The studies showed some variability in body fat percentage. For example, in one particular study [29], the collective group had an average body fat percentage of 17.5%, with males having a lower average of 13.4% compared to 24.4% for females. Another study [7] showed a reduction in the average body fat percentage for the entire group of 15.87%, again with males having a lower average of 11.13% compared to 22.98% for females. In addition, elite SUP athletes had a mean body fat percentage of 15.5%, suggesting a leaner body composition compared to the general population [22]. Additional research [30] suggested that preparation for SUP competitions could result in a decrease in body fat, with an average of 19% at baseline and 17% during race week. Overall, participants generally had an average BMI within the range considered normal for adults, ranging from 18.5 to 24.9 kg/m² [7, 22, 29]. However, some studies reported different values. For example, experienced SUP practitioners reported an average body fat percentage of 24.3% and a BMI of 76.5 kg/m², with an average height of 170 cm and an average weight of 70.5 kg [24]. In other cases, data are presented for all groups combined and by gender. Mean body fat percentages ranged from 23.50% to 24.90%, BMIs ranged from 1.67 to 1.79 kg/m², and mean weights spanned from 65.75 kg to 80.66 kg [21]. These observations highlight the diversity inherent in the anthropometry of SUP practitioners, demonstrating a spectrum of physical characteristics within this population. The sedentary population [10, 11] also demonstrated diversity in body fat percentage, BMI, height, and weight.

In summary, the research conducted on SUP athletes revealed variations in body fat percentage, BMI, height, and weight. The results suggest that, overall, SUP practitioners have average body fat and BMI levels within the range considered normal for adults. Specifically, gender differences were found, with males having lower average body fat and BMI values compared to females. Elite SUP athletes had a leaner body composition and lower average body fat percentage compared to the general population. In addition, there may be a reduction in body fat prior to SUP competition. However, it is important to note that there was variability in the reported means among the different studies. Body fat percentage, BMI, height, and weight varied within these studies, demonstrating the range of physical characteristics among SUP practitioners. This heterogeneity may be due to factors such as fitness level, experience, gender, age, and individual characteristics. Finally, studies of sedentary individuals also revealed a range of body fat percentage, BMI, height, and weight measurements. In conclusion, the available data underscore the range of anthropometric measures observed among SUP practitioners and serve as a testament to the physical heterogeneity inherent in this population.

Understanding the biomechanical principles applied to SUP can help identify limiting factors to performance, compare athlete groups, optimize paddling technique, and prevent injury. Despite the limited scope of the studies, their findings may prove invaluable to coaches, therapists, and participants who need to maximize performance and minimize the risk of injury during exercise [24]. Therefore, topics such as time-motion analysis, stroke parameters, electromyography (EMG), and global positioning system (GPS) will be addressed. Time-motion analysis (TMA) is a reliable method for analyzing athletic performance by examining video footage frame by frame. These systems are designed to track the motion of body segments, derive joint and segment kinematics, and provide additional information through further processing using complex muscle and/or skeletal models [31]. Motion analysis has been widely used in various sports for quantitative purposes, including evaluation of technique and competition [32]. The proliferation of high-resolution cameras in mobile communication devices has democratized this form of analysis [33], making it a valuable tool for evaluating SUP performance.

The importance of technique in SUP is underscored by the association between less-than-optimal stroke biomechanics and shoulder, elbow, and back injuries observed in similar sports such as kayaking and outrigger paddling [24, 34]. The first study to investigate the kinematics of the SUP stroke found significant differences in joint kinematics between experienced and inexperienced participants [24]. Specifically, inexperienced participants demonstrated greater total shoulder range of motion (ROM) (78.9 ± 24.9 vs. 56.6 ± 17.3) and less hip ROM (50.0 ± 18.5 vs. 66.4 ± 11.8) than experienced participants. In addition, experienced participants had more shoulder motion at the end of the paddle stroke (74.9 ± 16.3 vs. 35.2 ± 28.5 minimum shoulder flexion) and more elbow extension (6.0 ± 9.2 minimum elbow flexion vs. 24.8 ± 13.5) than inexperienced participants. These results suggest that experienced paddlers perform a more efficient SUP stroke, possibly due to a larger catch angle and longer stroke length, resulting in a higher peak power output. Differences in ankle-to-hip power and knee angle also suggest that experienced paddlers use more muscle groups during the stroke, resulting in greater overall efficiency.

