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Characterization of regional skin temperatures in recreational surfers wearing a 2mm wetsuit
Ergonomics
Abstract
The purpose of this study was to investigate skin temperatures across surfers’ bodies while wearing a wetsuit during recreational surfing. Forty-six male recreational surfers participated in this study. Participants were instrumented with eight wireless iButton thermal sensors for the measurement of skin temperature, a Polar RCX5 heart rate monitor and a 2-mm full wetsuit. Following instrumentation, participants were instructed to engage in recreational surfing activities as normal. Significant differences (p < 0.001) in skin temperature (Tsk) were found across the body while wearing a wetsuit during recreational surfing. In addition, regional skin temperature changed across the session for several regions of the body (p < 0.001), and the magnitude of these changes varied significantly between regions. We show for the first time that significant differences exist in skin temperature across the body while wearing a wetsuit during a typical recreational surfing session. These findings may have implications for future wetsuit design.
Practitioner Summary: This study investigated the impact of wearing a wetsuit during recreational surfing on regional skin temperatures. Results from this study suggest that skin temperatures differ significantly across the body while wearing a 2-mm wetsuit during recreational surfing. These findings may have implications for future wetsuit design.
... Additionally, wetsuits allow small amounts of water to pass through the suit from entry points or seams, creating a thin layer of warm water between the neoprene and skin, further aiding the thermoregulatory process (Naebe et al., 2013). However, while wetsuits can help to mitigate the effects of cold water and air, heat loss still occurs during a typical surf session (Corona et al., 2018;Naebe et al., 2013;Warner et al., 2019). ...
... Regional heat losses, as measured by changes in skin temperature, are unevenly distributed across the body in recreational surfers wearing wetsuits (Corona et al., 2018;Skillern et al., 2021;Warner et al., 2019). The greatest amount of heat loss during surfing was reported to occur in the lower legs (≈− 6.0 • C), thighs (≈− 4.5 • C), and lower abdomen (≈− 5.0 • C) (Corona et al., 2018;Skillern et al., 2021;Warner et al., 2019). ...
... Regional heat losses, as measured by changes in skin temperature, are unevenly distributed across the body in recreational surfers wearing wetsuits (Corona et al., 2018;Skillern et al., 2021;Warner et al., 2019). The greatest amount of heat loss during surfing was reported to occur in the lower legs (≈− 6.0 • C), thighs (≈− 4.5 • C), and lower abdomen (≈− 5.0 • C) (Corona et al., 2018;Skillern et al., 2021;Warner et al., 2019). These temperature differences are likely due to variations in submersion and interaction with water since surfing involves a unique combination of movement and physical activity. ...
The purpose of this study was to characterize the perception of heat loss, comfort, and wetness in recreational surfers wearing wetsuits, to compare these data with changes in skin temperature reported in prior studies, and to examine the impact of wetsuit thickness, zipper location, and accessory use on thermal sensation and comfort. Following their surf session, nine-hundred and three male (n = 735) and female (n = 168) recreational surfers responded to a series of questions regarding thermal comfort/sensation, wetsuit characteristics, and surfing history. Average whole body thermal sensation rating was 0.8 ± 3.6 on a scale of − 10 to +10 and average whole body thermal comfort rating was 1.5 ± 1.2, midway between "just comfortable" and "comfortable." Overall, surfers felt coldest in their feet, hands, and head. Under their wetsuits, surfers felt the coldest, wettest, and least comfortable in their chest, lower legs, lower arms, and upper back. Wetsuit accessory use had the greatest impact on regions identified as coldest, least comfortable, and wettest. These data suggest that wetsuit design should focus on optimizing water access points and improving accessories for the feet, hands, and head.
... Competitive and recreational surfing have increased in popularity in recent years [1]. Surfing occurs in diverse environments, including water that is far below body temperature [2][3][4][5]. Many surfers wear wetsuits to reduce convective heat loss to improve comfort and prolong the amount of time that they can be submerged in the water without developing hypothermia [3][4][5][6][7][8]. ...
... Surfing occurs in diverse environments, including water that is far below body temperature [2][3][4][5]. Many surfers wear wetsuits to reduce convective heat loss to improve comfort and prolong the amount of time that they can be submerged in the water without developing hypothermia [3][4][5][6][7][8]. The market for surfing wetsuits is growing rapidly; in North America alone, the total wetsuit market is projected to reach $300 million in 2022 and surfing wetsuits are expected to account for the largest segment at 45% (Grand View Research, Wetsuit Market Size, Share, Industry Report, 2022). ...
... Despite their popularity and widespread use, recent data suggest that there is potential for innovation and improvement in surfing wetsuits [9]. For example skin temperature, a physiological variable that is often used in apparel research to quantify heat transfer and insulation [10][11][12], has been reported to decrease significantly within minutes during a typical surf session while wearing a standard 2 mm thick wetsuit [3,4,7,8]. Heat loss does not occur homogenously across the body because regions that interact more with cold water lose heat faster [3,4,7,8]. Further, regions of the body that are more exposed to air were shown to be warmer under wetsuit materials with outer surfaces that more effectively repel water and absorb radiant heat from the sun [5]. ...
Silicone applied to the exterior of jersey-lined neoprene may increase heat absorption and water repulsion without the loss of strength and durability observed in smoothskin neoprene. The purpose of this study was to compare skin temperature under silicone-coated jersey-lined neoprene and smoothskin neoprene during recreational surfing. A secondary purpose was to compare density, tensile strength, and tangent modulus of these materials. Thirty male surfers wore a 2-mm thick wetsuit designed with the chest and back panels on one side constructed of smoothskin neoprene and the other side silicone-coated neoprene (n = 30). Separate surf protocols were carried out in laboratory (n = 10) and field (n = 20) settings while skin temperature was collected bilaterally at the upper chest, upper back, abdomen, and lower back. In the field, skin temperatures under the smoothskin and silicone-coated neoprene were not significantly different at the upper chest, upper back, and lower back. In the laboratory, there were no significant differences in skin temperatures under the two materials at the upper chest and lower back. However, in both studies the skin temperatures were significantly higher under smoothskin neoprene at the abdomen (p < 0.01). In addition, the skin temperature at the upper back in the laboratory study was significantly higher underneath the silicone-coated neoprene (p < 0.01). Silicone-coated neoprene exhibited similar tensile strength but greater tangent modulus compared to smoothskin neoprene. These findings suggest that silicone-coated neoprene and smoothskin neoprene have similar thermal characteristics across most body sites but differ in tensile stiffness.
... Wetsuits are worn to assist with thermoregulation and can help to protect surfers from the effects of prolonged cold-water exposure by reducing heat loss to the environment (Naebe et al., 2013;Corona et al., 2018;Warner et al., 2019). Wetsuits have been used for over 70 years (Rainey, 2009), but they have been the subject of limited research and innovation. ...
... Participants were asked to surf for a minimum of 40 min but were permitted to surf longer at their leisure. Previous experiments have demonstrated that the inclusion rate of surfers begins to drop significantly after a duration of 40 min (Corona et al., 2018;Warner et al., 2019); therefore, this duration threshold was selected to maximize participant inclusion. For data collection purposes, the session began when the participant entered the water (ankle height) and ended when they exited the water (Kellogg et al., 2020). ...
... For example, the average skin temperature profile across time observed here is similar to data reported for female surfers at the lower back location while wearing a commercially available 2-mm full wetsuit (Warner et al., 2019). In addition, the current skin temperature data for the lower back was colder, but followed a similar trajectory, when compared to skin temperature at the lower back in male recreational surfers wearing a 2-mm wetsuit (Corona et al., 2018). Finally, differences between left and right low back, even as early as the first epoch, were reported in a previous study comparing outer surface materials on different wetsuit halves (smooth skin vs jersey) (Smith et al., 2020). ...
Purpose
The purpose of this study was to determine whether there are differences in skin temperature under graphene-infused fleece and traditional polyester fleece materials in the interior of a wetsuit.
Design/methodology/approach
A total of 48 participants surfed for a minimum of 40 min in a custom wetsuit with a torso lined with graphene-infused fleece on one half and traditional polyester fleece on the other. Eight iButton thermistors were used to record skin temperatures bilaterally at the upper back, chest, abdomen and lower back every minute for the entire surf session. After surfing, participants responded to questions associated with their perception of warmth and comfort and their knowledge of fleece materials.
Findings
Skin temperatures did not differ between the two types of fleece at the upper back, chest and abdomen locations. Skin temperatures in the lower back were significantly warmer under the traditional polyester fleece compared to graphene-infused fleece. Participant responses associated with warmth were consistent with skin temperature measurements.
Practical implications
The results of this study indicate that a graphene-infused nylon fleece interior does not clearly influence skin temperature in surfers when compared to a traditional polyester fleece interior. While skin temperatures were significantly lower under the graphene-infused nylon fleece at the low back, the other three anatomical locations did not exhibit significant differences.
