What Do S, SB, and SM Mean in Para Swimming?

Watch any major para swimming meet and you will notice every heat labeled with a combination of letters and numbers – most commonly S, SB, or SM followed by a numeral. These codes are more than administrative shorthand; they are the backbone of fair competition.

This article breaks down what each letter group means, how the numbering system works, and the steps officials use to place athletes in the correct class so performances can be compared on equal footing.

The Purpose of Classification in Para Swimming

Para swimming welcomes athletes with a wide variety of physical, visual, and intellectual impairments. Because those impairments affect movement in different ways, a standardized system is needed to group swimmers so that races are decided by skill and conditioning rather than the degree of disability.

S, SB, and SM are the pillars of that system. They designate which stroke is being contested and set the stage for the numerical class that follows. Together, the letter and number inform coaches, officials, and spectators exactly which athletes are eligible to race head-to-head.

What the "S" Classes Cover

The single letter S stands for freestyle, backstroke, and butterfly events. A swimmer listed as S7, for example, will compete in those three strokes against others who share a similar functional ability level.

Numbers range from 1 to 10 for physical impairments, 11 to 13 for visual impairments, and 14 for intellectual impairments. Lower numbers indicate a more severe activity limitation, while higher numbers mean athletes have a greater range of motion and strength.

• S1–S10: Physical impairments ranked from most to least severe
• S11–S13: Visual impairment classes (all swimmers must wear blackout goggles)
• S14: Intellectual impairment class

Why Breaststroke Gets Its Own "SB" Category

Breaststroke relies on a symmetrical whip kick and simultaneous arm pull, movements that challenge certain impairment groups far more than freestyle or butterfly. To account for this, the International Paralympic Committee created a separate SB designation.

An SB class number is often one or two levels lower than a swimmer’s S class because the stroke demands different muscle groups and joint coordination. For instance, a competitor classified as S9 may race breaststroke in SB8.

Decoding the "SM" for Individual Medley

The individual medley (IM) combines all four strokes, so a third label, SM, is applied. Because IM includes breaststroke, the SM class usually mirrors the SB number rather than the S number.

If a swimmer is S6, SB5, and SM5, officials expect the combination of strokes within the medley to be fair relative to others in that SM class.

How Class Numbers Are Assigned

Classification panels consist of medical and technical experts who evaluate muscle strength, range of motion, coordination, and, for visually impaired athletes, field of vision and acuity. Assessments include a physical exam and in-water observation during training and competition.

After testing, the panel confirms a sport class and may designate it as New, Review, or Confirmed. Athletes under the New or Review status can be re-evaluated if their condition changes or technology (like prosthetics) evolves.

Common Misconceptions

One frequent misunderstanding is that an athlete with a higher number is automatically faster. In reality, training, technique, and race strategy still decide the podium. The numbers only level the playing field.

Another mistake is assuming the same class transfers across sports. A swimmer listed as S8 might have a completely different classification for wheelchair basketball or para triathlon because each sport stresses the body differently.

Key Takeaways

S, SB, and SM are simple letters that carry a complex responsibility: making para swimming fair, competitive, and engaging for everyone involved.

By understanding how each code translates to functional ability in specific strokes, spectators gain a deeper appreciation for the athletes’ performances and the meticulous work that happens behind the scenes to ensure every race is truly head-to-head.