Related Experiment Video

Updated: Jan 14, 2026

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers
09:24

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers

Published on: January 28, 2020

9.4K

Identification of a reverse crossover point during moderate-intensity exercise (>6 h; 69% VO2max) in a world-class

Timothy Noakes1, Alex Buga2, Jeff Volek2

  • 1Department of Human Biology, Division of Exercise Science and Sports Medicine, University of Cape Town, Cape Town, South Africa.

Frontiers in Nutrition
|October 24, 2025
PubMed
Abstract

Keywords:
carbohydrate oxidationfat oxidationglycogenreverse crossover pointtriathlon

More Related Videos

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise09:33

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise

Published on: December 19, 2024

1.4K
A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement08:27

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement

Published on: February 22, 2022

3.6K

Related Concept Videos

Exercise and Cardiac Output01:17

Exercise and Cardiac Output

Regular physical activity is essential for maintaining cardiovascular health, with aerobic exercises being particularly effective. According to the American Heart Association, 150 minutes of moderate to intense aerobic exercise per week is recommended for a healthy heart. Aerobic activities may include brisk walking, running, bicycling, cross-country skiing, and swimming, ideally performed three to five times per week.
Sustained exercise increases the muscles' oxygen demand, which can be...
1.8K
Exercise and Cardiovascular Response01:20

Exercise and Cardiovascular Response

Exercise significantly impacts cardiovascular response, which is crucial for understanding patient health and designing effective treatment plans.
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...
3.9K
Exercise Stress Test01:26

Exercise Stress Test

Introduction
Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.
Definition
An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.
Purposes
1.1K
Cardiac Output I:Effect of Heart Rate on Cardiac Output01:19

Cardiac Output I:Effect of Heart Rate on Cardiac Output

Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...
2.4K
Cardiac Output II: Effect of Stroke Volume on Cardiac Output01:22

Cardiac Output II: Effect of Stroke Volume on Cardiac Output

Cardiac output (CO), the amount of blood the heart pumps per minute, is a parameter in cardiovascular physiology determined by stroke volume and heart rate. Stroke volume, the amount of blood pushed from one of the ventricles per heartbeat, is influenced by preload, afterload, and contractility.
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
3.1K
Exercise and Muscle Performance01:27

Exercise and Muscle Performance

Exercise induces a range of adaptations in muscle tissue, depending on the type and duration of activity. Such physical training can be broadly categorized into two types: endurance exercises and resistance exercises.
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...
2.3K