Originality/value
Thermoregulation is an important consideration for the safety and performance of surfers in the ocean. Evidence suggests that the inner lining of a wetsuit may impact thermoregulation while surfing; however, no prior studies have compared interior materials.
... Surfing is an action sport that is rapidly increasing in popularity [1][2][3]. Although surfing is typically associated with warm and tropical climates, it often occurs in colder environments where exposure to elements can impact the performance and safety of athletes [4][5][6][7][8][9][10]. Therefore, it is important that surfers are well equipped with a wetsuit that can assist in thermoregulation and facilitate performance at a high level. ...
... Following written consent, participants were equipped with sixteen 1-Wire iButton Thermocron model DS1922L thermistors (Thermochron, Baulkham Hills, NSW, AUS), placed in eight locations on both their left and right side for bilateral comparison of the neoprene and TPE material. The thermistors were placed directly on the skin above the upper fibers of the pectoralis major, the rhomboid, the lateral triceps brachii, the inferior rectus abdominis, the inferior portion of latissimus dorsi, the flexor carpi radialis, the lateral vastus lateralis, and the medial gastrocnemius ( Fig. 2) [9,10]. Thermistors used at each location were randomized for each protocol to control for any unexpected variance in sensor behavior. ...
... After simple processing and visualization of the data in Excel they were further analyzed in MATLAB (R2020a, Natick, MA). This process involved compiling skin temperature data for each sensor location into 12 intervals (epochs) by averaging temperature every 5 min across the 60-min protocol, similar to analyses described previously [10,39]. A two-way repeated measures ANOVA was used to compare wetsuit material (TPE and neoprene) across time (12 epochs) at each anatomical location (eight locations). ...
Surf wetsuits are made of foamed chloroprene (neoprene), a synthetic rubber that is hard to recycle. Thermoplastic elastomer foam (TPE) may be a more sustainable replacement for neoprene in wetsuit design, but its impact on human thermoregulation and movement has not been evaluated. The purpose of this study was to compare skin temperature, oxygen consumption, heart rate, muscle activation, and arm kinematics while paddling in a thermoplastic elastomer vs. standard neoprene wetsuit. Thirty-three experienced surfers participated in one of two studies: a 60 min simulated surf session in a freshwater swim flume designed to evaluate skin temperature (n = 18), or a dry-land ergometer session designed to evaluate physiological and biomechanical aspects of surfboard paddling (n = 15). Skin temperatures under neoprene were significantly warmer than under thermoplastic elastomer at several anatomical locations including the upper chest (p < 0.01, ηpartial2 = 0.291), lower abdomen (p < 0.001, ηpartial2= 0.527), lower back (p < 0.005, ηpartial2 = 0.416), lower arm (p < 0.001, ηpartial2=0.537), upper leg (p < 0.001, ηpartial2= 0.717), and lower leg (p < 0.001, ηpartial2= 0.802). However, most participants did not perceive any temperature differences (50%) or felt that the thermoplastic elastomer was warmer (19%). There were no significant differences for any of the other physiological and biomechanical variables analyzed here (p > 0.05). These results suggest that thermoplastic elastomer foam is the less efficient insulator when compared to neoprene, but this difference may be imperceptible to the average surfer. Further, the thermoplastic elastomer wetsuit does not appear to add resistance to or alter upper extremity motion while paddling a dry land ergometer.
... Unlike swimming and triathlon where substantial research into the physiological and biomechanical effect of wetsuit design has been explored [25][26][27][28][29][30][31][32], in surfing this remains limited. Current research looks to biomechanics [6], thermoregulation [33][34][35] and physical wetsuit properties [36]. ...
... Important thermoregulatory key findings were noted across included wetsuit design studies. Anatomically regionspecific differences in skin temperature were noted, with the lower limb experiencing the greatest thermoregulatory losses; further differences were identified between males and females, with females demonstrating a greater mean temperature loss across all regions combined [33,35]. An outer layer of slick material provided a significantly higher mean [17] skin temperature in both field and laboratory conditions when compared to a jersey material [34]. ...
... The percentage of studies included was lower than expected. This can be attributed to the homogeny in equipment nomenclature between surfing and other water-based sports, for example studies into surfing and triathlon both use the term wetsuit [6,25,30,31,[33][34][35][36]44]. Additionally, there was a large volume of results investigating the business and marketing of surfing and associated apparel which did not meet the inclusion criteria for this review [48][49][50][51]. ...
Growth in the surfing equipment industry has led to increased scientific interest in this area, yet no current paper has reviewed and synthesized the effects of equipment design on surfing. Therefore, the aims of this study were to: (1) assess the volume and type of scientific literature that is available to the authors specific to surfing equipment and design, (2) summarise all surfing equipment and design studies completed to date specific to outcome measures and key findings and (3) identify knowledge gaps in the topic of surfing equipment design. This review was conducted in accordance with the PRISMA scoping review guidelines. A total of seven electronic databases were searched (PubMed, Embase, CINAHL, SPORTDiscus, Web of Science, SCOPUS, and Ovid). Google Scholar was also searched for grey literature. Inclusion criteria were mention of surfing equipment and relevant surfing outcome measures (physiological and mechanical). Exclusion criteria were no full text availability and works not available in English. Results from these articles were then extracted, summarised and presented. A total of 17 articles were selected for review and organized by theme of board, wetsuit and fin. Fin and wetsuit design were the most prominent themes (seven studies each respectively). Most were written within the past 5 years and written in the USA. Fin design studies were largely computational, whereas board and wetsuit design were mostly field and laboratory based. Within each study theme there were consistencies in outcome measures and measuring devices. Board design studies focused on paddling efficiency (VO2 and HR). Wetsuit design studies primarily assessed thermoregulation, and less so muscle activation and paddling biomechanics. Fin design studies focused on fin shape and configuration to assess lift and drag properties. Three key themes of board, wetsuit and fin design were noted; from this the authors were able to identify several knowledge gaps such as a lack of standardisation in equipment controls and study design procedures. Alongside improving standardisation, the use of wave pools presents as an area of interest in future research.
... Water is 25% more conductive than air, and therefore convective heat loss will be three to five times greater at regions of the body with increased water exposure, such as the legs, abdomen, forearms and hands [2,[12][13][14]. During a typical surf session, the regional differences in skeletal muscle activity in addition to water exposure create uneven skin temperatures across the body [15]. This may result in performance deficits since reductions in regional surface skin temperatures exhibited from increased water exposure are associated with reductions in skeletal muscle performance, such as force production and power output [16][17][18]. ...
... With wetsuit materials and design remaining relatively unchanged over the last 60 years, design esthetic and anatomical differences, such as bust and hip ratios, are the primary factors dictating current wetsuit models and design differences between sexes. Yet recent research suggests differences in regional skin temperatures between male and female surfers [15,19]. These two field studies suggest that females exhibit colder skin temperatures at the low back and forearm than males during a 40-min recreational surf session while wearing a 2-mm wetsuit [15,19]. ...
... Yet recent research suggests differences in regional skin temperatures between male and female surfers [15,19]. These two field studies suggest that females exhibit colder skin temperatures at the low back and forearm than males during a 40-min recreational surf session while wearing a 2-mm wetsuit [15,19]. However, it is important to note that reported differences in environmental factors (i.e. ...
The purpose of this study was to test the hypothesis that under controlled surf conditions, sex differences in skin temperature exist, but core temperature would not vary between sexes when performing a simulated surf session while wearing a 2-mm wetsuit. Twenty male and 13 female surfers engaged in a 60-min simulated surf protocol using a custom 2-mm wetsuit in an Endless Pool Elite Flume with water temperature set to 15.6 °C. Participants were instrumented with a heart rate monitor, eight skin temperature sensors, and a disposable sensor for measurement of core temperature. The surf simulation consisted of paddling, duck-diving and stationary activities at three paddling speeds (1.2, 1.4 and 1.6 m/s). Participants were asked their thermal sensation periodically during the protocol, and all data were collected at 1-min intervals. Results indicated no significant differences in core temperature between males (37.31 ± 0.35 °C) and females (37.32 ± 0.48 °C, p = 0.995). Upper arm and thigh skin temperatures were significantly lower in females (27.45 ± 1.04 °C and 23.53 ± 0.78 °C, respectively) than males (28.61 ± 1.32 °C and 24.73 ± 0.68 °C; p = 0.012 and p = 0.000, respectively). Conversely, skin temperatures in the abdomen were significantly lower in males (26.57 ± 1.44 °C) than females (27.75 ± 1.50 °C; p = 0.035). Meanwhile, perceptual data were inconclusive. The results suggest that although regional differences in skin temperature may exist between male and female surfers, they may be too small to translate into perceptual differences and are unnecessary when considering wetsuit design.
... Standard wetsuits are made of neoprene and mitigate heat loss during surfing by providing both an additional layer of insulation and trapping small amounts of water between the wetsuit and skin to be warmed by the body (10). The effectiveness of wetsuits in maintaining skin temperatures during surfing has recently been characterized in both male and female surfers during recreational surfing (2,11). The results from these studies suggest that heat loss across the body is heterogeneously distributed and that the regions of the body that have the greatest reductions in skin temperature are those that interact with the water the most (2,11). ...
