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. "
- 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.