what is the perfect backstroke body

What is the Perfect Backstroke Body?

admin Biomechanics, Blog, Dr. John Mullen, Latest&Greatest 2 Comments

Ideal body shape and structure is a common topic in swimming communities. It is most common for coaches to use their subjective eye when deciding if a swimmer has the perfect backstroke body (somatyape). A recent study by Sammoud (2018) assessed the key physical characteristics of young backstroke swimmers. The goal of this study was to determine what factors predict backstroke performance.

When assessing somatype, specifically the perfect backstroke body, human physique consists of three areas:

  • Body size: the physical magnitude of the body and its segments (stature, mass, surface area, etc).
  • Structure: shape describes the distribution of body parts expressed as ratios, such as the body mass index (BMI), the inverse ponderal index or the head length-to-body length (exclusive of head) ratio
  • Composition: the amount of various constituents in the body such as fat, muscle, bone, etc. (Nevill, Tsiotra, Tsimeas, & Koutedakis, 2009

Past studies by Sammoud and colleagues looked at the other competitive strokes and found:

  • Butterfly speed performance was strongly and positively associated with the segment length ratio [(arm-span)/(forearm-length) and girth ratio (calf-girth)/(ankle-girth)
  • Breaststroke performance was positively associated with the segment length ratio [arm-ratio = (hand-length)/(forearm-length)] and limb girth-ratio [girth-ratio = (forearm-girth)/(wrist-girth)] recently, Sammoud et al. (2018)

In this study, Sammoud looked to analyze the question on the perfect backstroke body and what predicts performance.

How to Find the Perfect Swimming Body

In total, 63 backstroke specialist swimmers (boys [n = 30; age: 13.98 ± 0.58 years]; girls [n = 33; age: 13.02 ± 1.20 years]) participated in this study. All participants were involved in five to six training sessions per week (distance 4000 ± 1000-m per session; 8 ± 1 hour per week) including the four swimming strokes. 

The multiplicative allometric model exploring the association between 100-m backstroke mean speed performance (m.s−1) and the different somatic characteristics:

  • Estimated that biological age
  • Sitting height
  • Leg length for the lower-limbs
  • Two girths (forearm and arm relaxed girth) are the main significant predictors of mean swim performance

What Factors Didn’t Predict Perfect the Perfect Backstroke Body

The results revealed that stature and body mass did not significantly contribute to the allometric model. This suggests that the advantage of longer levers was limb-segment-specific rather than a more general whole-body advantage.

What Factors Did Predict Perfect the Perfect Backstroke Body

The study found the following results were correlated with swimming performance in the 100-m backstroke:

  • Leg length
  • Forearm girth, specifically having a greater arm relaxed girth impairs performance.

Additionally, the study revealed that backstroke mean speed increases by 3.7% every additional year of the swimmers’ biological age. The results also indicated that girls’ backstroke mean speed performance is 4.1% less than boys.


Sammoud and colleagues noted several study limitations:

“We recognise the current study has a number of limitations. Primarily, we did not assess the long term effect of the somatic characteristics on measures of backstroke performance. In addition, we were unable to assess the contributions of other variables such as, (1) functional fitness (e.g., muscular strength, muscular power or flexibility) that might influence stroke mechanics (2) variables from other domains that may also play an important role in young swimmers’ performance (e.g. motor control, hydrodynamics, genetics), (3) biomechanical testing methods. “


  1. Sammoud, S., Nevill, A., Negra, Y., Bouguezzi, R., Helmi, C., & Hachana, Y. (2019). Key somatic variables in young backstroke swimmers. Journal of Sports Sciences,37(10), 1162-1167. doi:10.1080/02640414.2018.1546547

Written by Dr. GJohn Mullen, DPT.

Comments 2

  1. My best backstroker at the moment is a 13 year old female with thin body and who is double jointed at the elbows and somewhat more flexible at the shoulders as well than my other swimmers. This body structure also makes her a good butterfly swimmer.

  2. Well, I’m 200 pounds at 6’6″ tall and 71 years old. I just swam a half mile in the ocean. I’ve swum as much as 5 miles in the ocean in past decades, but that was then and this is now. Usually I alternate between the backstroke, the breaststroke and front stroke, often in that order. There’s a mile swim competition in Lavallette, this August, that I’m considering competing in. And though I was a lifeguard in the 1970s, I was never a fast swimmer. Probably my body density causes me to sink too low in the water, to be fast. Rowing was always my strongest event. But in swimming, the backstroke is the fastest for me. So I’m contemplating focusing mainly on the backstroke in my ocean swims, as I don’t want to be last in the competition, if I do compete.

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