Related Experiment Video
Updated: Mar 3, 2026

Determining and Controlling External Power Output During Regular Handrim Wheelchair Propulsion
Published on: February 5, 2020
Mechanical power, thrust power and propelling efficiency: relationships with elite sprint swimming performance
Giorgio Gatta1, Matteo Cortesi1, Ian Swaine2
1a Department for Life Quality Studies , University of Bologna , Bologna , Italy.
Abstract:
The purpose of this study was to explore the relationships between mechanical power, thrust power, propelling efficiency and sprint performance in elite swimmers. Mechanical power was measured in 12 elite sprint male swimmers: (1) in the laboratory, by using a whole-body swimming ergometer (W'TOT) and (2) in the pool, by measuring full tethered swimming force (FT) and maximal swimming velocity (Vmax): W'T = FT · Vmax. Propelling efficiency (ηP) was estimated based on the "paddle wheel model" at Vmax. Vmax was 2.17 ± 0.06 m · s-1, ηP was 0.39 ± 0.02, W'T was 374 ± 62 W and W'TOT was 941 ± 92 W. Vmax was better related to W'T (useful power output: R = 0.943, P < 0.001) than to W'TOT (total power output: R = 0.744, P < 0.01) and this confirms the use of the full tethered test as a valid test to assess power propulsion in sprinters and to estimate swimming performance. The ratio W'T/W'TOT (0.40 ± 0.04) represents the fraction of total mechanical power that can be utilised in water (e.g., ηP) and was indeed the same as that estimated based on the "paddle wheel model"; this supports the use of this model to estimate ηP in swimming.
Related Concept Videos
Power Expended by a Constant Force
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...
Power
Mechanical Efficiency of Real Machines
However, in reality, no machine can be truly ideal, and all of them experience some...
Cardiac Output and Stroke Volume
In an average resting adult male, the typical cardiac...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be...