... The effectiveness of wetsuits in maintaining skin temperatures during surfing has recently been characterized in both male and female surfers during recreational surfing (2,11). The results from these studies suggest that heat loss across the body is heterogeneously distributed and that the regions of the body that have the greatest reductions in skin temperature are those that interact with the water the most (2,11). Therefore, International Journal of Exercise Science http://www.intjexersci.com ...
... Therefore, International Journal of Exercise Science http://www.intjexersci.com 1575 it is not surprising that large reductions in skin temperature during surfing have been reported in the arms and legs (2,11), given the fact that paddling comprises approximately 50% of the time spent surfing (4,6,7). Interestingly, it has been reported that greater reductions in skin temperature occur in the distal portion of the extremities (forearm ~9-14%, calf ~18-19%) when compared to proximal portion of the extremities (upper arm ~5-6%, thigh ~15-16%) (2,11). ...
International Journal of Exercise Science 13(6): 1574-1582, 2020. Surfing is a worldwide sport that often requires participants to wear a wetsuit to assist in thermoregulation. In a recent study, forearm skin temperature decreased by approximately 3 °C while wearing a wetsuit during recreational surfing. The purpose of this study was to test the hypothesis that reducing water flow in and out of the wetsuit by cuffing the wetsuit at the wrist, with a novel cuff closure system (Velcro cuff), would result in greater forearm skin temperature while surfing. One hundred and twelve (94 male, 18 female) recreational surfers between the ages of 18-50 participated in this study. Forearm skin temperature was measured at 1-minute intervals across the surf session in both arms with four wireless iButton thermal sensors located two inches from the styloid process (wrist) and olecranon process (elbow). Following instrumentation, all subjects had one of their wrists randomly cuffed with a one-inch wide Velcro cuff that was tightened to 2 cm less than the circumference of the wrist plus wetsuit. Subjects were then instructed to engage in regular recreational surfing activities for a minimum of 30 minutes at seven beaches in North San Diego County from October to April. No significant differences were found between the average cuffed wrist skin temperature and the average uncuffed wrist skin temperature (p = 0.06). However, average cuffed forearm skin temperature was significantly higher than average uncuffed forearm skin temperature (p = 0.01). Results from this study suggest that cuffing the wrist of wetsuits is a simple technique that can be utilized by surfers to significantly improve forearm skin temperature during surfing. These findings may also have an implication on future wetsuit designs.
... Thirty-five to fifty million people participate in surfing worldwide [1,2]. Growing popularity has stimulated research into the physiological and biomechanical demands [3][4][5][6][7][8], as well as ways to improve performance [9,10] and safety [11]. Studies have focused on thermoregulation in surfers because of its relevance to both the safety and performance of athletes [3,8]. ...
... Growing popularity has stimulated research into the physiological and biomechanical demands [3][4][5][6][7][8], as well as ways to improve performance [9,10] and safety [11]. Studies have focused on thermoregulation in surfers because of its relevance to both the safety and performance of athletes [3,8]. Surfing presents unique challenges to thermoregulation because athletes interact with both the air and water, often in conditions that are cold and windy. ...
... Wetsuits are considered a critical piece of surfing equipment, the scientific literature describing their thermoregulatory properties, particularly during surfing, is sparse. Recent studies suggest that wetsuits are not optimally designed for surfers [3,8]. In particular, different regions of the body were shown to lose heat at different rates while surfing in a wetsuit; the abdomen and lower back have different changes in temperature when compared to both the chest and upper back [3,8]. ...
While some research does exist on wetsuit thermoregulation, there is currently a paucity in the literature describing how various types of neoprene materials affect skin temperatures. The purpose of this study was to test the hypothesis that the slick neoprene would lead to higher skin temperatures in comparison to the jersey material. Participants wore a custom wetsuit with the torso made of half slick and half jersey neoprene materials (n = 78). Participants either participated in one of two field studies or engaged in a simulated surfing session in a flume after sunset, where the influence of direct sun exposure was eliminated. In the field, participants wore four thermistors placed on either side of the chest and the upper back (n = 27) or the abdomen and the lower back (n = 31). Skin temperatures were measured across typical surfing sessions. In the laboratory, the participants (n = 20) wore all eight sensors in the anatomical locations described above, and skin temperatures were recorded across a simulated surfing session. In the field study, the mean skin temperatures under the slick neoprene were significantly higher when compared to the jersey neoprene for the upper chest (p < 0.001), upper back (p = 0.001), and lower back (p < 0.001) at all time points. In the laboratory study, skin temperatures were significantly higher under the slick neoprene at the upper chest and lower back (p < 0.001). These findings may be a result of greater heat absorptive properties of slick neoprene during exposure to the sun and the water-retaining properties of jersey-lined neoprene.
... These behaviors lead to inconsistent rates of convective heat loss through both water and air. We recently reported that heat loss, as measured by skin temperature, is heterogeneously distributed across the body of recreational male surfers wearing 2 mm wetsuits during an average surf session [17]. The greatest reduction in skin temperature (−6.4 • C) was reported to occur in the distal portion of the leg [17], which interacts with water for a greater percentage of time relative to other regions of the body. ...
... We recently reported that heat loss, as measured by skin temperature, is heterogeneously distributed across the body of recreational male surfers wearing 2 mm wetsuits during an average surf session [17]. The greatest reduction in skin temperature (−6.4 • C) was reported to occur in the distal portion of the leg [17], which interacts with water for a greater percentage of time relative to other regions of the body. ...
... Experimental procedures for this study have previously been described elsewhere from an identical study investigating skin temperatures of recreational male surfers wearing a wetsuit between the months of March and May [17]. Briefly, eight wireless iButton thermal sensors (type DS1921G; Maxim Integrated/Dallas Semiconductor Corp., San Jose, CA, USA) were attached to the skin of the calf, thigh, forearm, upper arm, chest, upper back, lower abdomen, and lower back with waterproof adhesive bandages (Nexcare TM Tegaderm TM , St. Paul, MN, USA) and measured skin temperature at 1 min intervals [25,26]. ...
The aim of this investigation was to examine regional skin temperatures in recreational female surfers’ wearing a 2 mm thick neoprene wetsuit while surfing and to compare these results to previously published data collected in males participating in an identical study. Female surfers (n = 27) engaged in surfing for at least 40 min while wearing a commercially available 2 mm full wetsuit. Skin temperature of eight different anatomical locations were measured with wireless iButton thermal sensors. Regional skin temperatures significantly differed (p < 0.001) across almost all anatomical regions. Furthermore, regional skin temperatures significantly decreased across time at all skin regions throughout an average surfing session (p < 0.001). The greatest reduction in skin temperature was observed in the lower leg (−5.4 °C). Females in the current study exhibited a significantly greater skin temperature decrease in the lower back (−15.2% vs. −10.8%, p = 0.022) and lower arm (−13.6% vs. −10.8%, p < 0.001) when compared to previous data published in males. Overall, results of the current study are consistent with data previously published on male recreational surfers. However, the current study provides preliminary evidence that the magnitude of change in skin temperature may differ between male and female recreational surfers at some anatomical locations.
... Heat loss, and heat perception, is individual in nature and it is known that for most humans water can start to markedly cool the body at 20 degrees Celsius and below [9]. Wetsuits, which are often used by surfers, are thought to ameliorate the rate of cooling; and this is supported by a small amount of research conducted with surfers which showed that a 2 mm wetsuit can prevent most heat loss for short periods in water temperature of 15 degrees Celsius or greater [10,11]. However, as wave quality and availability is often better in winter, surfers will often encounter combined chill factors well below 15 degrees Celsius. ...
... (www.preprints.org) | NOT PEER-REVIEWED | Posted: 2 July 2024 doi:10.20944/preprints202407.0147.v110 ...
Surfing is a growing, high participation recreational and competitive activity. It is relatively unique being performed on, in, and through water with a range of temperatures. In other sports, warm-up and heat retention have proved useful at augmenting performance and ameliorating injury risk. Little work has been done examining this in surfing. The purpose of this work was to measure thermal profiles in surfers with and without warm-up and passive heat retention, and secondarily to assess any potential influence on free surfing. A repeated measures pre- and post- design was adopted whereby participants surfed in an artificial wave pool following an active warm-up combined with passive heat retention (experimental condition), and after no warm-up (control). Core body temperature was measured both occasions. Our results showed a clear advantage to body temperature for the experimental condition versus control. Both groups showed a warm-up effect in the water itself, presumably due to further activity (e.g. paddling) and wetsuit properties. Finally, performance trended to being superior following warm-up. We conclude, body warmth in surfers may be facilitated by an active warm-up and passive heat retention. In free surfing this is associated with a trend towards better performance; it may also reduce injury risk.