One study [25] examined the effects of SUP training on balance stability in older adults. Participants performed various demanding postures to assess their balance before and after the training. Kinematic analysis of body sway was performed by attaching flat markers to the acromion of the right shoulder and the seventh cervical vertebra using the KINOVEA software. The results showed a significant reduction in trunk sway in the SUP training group compared to the control group. This improvement was observed in both the Romberg posture and the tiptoe posture. Furthermore, SUP training also resulted in improved balance stability under conditions of visual deprivation.

In the context of stroke parameters in SUP and the distances achieved, it is important to distinguish between those obtained during training sessions, competitive events, and study protocols. In a competitive context, during a marathon race [23], there were differences in the distance covered due to external variables on the race day and their consequent impact on results. The results showed that the average distance covered by the participants was 13.56 km, ranging from 13.34 km to 13.87 km. In the calm water field tests [27, 35], subjects performed 30 minutes of continuous exercise and covered a distance of 4,173.8 ± 241.8 m and 3,700 m, respectively. In the laboratory ergometer tests [10], the values for the aerobic and anaerobic performance conditions were presented separately for the baseline, pre- and post-training tests. For the aerobic condition, the mean distance covered was 366.68 ± 71.90 m in the baseline test, 336.21 ± 101.97 m in the pre-training test, and 486.80 ± 134.64 m in the post-training test. For the anaerobic condition, the mean distance covered was 14.90 ± 2.96 m in the baseline test, 15.28 ± 2.68 m in the pre-training test, and 17.17 ± 2.48 m in the post-training test. In terms of profiling [22] and providing original data on elite SUP athletes, as well as comparisons with recreational and sedentary individuals with no prior exposure to the sport, men achieved the following distances in aerobic testing: 747.59 ± 128.66 m for the elite group, 503.51 ±159.97 m for the recreational group, and 368.90 ±68.42 m for the sedentary group. For the maximum anaerobic power tests, the distances achieved were 20.60 ± 3.08 m for the elite group, 17.29 ± 3.60 m for the recreational group, and 14.07 ± 2.88 m for the sedentary group. The studies reviewed represent a wide range of distances covered in different contexts. In competitive events, participants covered an average distance of 13.56 km. In field tests, one athlete achieved a total distance of 3700 m in 30 minutes in calm water, while in another study, subjects achieved a total distance of 4,173.8 ± 241.8 m in 30 minutes of continuous exercise. In laboratory ergometer tests, the distances covered were presented separately for different conditions, such as aerobic and anaerobic, and ranged from 14.90 m to 486.80 m. In a study comparing elite athletes, recreational athletes, and sedentary individuals, the distances covered also showed differences between the groups [22].

When analyzing speed, the marathon performance showed a mean speed of 9.78 ± 0.70 m/s, with male participants showing a slightly higher mean speed of 10.13 ± 0.53 m/s compared to female participants, who maintained a mean speed of 9.07 ± 0.41 m/s [11]. During maximal aerobic SUP testing, speeds were slightly slower. Under calm water conditions without current interference, an athlete achieved a mean speed of 2.19 ± 0.32 m/s during a maximal SUP test [35]. Using an ergometer [22], the maximal speed during an aerobic test was 2.18 ± 0.16 m/s for the elite class, 1.93 ± 0.24 m/s for the recreational group, and 1.50 ± 0.15 m/s for the sedentary group. When assessing anaerobic performance, the elite group reached a maximum speed of 2.35 ± 0.32 m/s, the recreational group reached 1.99 ± 0.40 m/s, and the sedentary group reached 1.62 ± 0.31 m/s. Notably, both tests showed significant differences between the elite group and the other participant groups.

