Gear & Technology, Podcast, Science and Physiology, Swimming

Maria Francesca Piacentini, PhD | EP#392

 May 29, 2023

By  Bernardo Gonçalves


Maria Francesca Piacentini - That Triathlon Show

Maria Francesca Piacentini, PhD, is Associate Professor at the University of Rome Foro Italico. Her research interests include overreaching and overtraining, training monitoring, and more recently, open water swimming and particularly the use of wetsuits in triathlon and open water swimming.

In this episode you'll learn about:

  • An overview of the literature of wetsuits, and how wetsuits change performance, biomechanical, physiological and perceptual variables
  • Comparing wetsuit and non-wetsuit swimming at a fixed speed and using a longer protocol to assess fatiguability with and without wetsuit
  • Discussion points on wetsuit familiarity, when and how to use a wetsuit in training, using a trisuit underneath the wetsuit, the impact of water temperature, etc. 

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Maria's background

03:05 -

  • I am a professor at the University of Rome, Faro Italico, one of the three European universities dedicated entirely to sports science. Since my PhD studies in Brussels, where I focused on central fatigue, I have been interested in endurance sports. 
  • Around 2015, I delved into open-water swimming and realised there was a lack of literature and guidance for athletes and coaches in this Olympic discipline.
  • My former PhD student, Roberto Ballasarre, and I became intrigued by the research on wetsuits, particularly concerning open-water swimmers. 
  • These swimmers are skilled in the water but often unfamiliar with using a wetsuit, despite its necessity for extended periods. This sparked our initial research question and motivated us to investigate wetsuit usage in open-water swimming.

Wetsuit racing

04:25 -

  • In open-water swimming, wetsuits are not commonly used compared to triathlon races. 
  • This is because there are fewer races where wetsuits are required. Until 2017, wetsuits were not regulated by FINA and were not a common part of open-water swimming. 
  • The decision to use a wetsuit depends on the water temperature, and the regulations are more stringent compared to triathlons. 
  • For example, in a recent race in Sardinia, wetsuits were used, but typically they would not be utilised. 
  • The water temperature and atmospheric conditions play a significant role in determining whether wetsuits are necessary.

Wetsuit research

05:38 -

  • Before starting our research on wetsuits, we wanted to understand their previous use and effects. 
  • Wetsuits are primarily made of neoprene, a synthetic rubber with bubbles that provide insulation. 
  • Athletes wearing wetsuits noticed that their legs stayed buoyant, and they swam faster. 
  • Our literature review confirmed that wearing a wetsuit does enhance speed. 
  • Here are three key factors contributing to this improvement:
    1. Increased Buoyancy: Wetsuits increase buoyancy, allowing swimmers to float more and maintain a horizontal body position. This reduces the frontal area and minimises drag, the resistance encountered while moving through the water.
    2. Reduced Friction Drag: The material of a wetsuit decreases friction drag caused by the fluid reacting against the skin, hair, and clothes. This smoother surface reduces resistance and improves efficiency.
    3. Improved Stroke Efficiency: Wetsuits have been found to enhance stroke length, the distance covered with each stroke. This is measured using the stroke index, which is the product of speed and stroke length. The increased stroke efficiency has a positive impact on energy expenditure and performance.

Wetsuit speed increase

09:25 -

  • The percentage of the benefit obtained from correct positioning in swimming ranges between 6 and 11%. 
  • The extent of benefit depends on factors such as task length, speed, and swimmer ability. 
  • Longer tasks generally yield more benefit, while shorter tasks offer less. The swimmer's ability can amplify or diminish the magnitude of the benefit. 
  • Weaker swimmers tend to experience more significant advantages from correct positioning due to their less efficient water positioning. Weak swimmers also benefit more as they tend to swim at slower speeds. 
  • Increasing speed during swimming can enhance hydrostatic lift, leading to further upward movement in the water.
  • Wearing a wetsuit allows for better positioning in the water.
  • It enhances stroke efficiency, leading to a more effective swimming technique.
  • Athletes often perceive these benefits when using a wetsuit.
  • When comparing swimming with and without a wetsuit at the same speed, there is a decrease in energy cost and reduced perceived exertion.
  • Wetsuit usage can make athletes feel less fatigued during swimming.
  • In terms of distance coverage, wearing a wetsuit enables swimmers to cover a greater distance in less time.

