Do wet suits affect swimming speed?

The Effects of a Wetsuit on Biomechanical, Physiological, and Perceptual Variables in Experienced Triathletes

PURPOSE

Wetsuits have been shown to change swim biomechanics and, thus, increase performance, but not all athletes are comfortable with their use because of possible modifications in motor coordination. The aim of this study was to evaluate the effects of wetsuit use on biomechanical, physiological, and perceptual variables.

METHODS

Eleven national- and international-level triathletes, familiar with wetsuit use, performed 7 × 200-m front crawl at constant preset speed twice, with and without a full wetsuit. The trunk incline (TI) and index of coordination (IdC) were measured stroke by stroke using video analysis. Stroke, breaths, and kick count, and timing (as breathing/kick action per arm-stroke cycle); stroke length (SL); and underwater length were analyzed using inertial-measurement-unit sensors. Heart rate (HR), rating of perceived exertion (RPE), and swimming comfort were monitored during the task.

RESULTS

A lower TI; IdC; number of strokes, kicks, and breaths; HR; and RPE for each 200 m were found in wetsuit compared with swimsuit condition. Higher values of SL and underwater length were found in wetsuit, whereas no differences were found in swimming comfort and timing of kicks and breaths. An increase for swimsuit condition in number of strokes and breaths, HR, and RPE was found during the task compared with the first 200 m.

CONCLUSION

Wetsuit use reduces TI and, thus, drag; increases propelling proficiency; and shows lower fatigability, without modifying motor coordination, compared with swimsuit use at the same speed. The use of a wetsuit during training sessions is recommended to increase comfort and the positive effects on performance.

Middle-distance Front Crawl Determinants When Using a Wetsuit

Our aim was to establish the determinants explaining the wetsuit advantages in middle-distance swimming efforts. Thirty-one triathletes and open water swimmers performed two 400 m front crawl bouts in a 25 m swimming pool with swim and wetsuits (with 48 h rest in-between). Anthropometric, kinematic and physiological variables were measured and Pearson correlation coefficients and stepwise linear regression analysis were used to determine their relationships. Associations observed in the 400 m front crawl included time improved using wetsuit with swimmers age (r=0.38; p=0.017), cross-sectional area (r=0.33; p=0.034), wetsuit upper limbs thickness (r=-0.49; p=0.010), ΔInternational Swimming Federation Points (r=-0.39;p=0.016), Δstroke rate (SR, r=0.48; p=0.003), Δstroke length (SL, r=-0.39; p=0.015), Δpropelling efficiency (r=-0.37; p=0.019) and Δblood lactate concentrations (r=0.30; p=0.048) in the total sample. In females, associations were found between the time improved and wetsuit upper and lower limbs thickness (both r=-0.78; p=0.011), and in males associations were found between time improved and age (r=0.43; p=0.030), ΔSR (r=0.56; p=0.005) and ΔSL (r=-0.44; p=0.026). Furthermore, 48% of the 400 m front crawl time improved was explained by wetsuit upper limbs thickness and SR changes (total sample), 62% explained by the wetsuit lower limbs thickness (females) and 48% of this enhancement was related to age and SR changes (males). Therefore, faster upper and lower limbs actions and wetsuit upper and lower limbs thickness are beneficial for 400 m front crawl performance improvement.

The Influence of Equipment and Environment on Children and Young Adults Learning Aquatic Skills

Learning aquatic skills is an important component of developing physical literacy in children. Aquatic skills such as floating, swimming and safe entry/exit promote engagement in different water environments and may help preserve lives in an emergency. This scoping review was conducted to evaluate the influence of task constraints (i.e., equipment) and environmental constraints (i.e., physical and social) on how children learn foundational aquatic skills. In developed countries, children are typically taught in swimming pools under direct supervision. It is also not uncommon to see children and infants learning to swim with assistive equipment (e.g., buoyancy aids). However, perhaps surprisingly, the evidence on how and where children learn aquatic skills does not uniformly promote such practices. For example, the use of flotation devices has not been proven to aid skill learning. Some researchers have advocated that children should learn aquatic skills whilst wearing outdoor clothing. One benefit of children wearing clothing is an increased capacity to practice in colder water (such as the ocean, rivers, or lakes). Overall, whilst practitioners often use equipment for various reasons it seems that not all equipment is equally useful in promoting the acquisition of aquatic skills. In less developed countries, with limited access to swimming pools and fewer resources for private instruction, a range of different open water aquatic environments and practices, such as swimming in temporarily flooded areas, have been reported. Such strategies are in urgent demand of further research given that drowning rates in less developed countries around the world exceed those in developed nations. It can be argued that learning in pools does not afford the opportunities to develop the whole range of adaptive skills that may be required in different open water environments such as navigating currents and waves, floating whilst clothed, or making life-saving decisions. Consequently, a shift toward teaching in open water environments has occurred in several countries. This review provides an evidence-base upon which practitioners can design more effective aquatic education programs for children.