... Romanin et al. 4 listed only 17 scientific contributions in a review article in 2021 (13 journal publications and 4 conference proceedings). Among these, 11 studies focused on the hydrodynamic properties of surfboards (3×) [5][6][7] and fins (7×) 3,[8][9][10][11][12] , while the remaining 7 studies analyzed specific features of surfers' wetsuits [13][14][15][16][17][18][19] . ...
The popularity of surfing has increased during the last 20 years with the growing number of river waves and artificial wave pools. For these different surfing conditions, hydrodynamic characteristics of boards and fins and their optimization become interesting for industry and science to analyze the biomechanics and physiology during surfing. In this work, a measuring system was developed assembled of four small pressure sensors included in a 3D-printed fin within a 2-fin configuration. The measurements were controlled by an acquisition board mounted into a surfboard. The system was initially tested in a water tank and exhibited a high accuracy of measured pressure. Afterwards, a surfer surfed the instrumented surfboard on a river wave and performed three cycles of surfing from one side of the wave channel to the other. The results showed a pressure difference between both sides of the instrumented fin that produces periodical lift forces directed away from the surfboard. Thereby, the maximum lift force was produced during the surfer’s motion from one side of the channel side to the other. It is assumed to increase the stability of the surfer’s back foot in combination with the right fin producing a lift force in opposite direction.
... Heat loss, and heat perception, is individual in nature and it is known that for most humans water can start to markedly cool the body at 20 degrees Celsius and below [9]. Wetsuits, which are often used by surfers, are thought to ameliorate the rate of cooling; this is supported by a small amount of research conducted with surfers which showed that a 2 mm wetsuit can prevent most heat loss for short periods in water temperatures of 15 degrees Celsius or greater [10,11]. However, as wave quality and availability is often better in winter, surfers will often encounter combined chill factors well below 15 degrees Celsius. ...
Surfing is a growing, high-participation recreational and competitive activity. It is relatively unique, being performed on, in, and through water with a range of temperatures. In other sports, warm-up and heat retention have proved useful at augmenting performance and ameliorating injury risk. Little work has been carried out examining this in surfing. The purpose of this work was to measure thermal profiles in surfers with and without warm-up and passive heat retention, and secondarily to assess any potential influence on free surfing. A repeated measures pre- and post- design was adopted whereby participants surfed in an artificial wave pool following an active warm-up combined with passive heat retention (experimental condition) and after no warm-up (control). Core body temperature was measured both occasions. Our results showed increases in core body temperature were greater for the experimental condition versus control (p = 0.006), and a time effect exists (p < 0.001)—in particular, a warm-up effect in the water itself was shown in both groups, possibly due to further activity (e.g., paddling) and wetsuit properties. Finally, performance trended to being superior following warm-up. We conclude that body warmth in surfers may be facilitated by an active warm-up and passive heat retention. In free surfing, this is associated with a trend towards better performance; it may also reduce injury risk.
... Heat loss, and heat perception, is individual in nature and it is known that for most humans water can start to markedly cool the body at 20 degrees Celsius and below 9 . Wetsuits, which are often used by surfers, are thought to ameliorate the rate of cooling; and this is supported by a small amount of research conducted with surfers which showed that a 2 mm wetsuit can prevent most heat loss for short periods in water temperature of 15 degrees Celsius or greater 10,11 . However, as wave quality and availability is often better in winter, surfers will often encounter combined chill factors well below 15 degrees Celsius. ...
Surfing is a growing, high participation recreational and competitive activity. It is relatively unique being performed on, in, and through water with a range of temperatures. In other sports, warm-up and heat retention have proved useful at augmenting performance and ameliorating injury risk. Little work has been done examining this in surfing. The purpose of this work was to measure thermal profiles in surfers with and without warm-up and passive heat retention, and secondarily to assess any potential influence on free surfing. A repeated measures pre- and post- design was adopted whereby participants surfed in an artificial wave pool following an active warm-up combined with passive heat retention (experimental condition), and after no warm-up (control). Core body temperature was measured both occasions. Our results showed a clear advantage to body temperature for the experimental condition versus control. Both groups showed a warm-up effect in the water itself, presumably due to further activity (e.g. paddling) and wetsuit properties. Finally, performance trended to being superior following warm-up. We conclude, body warmth in surfers may be facilitated by an active warm-up and passive heat retention. In free surfing this is associated with a trend towards better performance; it may also reduce injury risk.
... The swimsuit is, in essence, a secondary skin, a close-fitting item that should provide continuous comfort and support during the wearers' physical activity associated with swimming. 7,8 The production of the aesthetic design of a swimsuit is a secondary requirement. The primary requirement for the manufacturing of swimsuits is the performance of the material/materials relative to the female body type and physiology. ...
Among the fitness and body shaping exercises of Chinese women, swimming has become an increasingly popular sporting activity. Swimsuits are fundamental to participation in this sport and paramount to achieving the wearers' aim of participation. A survey of 3348 Chinese women showed that body fit is central to the purchase of a swimsuit, whether one piece or two piece, with the two-piece swimsuit proving the most popular in terms of comfort. This survey revealed that the comfort of a swimsuit is relative to the design variables of the swimsuit style, the material/body cover factor and, informed by the female form, body size and body shape. This is particularly pertinent in both the right and left anterior mammary regions and also the left lateral mammary region for the female wearer to stay comfortable during swimming when she moves in the water. This study investigated the factors that affect the comfort of women wearing swimsuits when they swim. The two-piece swimsuit was considered the most comfortable. It was also found that swimsuits negatively affect women's chest area. These results present important considerations for swimsuit manufacturers.
... Although, to our best knowledge, no research has been conducted looking specifically at neurophysiological changes from exposure to cold in surfers, research suggests that surfing can involve changes to body temperature, even when surfers are wearing wetsuits. For instance, Warner, Nessler, and Newcomer (2019) and Corona, Simmons, Nessler, and Newcomer (2018) found that surfing led to significantly decreased skin temperatures at several locations, especially the legs, lower back and forearms where skin temperature dropped below 30°C after only a 40minute surf session. The average water temperature in these studies were 16.0 ± 0.1°C and 14.6 ± 0.2°C, which reflects common water temperatures for winter and spring surfing in many surfing locations around the world such as California, southern and western Australia, and much of Europe. ...
There is growing interest in surfing as a recreational activity that may facilitate skill development and improved mental health. However, there remains uncertainty regarding the causal processes through which surfing may improve psychological well-being. With the aim to guide future research, we review potential mechanisms that may underpin the psychotherapeutic effects of surfing. A range of plausible factors are identified, including exercise, water immersion, exposure to sunlight, transcendent experiences, reductions in rumination and the satisfaction of basic psychological needs. Further research is needed to clarify the effectiveness of surfing-based therapies and to establish the relative contributions of the causal mechanisms at play.
... In contrast, a wetsuit designed for swim performance such as a triathlon typically has a smooth surface and thickness needs to be within specific governing body rules. The commonality between wetsuits is that they assist in theromoregulation in part by insulating properties of wetsuit material as well as warming of water between the skin and the material of the wetsuit ultimately providing insulation from cold temperatures (Corona et al., 2017;Naebe, 2013;Wakabayashi, et al., 2006). ...
Background: Triathletes typically wear a wetsuit during the swim portion of an event, but it is not clear if muscle activity is influenced by wearing a wetsuit. Purpose: To investigate if shoulder muscle activity was influenced by wearing a full-sleeve wetsuit vs. no wetsuit during dryland swimming. Methods: Participants (n=10 males; 179.1±13.2 cm; 91.2±7.25 kg; 45.6±10.5 years) completed two dry land swimming conditions on a swim ergometer: No Wetsuit (NW) and with Wetsuit (W). Electromyography (EMG) of four upper extremity muscles was recorded (Noraxon telemetry EMG, 500 Hz) during each condition: Trapezius (TRAP), Triceps (TRI), Anterior Deltoid (AD) and Posterior Deltoid (PD). Each condition lasted 90 seconds with data collected during the last 60 seconds. Resistance setting was self-selected and remained constant for both conditions. Stroke rate was controlled at 60 strokes per minute by having participants match a metronome. Average (AVG) and Root Mean Square (RMS) EMG were calculated over 45 seconds and each were compared between conditions using a paired t-test (α=0.05) for each muscle. Results: PD and AD AVG and RMS EMG were each greater (on average 40.0% and 66.8% greater, respectively) during W vs. NW (p<0.05) while neither TRAP nor TRI AVG or RMS EMG were different between conditions (p>0.05). Conclusion: The greater PD and AD muscle activity while wearing a wetsuit might affect swimming performance and /or stroke technique on long distance event.
Background:
Infrared thermography (IRT) does not require contact with the skin, and it is a convenient, reliable and non-invasive technique that can be used for monitoring the skin temperature (TSK).
Objectives:
The aim of this study was to monitor the variations in the regional TSK during exercise on 28 regions of interest (ROIs) (forehead, face, chest, abdomen, back, lumbar, anterior and posterior neck, and posterior and anterior views of the right and left hands, forearms, upper arms, thighs, and legs) with IRT.