Furthermore, the literature has shown that the maximum speed values were significantly increased in the field environment (average of 3.09 ± 0.32 m/s) compared to the laboratory setting (2.17 ± 0.13 m/s) [7]. However, the differences in speed measurements between the two settings are likely due to the different methods used to quantify speed. The laboratory-based speed measurement is based on the moment of inertia of the ergometer flywheel, whereas the field-based measurement was obtained using the integrated GPS and gas analysis system. In summary, some studies [7, 10, 11, 22, 35] reported different values for maximal speed in different conditions and participant groups. A higher mean maximal speed was found in the field compared to the laboratory setting. In addition, elite athletes had higher maximal speeds in both aerobic and anaerobic conditions compared to recreational and sedentary individuals. Furthermore, gender differences in maximal speeds were observed, with male participants achieving higher mean and maximal speeds than female participants.

During a 30-minute session in calm waters, the record paddle rate was 52.63 ± 2.62 paddles per minute, with an average distance covered per paddle of 2.39 ± 0.39 meters [35]. The use of ergometers to assess the maximum paddle rate (the maximum number of SUP paddles per minute) and the average length of each SUP paddle varied significantly between different groups [22]. The elite group had a maximum paddle rate of 69.6 paddle/min and a mean paddle length of 2.19 meters, while the recreational group had a maximum paddle rate of 55.47 paddle/min and a mean paddle length of 2.24 meters. In contrast, the sedentary group had a maximum paddle rate of 42.27 paddle/min and a mean paddle length of 2.34 meters. These results suggest that elite paddlers, on average, performed more paddles in each time period but paddled for a shorter average paddle length compared to their recreational and sedentary counterparts. In one study [10], the results showed a significant increase in mean paddle length (2.38 ± 0.46 m at baseline and 2.52 ± 0.40 m after training) and maximum paddle length (2.89 ± 0.66 m at baseline and 2.96 ± 0.61 m after training) after SUP training. These changes indicate an improvement in paddling efficiency and power. In addition, the maximum paddle rate (paddles/min) also increased after training (43.77 ± 4.71) compared to baseline (41.15 ± 9.10), suggesting an improvement in the ability to perform high-speed paddles. During a 30-minute session, an individual participant maintained an average paddle rate of approximately 52.63 paddles per minute, with each paddle covering an average of 2.39 meters [35]. Significant differences in paddle rate and paddle length were found between the different groups, with the elite group performing higher rates with shorter lengths compared to the recreational and sedentary groups [22]. In contrast, one study [10] reported a significant improvement in mean and maximal paddle length, suggesting an improvement in paddle efficiency and power after SUP training, and an increase in maximal paddle rate, suggesting an improvement in the ability to perform high-speed paddles.

Surface electromyography (sEMG) is a widely used research tool in sports due to its ability to provide dynamic analysis, making it an important tool for optimizing movement, sports equipment, training techniques, and, ultimately, sports performance [36, 37]. The comprehensive assessment and feedback provided by sEMG analysis of muscular action allows for the optimization of athletic training and performance [38]. In addition, a complete understanding of the biomechanical demands of the sport can be achieved by synchronizing the EMG system with other technologies, such as cameras and electro-goniometers, that provide kinetic and kinematic data [39]. This integration allows researchers to gain a more accurate and detailed understanding of the movement patterns and muscular activity and to use this information to improve training and performance. EMG analysis can provide valuable information about muscle activation patterns and timing during different phases of the paddle stroke in the context of SUP [40]. One study [6] aimed to compare muscle activation patterns in kneeling and standing SUP positions using EMG analysis. The researchers measured the activity of the rectus femoris, biceps femoris, tibialis anterior, gastrocnemius, erector spinae, and upper trapezius muscles while participants paddled in both positions. The results showed significantly higher activation of the rectus femoris and biceps femoris muscles in the standing position compared to the kneeling position, while the anterior tibialis muscle showed significantly higher activation in the kneeling position compared to the standing position. The gastrocnemius muscle showed similar activation levels in both positions. The erector spinae and upper trapezius muscles also showed higher activation levels in the standing position, although the difference was not statistically significant. Overall, the study suggests that the standing position in SUP results in greater activation of the leg muscles, while the kneeling position results in greater activation of the anterior tibialis muscle.