Causes for improved stroke efficiency and length

11:05 -

  • The effectiveness of wearing a wetsuit during swimming depends on two main parameters. 
  • These parameters, combined with the wetsuit itself, contribute to reducing the energy cost of swimming. 
  • As a result, wearing a wetsuit can lead to lower oxygen consumption during swimming, making it a beneficial choice.

Summary from the literature review

12:45 -

  • The use of wetsuits in swimming provides several advantages and improvements.
  • Physiologically, wearing a wetsuit increases oxygen levels during submaximal and stable speeds and velocity at VO2 max or lactate threshold.
  • Biomechanically, stroke rate and length are influenced by wetsuits, although the specific changes can vary depending on testing protocols and speeds.
  • Wearing a wetsuit typically leads to fewer kicks per stroke cycle, preserving energy for other parts of the triathlon.
  • Perceived effort decreases when swimming with a wetsuit, but individual comfort levels may vary.
  • Overall performance is enhanced with wetsuits, as seen in ITU triathlon races over the decades.
  • Technological advancements in wetsuit design have likely contributed to increased comfort and performance benefits.
  • When comparing research findings on wetsuit use over a long period, changes in comfort and performance should be considered.

Open questions to answer in future research 

16:45 -

  • I would like to comment on the limited population tested in previous studies. Most studies have focused on comparing triathletes with pool swimmers, with only one study considering open-water swimmers who use wetsuits. 
  • Pool swimmers, despite being proficient swimmers, often feel discomfort with wetsuits, while triathletes, who may be less efficient swimmers, tend to feel more comfortable with them. 
  • The body composition of triathletes and pool swimmers differs slightly, impacting buoyancy and the observed effects of wetsuits. 
  • It is essential to compare the same population that will be utilising wetsuits.
  • It would be interesting to examine tests conducted in a proper environmental setting, such as open-water swimming, as most studies have been conducted in controlled pool environments. 
  • However, conducting tests in open water, especially without wetsuits, can be challenging due to the need for devices and logistics. 
  • Exploring sex differences in buoyancy and stroke characteristics and considering age group differences and swimming expertise, particularly in the triathlete population, would provide valuable insights.
  • Additionally, investigating the effects of wetsuits on longer swimming tasks is crucial. 
  • It is hypothesised that longer tasks may lead to more significant changes in motor coordination, potentially resulting in increased fatigue with wetsuits. 
  • While some parameters have been studied before, our research examined how athletes alter their swimming patterns in different conditions and how these variations may impact long-term fatigue with wetsuits.

Protocol and demographic of Maria's study

20:25 -

  • The study aimed to assess the effects of a full-body wetsuit, explicitly comparing it to a sleeveless wetsuit, on biomechanical, physiological, and perceptual variables during a long segmented task. 
  • The task consisted of seven sets of 200 meters with one minute of recovery between sets. 
  • All 200 meters were performed at the athletes' self-reported 1500-meter race pace, both with and without the wetsuit. 
  • This allowed for speed normalisation and measurement of the differences between wetsuit and non-wetsuit conditions.
  • One of the study's most exciting and novel aspects was examining how biomechanics and physiology changed with fatigue within the same task. 
  • This involved analysing the differences in the last 200 meters between the wetsuit and non-wetsuit conditions. 
  • The study initially recruited 15 well-trained triathletes, but four were later discarded due to the inability to maintain the same speed in both situations, with a threshold of a 3% time difference.
  • Each athlete performed the protocol twice in a counterbalanced order. Heart rate was monitored using a strap, with measurements taken before, after each 200-meter set, and at the end of the test.
  • The underwater camera recording allowed for measuring parameters such as stroke length, stroke rate, kick count, and stroke index, which were previously mentioned as areas of focus in the study.