Wetsuit Use During Open Water Swimming. Does It "Suit" Everybody? A Narrative Review

PURPOSE

Although wearing a wetsuit while swimming, when permitted, is primarily for safety reasons (ie, to protect against hypothermia), changes in buoyancy, biomechanics, and exercise performance have been reported. This narrative review covers the benefits of different wetsuit models on performance in swimming and triathlon.

METHODS

A computer search of online databases was conducted to locate relevant published research until March 2021. After the screening process, 17 studies were selected for analysis.

RESULTS

Most of the selected studies involved pool swimmers or triathletes completing short or middle distances in a pool while using a full or a long sleeveless wetsuit. Swimming with wetsuit elicited significant improvements in performance (maximum 11%), mainly by decreasing drag and energy cost, by increasing buoyancy, and by affecting technique. Different rates of change in each factor were found according to swimming ability and wetsuit model. In addition, wearing a wetsuit was often rated as uncomfortable by athletes.

CONCLUSIONS

Although improvement in swimming performance by wearing a wetsuit has been reported in the literature, the amplitude of the improvement remains questionable. The enhancement in swimming performance is attributable merely to improvements in propulsion proficiency and buoyancy, as well as a reduction in drag. The extent to which athletes are familiar with the use of a wetsuit, their swimming ability, and the wetsuit model may play important roles in this improvement. More studies simulating competition and comparing elite versus nonelite athletes are needed.

Swimming with Swimsuit and Wetsuit at Typical vs. Cold-water Temperatures (26 vs. 18 ℃)

This study aimed to compare three swimming conditions in a swimming flume with water at 26 ℃ (using swimsuit) and 18 ℃ (randomly with swimsuit and wetsuit). Seventeen swimmers (32.4±14.7 years old, 175.6±0.06 cm height, and 70.4±9.8 kg body mass) performed three bouts until exhaustion at a 400-m front crawl pace (24 h intervals). ANOVA repeated measures compared the experimental conditions. Swimming at 26 ℃ with swimsuit evidenced a higher metabolic demand (total energy expenditure; (E)), comparing to 18 ℃ swimsuit (p=0.05) and with 18 ℃ wetsuit (p=0.04). The 26 ℃ swimsuit condition presented higher peak oxygen uptake (VO2peak), blood lactate concentrations ([La-]_peak), rate of perceived exertion (RPE), maximal heart rate (HR_max), anaerobic lactic energy (AnL), E, energy cost (C), V̇O2 amplitude (Ap), and stroke rate (SR), but lower stroke length (SL) and stroke index (SI) than 18 ℃ wetsuit. The 18 ℃ swimsuit condition (comparing to wetsuit) lead to higher V̇O2peak, [La-]_peak, HR_max, E_, C, Ap, and SR but lower SL and SI. Swimming at aerobic power intensity with swim and wetsuit at 18 ℃ does not induce physiologic and biomechanical disadvantages compared to 26 ℃. The results suggested that the use of wetsuit might increase performance at 18 ℃ water temperature for competitive master swimmers. Its use is thus recommended in open water swimming competitions when the water temperature is 18-20 ℃.

Is Swimmers' Performance Influenced by Wetsuit Use?

PURPOSE

To observe changes in performance, physiological, and general kinematic variables induced by the use of wetsuits vs swimsuits in both swimming-pool and swimming-flume conditions.

METHODS

In a randomized and counterbalanced order, 33 swimmers (26.46 [11.72] y old) performed 2 × 400-m maximal front crawl in a 25-m swimming pool (with wetsuit and swimsuit), and their mean velocities were used later in 2 swimming-flume trials with both suits. Velocity, blood lactate concentration, heart rate (HR), Borg scale (rating of perceived exertion), stroke rate, stroke length (SL), stroke index, and propelling efficiency were evaluated.