Patients and methods:
12 physically active young males were monitored with IRT during the following three phases: a) 30 minutes before exercise b) while performing one hour of moderate intensity exercise on a treadmill at 60% of the VO2max, and c) 60 minutes after exercise.
Results:
During pre-exercise, all TSK reached a steady-state (P ≤ 0.05), which ensured adequate thermal stabilisation. At the beginning of exercise, there was a significant reduction in the TSK in most ROIs after 10 minutes of activity, except for the lower limbs (legs and thighs). After one hour of recovery, in the anterior view of the hands and thighs and in the posterior view of the legs, there were significant increases in the TSK compared to pre-exercise.
Conclusions:
There were significant distinctions in the skin temperature distribution during exercise according to the activity of the area under consideration during exercise, which may be important in the development of physiological models and heat flux analyses for different purposes.
Surfers often wear wetsuits while paddling in the ocean. This neoprene covering may be beneficial to upper extremity movement by helping to improve proprioceptive acuity, or it may be detrimental by providing increased resistance. The purpose of this study was to evaluate the effects of wearing a wetsuit on muscle activation, upper extremity motion, heart rate, and oxygen consumption during simulated surfboard paddling in the laboratory. Twelve male, recreational surfers performed two paddling trials at a constant workload on a swim bench ergometer both with and without a wetsuit. Kinematic data and EMG were acquired from the right arm via motion capture, and oxygen consumption and heart rate were recorded with a metabolic cart and heart rate monitor. Wearing a wetsuit had no significant effect on oxygen consumption or heart rate. A significant increase in EMG activation was observed for the middle deltoid but not for any of the other shoulder muscle evaluated. Finally, approximate entropy and estimates of the maximum Lyapunov exponent increased significantly for vertical trajectory of the right wrist (i.e. stroke height) when a wetsuit was worn. These results suggest that a 2mm wetsuit has little effect on the energy cost of paddling at lower workloads but does affect arm motion. These changes may be the result of enhanced proprioceptive acuity due to mechanical compression from the wetsuit.
Background:
Human thermal responses during prolonged whole-body immersion in cold water are of interest for the military, especially French SEALS. This study aims at describing the thermo-physiological responses.
Methods:
There were 10 male military divers who were randomly assigned to a full immersion in neutral (34 degrees C), moderately cold (18 degrees C), and cold (10 degrees C) water wearing their operational protective devices (5.5 mm wetsuit with 3.0 mm thick underwear) for 6 h in a static position. Rectal temperature (T(re)) and 14 skin temperatures (T(sk)), blood analysis (stress biomarkers, metabolic substrates), and oxygen consumption (Vo2) were collected.
Results:
At 34 degrees C, there were no significant modifications of the thermo-physiological responses over time. The most interesting result was that rates of rectal temperature decrease (0.15 +/- 0.02 degrees C x min(-1)) were the same between the two cold stress experimental conditions (at 18 degrees C and 10 degrees C). At the final experiment, rectal temperature was not significantly different between the two cold stress experimental conditions. Mean T(sk) decreased significantly during the first 3 h of immersion and then stabilized at a lower level at 10 degrees C (25.6 +/- 0.8 degrees C) than at 18 degrees C (29.3 +/- 0.9 degrees C). Other results demonstrate that the well-trained subjects developed effective physiological reactions. However, these reactions are consistently too low to counterbalance the heat losses induced by cold temperature conditions and long-duration immersion.
Conclusion:
This study shows that providing divers with thermal protection is efficient for a long-duration immersion from a medical point of view, but not from an operational one when skin extremities were taken into account.
Wetsuits are an integral part of surfing especially in the southern regions of Australia. There is currently little information about mechanical, comfort and thermal properties of wetsuits. There is a demand from wetsuit manufacturers to better understand the neoprene properties and wetsuit performance. The performance characteristics of eight topselling wetsuits, from both high end and low end of the market, were examined. These characteristics include thickness, elasticity, bursting strength, hydrophobicity, thermal conductivity and seal strength. Tensile assessment revealed that neoprene foam was strong and its stretch recovery was well beyond 1.6 times of the original length. Neoprene was found to be hydrophobic with very low surface energy. High-end wetsuits with higher thickness showed slightly higher thermal resistance than low-end wetsuits, indicating that both thickness and bulk density of neoprene influenced thermal properties.
High-end wetsuits with fluid seal were stronger than low-end wetsuits with stitched seal.
In an island nation such as New Zealand with easy access to surf beaches, surfing activities are very popular and, while generally perceived as a healthy form of outdoor recreation, they do have attendant risks. This study reports on non-drowning, surfing-related incidents that required medical first aid on beaches during five summer seasons from 2007–2012. Retrospective descriptive analysis of data from lifeguard first-aid reports found that 16% (n = 1,327) of injuries were the consequence of surfing activity. More males than females were treated for surfing injuries (68% male, 31% female). Lacerations (59%) and bruising (15%) accounted for most of the injuries. The head was the most common site of injury (32%), and
most injuries were caused by contact with the victim’s own board (50%). Ways of promoting surf safety via equipment modification, the use of protective head gear, the management of surfing activity by lifeguards, and public education are discussed.
The purpose of the present study was to measure and compare peak oxygen uptake and paddling efficiency in recreational and competitive junior male surfers. Eight male recreational surfers (mean age 18 years, s=2; mass 66.8 kg, s=13.0; height 1.75 m, s=0.10) and eight male competitive surfers (mean age 18 years, s=1; mass 68.0 kg, s=11.7; height 1.72 m, s=0.10) performed an incremental paddling test consisting of four 3-min constant load work stages followed by a ramp increase in power output of 20 W · 30 s until exhaustion. The oxygen uptake–power output relationship of the four constant load work stages and peak values obtained during the incremental paddling test were used to calculate paddling efficiency. No differences (P>0.05) were observed between the recreational and competitive surfers for peak oxygen uptake (recreational: 2.52 litres · min, s=0.5; competitive: 2.66 litres · min, s=0.35) or efficiency (recreational: 24%, s=3; competitive: 21%, s=4). Blood lactate concentration was significantly greater in recreational (2.4 mmol · l, s=0.9) than competitive surfers (1.6 mmol · l, s=0.5) during submaximal paddling. There were no differences in peak oxygen uptake or paddling efficiency between recreational and competitive surfers suggesting that peak oxygen uptake and efficiency are not sensitive to differences in surfing ability. The increase in blood lactate concentration during submaximal paddling in recreational compared with competitive surfers suggests that other determinants of paddling endurance, such as blood lactate threshold, might be better at distinguishing surfers of differing ability.
1. Human subjects were exposed to partial- and whole-body heating and cooling in a controlled environmental chamber to quantify physiological and subjective responses to thermal asymmetries and transients.2. Skin temperatures, core temperature, thermal sensation, and comfort responses were collected for 19 local body parts and for the whole body.3. Core temperature increased in response to skin cooling and decreased in response to skin heating.4. Hand and finger temperatures fluctuated significantly when the body was near a neutral thermal state.5. When using a computer mouse in a cool environment, the skin temperature of the hand using the mouse was observed to be 2–3 °C lower than the unencumbered hand.
The common approach to the multiplicity problem calls for controlling the familywise error rate (FWER). This approach, though, has faults, and we point out a few. A different approach to problems of multiple significance testing is presented. It calls for controlling the expected proportion of falsely rejected hypotheses – the false discovery rate. This error rate is equivalent to the FWER when all hypotheses are true but is smaller otherwise. Therefore, in problems where the control of the false discovery rate rather than that of the FWER is desired, there is potential for a gain in power. A simple sequential Bonferroni-type procedure is proved to control the false discovery rate for independent test statistics, and a simulation study shows that the gain in power is substantial. The use of the new procedure and the appropriateness of the criterion are illustrated with examples.
This study was a performance analysis of surfing athletes during competitive surfing events in an attempt to inform the development of surfing-specific conditioning. Twelve nationally ranked surfers were fitted with heart rate (HR) monitors and global positioning system (GPS) units and videoed during the heats of 2 sanctioned competitions. Means and SDs represented the centrality and spread of analyzed data. From the 32 videos analyzed, the greatest amount of time spent during surfing was paddling (54 ± 6.3% of the total time) (% TT). The remaining stationary represented 28 ± 6.9% TT, wave riding, and paddling for a wave represented only 8 ± 2% TT and 4 ± 1.5% TT, respectively. Surfers spent 61 ± 7% of the total paddling bouts and 64 ± 6.8% of total stationary bouts between 1 and 10 seconds. The average speed recorded via the GPS for all the subjects was 3.7 ± 0.6 km·h(-1), with an average maximum speed of 33.4 ± 6.5 km·h(-1) (45 km·h(-1) was the highest speed recorded). The average distance covered was 1,605 ± 313 m. The mean HR during the surf competitions was 139 ± 11 b·min(-1) (64% HRmax), with a (mean) peak of 190 ± 12 b·min(-1) (87% HRmax). Sixty percent TT was spent between 56 and 74% of the age-predicted HR maximum (HRmax), 19% TT >46% HRmax, and approximately 3% TT >83% HRmax. Competitive surfing therefore involves intermittent high-intensity bouts of all out paddling intercalated with relatively short recovery periods and repeated bouts of low-intensity paddling, incorporating intermittent breath holding. Surfing-specific conditioning sessions should attempt to replicate such a profile.