The use of GPS in sports allows practitioners to evaluate athletic training programs and researchers to better investigate applied research questions [41]. Such devices have primarily been used to study exercise monitoring in athletes [42] and neuromuscular fatigue [43]. To date, there are only seven studies that have used GPS technology in SUP to track athletes' events [23], sessions [4, 20], and laboratory or field studies [7, 13, 26, 35]. These studies have provided valuable information on the external demands of SUP in competition, session, or testing, such as stroke rate, distance per stroke, distance paddled by athletes, speeds generated while surfing, course completion time, course distance, average speed, maximum speed, peak speed, distance per minute, and the impact of weather conditions. These variables provide insight into the sport and the workloads encountered, providing coaches with valuable information that can be used to develop and prescribe training/session programs.

Physical performance in various competitive sports events is largely dependent on the integrated state of various physiological mechanisms [44]. Thus, aerobic and anaerobic capacities are key determinants of elite profiles [7] and performance outcomes [23]. Monitoring HR, anaerobic threshold, and energy expenditure during SUP are the indicators discussed below. HR has been analyzed in cross-sectional observational studies [20, 22, 26] in the laboratory [28], in the field [7, 35], in training programs [10], in competitions [11], and in training sessions [4]. A total of eight studies were conducted with SUP practitioners of different performance levels. The reviewed studies suggest that HR is an important physiological response during SUP and can be used to monitor exercise intensity and performance. Some studies [7, 10, 22, 23] indicated that there were no significant differences in maximal HR between elite, recreational, and sedentary participants and that HR measurements were consistent between laboratory and field testing. In addition, HR remained relatively stable after the implementation of a training program, suggesting that it is a reliable indicator of exercise intensity.

SUP surfers spend a significant portion of their sessions at HRs above 70% of their maximum HR [4]. The highest HRs have been observed when surfers fall off the board and when paddling back out, suggesting that these activities are particularly demanding. Paddling cadence can affect HR, with higher cadences resulting in higher HRs during an 8-minute test [13]. Laboratory data suggest that as the SUP stroke rate increases, HR also increases, reflecting an increase in exercise intensity. Field data suggest that as the SUP stroke rate increases in the outdoor environment, the HR also increases, reflecting a higher exercise intensity [26]. Comparing the two situations, the mean HR and percentage of maximal HR were higher during the laboratory test at 30 strokes per minute but not at 10 or 20 strokes per minute. During a 30-minute maximal effort SUP test, HR remained relatively stable, indicating that athletes were able to maintain a consistent level of intensity throughout the test [35]. Male and female participants have similar peak HRs during SUP, but males have a higher average HR [20]. In addition, SUP can be considered a vigorous aerobic activity based on HRs relative to the predicted maximum HR for age. Overall, the reviewed studies suggest that HR is a valuable indicator of exercise intensity and performance during SUP, with HRs above 70% of maximum HR being common during sessions. Paddling cadence can also affect HR, with higher cadences resulting in higher HRs. It is important to control the pace during SUP in order to maintain an appropriate level of intensity throughout the session.

A total of seven studies have evaluated the anaerobic threshold and energy expenditure during SUP. These assessments were performed both in the laboratory using ergometers [7, 10, 11, 22, 28], by comparing data from laboratory and field conditions [7, 26], and by field testing [27]. Peak aerobic power was significantly higher in elite SUP athletes compared to the recreational and sedentary groups [22]. Peak aerobic power was also significantly higher in the elite group than in the others. The study also found gender differences, with elite men having higher VO_2max than elite women, and sedentary women having the lowest mean VO_2max. Field-based measures of maximal aerobic power were significantly higher (+5.28%) than laboratory-based measures [7]. Men had significantly higher maximum aerobic power than women in both the laboratory and the field, and there was a strong positive correlation (r = 0.907) between absolute V̇O_2max recorded in the laboratory and the field. Field measurements were higher in 80% of the subjects tested, with only two subjects showing higher values in the laboratory.