RESULTS

The 400-m performance in the swimming pool was 0.07 m·s-1 faster when using the wetsuit than when using the swimsuit, evidencing a reduction of ∼6% in time elapsed (P < .001). Maximal HR, maximal blood lactate concentration, rating of perceived exertion, stroke rate, and propelling efficiency were similar when using both swimsuits, but SL and stroke index presented higher values with the wetsuit in both the swimming pool and the swimming flume. Comparing swimming conditions, maximal HR and maximal blood lactate concentration were lower, and SL, stroke index, and propelling efficiency were higher when swimming in the flume than when swimming in the pool with both suits.

CONCLUSIONS

The 6% velocity improvement was the result of an increase of 4% in SL. Swimmers reduced stroke rate and increased SL to benefit from the hydrodynamic reduction of the wetsuit and increase their swimming efficiency. Wetsuits might be utilized during training seasons to improve adaptations while swimming.

High-Speed Swimsuits and Their Historical Development in Competitive Swimming

The goal of this research was to review the experimental studies that have analyzed the influence of “high-speed swimsuits” on sports performance up to the appearance of the model “Jammer” in competitive swimmers. The design was a review following PRISMA Methodology, in which 43 studies were reviewed of a total of 512. Several searches were conducted in electronic databases of the existing research in this field (Google Scholar, Dialnet, Web of Sciences, and Scopus). The only studies excluded were those that reviewed the effects with neoprene and tests with triathletes. The studies that were included were published and peer-reviewed from 1999 to 2018 in which the effect of high-speed swimsuits was analyzed. The results showed the possible effects that high-speed swimwear can have in relation or not to competitive performance, biomechanical, physiological and psychological factors, flotation, drag, the material and the design until the introduction of the model “Jammer.” As conclusions, the lack of consensus due to the variety of fields of study means that improvements in competitions are still not clarified. In addition, the change in the rules may have effects on swimmers even though they have beaten records with other swimwear. Finally, the debate concerning whether medals were won unfairly or not is proposed.

The relationship of wearing a wetsuit in long-distance open-water swimming with sex, age, calendar year, performance, and nationality - crossing the "Strait of Gibraltar"

Aim

The aim of the present study was to investigate the relationship of wearing a wetsuit with sex, age group, nationality, calendar year, and performance in crossing the “Strait of Gibraltar”(14.3 km).

Materials and methods

A sample of 1,130 open-water (females, n=180, age 35.9±11.9 years; males, n=950, age 40.0±10.2 years) ultra-distance swimmers crossing the “Strait of Gibraltar” since 1950 was analyzed.

Results

Male, older, and Spanish swimmers used wetsuits more often than female, younger, and athletes of other nationalities, respectively, and the use of the wetsuit has increased during the past three decades. Swimmers with wetsuits were faster than those without. Male athletes aged 30–34 years were faster than athletes >60 years. Female athletes were younger than male athletes, and swimmers with wetsuits were older than those without. The Spanish were faster than the American swimmers and athletes from other nationalities, and the American swimmers were the oldest.

Conclusion

In summary, swimmers were faster when using a wetsuit, and local Spanish swimmers were the fastest and also used wetsuits most frequently. Male and older swimmers used wetsuits more often than other swimmers, and the use of wetsuits has increased in the last three decades.

Swimming performances in long distance open-water events with and without wetsuit

Background

Existing literature showed improved swimming performances for swimmers wearing wetsuits competing under standardized conditions in races held in pools on short to middle distances. Data about the influence of wetsuits on swimming performances in long and ultra-long open-water swimming races are missing. It is unknown whether the benefit of wearing wetsuits is comparable in men and women. The aim of this study was to investigate the influence of wearing a wetsuit on open-water swimming performances at the 26.4 km ‘Marathon Swim in Lake Zurich’ in Lake Zurich, Switzerland, and the 3.8 km Lake Ontario Swim Team-Race (LOST-Race) in Lake Ontario, Canada.

Methods

Race times of the fastest female and male swimmers competing with and without wetsuit were compared using multi-level regression analyses and analysis of variance.