23:00 -

  • Several key findings emerged in comparing the differences between the wetsuit and non-wetsuit conditions. 
  • The wetsuit condition showed a more favourable trunk incline, indicating improved body positioning in the water. 
  • There was also a lower kick count per cycle, decreased breathing count, lower heart rate, and reduced rating of perceived exertion for each 200-meter segment compared to the swimsuit condition.
  • These findings are significant as they suggest that athletes experienced less fatigue while maintaining the same speed in the wetsuit condition. 
  • The increased stroke length and index observed in the wetsuit condition further support this notion of improved performance. 
  • These benefits are attributed to the enhanced buoyancy provided by the wetsuit.
  • Interestingly, within each task, certain parameters only showed specific changes in the swimsuit condition. 
  • These included an increase in the rating of perceived exertion, breathing count, and heart rate, indicating more significant fatigue in the swimsuit condition compared to the wetsuit condition. 
  • Additionally, stroke index and length significantly decreased with fatigue in the swimsuit condition, whereas they remained relatively stable in the wetsuit condition.
  • The study was conducted in collaboration with the Triathlon Federation, ensuring that the research had practical relevance and applicability to the field. 
  • However, it is worth noting that the study primarily focused on longer tasks within the context of triathlon. 
  • Nevertheless, there is recognition of the potential value of investigating the effects of wetsuits in even longer-duration activities, such as two-hour swims.
  • The interest in longer tasks stems from the world of open water swimming, where athletes often experience changes in pace and exertion towards the end of a race. 
  • Understanding how wetsuits may influence performance and comfort during these extended durations, particularly when swimmers push their limits, would provide valuable insights.
  • Exploring factors such as shoulder constraints and overall comfort concerning the increased speed exhibited by open-water swimmers in the latter stages of a two-hour swim would be particularly intriguing.

Perceived comfort

26:57 -

  • The participants in the study reported a positive level of comfort with the wetsuit at the end of the tasks. 
  • It's worth noting that they were wearing their own wetsuits, which they were already familiar with. 
  • This familiarity with their race kit and the race situation is crucial for achieving comfort and experiencing the desired effects. 
  • While observing these effects without prior familiarisation is possible, there may be a higher likelihood of discomfort in such cases. 
  • Therefore, training with the wetsuit and becoming familiar with it is highly recommended.
  • Additionally, it should be noted that swimming with a wetsuit in a pool with a temperature of 28 degrees Celsius may not accurately reflect real-world race conditions. 
  • The comfort level and performance benefits observed in the study were based on this controlled environment but may vary in open water or under different temperature conditions.

Practical applications of this study

28:30 -

  • Based on the study's findings, there are several practical applications for triathletes to consider. 
  • Firstly, it is beneficial for triathletes to train with a wetsuit to familiarise themselves with its effects, especially during longer tasks. 
  • The study indicated that motor coordination and muscle activation remained similar when using a wetsuit, suggesting that training with it will not disrupt or fatigue other muscles.
  • When approaching competition, it is recommended to incorporate wetsuit training into the preparation phase. 
  • This includes training with the complete race kit, including a tri-suit underneath the wetsuit, to ensure comfort and familiarity with the entire setup. 
  • If possible, training in open water should be prioritised, particularly in locations where races will occur. 
  • This allows triathletes to acclimate to cold water conditions, which is essential when using a wetsuit.
  • As for future research, conducting longer tasks with different groups of triathletes, including age group athletes of varying expertise levels, would provide valuable insights. 
  • Additionally, exploring the effects of wetsuits on open-water swimmers could be an exciting area of study. Overall, incorporating wetsuit training and understanding its impact on performance can guide athletes in optimising their training strategies.
  • It is crucial to emphasise the importance of practising not only putting on a wetsuit but also removing it efficiently during T1 transitions. 
  • While wetsuits have become tighter, making it necessary to practice their removal, the challenge is amplified when swimming in cold waters. 
  • Unzipping and manoeuvring the wetsuit can be particularly challenging in such conditions.
  • While we have covered a significant amount of information, it is essential to acknowledge that the literature on this subject is vast.
  • This summary represents a fraction of the studies conducted thus far. 
  • However, more research is still needed, especially in real-world situations and colder water temperatures. 
  • Understanding how physiological responses differ with and without a wetsuit in open water and colder conditions would greatly benefit triathletes and contribute to their performance optimisation.

Rapid fire questions

32:50 -

What is your favourite book or resource related to endurance sports?

Sempre con le ali ai piedi. Una vita da campione olimpico - Stefano Baldini's autobiography

Il guardiano della collina dei ciliegi - book by Franco Faggiani (about Japanese marathon runner Shizo Kanakuri)

What is an important habit that you have benefited from athletically, professionally or personally?

I like to have control, be well-prepared, and ensure that everything turns out well.

Who's somebody that you look up to or that has inspired you?

My PhD mentor and supervisor, Professor Mason from the Free University of Brussels


Bernardo Gonçalves

Bernardo is a Portuguese elite cyclist and co-founder of SpeedEdge Performance, a company focused on optimising cycling and triathlon performance. He writes the shownotes for That Triathlon Show, and also produces social media content for each new episode.

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