Related Experiment Video
Updated: May 11, 2026
07:19
Comparison of Kinetic Characteristics of Footwork during Stroke in Table Tennis: Cross-Step and Chasse Step
Published on: June 16, 2021
Backstroke start kinematic and kinetic changes due to different feet positioning
Karla de Jesus1, Kelly de Jesus, Pedro Figueiredo
1a University of Porto , Faculty of Sport, Centre of Research, Education, Innovation and Intervention in Sport , Porto , Portugal.
Journal of Sports Sciences
|May 22, 2013
Summary
The 2005 backstroke start rule change led to two variants: feet emerged and feet immerged. Both have unique biomechanical advantages, with immerged starts offering better initial velocity and emerged starts providing greater take-off power.
Area of Science:
- Sports Science
- Biomechanics
- Swimming Performance
Background:
- International backstroke swimming start rules were revised in 2005.
- This led to the exploration of different start techniques.
Purpose of the Study:
- To compare the biomechanical differences between two backstroke start variants: feet in complete immersion versus feet in emersion.
- To identify the advantages of each start variant for elite swimmers.
Main Methods:
- Six elite swimmers performed maximal 15 m backstroke starts using both feet-emerged and feet-immersed techniques.
- Bi-dimensional kinematic analysis using dual-media cameras and kinetic data from an underwater force plate and load cell were employed.
Main Results:
- Feet-immersed starts showed a greater horizontal starting position and velocity at hands-off.
- Feet-emerged starts demonstrated longer wall contact time and greater take-off velocity.
- Both variants resulted in similar horizontal water reach, back arc angle, and 5m start times.
Conclusions:
- Coaches should leverage the specific mechanical benefits of both feet-immersed and feet-emerged backstroke starts.
- Emphasizing the maintenance of these advantages during the flight phase is crucial for optimizing backstroke start performance.
More Related Videos
Related Concept Videos
01:17Kinematic Equations - II
The second kinematic equation expresses the final position of an object in terms of its initial position, the distance traveled with the initial constant velocity, and the distance traveled due to a change in velocity. Similar to the first kinematic equation, this equation is also only valid when the acceleration is constant throughout the motion of an object.
Suppose a car merges into freeway traffic on a 200 m long ramp. If its initial velocity is 10 m/s and it accelerates at 2 m/s2, then the...
Suppose a car merges into freeway traffic on a 200 m long ramp. If its initial velocity is 10 m/s and it accelerates at 2 m/s2, then the...
01:26Kinematic Equations - I
When an object moves with constant acceleration, the velocity of the object changes at a constant rate throughout the motion. The kinematic equations of motions are derived for such cases where the acceleration of the object is constant. The first kinematic equation gives an insight into the relationship between velocity, acceleration, and time. We can see, for example:
01:18Kinematic Equations - III
The first two kinematic equations have time as a variable, but the third kinematic equation is independent of time. This equation expresses final velocity as a function of the acceleration and distance over which it acts. The fourth kinematic equation does not have an acceleration term and provides the final position of the object at time t in terms of the initial and final velocities. This equation is useful when the value of the constant acceleration is unknown.
Using the kinematic equations,...
Using the kinematic equations,...
01:24Relative Motion Analysis - Velocity
A stroke engine has a slider-crank mechanism that converts rotational motion from the crank into linear motion of the slider or vice versa. This mechanism consists of three main parts: the crank, the connecting rod, and the slider.
When an external force is exerted, it sets the crank into a rotational movement. This, in turn, instigates the motion of the connecting rod, leading to what is referred to as a general plane motion. This process involves two key points - point A on the connecting rod...
When an external force is exerted, it sets the crank into a rotational movement. This, in turn, instigates the motion of the connecting rod, leading to what is referred to as a general plane motion. This process involves two key points - point A on the connecting rod...
01:15Kinematic Equations: Problem Solving
When analyzing one-dimensional motion with constant acceleration, the problem-solving strategy involves identifying the known quantities and choosing the appropriate kinematic equations to solve for the unknowns. Either one or two kinematic equations are needed to solve for the unknowns, depending on the known and unknown quantities. Generally, the number of equations required is the same as the number of unknown quantities in the given example. Two-body pursuit problems always require two...