Researched, produced, and prepared by Brent S. Rushall, Ph.D., R.Psy.


Michael Klim once was one of the world's premier crawl-stroke swimmers. In a semi-final at the Sydney Olympic Games, he briefly held the world record for 100m freestyle having recorded a time of 48.18 seconds. As was analyzed and explained in a previous issue of How Champions Do It, he has been coached to perform a butterfly kick with his crawl stroke arm action (click here to visit that issue LINK). In the final of 100-m freestyle at the Sydney Games, he used this hybrid stroke starting about 5 meters from the finish. It slowed him considerably, and he finished out of the medals. Hybrid stroking of this form is biomechanically unsound.

At the 2001 Australian World Championships Trials held in Hobart, Tasmania, Michael Klim failed to qualify for any individual freestyle event for the World Championships. What was remarkable was that he performed more hybrid stroke swimming during the 100 m than at the Olympics!

In this analysis, Michael Klim's performance in the 100-m freestyle final is analyzed. Two parts of the race are compared. His orthodox stroke at 70 m into the race is demonstrated on the right in all displays. On the left is the hybrid stroke that was performed at 78 m into the race. Michael Klim was leading at 70 m. By the time the roughly 10 m of hybrid swimming was completed, he was a distinct third behind Ian Thorpe and Ashley Callus. A very clear demonstration of how the hybrid stroke is slower than the orthodox crawl stroke was provided.

This analysis compares the kinematic factors involved in the hybrid (butterfly-kick) stroke and the orthodox crawl stroke. Each frame is .1 seconds apart.

This stroke analysis includes moving sequences in real time where each frame is displayed for .5 of a second, and still frames.

The following image sequences are in real time. It will play through 10 times and then stop. To repeat the sequence, click the browser's "refresh" or "reload" button. The left image is the hybrid stroke and the right image the orthodox stroke.

The following image sequence shows each frame for half a second. It will play through 10 times and then stop. To repeat the sequence, click the browser's "refresh" or "reload" button. The left image is the hybrid stroke and the right image the orthodox stroke.

At the end of the following narrative, each frame is illustrated in detail in a sequential collage.

Notable Features

This first series of frames suggests that the butterfly kicking action does the following.

  1. Shortens the effective propulsive pull of the arms.
  2. Increases stroke rate (due to the shorter pulling cycle) although velocity is decreased.
  3. Disrupts streamlining.
  4. Increases frontal drag resistance and wave resistance.
  5. Produces unnecessary vertical forces.

Collage #1

Notable Features (continued)

Frames B7 through B11 exhibit the following features about the hybrid stroke pattern.

Frames C7 through C13 exhibit the following features about the orthodox stroke pattern.

Collage #2

General Conclusions

The introduction of a butterfly kick into a crawl stroke movement pattern decreases swimming velocity. There are several detrimental effects when the hybrid stroke is swum.

  1. The effective pull of the arms is shortened, mainly by "chopping-off" the latter part of the potential arm stroke. That reduction usually occurs by collapsing the elbow early in the pull.
  2. Stroke rate increases while swimming velocity decreases. The timing of the stroke changes to that exhibited in the orthodox stroke.
  3. The vertical undulating movements of the hips that occur as reactions to downward butterfly kicks, dramatically increases wave resistance making the stroke more tiring and energy consuming.
  4. Streamlining is disrupted in the hybrid stroke, the increased resistance to progression through the water possibly contributing the most to the diminution in swimming velocity. To facilitate performing the butterfly kick, the torso and thighs are angled downward for an instant, attaining a position that should be avoided in any stroke.
  5. At no time in any of the hybrid kicks in these sequences are the forces developed mainly backward (as in butterfly swimming). The forces created are not equivalent to those produced in full butterfly swimming. The assumption that they would be is false.
  6. Performing a butterfly kick de-emphasizes the arm pull as the added effort to execute it dominates the swimmer's movement pattern. When a movement is dominant, but non-propulsive, it is a wrong movement and one that needs to eliminated and avoided.
  7. Performing a butterfly kick with a crawl stroke arm action is STUPID.

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