The heart rates and subsequent estimated energy expenditure during approximately one hour of recreational surfing were examined. Six male volunteers, mean age 21.2 (±2.7) years, height 175.8 (±5.53) cm and weight 68.9 (±5.67) kg, participated in this study. Heart rate data were gathered using a modified Sports Tester PE3000S microcomputer telemetry system. These data were used to estimate energy expenditure using a regression formula of oxygen uptake versus heart rate data established during a progressive peak oxygen uptake test on a Repco Swim Bench Ergometer. Mean heart rate while recreational surfing was 135 (±6.9) beats.min-1, while mean values for paddling and stationary were 143 (±10.5) beats.min-1 and 127 (±6.9) beats.min-1 respectively. There was a statistically significant difference (p <0.001) between mean heart rates for these activities. Mean heart rates for the total time surfing, paddling and stationary represented 75% (±4.2), 80% (±4.8) and 71% (±5.5) respectively of the group's mean peak heart rate attained in the laboratory. Mean total time spent stationary, paddling and riding waves represented 35%, 44% and 5% of the total time surfing respectively. The mean peak oxygen uptake (±SD) value for the group as determined during simulated paddling in the laboratory was 3.75 (±0.83) l.min-1. Mean estimated oxygen uptake while recreational surfing was 1.68 (±0.25) l.min-1, which represented 46% of the groups mean laboratory value. The mean peak oxygen uptake while recreational surfing was 2.78 (±0.50) l.min-1, which represented 75% of the group’s mean laboratory value. Mean estimated energy expenditure for the total me surfing was 2077 kJ (±322.1). The estimated mean energy expenditure of 33.7 kJ.min-1, suggests that recreational surfing is comparable with a variety of other recreational sporting activities in terms of energy cost including freestyle swimming (20.9-46.0 kJ.min-1), tennis (30.1-41.8
kJ.min-1) and cycling at 20.8 km.hr-1 (18.8-46.0 kJ.min-1) (Åstrand & Rodahl 1986).
The effects of 30 min of cooling (15°C water) and warming (40°C water) on arm muscle function were measured. A reference condition (24°C air) was included. Of nine young male subjects the maximal grip force (F
max), the time to reach 66% ofF
max (rate of force buildup) and the maximal rhythmic grip frequency were determined, together with surface electromyographic activity (EMG) of a forearm muscle (flexor digitorum superficialis). The results showed that in contrast to warming, cooling resulted in a significant decrease of 20% in the FmaX and a significant 50% decrease in force build-up time and the maximal rhythmic grip frequency. The relationship between the root mean square value (rms) of the EMG and the static grip force did not change due to temperature changes. The median power frequency (MPF) in the power spectrum of the EMG signal decreased by 50% due to cooling but remained unchanged with heating. During a sustained contraction at 15% ofF
max (F
max depending on the temperature) the increase in the rms value with contraction time was 90% larger in the warm condition and 80016 smaller in the cold condition compared to the increase in the reference condition. The MPF value remained constant during the warm and reference conditions but in the cold it started at a 50% lower value and increased with contraction time. Since the endurance time was not affected in the cold but 60% reduced in the warm, it was concluded that neither the rms nor the MPF reflected unambiguously the temperature related changes in functional performance of muscle strain with an equal relative load.
Contemporary Korean women divers wear wet suits during diving work to avoid the cold water stress. The present study was undertaken to evaluate the effect of wearing wet suits on the daily thermal balance of divers and on the duration of diving work. Rectal (TR) and skin temperatures and O2 consumption (VO2) were measured in four divers before and during diving work in summer (22.5 degrees C water) and winter (10 degrees C water). Subjects wore either wet suits (protected) or cotton suits (unprotected) for comparison. TR decreased 0.4 degrees C in summer and 0.6 degrees C in winter after 2 h of diving work in protected divers, while it decreased to 35 degrees C in 60 min in summer and in 30 min in winter in unprotected divers. Mean skin temperature of protected divers decreased to 31 degrees C in summer and 28 degrees C in winter, while that of unprotected divers decreased to 24 degrees C in summer and 13 degrees C in winter. VO2 toward the end of the diving work period increased by 80 (summer) and 140% (winter) in protected divers and by 160 (summer) and 250% (winter) in unprotected divers. From these values total thermal cost of diving work was estimated to be 260 and 370 kcal . day-1 in summer and winter, respectively.
The purpose of this study was to evaluate the relationship between different levels of body cooling and muscle performance decrement and to study the motor co-ordination of the working agonist-antagonist muscle pair of the lower leg. Eight volunteer male subjects dropped from a 40-cm bench on to a force plate and performed a maximal rebound jump (stretch-shortening cycle). The jumps were performed after 60-min exposures to 27 degrees C, 20 degrees C, 15 degrees C and 10 degrees C. In comparison to those at 27 degrees C, all the exposures to lower temperatures decreased the flight time of the jump, average force production and take-off velocity in a dose-dependent manner. The changes in electromyogram (EMG) activity also behaved in a dose-dependent manner. During pre-activity and stretch phases the integrated EMG (iEMG) activity of the agonist muscle (triceps surae) increased due to cooling (at 10 degrees C, P < 0.05). In contrast, during the shortening phase iEMG of the agonist muscle decreased due to cooling (at 15 degrees C and 10 degrees C, P < 0.05). Moreover, the activity of the antagonist muscle (tibialis anterior) increased due to cooling (at 15 degrees C and 10 degrees C, P < 0.01). The mean power frequency of the agonist muscle during the shortening phase was shifted from 124 (SEM 12) Hz (at 27 degrees C) to 82 (SEM 7) Hz (at 10 degrees C, P < 0.01). We concluded that there was a dose-dependent response between the degree of cooling and the amount of decrease in muscle performance as well as EMG activity changes. A relatively low level of cooling was sufficient to decrease muscle performance significantly.
This study examined whether serial cold-water immersions over a 10-h period would lead to fatigue of shivering and vasoconstriction. Eight men were immersed (2 h) in 20 degrees C water three times (0700, 1100, and 1500) in 1 day (Repeat). This trial was compared with single immersions (Control) conducted at the same times of day. Before Repeat exposures at 1100 and 1500, rewarming was employed to standardize initial rectal temperature. The following observations were made in the Repeat relative to the Control trial: 1) rectal temperature was lower and heat debt was higher (P < 0.05) at 1100; 2) metabolic heat production was lower (P < 0.05) at 1100 and 1500; 3) subjects perceived the Repeat trial as warmer at 1100. These data suggest that repeated cold exposures may impair the ability to maintain normal body temperature because of a blunting of metabolic heat production, perhaps reflecting a fatigue mechanism. An alternative explanation is that shivering habituation develops rapidly during serially repeated cold exposures.
Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11 degrees C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient metabolic heat to offset the effects imposed by the cold environment, then temperatures of 11 degrees C can be detrimental to performance. Similarly, when the performance involves dynamic explosive contractions, then a Cold ambient temperature can have a negative influence. Additional factors such as the exercising medium, air or water, and the anthropometric characteristics of the athlete will also make a difference to the strategies that can be adopted to offset any negative impact of a cold environment on performance. To plan for a performance in the cold requires an understanding of the mechanisms underpinning the physiological response. This review attempts to outline these mechanisms and how they can be manipulated to optimize performance.
The present study investigated the effect of non-uniform skin temperature distribution on thermoregulatory responses and subjective thermal sensation during water immersion. Ten healthy male subjects carried out 60 min water immersion twice, once with uniform (UST) and once with non-uniform (NUST) skin temperature. In UST condition, subjects immersed at 29°C in naked condition, while in NUST condition, subjects immersed at 26°C with partial coverage wetsuit (PCWS). The PCWS covers trunk region, upper arms, and thighs. The non-uniform skin temperature distribution, higher at trunk and lower at distal extremities, was observed in NUST condition. Shivering thermogenesis was not influenced by the skin temperature distribution at the experimental condition of this study. On the other hand, the tissue insulation (I
tissue) was significantly higher in NUST condition compared to the UST condition. The increment of I
tissue might have been caused by the peripheral vasoconstriction induced by the cold input from the distal extremities in NUST condition. The higher I
tissue in NUST condition might lead to the significantly higher esophageal temperature compared to UST condition. No difference was observed in thermal sensation between the two conditions. Subjects felt slightly more comfortable in NUST condition than in UST condition. In conclusion, the non-uniform skin temperature distribution, higher at trunk and lower at distal extremities, might affect the peripheral vasoconstriction to increase the I
tissue. On the other hand, shivering thermogenesis and subjective thermal sensation were not affected by the non-uniform skin temperature distribution at the present experimental condition.
