Compare the technique in the two images below.

Technique

 

The image on the left has three major technique limitations. The image on the right is a model of optimal technique (MONA).

 

Limitation Effect Effective Technique Effect
The head is almost completely above the surface. An increase in the head/torso angle causes more resistance.  The water level is at the hairline. The head/torso angle is minimal.
The left wrist is above the left elbow. An ineffective arm entry positions the hand and the shoulder at the same level. The left elbow is above the left wrist. An effective arm entry with a downward angle positions the hand below the shoulder.
Both arms are simultaneously in front of the shoulders. The arm coordination is negative.  The arms in opposition. The arm coordination is zero.

 

The image on the left replicates the swimmer who just set a world record of 46.4 seconds in the 100 meter freestyle at the 2024 Paris Olympics.

The image on the right could achieve Counsilman’s prediction of swimming a 40 second 100 meter freestyle (over six seconds faster than the world record).