Physiological Outcomes of High-intensity Interval Training With Post-exercise Blood Flow Restriction

Study Overview
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Brief Summary
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This research study revolves around the physiological outcomes of using post-exercise blood flow restriction (BFR) with high intensity short interval training (ST) The main aims of this study are to compare (i) aerobic performance outcomes, and (ii) anaerobic and muscular performance outcomes - between 2 groups of participants after either undergoing 3 weeks of ST + post-exercise BFR (BFR-ST) or traditional ST.

Detailed Description
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This research study revolves around the physiological outcomes of using post-exercise blood flow restriction (BFR) with high-intensity interval exercise training (HIIT), specifically high intensity short interval training (ST) protocol of 30s work, 30s rest, for the recreational endurance athlete. In previous research, it has been shown that using BFR during rest intervals of a ST protocol would elicit greater physiological stresses in terms of higher heart rate, greater muscle activation, reduced oxygenation within the muscle tissue during exercise, and increased blood lactate post-exercise as compared with the control condition. However, the physiological outcomes of this type of training method over a longer-term (9 sessions over 3 weeks) have not been explored. The main aims of this study is to compare the physiological outcomes, - (i) aerobic performance outcomes, and (ii) anaerobic and muscular performance outcomes - between 2 groups of participants after either undergoing 3 weeks of ST + post-exercise BFR (BFR-ST) or traditional ST . The hypotheses for this study are: the BFR-ST group would experience a (i) greater improvement in maximal aerobic capacity, function and time trial performance and, (ii) greater improvement in anaerobic power and capacity as well as muscular strength and power, as compared with the ST group.

Official Title
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Physiological Outcomes of High-intensity Interval Training With Post-exercise Blood Flow

Conditions
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Exercise Performance

Intervention / Treatment
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* Other: BFR-ST
* Other: ST


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male 18-40 years Actively performing endurance exercise (running or cycling) for at least 2 sessions (1 - 1.5h) per week Healthy (free from illnesses) and no musculoskeletal injuries for the past 6 months No history of cardiometabolic, vascular diseases or similar conditions (e.g., high blood pressure, peripheral vascular diseases, heart diseases, metabolic syndrome, diabetes, stroke, etc.). Pass the pre-participation health screening tests - Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) and Australian Institute of Sport Blood Flow Restriction (AIS BFR) pre-screening questionnaire (no history of any risk factors). Achieve a maximum oxygen uptake (VO2max) of ≥40ml/kg/min during a maximal aerobic power cycling screening test. Non-smoker Drink alcohol less than 3 times each week and less than 3 drinks each time Exclusion Criteria: Persons with any form of illnesses and/or musculoskeletal injuries for the past 6 months Any history of cardiometabolic, vascular diseases or similar conditions which may worsen with the use of blood flow restriction during exercise Fail the pre-participation health screening tests Below 40ml/kg/min VO2max during maximal aerobic power cycling test Smoker Consumption of alcohol beyond that stated in the inclusion criteria. History of asthma or taking medication for asthma.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Two groups exposed to 9 sessions of high intensity short interval training with or without blood flow restriction between sets of exercise.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Blood flow restriction with short interval training (BFR-ST)<br>9 sessions of high intensity short interval training with blood flow restriction. | Other: BFR-ST<br>* Undergo 9 sessions of high intensity short interval training involving 3 sets of 8-10 repetitions of 30 secs interval cycling and 30 secs recovery at 100-110% of maximal aerobic power. In between sets there will be 3 mins of passive rest. Blood flow restriction will be applied for 2 mins during the passive rest at 80% of limb occlusion pressure.<br>|
| Sham Comparator: Sham altitude with short interval training (ST)<br>9 sessions of high intensity short interval training in an altitude chamber. | Other: ST<br>* Undergo 9 sessions of high intensity short interval training involving 3 sets of 8-10 repetitions of 30 secs interval cycling and 30 secs recovery at 100-110% of maximal aerobic power. In between sets there will be 3 mins of passive rest. Cycling will be conducted in an environmental chamber and participants informed that the altitude is set to 2500m - actual altitude will be sea level.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximum oxygen uptake and power |  | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) | 
| 20 km Cycling time trial |  | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) | 
| Wingate test of anaerobic power | Peak and mean power and rate of fatigue | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise economy | Oxygen uptake at a fixed load of 50% of maximum aerobic power | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) | 
| Isometric mid-thigh pull | Maximal strength assessment of lower body | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) | 
| Countermovement jump height | Vertical jump height assessment | Will be assessed at baseline (Day 0 - Pre) and the change in this outcome 24 hours after 9 sessions of training over 3 weeks (Post) |