Athlete Development Model - Anthropometric Factors and Body Compostion Q&A - English
What's the importance of psychological aspect do influence the morphological factors?
Great question – it lights the nature & nurture debate/approach.
Some research exists in the general population around Body Dissatisfaction and how that influences BMI & nutritional practices/eating habits. They studied 362 adolescents aged 10-15 years. The females reported feeling under more social pressure to be leaner (thinner). They used a self-reporting scale and those that showed higher body dissatisfaction and had a higher BMI and body fat % were more likely to have disordered eating behaviours.
Fortes et al did a similar study, using similar self-reporting, with 47 athletes aged 12-16 years from gymnastics, synchro swimming and diving and reported similar findings.
Bearing in mind that your morphology is polygenic, i.e. heavily influenced by your genes.
Is there an age where you would be relatively certain that body type/shape will have settled down and remain consistent?
In younger athletes you would anticipate seeing a 6-year-old female with ~14% body fat, rising to 25% by the time she is 17 years. In 6-year old boys it would be around 11%, going up to 15% by the time they were 17. [4,5]
There is a recently published study of almost 8500 participants aged 40-80 years by Frenzel et al that indicated that body shape tends to stay relatively consistent as we age, with slim people remaining slim and obese people remaining obese.
How do morphological characteristics impact biomechanics?
Interesting question to consider the biomechanics and can we separate that from performance indices or physiological aspects.
Swim – Taller swimmers tend to generate less wave resistance and have the greater potential for faster speeds due to their length (hull). Although size will influence drag, taller swimmers tend to be more energy efficient with a better propulsive efficiency. Front crawl/freestyle swimmers tend to have longer lower limbs than breaststroke swimmers. Taller swimmers will have a higher center of mass (CM) so off the blocks/pontoon they should enter the water further away from the blocks than shorter stature swimmers. 
One study  compared a 150cm – vs- 185cm swimmer over 100m. The taller swimmer swam 94.3m compared to the shorter swimmer swimming 95.5m and the taller swimmer was effectively 1.3% faster based on size alone.
Bike – Studies indicate that the athlete accounts for ~70% of the drag created on a bike. [9,10]
One study  was conducted with track cyclists, it was based on several professional cyclists working at 90% VO2max for 10 minutes, so has some face validity for triathletes. Take home messages were:
- Torso angle strongly influences the drag area. E.g. how low you get.
- Shoulder angle strongly influences the power output.
- Low torso angle and medium shoulder angle optimised the surplus power. However, the lowest possible torso angle was not always the best position. The position which results in the highest power output is not necessarily the position in which the aerodynamic drag is reduced the most.
Changes in position and gains in drag vary between athletes due to individual differences in body size and shape. Position should be optimised individually.
Laferdini et al considered some biomechanical aspects in their study of 6 trained -vs- 6 non-trained cyclists; specifically looking at muscle volume of vastus lateralis (outside of quad/thigh) and how that would influence cycling efficiency. They reported that VO2 uptake was a better performance indicator than muscle volume or pedal force effectiveness.
Run - Given this is weight bearing there are a whole load of variables to consider. Here single sport research has been considered as triathletes tend to start the run in a compromised state.
In running I feel it is one of those "it depends" answers given the influence that lower limb & foot morphology [12,13] can have on affecting run biomechanics, as well as aging . Trying not just looking at mass effect on times.
Maldonado et al (2001)  considered athlete morphology (height & weight) in relation to running energy costs in 1500m to marathon runners. The 5-10km runners were elite males ~174cm, ~61kgs & 13% body fat. The 5-10km runners had the higher VO2 values but also expended the most energy. This study concluded that anthropometric measures were not correlated to performance.
Should we train different body types differently, e.g. do ectomorphs get injured more, do mesomorph resist injury better, should you vary strength training. Equally should ectomorphs do more strength training or a different type of strength training? Should Mesomorphs do more endurance training?
Each case should be studied individually, referencing the principle of individualisation in relation to the specific physiological demands of their target competition(16).
If an athlete has a ectomorph somatotype and wants to compete in races where it demands a continuous use of maximal power on the bike (mixed team relay), coaches should implement a strategy to make them gain strength, and therefore, modify their somatotype to a more ecto-mesomorph.
If and athlete has an endomorph somatotype and wants to run a marathon, will be advisable to lose some weight. The average steps he will perform in the race will be around 55,000. Considering that his body need to support his body weight from 1.5-3 times his BWM every time he lands on the floor (peak impact), unless all his entire body and structures (joins, ligaments, muscles, etc.) are ready to cope with that, the likely risk of suffering an injury is very high.
In the case of the mesomorphs, once again it will depend on the type of race and distance they are taking part in and their physiological profile. Join us on next week webinar where all these concepts will be covered.
As far as we know, there is no specific research in the field of triathlon where the somatotype of the athlete has been correlated with the risk of injury.
- Fortes et al, (2013). Effects of psychological, morphological and sociodemographic variables on adolescents' eating behaviour. Revista Paulista de Pediatria, 31(2), pp. 182-188.
- Fortes et al (2013). Body dissatisfaction, psychological commitment to exercise and eating behaviour in young athletes from aesthetic sports. Brazilian Journal of Kinathropometry, 15(6), pp.695-704.
- Lippi et al (2010). Genetics and sport. British Medical Bulletin, 93, pp. 27-47.
- Greene, L., & Pate, R. (2015). Training young distance runners. Human Kinetics, Champaign, IL.
- Stafford, I (2011). Coaching children in sport. Routledge, Abingdon, OX.
- Frenzel, et al (2020). The aging human body shape. Aging and Mechanisms of Disease, 6(5), pp. 1-15.
- Kjendlie, P. L., & Stallman, R. (2011). Morphology and Swimming performance. In Seifert, Chollet & Mujika (eds) World Book of Swimming. Nova Science Publisher, New York, NY. pp. 203-223.
- Kjendlie, P. L., & Stallman, R. K. (2005). True race distance in swimming is dependent on body size. ECSS Annual Conference, Belgrade.
- Underwood et al, (2011). Aerodynamic drag and biomechanical power of a track cyclist as a function of shoulder and torso angles. Sports Engineering, 14, pp. 147–154.
- Hooker, J., & Jobson, S. (2012). Performance Cycling: The Science of Success. Bloomsbury; London.
- Lanferdini et al, (2014). Relationship between biomechanical and physiological variables with aerobic power in cycling. Journal of Science and Cycling, 3(1), pp. 9-15.
- Mei, et al. (2015). A comparative biomechanical analysis of habitually unshod and shod runners based on a foot morphological difference. Human Movement Science, 42, pp. 32-53.
- Saunders, et al (2004). Factors affecting running economy in trained distance runners. Sports medicine, 34(7), pp. 465-485.
- Korhonen et al. (2009). Biomechanical and Skeletal Muscle Determinants of Maximum Running Speed with Aging. Medicine and Science in Sports and Exercise, 41 (4), pp. 844–856
- Maldonado et al (2011). Influence of Body Mass and Height on the Energy Cost of Running in Highly Trained Middle- and Long-Distance Runners. International Journal of Sports Medicine, 23, pp. 268-272.
- Millet, Gregoire & Vleck, Veronica & Bentley, David. (2011). Physiological requirements in triathlon. Journal of Human Sport and Exercise. 6. 10.4100/jhse.2011.62.01.