Higher Peak Fat Oxidation During Rowing vs. Cycling in Active Men and Women.

ABSTRACT: Astorino, TA, Oriente, C, Peterson, J, Alberto, G, Castillo, EE, Vasquez-Soto, U, Ibarra, E, Guise, V, Castaneda, I, Marroquin, JR, Dargis, R, and Thum, JS. Higher peak fat oxidation during rowing vs. cycling in active men and women. J Strength Cond Res 35(1): 9-15, 2021-This study compared fat and carbohydrate oxidation (CHOOx) between progressive rowing and cycling. Initially, 22 active healthy adults (age = 27 ± 8 years) performed incremental cycling and rowing to volitional fatigue to assess maximal oxygen uptake (V̇o2max) and maximal heart rate (HRmax). The order of 2 subsequent sessions was randomized, performed 2 hours postmeal, and included a warm-up followed by three 8-minute stages of rowing or cycling at 60-65, 70-75, and 80-85 %HRmax. During exercise, power output was modified to maintain work rate in the desired range. Gas exchange data and blood samples were obtained to measure fat and CHOOx and blood lactate concentration. Fat oxidation (FOx) increased during exercise (p < 0.001) and there was a main effect of mode (p = 0.03) but no modeXintensity interaction (p = 0.33). Peak FOx was higher in response to rowing vs. cycling (0.23 ± 0.09 g·min-1 vs. 0.18 ± 0.07 g·min-1, p = 0.01). Carbohydrate oxidation increased during exercise (p < 0.001) but there was no effect of mode (p = 0.25) or modeXintensity interaction (p = 0.08). Blood lactate concentration was lower (p = 0.007) at the end of rowing vs. cycling (3.1 ± 1.0 mM vs. 3.9 ± 1.6 mM, d = 1.1). Prolonged rowing having equivalent calorie expenditure and intensity vs. cycling elicits higher peak FOx, which is likely attributed to greater muscle mass used during rowing.

Within-session responses to high-intensity interval training in spinal cord injury.

AIM: Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. PURPOSE: To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. METHOD: Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. RESULTS: Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. CONCLUSIONS: Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

Interval training elicits higher enjoyment versus moderate exercise in persons with spinal cord injury.

BACKGROUND: High intensity interval training (HIIT) is a robust and time-efficient approach to improve multiple health indices including maximal oxygen uptake (VO2max). Despite the intense nature of HIIT, data in untrained adults report greater enjoyment of HIIT versus continuous exercise (CEX). However, this has yet to be investigated in persons with spinal cord injury (SCI). OBJECTIVE: To examine differences in enjoyment in response to CEX and HIIT in persons with SCI. DESIGN: Repeated measures, within-subjects design. SETTING: University laboratory in San Diego, CA. PARTICIPANTS: Nine habitually active men and women (age = 33.3 ± 10.5 years) with chronic SCI. INTERVENTION: Participants performed progressive arm ergometry to volitional exhaustion to determine VO2peak. During subsequent sessions, they completed CEX, sprint interval training (SIT), or HIIT in randomized order. OUTCOME MEASURES: Physical activity enjoyment (PACES), affect, rating of perceived exertion (RPE), VO2, and blood lactate concentration (BLa) were measured. RESULTS: Despite a higher VO2, RPE, and BLa consequent with HIIT and SIT (P < 0.05), PACES was significantly higher (P = 0.03) in response to HIIT (107.4 ± 13.4) and SIT (103.7 ± 12.5) compared to CEX (81.6 ± 25.4). Fifty-five percent of participants preferred HIIT and 45% preferred SIT, with none identifying CEX as their preferred exercise mode. CONCLUSION: Compared to CEX, brief sessions of submaximal or supramaximal interval training elicit higher enjoyment despite higher metabolic strain. The long-term efficacy and feasibility of HIIT in this population should be explored considering that it is not viewed as more aversive than CEX.

High-Intensity Interval Training Elicits Higher Enjoyment than Moderate Intensity Continuous Exercise.

Exercise adherence is affected by factors including perceptions of enjoyment, time availability, and intrinsic motivation. Approximately 50% of individuals withdraw from an exercise program within the first 6 mo of initiation, citing lack of time as a main influence. Time efficient exercise such as high intensity interval training (HIIT) may provide an alternative to moderate intensity continuous exercise (MICT) to elicit substantial health benefits. This study examined differences in enjoyment, affect, and perceived exertion between MICT and HIIT. Twelve recreationally active men and women (age = 29.5 ± 10.7 yr, VO2max = 41.4 ± 4.1 mL/kg/min, BMI = 23.1 ± 2.1 kg/m2) initially performed a VO2max test on a cycle ergometer to determine appropriate workloads for subsequent exercise bouts. Each subject returned for two additional exercise trials, performing either HIIT (eight 1 min bouts of cycling at 85% maximal workload (Wmax) with 1 min of active recovery between bouts) or MICT (20 min of cycling at 45% Wmax) in randomized order. During exercise, rating of perceived exertion (RPE), affect, and blood lactate concentration (BLa) were measured. Additionally, the Physical Activity Enjoyment Scale (PACES) was completed after exercise. Results showed higher enjoyment (p = 0.013) in response to HIIT (103.8 ± 9.4) versus MICT (84.2 ± 19.1). Eleven of 12 participants (92%) preferred HIIT to MICT. However, affect was lower (p<0.05) and HR, RPE, and BLa were higher (p<0.05) in HIIT versus MICT. Although HIIT is more physically demanding than MICT, individuals report greater enjoyment due to its time efficiency and constantly changing stimulus. TRIAL REGISTRATION: NCT:02981667.