Cardiorrespiratory response comparison between resisted and endurance HIIT protocols

Abstract

INTRODUCTION: High Intensity Interval Training (HIIT) has been proposed as an effective training method to improve cardiorespiratory fitness in general population. However, HIIT training can be performed under different protocols that could involve different cardiovascular adaptations. Resisted (RHIIT) and endurance (EHIIT) are the most common protocols presented in sports centers, being interval strength training for RHIIT or indoor cycling for EHIIT the most representatives and populars. We compared the two different protocols in order to analyze which exercise elicit a greater cardiorespiratory fitness response. METHODS: 35 subjects, age 34.11±3.87 yo, weight 73.19±12.52 kg and height 165.72±24.28 cm, were divided into 2 groups, EHHIT (N=15) and RHIIT (N=20). All subjects performed a session of each of these group exercise modes, measuring the following: lactate level (Lac) before and after session, Rating of Perceived Exertion (RPE) with Borg scale (10 point) at the end, and heart rate (HR) during the session. Sessions were divided into zones of HR intensity (1] <70; 2] 70-80; 3] 80-90; 4] >90 %HRmax). The EHIIT mode consisted of 10 minutes of warm-up (85-95RPM) and cool down, main part of 25 minutes (65-100RPM). RHHIT included 10 minutes of warm-up (treadmill) and cool down, main part: metabolic training (6 burpees), weightlifting (3 PushPress), and gymnastic exercises (9 hanging knee raise). RESULTS: The T test showed HRmean was higher in EHIIT compared to RHIIT (148.80±16.23 vs 134.90±19.150ppm respectively, p=0.027). Percentage of exercise time was lower in zone 1 and higher in zone 3 during EHIIT (15.50±22.10%) compared to RHIIT (15.50±22.10% vs 30.24±17.92%, p=0.037 and 32.19±20.17% vs. 19.57±11.54%, p=0.025 respectively). There were no significant differences in HRmax, Kcal, Lac, time in zone 2 and zone 4 between EHIIT and RHIIT. CONCLUSION: Greater HRmean and longer exercise time in higher intensity zones observed during EHIIT indicate that this type of protocols (i.e. indoor cycling) have a greater exercise cardiorespiratory load than RHIIT protocols (i.e. interval strength training). Thus, in order to improve cardirrespiratory fitness, EHIIT exercise are more recommendable.