Related Experiment Video
Updated: Jun 14, 2025

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Training Intensity Distribution of a 7-Day HIIT Shock Microcycle: Is Time in the "Red Zone" Crucial for Maximizing
Tilmann Strepp1, Julia C Blumkaitis2, Mahdi Sareban3
1Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400, Hallein/Rif, Salzburg, Austria. tilmann.strepp@plus.ac.at.
The intensity measure used significantly impacts training intensity distribution (TID) calculations during high-intensity interval training shock microcycles (HIIT-SM). Heart rate monitoring may underestimate intensity, while velocity-based measures correlate best with endurance performance improvements.
Area of Science:
- Exercise Physiology
- Sports Science
- Training Methodology
Background:
- Training intensity distribution (TID) computation varies with the intensity measure used.
- Microcycles, specifically high-intensity interval training shock microcycles (HIIT-SM), have been understudied regarding TID.
- Time spent in high-intensity zones during HIIT is crucial for endurance performance.
Purpose of the Study:
- To compare TID based on running velocity (TIDV), running power (TIDP), and heart rate (TIDHR) during a 7-day HIIT-SM.
- To explore the relationship between time in the high-intensity zone (Z3) measured by different methods and changes in endurance performance.
Main Methods:
- A randomized controlled trial involving 29 endurance-trained participants.
- Three groups: HIIT-SM only (HSM), HIIT-SM with low-intensity training (HSM+LIT), and a control group.
- 10 HIIT sessions over 7 days, with TID and Z3 analysis using velocity, power, and heart rate.
Main Results:
- TIDV and TIDP showed a polarized pattern, while TIDHR exhibited a pyramidal pattern.
- Time in Z3HR was significantly lower than in Z3V and Z3P.
- Time in Z3V demonstrated a moderate dose-response relationship with improvements in peak power output and time trial performance.
Conclusions:
- The choice of intensity measure significantly influences TID during HIIT-SM.
- Heart rate monitoring may underestimate training intensity in HIIT-SM and should be used cautiously.
- Velocity-based intensity measures are most relevant for assessing endurance performance changes following HIIT-SM.
More Related Videos
10:34A Swimming-Induced Zebrafish Exercise Apparatus for Versatile Training Approaches
Published on: October 18, 2024
07:40Impact of High-intensity Interval Exercise and Moderate-Intensity Continuous Exercise on the Cardiac Troponin T Level at an Early Stage of Training
Published on: October 10, 2019
Related Concept Videos
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be...