasian (C) and African American adults show that ethnicity does not mediate responsiveness to exercise training. It is unknown if Hispanics (H), who face elevated health risks and are less active than C, exhibit a similar response to exercise training. This study compared cardiorespiratory and hemodynamic responses to high intensity interval training (HIIT) between C and H women. Twelve C and ten H women ages 19–35 yr who were non-obese and inactive completed nine sessions of HIIT over a 3 wk period. Maximal oxygen uptake (VO2max) was assessed twice at baseline during which thoracic impedance was used to evaluate heart rate (HR), stroke volume (SV) and cardiac output (CO). Habitual physical activity was assessed using accelerometry. Results showed a significant main effect of training for VO2max in C and H (F = 13.97, p = 0.001) and no group by training interaction (p = 0.65). There was a main effect of training for CO and SV in C and H (F = 7.57, p = 0.01; F = 7.16, p = 0.02), yet post hoc analyses revealed significant increases were only exhibited in C. There was a tendency for a group by training interaction for a-VO2diff (F = 1.32, p = 0.054), and a large effect size was seen in H (d = 1.02). Overall, data show no effect of ethnicity on changes in VO2max with low-volume HIIT, yet C and H may achieve this outcome differently. Longer studies in similar populations are needed to verify this result. [ABSTRACT FROM AUTHOR]

Incidence of obesity is increasing worldwide which is deleterious to health due to its association with increased risk of cardiovascular disease, diabetes, and some cancers. Completion of regular physical activity in individuals with obesity increases maximal oxygen uptake (VO 2 max). However, whether individuals with obesity can exhibit 'true' VO 2 max is unresolved. This study examined efficacy of verification testing (VER) to identify 'true' VO 2 max in 17 inactive women with obesity (age, body fat, and VO 2 max = 37 ± 10 yr, 48.7 ± 3.5 %, and 19.4 ± 3.0 mL/kg/min, respectively). They performed ramp exercise (RAMP) to volitional fatigue followed by VER at 105 percent peak power output (%PPO) at baseline and after 3 and 6 wk of high intensity interval training. Results showed no difference in ramp and verification-derived VO 2 max (1.99 ± 0.37 L/min vs. 1.98 ± 0.32 L/min, 2.00 ± 0.40 L/min vs. 2.04 ± 0.38 L/min, and 2.08 ± 0.34 L/min vs. 2.08 ± 0.32 L/min at 0, 3 and 6 wk of training), although in 40 % of VER tests, VO 2 max was greater than the RAMP value. Overall, verification testing may be adopted as an additional approach to confirm 'true' VO 2 max attainment in obese women as ramp exercise frequently underestimates VO 2 max in this population.