The common approach to the multiplicity problem calls for controlling the familywise error rate (FWER). This approach, though, has faults, and we point out a few. A different approach to problems of multiple significance testing is presented. It calls for controlling the expected proportion of falsely rejected hypotheses — the false discovery rate. This error rate is equivalent to the FWER when all hypotheses are true but is smaller otherwise. Therefore, in problems where the control of the false discovery rate rather than that of the FWER is desired, there is potential for a gain in power. A simple sequential Bonferronitype procedure is proved to control the false discovery rate for independent test statistics, and a simulation study shows that the gain in power is substantial. The use of the new procedure and the appropriateness of the criterion are illustrated with examples.
This book is designed to be a physician's guide for those interested in diving and hyperbaric environments. It is not a detailed document for the erudite researcher; rather, it is a source of information for the scuba-diving physician who is searching for answers put to him by his fellow nonmedical divers. Following the publication of The Underwater Handbook: A Guide to Physiology and Performance for the Engineer there were frequent requests for a companion volume for the physician. This book is designed to fill the void. Production of the book has been supported by the Office of Naval Research and by the Bureau of Medicine and Surgery, Research and Development Command, under Navy Contract No. NOOOOI4-78-C-0604. Our heartfelt thanks go to the many authors without whose contributions the book could not have been produced. These articles are signed by the responsible authors, and the names a~e also listed alphabetically in these preliminary pages. Every chapter was officially reviewed by at least one expert in the field covered and these reviewers are also listed on these pages. Our thanks go to them for their valuable assistance. We are grateful to Marthe Beckett Kent for editing Chapter III. Our thanks also go to Mrs. Carolyn Paddon for typing and retyping the manuscripts, and to Mrs. Catherine Coppola, who so expertly handled the many fiscal affairs.
The purpose of this study was to investigate how altering surfboard volume (BV) affects energy expenditure during paddling. Twenty surfers paddled in a swim flume on five surfboards in random order twice. All surfboards varied only in thickness and ranged in BV from 28.4 to 37.4 L. Measurements of heart rate (HR), oxygen consumption (VO2), pitch angle, roll angle, and paddling cadence were measured. VO2 and HR significantly decreased on thicker boards [VO2: r = -0.984, p = 0.003; HR: r = -0.972, p = 0.006]. There was also a significant decrease in pitch and roll angles on thicker boards [Pitch: r = -0.995, p < 0.001; Roll: r = -0.911, p = 0.031]. Results from this study suggest that increasing BV reduces the metabolic cost of paddling as a result of lower pitch and roll angles, thus providing mechanical evidence for increased paddling efficiency on surfboards with more volume.
Practioner Summary
This study investigated the impact of surfboard volume on energy expenditure during paddling. Results from this study suggest that increasing surfboard volume reduces the metabolic cost of paddling as a result of lower pitch and roll angles, thus providing mechanical evidence for increased paddling efficiency on surfboards with more volume.
Participation in surfing has evolved to include all age groups. Therefore, the purpose of this study was to determine whether activity levels and cardiovascular responses to surfing change with age. Surfing time and heart rate (HR) were measured for the total surfing session and within each activity of surfing (paddling, sitting, wave-riding and miscellaneous). Peak oxygen consumption (VO2peak) was also measured during a laboratory-based simulated surfboard paddling on a modified swim bench ergometer. VO2peak decreased with age during simulated paddling (r=-0.455, p<0.001, n=68). Total time surfing (p=0.837) and time spent within each activity of surfing did not differ with age (n=160). Mean HR during surfing significantly decreased with age (r=-0.231, p=0.004). However, surfing HR expressed as a percent of age-predicted maximum increased significantly with age. Therefore, recreational surfers across the age spectrum are achieving intensities and durations that are consistent with guidelines for cardiovascular health.
Despite the nation's rising epidemic of childhood obesity and diabetes, schools struggle to promote physical activities that help reduce risks for cardiovascular disease. Emerging data suggest that adopting novel activities into Physical Education (PE) curriculum may serve as an effective strategy for increasing physical activity in children. The purpose of this investigation was to characterize activity in the water and heart rates (HR) of high school students participating in surf PE courses. Twenty-four male (n=20) and female (n=4) high school students (mean age=16.7±1.0 yrs) that were enrolled in surf PE courses at two high schools participated in this investigation. Daily measurements of surfing durations, average HR, and maximum HR were made on the students with HR monitors (PolarFT1) over an 8 week period. In addition, HR and activity in the water was evaluated during a single session in a subset of students (n=11) using a HR monitor (PolarRCX5) and a video camera (Canon HD). Activity and HR were synchronized and evaluated in 5-second intervals during data analysis. The average duration that PE students participated in surfing during class was 61.7±1.0 min. Stationary, paddling, wave riding, and miscellaneous activities comprised 42.7 ± 9.5, 36.7 ± 7.9, 2.9 ± 1.4, and 17.8 ± 11.4 percent of the surf session, respectively. The average and maximum HRs during these activities were 131.1±0.9 and 177.2±1.0 bpm, respectively. These data suggest that high school students participating in surf PE attained HRs and durations that are consistent with recommendations with cardiovascular fitness and health. In the future, PE programs should consider incorporating other action sports into their curriculum to enhance cardiovascular health.
Water-based activities may result in the loss of thermal comfort (TC). We hypothesized that in cooling water, the hands and feet would be responsible. Supine immersions were conducted in up to five clothing conditions (exposing various regions), as well as investigations to determine if a “reference” skin temperature (Tsk) distribution in thermoneutral air would help interpret our findings. After 10 min in 34.5 °C water, the temperature was decreased to 19.5 °C over 20 min; eight resting or exercising volunteers reported when they no longer felt comfortable and which region was responsible. TC, rectal temperature, and Tsk were measured. Rather than the extremities, the lower back and chest caused the loss of overall TC. At this point, mean (SD) chest Tsk was 3.3 (1.7) °C lower than the reference temperature (P = 0.005), and 3.8 (1.5) °C lower for the back (P = 0.002). Finger Tsk was 3.1 (2.7) °C higher than the reference temperature (P = 0.037). In cool and cooling water, hands and feet, already adapted to colder air temperatures, will not cause discomfort. Contrarily, more discomfort may arise from the chest and lower back, as these regions cool by more than normal. Thus, Tsk distribution in thermoneutral air may help understand variations in TC responses across the body.
The present study aimed to evaluate the potential association with anthropometry and upper-body pulling strength with sprint kinematics of competitive surfers. Ten competitive male surfers (23.9±6.8 years, 177.0±6.5 cm, 72.2±2.4 kg) were assessed for stature, mass, arm-span, ∑ 7 site skinfold thickness, pronated pull-up strength, and sprint paddling performance from a stationary start to 15 m. Pearson correlation analysis, and independent t-tests were used to compare potential differences between the slower and faster group of sprint paddlers. Strong associations were found between relative (total kg lifted/athlete mass) upper-body pulling strength and sprint paddling time to 5, 10, and 15 m, and peak sprint paddling velocity (r= 0.94, 0.93, 0.88, 0.66, respectively, p<0.05) and relative upper-body pulling strength was found to be superior (p<0.05) in the faster group, with large effect (d=1.88). The results of this study demonstrate a strong association between relative upper-body pulling strength and sprint paddling ability in surfers. Strength and conditioning coaches working with competitive surfers should implement strength training with surfers, including an emphasis on developing relative strength, as this may have a strong influence on sprint paddling performance.
Infrared thermography was used to provide illustrations of the regional differences of temperature of the surface of the human body before and after immersion in water of 7.5° C for 15 min. Thermal gradients over the surface are increased by cold water immersion, with areas such as the lateral thorax, upper chest, and groin having the highest temperatures. It is predicted that heat loss in the water would be greatest from such areas and that these findings would be useful in the design of thermally protective lifejackets and for advice on body posture in the water to minimize heat loss. Swimming activity increased the amount of the body surface having higher relative temperatures, thereby increasing overall heat loss.
The influence of muscle temperature (Tm) on maximal muscle strength, power output, jumping, and sprinting performance was evaluated in four male subjects. In one of the subjects the electromyogram (EMG) was recorded from M. vastus lateralis, M. biceps femoris, and M. semitendinosus. Tm ranged from 30.0 degrees C to 39 degrees C. Maximal dynamic strength, power output, jumping, and sprinting performance were positively related to Tm. The changes were in the same order of magnitude for all these parameters (4-6% x degrees C-1) Maximal isometric strength decreased by 2% x degrees C-1 with decreasing Tm. The force-velocity relationship was shifted to the left at subnormal Tm. Thus in short term exercises, such as jumping and sprinting, performance is reduced at low Tm and enhanced at Tm above normal, primarily as a result of a variation in maximal dynamic strength.