Six weeks of SUP training resulted in significant improvements in both absolute and relative aerobic power, with increases of 18.86% and 23.57%, respectively [10]. In addition, there was a weak negative correlation (r = -0.32) between the age of participants and the percentage increase in VO_2max throughout the study. The study also found significant improvements in anaerobic fitness, with a 41.74% increase in anaerobic power production and a 42.11% increase in relative power production over the training period. A long-term intervention [11] showed significant improvements in both aerobic (2.8 ml/kg/min; +13.0%) and anaerobic (2 W; +20.8%) power. The most significant improvements were observed in one participant who increased aerobic power by 6.3 ml/kg/min and anaerobic power by 5.3 W.

In the laboratory, significant main effects were observed for energy expenditure (EE), metabolic equivalents (METs), V̇O₂, and ventilation (VE) as SUP paddling rates progressed from 10 to 30 strokes per minute. Similarly, in the field setting, significant main effects were observed for estimated EE, METs, and V̇O₂, with all variables increasing significantly as SUP paddling rates increased from 10 to 30 strokes per minute. Moreover, economy (45.3 ± 5.7 KJ·l^-1 at 45 rpm vs. 38.1 ± 5.3 KJ·l^-1 at 65 rpm; p = 0.010) and gross efficiency (13.4 ± 2.3% at 45 rpm vs. 11.0 ± 1.6% at 65 rpm; p = 0.012) were higher at 45 rpm than at 65 rpm during an 8-minute test. The respiratory exchange ratio was lower at 4 minutes than at 8 minutes at both cadences of 55 rpm (4 min, 0.950 ± 0.065 vs. 8 min, 0.964 ± 0.053) and 65 rpm (4 min, 0.951 ± 0.030 vs. 8 min, 0.992 ± 0.047; p < 0.05). In addition, VO₂ and lactate were lower at 45 rpm (VO₂, 34.4 ± 6.0 mL·kg^-1·min^-1; lactate, 3.5 ± 1.0 mmol·l^-1) compared to 55 rpm (VO₂, 38.6 ± 5.2 mL·kg^-1·min^-1; lactate, 4.2 ± 1.2 mmol·l^-1) and 65 rpm (VO₂, 38.7 ± 5.9 mL·kg^-1·min^-1; lactate, 5.3 ± 1.8 mmol·l^-1) at 8 minutes. Additionally, lactate was higher at 65 rpm than at 55 rpm at 8 minutes. Athletes had a higher aerobic and anaerobic capacity compared to recreational and sedentary individuals. There were also gender differences, with elite males having higher mean VO_2max values than elite females and sedentary females having the lowest VO_2max values. In additional, maximal aerobic power measured in the field was found to be significantly higher than that measured in the laboratory. Studies have also shown that SUP rowing rates affect several physiological measures, with all variables increasing significantly as SUP rowing rates increased from 10 to 30 strokes per minute. Finally, economy and gross efficiency were found to be higher at lower rowing rates (45 strokes per minute) than at higher rates (65 strokes per minute) during an 8-minute test.

Equipment innovation aims to increase access to sport and improve performance [45], and it is necessary to understand the variables that affect performance before designing equipment. Once these variables are identified, equipment can be designed to modify them and achieve the desired outcomes [46]. The ergometer is an important piece of equipment for a rower because it facilitates the in-water rowing mechanism [47]. There are notable differences between in-water strokes and out-of-water strokes when using an ergometer or rowing boat, particularly with respect to the gear ratio, the pattern of force increase, and the magnitude of the force produced [48, 49]. In SUP, the devices that have been used for biomechanical and physiological analysis include swimming ergometers [13] and SUP-specific ergometers [7, 10, 11, 22, 24, 26].

In technology assessment, one study evaluated the intra-test reliability of a proposed outdoor field evaluation methodology for three levels of SUP technology [50]: boards, paddles, and fins. The study compared two different SUP boards: the high-tech Sprint board and the basic Allstar board. The Sprint board outperformed the Allstar board in terms of paddle speed and stability, while the Allstar board had the worst performance. The study also evaluated three types of SUP paddles: carbon, hybrid, and aluminum. The results showed that the high-tech carbon paddle performed better in terms of paddle speed. However, there were no significant differences in performance regarding board stability or wind resistance. Finally, three types of SUP fins were evaluated: carbon, fiberglass, and plastic fins. The high-tech carbon fins performed better in terms of paddle speed and stability, while the basic plastic fins performed the worst. Another study proposes a parametric method for customizing fins through additive manufacturing (3D printing) [51]. The methodology is based on a parametric model that allows users to adjust the dimensions of the fins according to their preferences and abilities. Specifically, the fin system, its position on the board, cant, depth, sweep, base length, base foil profile, tip sharpness, tip thickness, and overall dimensions can be adjusted within a limited range of values, resulting in a 3D printable geometry. The method of creating the parametric system is sufficiently detailed to be replicable and constructed by designers, and future research directions are outlined to improve SUP performance and expand the well-established culture of experimentation within the sport.