Results

In the ‘Marathon Swim’ in Lake Zurich, wearing a wetsuit had no effect on race time regarding the gender where athletes wearing a wetsuit were not faster than athletes without wetsuit. However, the ten fastest men wearing a wetsuit (410.6 ± 26.7 min) were faster (32.7%, p < 0.01) than the ten fastest women without wetsuit (544.9 ± 81.3 min). In the ‘LOST-Race’, the top ten men wearing a wetsuit (51.7 ± 2.5 min) were faster (13.2%, p < 0.01) than the top ten women wearing a wetsuit (58.5 ± 3.2 min). Additionally, the top ten men without wetsuit (52.1 ± 2.4 min) were faster (19.6%, p < 0.01) than the top ten women without wetsuit (62.3 ± 2.5 min). The top ten women wearing a wetsuit (58.5 ± 3.2 min) were faster (6.5%, p < 0.01) than top ten women without a wetsuit (62.3 ± 25 min).

Conclusions

These results suggest that wearing a wetsuit had a positive influence on swimming speed for both women and men but the benefit of the use of wetsuits seemed to depend on additional factors (i.e. race distance). Women seemed to benefit more from wearing wetsuits than men in longer open-water ultra-distance swimming races.

Factors related to the advantageous effects of wearing a wetsuit during swimming at different submaximal velocity in triathletes

This study was designed to compare the effects of wetsuit (WS) to swimsuit (SS) at identical relative velocities in a swimming flume. Thirteen triathletes performed a continuous progressive swimming test and submaximal steady state swimming tests with a WS and with a SS. Maximal oxygen uptake (VO2max) and the associated velocity at which the VO2max was achieved (VVO2max) were determined during the continuous progressive tests. Two 5 min swims (at 60% VVO2max (V(60%)) and 80% VVO2max (V(80%))) were then conducted to measure VO2max, blood lactate concentration (LA), rating of perceived exertion (RPE), the energy cost of swimming (Cs), stroke rate (SR) and stroke length (SL). No difference was found in VO2max, but VVO2max with a WS was 5.4% higher than with a SS. VO2 with a WS was lower than with a SS alone at V(60%), but not at V(80%). Cs with a WS was lower by 14.4% at V(60%) and 7.5% at V(80%) than with a SS. No differences were found in LA and RPE between suit conditions during both submaximal swims. Wearing a WS did not affect SL, but SR tended to be higher in a WS for both submaximal velocities. These results suggest that the benefits of wearing a WS are not only improvement in swimming performance and propulsion efficiency, but reduction in gross energy consumption in the swimming portion of triathlon races. Furthermore, when wearing a WS, incremental changes in SR rather than SL are associated with improved swimming performance.

Triathlon Wet Suit and Technical Parameters at the Start and End of a 1500-m Swim

The aim of this study was to determine the effect of wearing a triathlon wet suit on the technical parameters of the front crawl stroke. Eight highly trained male triathletes were filmed with underwater camcorders during two 1500-m swim tests: one with a wet suit (WS) and the other with a standard suit (SS). Two conditions were considered: Condition I (CI) and Condition XV (CXV), representing the 1st and the 15th 100-m, respectively. Views were synchronized and digitized using kinematic analysis software (Schleihauf, 1994) to obtain 3-D coordinates of the anatomical landmarks of the body. Results showed that the wet suit and duration of the exercise significantly influenced stroke parameters. The swim with WS was characterized by greater stroke length and a progressive increase in stroke frequency, resulting from a more extended elbow position during the stroke and from a decrease in the absolute and relative times of the propulsive phase. These changes indicated more efficient upper limb action. The duration of exercise modified the swim with WS and SS. The loss of velocity observed in CXV was related to a decrease in stroke length, or more precisely a reduction in lever arm length during the aquatic phase, insufficiently offset by a slight increase in stroke frequency. These two motor responses, a less extended elbow position and a stroke frequency increase, emerged as an easier motor solution for coping with the effect of fatigue. This solution could be regarded as an adaptation to the duration of the exercise.