The influence of exercise intensity on thermoregulation was studied in 8 men and 8 women volunteers during three levels of arm-leg exercise (level I: 700 ml oxygen (O2).min-1; level II: 1250 ml O2.min-1; level III: 1700 ml O2.min-1) for 1 h in water at 20 and 28 degrees C (Tw). For the men in Tw 28 degrees C the rectal temperature (Tre) fell 0.79 degree C (P less than 0.05) during immersion in both rest and level-I exercise. With level-II exercise a drop in Tre of 0.54 degree C (P less than 0.05) was noted, while at level-III exercise Tre did not change from the pre-immersion value. At Tw of 20 degrees C, Tre fell throughout immersion with no significant difference in final Tre observed between rest and any exercise level. For the women at rest at Tw 28 degrees C, Tre fell 0.80 degree C (P less than 0.05) below the pre-immersion value. With the two more intense levels of exercise Tre did not decrease during immersion. In Tw 20 degrees C, the women maintained higher Tre (P less than 0.05) during level-II and level-III exercise compared to rest and exercise at level I. The Tre responses were related to changes in tissue insulation (I(t)) between rest and exercise with the largest reductions in I(t) noted between rest and level-I exercise across Tw and gender. For mean and women of similar percentage body fat, decreases in Tre were greater for the women at rest and level-I exercise in Tw 20 degrees C (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
The effect of changing muscle temperature on performance of short term dynamic exercise in man was studied. Four subjects performed 20 s maximal sprint efforts at a constant pedalling rate of 95 crank rev.min-1 on an isokinetic cycle ergometer under four temperature conditions: from rest at room temperature; and following 45 min of leg immersion in water baths at 44; 18; and 12 degrees C. Muscle temperature (Tm) at 3 cm depth was respectively 36.6, 39.3, 31.9 and 29.0 degrees C. After warming the legs in a 44 degrees C water bath there was an increase of approximately 11% in maximal peak force and power (PPmax) compared with normal rest while cooling the legs in 18 and 12 degrees C water baths resulted in reductions of approximately 12% and 21% respectively. Associated with an increased maximal peak power at higher Tm was an increased rate of fatigue. Two subjects performed isokinetic cycling at three different pedalling rates (54, 95 and 140 rev.min-1) demonstrating that the magnitude of the temperature effect was velocity dependent: At the slowest pedalling rate the effect of warming the muscle was to increase PPmax by approximately 2% per degree C but at the highest speed this increased to approximately 10% per degree C.
The present study was undertaken to investigate energy balance in professional male breath-hold divers in Tsushima Island, Japan. In 4 divers, rectal (Tre) and mean skin (Tsk) temperatures and rate of O2 consumption (VO2) were measured during diving work in summer (27 degrees C water) and winter (14 degrees C water). Thermal insulation and energy costs of diving work were estimated. In summer, comparisons were made of subjects clad either in wet suits (protected) or in swimming trunks (unprotected), and in winter, they wore wet suits. The average Tre in unprotected divers decreased to 36.4 +/- 0.2 degrees C at the end of 1-h diving work, but in protected divers it decreased to 37.2 +/- 0.3 degrees C in 2 h in summer and to 36.9 +/- 0.1 degree C in 1.5 h in winter. The average Tsk of unprotected divers decreased to 28.0 +/- 0.6 degrees C in summer and that of protected divers decreased to 32.9 +/- 0.5 degrees C in summer and 28.0 +/- 0.3 degrees C in winter. Average VO2 increased 190% (from 370 ml/min before diving to 1,070 ml/min) in unprotected divers in summer, but in protected divers it rose 120% (from 360 to 780 ml/min) in summer and 110% (from 330 to 690 ml/min) in winter. Overall thermal insulation (tissue and wet suit) calculated for protected divers was 0.065 +/- 0.006 degree C X kcal-1 X m-2 X h-1 in summer and 0.135 +/- 0.019 degree C X kcal-1 X m-2 X h-1 in winter.(ABSTRACT TRUNCATED AT 250 WORDS)
Maximal isometric forces during both twitch and tetanus are largely temperature independent in muscles from both endothermic and ectothermic vertebrates. Anuran muscle can develop maximal force at lower temperatures than mammalian muscle. Tetanic tension is maximal at normally experienced body temperatures in a variety of animals, but twitch tension seldom is. Thermal dependence of twitch tension varies with muscle fiber type: tension decreases with increasing temperature in fast-twitch muscles and remains constant in slow-twitch muscles. In contrast to the low temperature dependence of force generation, rates of development of tension (time to peak twitch tension and tetanic rise time) and maximal velocity of shortening and power output are markedly temperature dependent, with average temperature coefficient (Q10) values of 2.0-2.5 Q10 values for rate processes of anuran muscle are only slightly lower than those of mammalian muscle. High body temperatures permit rapid rates of muscle contraction; animals active at low body temperatures do not achieve the maximal rate performance their muscles are capable of delivering. Thermal acclimation or hibernation does not appear to result in compensatory adjustments in either force generation or rate processes. In vivo, dynamic processes dependent on contractile rates are positively temperature dependent, although with markedly lower Q10 values than those of isolated muscle. Static force application in vivo is nearly temperature independent.
The primary objective of this investigation was to determine the thermal and metabolic effects of wearing a rubberized wet suit (WS) while swimming for 30 min in 20.1, 22.7, and 25.6 degrees C water. Metabolic and body temperature measurements were recorded in each water temperature with subjects wearing either a WS or a competitive swimming suit (SS). Immediately after each swim the subjects cycled for 15 min on a stationary cycle ergometer. Energy expenditure (VO2), heart rate, post-swim blood lactate, work completed on the cycle ergometer, and rating of perceived exertion (RPE) were similar in all trials. Mean (+/- SE) core temperature (Tc) during swimming in the SS trials increased 0.56 (+/- 0.33), 0.48 (+/- 0.20), and 1.22 (+/- 0.24) degrees C, whereas in the WS trial Tc rose 0.62 (+/- 0.22), 1.02 (+/- 0.15), and 0.89 (+/- 0.13) degrees C in the 20.1, 22.7, and 25.6 degrees C treatments, respectively. Following swimming many of the subjects experienced a decrease in Tc, but it was significantly elevated above preimmersion by the end of cycling in all trials except the SS 20.1 degrees C trial. Mean trunk temperatures (Ttr) during swimming in the WS trials were 4.32 +/- 0.16 (20.1 degrees C), 3.90 +/- 0.25 (22.7 degrees C), and 3.21 +/- 0.20 (25.6 degrees C) degrees C warmer than in the SS. Ttr rose after the subjects exited the water, but remained significantly below baseline throughout cycling in all trials.(ABSTRACT TRUNCATED AT 250 WORDS)
Certain previous studies suggest, as hypothesized herein, that heat balance (i.e., when heat loss is matched by heat production) is attained before stabilization of body temperatures during cold exposure. This phenomenon is explained through a theoretical analysis of heat distribution in the body applied to an experiment involving cold water immersion. Six healthy and fit men (mean +/- SD of age = 37.5 +/- 6.5 yr, height = 1.79 +/- 0.07 m, mass = 81.8 +/- 9.5 kg, body fat = 17.3 +/- 4.2%, maximal O2 uptake = 46.9 +/- 5.5 l/min) were immersed in water ranging from 16.4 to 24.1 degrees C for up to 10 h. Core temperature (Tco) underwent an insignificant transient rise during the first hour of immersion, then declined steadily for several hours, although no subject's Tco reached 35 degrees C. Despite the continued decrease in Tco, shivering had reached a steady state of approximately 2 x resting metabolism. Heat debt peaked at 932 +/- 334 kJ after 2 h of immersion, indicating the attainment of heat balance, but unexpectedly proceeded to decline at approximately 48 kJ/h, indicating a recovery of mean body temperature. These observations were rationalized by introducing a third compartment of the body, comprising fat, connective tissue, muscle, and bone, between the core (viscera and vessels) and skin. Temperature change in this "mid region" can account for the incongruity between the body's heat debt and the changes in only the core and skin temperatures. The mid region temperature decreased by 3.7 +/- 1.1 degrees C at maximal heat debt and increased slowly thereafter. The reversal in heat debt might help explain why shivering drive failed to respond to a continued decrease in Tco, as shivering drive might be modulated by changes in body heat content.
Biophysics of Heat Transfer and Clothing Considerations.” In Human Performance Physiology and Environmental Medicine at Terrestrial Extremes
- R R Gonzalez
In Human Performance Physiology and Environmental Medicine at Terrestrial Extremes
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Gonzalez, R. R. 1988. "Biophysics of Heat Transfer and Clothing
Considerations. " In Human Performance Physiology and
Environmental Medicine at Terrestrial Extremes, edited by K. B.
Pandolf, M. N. Sawka, and R. R. Gonzalez, 45-95. Indianapolis,
IN: Benchmark Press.
The Physician's Guide to Diving Medicine
- C W Schilling
Schilling, C. W. 1984. The Physician's Guide to Diving Medicine.
New York: Plenum Press.