Each frame is .1 second apart. John Olsen's split time for this swim was 48.17 seconds, the fastest of any of the USA team.
- Frame #1: The left arm at entry is stretched well out in front over the water. The right arm pull nears completion of force production caused by upper arm adduction and will soon begin to extend at the elbow. The head looks forward, which contributes to an overall slight angle off streamline. The left leg prepares to kick to counterbalance the right arm exit.
- Frame #2: The left arm presses down and begins to flex at the elbow. The right arm is in the early stages of extension with the hand/forearm propelling surface still almost vertical. The left leg kicks but only to a minor degree. The right leg prepares to kick to counterbalance the early stages of the left arm pull. The head turns to breathe.
- Frame #3: The left upper arm begins to medially rotate. In frames #2-4 the elbow remains "high" while the hand and forearm move to a much greater degree. This is the initiation of an "elbow-up" position. The right leg kicks to counterbalance the increased vertical force component of the left arm repositioning movement. The swimmer's overall position remains off streamline.
- Frame #4: Left arm elbow bend and medial rotation continues. The left leg kick finishes, as the forces generated by the left arm are now predominantly horizontal.
- Frame #5: Rapid left upper-arm-adduction occurs while the hand/forearm is positioned as the propelling surface. Right arm recovery has been rapid and the left leg prepares to kick to counterbalance its impending entry. The head returns and looks forward.
- Frame #6: Left arm propulsion continues as the upper arm adducts. However, there seems to be a "letting go" of the elbow as it has traveled further than the hand. The right arm enters stretched well in front but at an earlier time relative to the opposite arm pull than was demonstrated in frame #1. The head looks down more and is deeper in the water improving overall streamline. The left leg kicks to counterbalance the right arm entry.
- Frame #7: Left arm propulsion is now powered by elbow extension. The propelling surface is maintained in largely a vertical orientation. The right arm, instead of being repositioned to create propulsion is held out in front and presses down. The left leg kicks to counterbalance the vertical force component created by the right arm action. The head angle increases as the swimmer looks forward.
- Frame #8: The right arm downward press continues and the counterbalancing left leg kick is very deep when compared to that of the right leg during the left arm's repositioning movement. The drag resistances created by the whole leg can be seen by the large amount of turbulence following the total limb. There can be no propulsion from a leg kick in this position. Body roll to the right is much greater than to the left (compare to that illustrated in frame #3).
- Frame #9: Right arm propulsion is developed not in an elbow-up position but rather as a long lever. The force emanating from the arm in this position has considerable vertical and horizontal components. The right hand is much deeper than the left at any stage of its pull. The head continues to look ahead.
- Frame #10: Right arm propulsion continues but is compromised. Upper arm adduction moves the arm but coupled with bending at the elbow the propelling surface is angled rather than vertical. That orientation produces slippage and also facilitates an increased lift force. The right arm recovers fast. The left leg drops down in a "trim-tab" manner to correct/counterbalance some unidentifiable movement.
- Frame #11. The right elbow moves faster than the hand suggesting a loss in force generation. The left knee drops out of streamline preparatory to kicking. This is probably due to large right-arm vertical-force components caused by sliding the hand/forearm upward.
- Frame #12: The position of frame #1 is repeated and the stroke cycle recommences.
John Olsen exhibits an uneven stroke. The timing and movement sequences of both arms are different. While the left arm exhibits a desirable elbow-up position, the right arm does not. The long downward press of the right arm would cause a drop in the swimmer's momentum due to an inertial lag. That delay would consume energy more inefficiently. In the middle of the pull of both arms the elbow moves faster than the hand suggesting a diminution in propulsive power due to a letting-go and change in the angle of the propulsive surface.
The head position could be improved. Its forward-looking position does produce a slight body angle for part of the stroke resulting in increased frontal resistance.