The effect of wet suit use by triathletes: an analysis of the different phases of arm movement

We analysed stroke phases and arm and leg coordination during front crawl swimming with and without a wet suit. Twelve nationally and internationally ranked French male triathletes performed three swim trials in randomized order using the front crawl stroke with and without a wet suit. All triathletes swam at three different swim velocities, corresponding to the paces appropriate for the 800 m (V800), 100 m (V100) and 50 m (V50) events. The different stroke phases and arm and leg coordination were identified by video analysis. Arm coordination was quantified using a new index of coordination, which expresses the three major modalities of opposition, catch-up and superposition in swimming. At all swim velocities, no significant differences in leg movements with or without the wet suit were noted. However, the wearing of the wet suit was associated with a significantly greater stroke length at the paces appropriate for the 100 and 50 m events (+3.46% and +3.10% at V100 and V50, respectively; P<0.01); a significantly greater stroke index at all three velocities (+5.18%, +5.21% and +5.91% at V800, V100 and V50, respectively; P<0.01); a significantly shorter pulling phase (-10.97%; P<0.05) and lower index of coordination (-21.87%; P<0.01) at the pace appropriate for the 800 m; and a significantly greater entry and catch phase (+9.81%; P<0.05) at the pace appropriate for the 100 m. We conclude that the wet suit amplified the coordination mode of the triathletes (i.e. catch-up coordination) without modifying stroke rate, recovery phase or leg movements.

Effect of a FastSkin suit on submaximal freestyle swimming

PURPOSE

Nine male collegiate swimmers swam three 183-m freestyle trials at "moderate, moderately hard, and hard" paces while wearing a traditional brief-style suit and on another occasion while wearing a newly designed suit covering the torso and legs with a material designed to reduce drag (FS).

METHODS

Postswim blood lactate concentration, V0(2), and rating of perceived exertion were measured. Average stroke length and rate, and breakout distance were determined for each swimming trial. Passive drag and buoyant force were also determined on swimmers while wearing both suits.

RESULTS

Swimmers swam at a higher mean velocity while wearing the FS (pooled mean % difference = 2%), but this was accompanied by a significant increase in V0(2) (4% difference, P< 0.05) and blood lactate concentration (10% difference, P< 0.05). Comparison of physiological responses at standardized freestyle swimming speeds of 1.4 and 1.6 m.s revealed no significant difference between the two suit conditions. Passive drag of the swimmers while being towed was not significantly different between the suits. Swimmers were significantly more buoyant while wearing the brief-style suit than the FS suit (P< 0.05).

CONCLUSION

These findings provide no evidence of either physical or physiological benefits of wearing these suits during submaximal freestyle swimming.

Specific aspects of contemporary triathlon: implications for physiological analysis and performance

Triathlon competitions are performed over markedly different distances and under a variety of technical constraints. In 'standard-distance' triathlons involving 1.5km swim, 40km cycling and 10km running, a World Cup series as well as a World Championship race is available for 'elite' competitors. In contrast, 'age-group' triathletes may compete in 5-year age categories at a World Championship level, but not against the elite competitors. The difference between elite and age-group races is that during the cycle stage elite competitors may 'draft' or cycle in a sheltered position; age-group athletes complete the cycle stage as an individual time trial. Within triathlons there are a number of specific aspects that make the physiological demands different from the individual sports of swimming, cycling and running. The physiological demands of the cycle stage in elite races may also differ compared with the age-group format. This in turn may influence performance during the cycle leg and subsequent running stage. Wetsuit use and drafting during swimming (in both elite and age-group races) result in improved buoyancy and a reduction in frontal resistance, respectively. Both of these factors will result in improved performance and efficiency relative to normal pool-based swimming efforts. Overall cycling performance after swimming in a triathlon is not typically affected. However, it is possible that during the initial stages of the cycle leg the ability of an athlete to generate the high power outputs necessary for tactical position changes may be impeded. Drafting during cycling results in a reduction in frontal resistance and reduced energy cost at a given submaximal intensity. The reduced energy expenditure during the cycle stage results in an improvement in running, so an athlete may exercise at a higher percentage of maximal oxygen uptake. In elite triathlon races, the cycle courses offer specific physiological demands that may result in different fatigue responses when compared with standard time-trial courses. Furthermore, it is possible that different physical and physiological characteristics may make some athletes more suited to races where the cycle course is either flat or has undulating sections. An athlete's ability to perform running activity after cycling, during a triathlon, may be influenced by the pedalling frequency and also the physiological demands of the cycle stage. The technical features of elite and age-group triathlons together with the physiological demands of longer distance events should be considered in experimental design, training practice and also performance diagnosis of triathletes.

