Acute High Intensity Interval Training and Blood Flow Restriction

Acute Responses to High-intensity Interval Exercise (HIIE) and Blood Flow Restriction (BFR)

The study aims to look at the blood flow restriction (BFR) + high intensity interval training (HIIT) variables to induce an optimal acute training stimulus (i.e., acute responses in main outcome measures of muscular activation, muscular deoxygenation, and secondary outcome measures of heart rate (HR), blood lactate (bLa), subjective ratings of perceived exertion and discomfort)

The hypotheses for this study are: (i) BFR increases muscular deoxygenation, muscular activation when HIIT exercise is of the same intensity, (ii) however, comparing between a lower BFR + HIIT exercise intensity (e.g. 80% V̇O2max) and higher HIIT exercise intensity (e.g. 100% V̇O2max), muscular deoxygenation and activation will be similar but HR will be lower in the BFR + HIIT condition.

This study revolves around the optimisation of blood flow restriction (BFR) and high-intensity interval training (HIIT) protocols for the racket sport athlete. The study aims to look at the BFR + HIIT variables to induce an optimal acute training stimulus. This can be achieved with the consideration of two main research questions: (i) What is the ideal combination of BFR cuff pressure and exercise intensity (i.e. cycling) to elicit favourable training stimuli, i.e., acute responses in main outcome measures of muscular activation, muscular deoxygenation, and secondary outcome measures of heart rate (HR), blood lactate (bLa), subjective ratings of perceived exertion and discomfort?; (ii) How does BFR + HIIT compare with traditional HIIT at a similar or higher exercise intensity in terms of these acute responses?

The hypotheses for this study are: (i) BFR increases muscular deoxygenation, muscular activation when HIIT exercise is of the same intensity, (ii) however, comparing between a lower BFR + HIIT exercise intensity (e.g. 80% V̇O2max) and higher HIIT exercise intensity (e.g. 100% V̇O2max), muscular deoxygenation and activation will be similar but HR will be lower in the BFR + HIIT condition.

Inclusion Criteria:

• Male
• Age: 18-40 years
• Competed in competitive varsity sports (endurance, tennis, badminton, squash, football, basketball, etc.) at the varsity/club level
• Actively training 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 (high blood pressure, peripheral vascular diseases, heart diseases, metabolic syndrome, diabetes, stroke, etc.).
• Pass pre-participation health screening tests - Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) and Australian Institute of Sport (AIS) Blood Flow Restriction (BFR) pre-screening questionnaire (no history of any risk factors).
• Maximal oxygen uptake (VO2max) of ≥40mmol/min/kg during a maximal aerobic cycling test.
• Non-smoker
• Drink alcohol less than 3 times each week and less than 3 drinks each time

Exclusion Criteria:

• Any diagnosed form of cardiometabolic disease (CVD, diabetes, metabolic syndrome, hypertension)
• Any symptoms contraindication of exercise testing (eg chest pains)
• Any balance or dizziness problems
• Any chronic medical conditions (whether medicated or not)
• Any bone joint problems
• Any Physician diagnosed contraindications to exercise