Related Experiment Video
Updated: Jul 20, 2026
11:15
Determining the Contribution of the Energy Systems During Exercise
Published on: March 20, 2012
Delta efficiencies of running and cycling
K E Bijker1, G De Groot, A P Hollander
1Faculty of Human Movement Sciences, Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands. k.bijker@fbw.vu.nl
Medicine and Science in Sports and Exercise
|August 31, 2001
Summary
Running delta efficiency (45.5%) is significantly higher than cycling delta efficiency (25.7%). This difference persists even when controlling for metabolic intensity and external load application methods.
Area of Science:
- Exercise Physiology
- Biomechanics
- Human Performance
Background:
- Delta efficiency quantifies the energy cost of increasing work rate.
- Understanding differences in delta efficiency between activities like running and cycling is crucial for optimizing training and performance.
Purpose of the Study:
- To compare the delta efficiencies of running versus cycling.
- To investigate factors influencing delta efficiency, such as external load application.
Main Methods:
- Twelve subjects underwent submaximal running and cycling tests at equal metabolic intensities.
- Rest periods were incorporated to prevent fatigue, and pedaling/stride frequencies were standardized.
- External load was applied via treadmill inclination and horizontal impeding forces.
Main Results:
- Mean delta efficiency for running was 45.5%, significantly higher than cycling's 25.7%.
- The method of applying external load did not affect delta efficiency in either activity.
Conclusions:
- Differences in metabolic intensity and external load application do not explain the observed delta efficiency disparity between running and cycling.
- The higher delta efficiency in running may be attributed to greater metabolic load from arm and trunk muscular activity not directly contributing to external work.
Related Concept Videos
01:16Efficiency of The Carnot Cycle
The hypothetical Carnot cycle consists of an ideal gas subjected to two isothermal and two adiabatic processes. Since the internal energy of an ideal gas depends only on its temperature, which is the same before and after the completion of the Carnot cycle, there is no change in its internal energy. Hence, using the first law of thermodynamics, the total heat exchanged by the ideal gas equals the total work done. Thus, we can quantify the efficiency of the Carnot cycle via the heat exchanged...
01:27Otto and Diesel Cycle
An Otto engine is a four-stroke engine that uses a mixture of gasoline and air as the working fuel. The fuel is injected into the cylinder, and the piston is moved completely down so that the cylinder is at maximum volume. By moving the piston up, adiabatic compression takes place. The spark plug ignites the gasoline-air mixture, and the burning fuel adds heat to the system at a constant volume. The heated mixture expands adiabatically and gets further cooled by exhausting heat, and this cyclic...
01:14Mechanical Efficiency of Real Machines
The mechanical efficiency of a machine is a fundamental concept that describes how effectively a machine can convert input work into output work. According to this concept, the efficiency of a machine is equal to the ratio of the output work to the input work. An ideal machine, meaning a machine that has no energy losses, has an efficiency of one. This implies that the input work and the output work are equal.
However, in reality, no machine can be truly ideal, and all of them experience some...
However, in reality, no machine can be truly ideal, and all of them experience some...
01:17Exercise 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 met...
Sustained exercise increases the muscles' oxygen demand, which can be met...
01:26Carnot Cycle and Efficiency
The Second Law of Thermodynamics asserts that it's impossible for any heat engine to achieve 100% efficiency. While contemplating the maximum possible efficiency, Nicolas Sadi Carnot conceptualized an ideal heat engine. This engine gets its energy from a high-temperature reservoir. It then performs some work and releases the remaining energy into a low-temperature reservoir.The Carnot cycle, named after Sadi Carnot, is fully reversible. The cycle consists of four distinct stages. In the first...
01:29Distance Problem
When an object's velocity changes over time, the total distance traveled can be determined by summing small displacement intervals over short increments. This approach approximates the true distance through numerical summation and the use of integral calculus. An estimate of the total displacement can be obtained by measuring velocity at regular intervals and multiplying each value by the corresponding time step.If a runner accelerates over the first three seconds of a race, speed measurements...