The effects of wet suits on physiological and biomechanical indices during swimming

The objectives of this study were to verify the effects of wet suits (WS) on the performance during 1500m swimming (V1500), on the velocity corresponding to the anaerobic threshold (VAT) and on the drag force (AD) as well as its coefficient (Cx). 19 swimmers randomly completed the following protocols on different days (with and without WS): 1) maximal performance of 1500m swimming; 2) VAT in field test, with fixed concentration of blood lactate (4 mM) and 3) determination of hydrodynamic indices (AD and Cx). The results demonstrated significant differences (p < 0.05) in the VAT (1.27 +/- 0.09; 1.21 +/- 0.06 m.s-1), and in the V1500 (1.21 +/- 0.08; 1.17 +/- 0.08 m.s-1), with and without WS, respectively. However the AD, and its Cx did not present significant differences (p>0.05) for the respective maximal speeds of swimming. In summary, we can conclude that WS allows swimmers to reach greater speeds in both, long- and short-course swims. This improvement can be related to the decrease of the AD, since with higher speeds (with WS) the subjects presented the same resistance, as they did when compared to speeds without a WS. Moreover, these data suggest that the methodology used in this study to determine the Cx is unable to detect the improvement caused by WS.

Hyperthermia during Olympic triathlon: influence of body heat storage during the swimming stage

The purpose of this project was to determine whether mild heat stress induced by wearing a wet suit while swimming in relatively warm water (25.4 +/- 0.1 degrees C) increases the risk of heat injury during the cycling and running stages of an International distance triathlon in a hot and humid environment (32 degrees C and 65% RH). Five male triathletes randomly completed two simulated triathlons (swim = 30 min; bike = 40 km; run = 10 km) in the laboratory using a swimming flume, cycle ergometer, and running treadmill. In both trials, all conditions were identical, except for the swimming portion in which a neoprene wet suit was worn during one trial (WS) and a swimming suit during the other (SS). The swim portion consisted of a 30-min standardized swim in which oxygen consumption (VO2) was replicated, regardless of WS or SS. During the cycling and running stages, however, the subjects were asked to complete the distances as fast as possible. Core temperature (Tc) was not significantly different between the SS and WS trials at any time point during the triathlon. However, mean skin temperature (Tsk) and mean body temperature (Tb) were higher (P < 0.05) in the WS at 15 (Tsk = +4.1 degrees C, Tb = +1.5 degrees C) and 30 min (Tsk = +4 degrees C, Tb = +1.6 degrees C) of the swim. These Tsk and Tb differences were eliminated by 15 min of the cycling stage and remained similar (P > 0.05) through the end of the triathlon. Moreover, there were no differences (P > 0.05) in VO2, heart rate (HR), rating of perceived exertion (RPE), or thermal sensation (TS) between the WS and SS. Additionally, no significant differences were found in cycling (SS = 1:14:46 +/- 2:48 vs WS = 1:14:37 +/- 2:54 min), running (SS = 55:40 +/- 1:49 vs WS = 57:20 +/- 4:00 min), or total triathlon times (SS = 2:40:26 +/- 1:58 vs WS = 2:41:57 +/- 1:37 min). These data indicate that wearing a wet suit during the swimming stage of an international distance triathlon in 25.4 degrees C water does not adversely affect the thermoregulatory responses of the triathlete on the subsequent cycling and running stages.

Wetsuits, body density and swimming performance

To determine the influence of body composition upon swimming performance with and without wetsuits, 14 competitive female swimmers (mean (s.d.) age, 19.9 (0.9) years) were measured for body density while wearing both wetsuits and normal swimsuits. Subjects swam 400 and 1500 m trials with and without wetsuits, randomly, over a 12-day period. Six subjects participated in an additional trial while wearing neoprene leg-bands fitted over the wetsuit. Mean (s.d.) subject density without and with wetsuits was 1.048 (.009) and 1.021 (.007) g/ml respectively. Wetsuits reduced (P less than 0.05) swim times for the 400 (-4.96%) and 1500 m swim (-3.23%) compared with swimsuit trials. The neoprene bands increased (P less than 0.05) swim times relative to swimsuit and wetsuit trials. With wetsuits, swim times were inversely (P less than 0.05) related to density for the 400 (r = -0.46) and 1500 m swim (r = -0.54) suggesting that wetsuits increase performance by increasing buoyancy and that lean subjects benefit more from wearing wetsuits than do fatter subjects.