In evaluating the stability of the human-SUP system under varying water conditions, one study [52] found that the position of the rider on the board plays a critical role in the stability of the system, with a central position providing greater stability. In addition, the study developed a stability map for the coupled system by modeling the governing equations of the buoyant body system and performing asymptotic stability analysis. The analytical results of the eigenvalue contours from the stability analysis were compared to current industrial SUP dimensions, allowing users to select a SUP board that balances stability and maneuverability.

An analysis of two SUP events from different years to determine if there were any changes in their participation or behavior during the race and whether such events should be approached differently by practitioners [53] suggested that the differences were more related to the distance of the race than to the specific characteristics of each event. The study also suggested the use of a Perceived Intensity Chart diagram to assess the competitiveness and quality of a SUP event. In addition, optimizing equipment choices and implementing technologies such as GPS trackers can positively impact competitors' performance and provide a better understanding of the dynamics of SUP racing.

Overall, the studies highlighted the importance of equipment innovation in improving performance and increasing accessibility to the sport of SUP. The use of ergometers and specific biomechanical and physiological analysis devices can help to understand the variables that affect performance and facilitate the design of equipment to modify them. Furthermore, technological evaluations of SUP equipment, such as boards, paddles, and fins, have shown significant differences in performance based on material and design. Finally, understanding the stability of the human-SUP system in varying water conditions is critical to selecting an SUP board that balances stability and maneuverability. In conclusion, these studies demonstrate the potential for technology and innovation to enhance the sport of SUP and encourage research to improve performance and expand the culture of experimentation within the sport.

The first article that met the inclusion criteria for this study was published in 2014, coinciding with the resurgence of the field at the beginning of the century. A lack of both overall studies and comparable studies limited this review. As mentioned previously, research on SUP performance is an emerging area, and as a result, only 21 studies from a small number of research groups met the inclusion criteria for this review. In addition, the review was limited to English-language publications and conference abstracts, which may have excluded important published studies on SUP performance. Although an extensive database search was conducted, the use of other databases could have further strengthened this review. The studies included in this review were diverse and segmented, lacking consistency in thoroughly characterizing specific domains. Moreover, the diversity of research questions and methodologies used in these studies makes it difficult to compare results and draw concrete conclusions to guide future recommendations. Nevertheless, the volume of SUP-related research is increasing. This trend illustrates the evolution of scientific curiosity in the field of SUP as researchers seek to address pertinent questions that span both broad and specific topics.

Future SUP research has significant potential to advance understanding in several research areas. In SUP biomechanics, motion analysis, aided by increasingly accessible motion capture technologies, will facilitate the study of how variables such as paddle angle, stroke length, and rhythm affect performance. The integration of surface electromyography into the study of muscular activation patterns during different phases of the paddle stroke contributes to the understanding of paddle biomechanics. The interplay between physiological factors and SUP performance requires a continued focus on investigating the aerobic and anaerobic capacities of practitioners at different skill levels. Additionally, monitoring HR, anaerobic threshold, and energy expenditure during SUP provides insight into how these physiological factors relate to performance. A more complete understanding of how the physical and technical aspects interact can be achieved by correlating biomechanical, sEMG, and GPS data. Continued improvements in board and paddle materials and design may result in improved performance for practitioners. Ergonomics and technical evaluation of equipment play an equally important role, providing insight into force generation during paddling and the reliability of different types of equipment. From a safety perspective, research into preventative measures and understanding ocean conditions is essential. As SUP grows in popularity, research must also address its environmental impact, with a particular focus on coastal erosion and mitigation methods.