Padel sport has become one of the fastest growing and most popular sports around the world [1]. It was estimated that more than 25 million active padel players are present considering both professional as well as non-professional (federative licensed players 65% male and 35% female) in different parts of the world (International Padel Association, 2023). Padel is a hybrid sport that combine elements of both tennis and squash often played as doubles. Although rules of game does not specifically differ based on gender unlike lacrosse, however performance during game may show some variability attributed to either anatomical structure of males and females, different body control mechanisms, or sufficient volume of strength, agility and speed [2,3]. This sport activity involves rapid movement of players in multiple directions [4], thus training is very important to maintain dynamic balance and coordination during game and transferring motion to terminal segments of lower body peripheries like foot kinetics [5,6].   Being a racquet sport with periods of intense and light play, this game involves sudden acceleration or deceleration movements like backward, forward, lateral and truck rotation on pelvis (wider pelvis in females than males may also be related to angulation of core muscle attachments in them) which benefits anticipation during ball’s trajectory [2]. Thus, stable and coordinated movement during play allow the players to keep body’s Center of Gravity (COG) aligned [7]. Core muscles strength (both local and global) like rectus abdominus, obliques, traverse abdominis, erector spine, multifidus [3]; remains key in fulfilling this requirement and allows force generation due to high intensity motion [8]. Therefore, optimum training module for both male and female players become very important factor in preventing sports injury during game and in practice sessions [8,9].   As the game requires uninterrupted, smooth, coordinated and stable transfer of energy from upper extremity, core to lower extremities, therefore factors like muscle mass (both male and female), anthropometric parameter like BMI, age, sex etc., along with core strength may also affect these indicators [3,10]. Furthermore, when we consider padel sport through gender perspective, it has been documented that differences in balance and core strength arise as a result of combination of a different biological, biomechanical, hormonal and neuromuscular factor. According to study, it was concluded that gender does show stringer correlation between core stability and athletic performance. However, this observation was not clearly documented in case of padel players in particular, although evidences from different geographical regions indicates it may have been associated with athletic performance of the players. Hence, considering gender, it becomes important to understand how this affects dynamic stability and core strength in padel players.   Existing literatures have provided enough evidences regarding comparison between male and female players across different sports such as tennis, football, however, clarity with respect to padel players was found to be scant. Studies by Pradas et al. [11] compared fitness profiles of padel players between male and female but has not evaluated the functional balance test and dynamic core activation during actual game play. Considering this, authors of this study has decided to explore similar correlation among male and female players using neuro-muscular tool to understand the dichotomy between core endurance and functional balance among padel players. Furthermore, this correlation has not been explored in Jeddah city, which has recently gained a lot of popularity in this region. Therefore, the objective of this study was to investigate and assess correlation between core muscle strength (using plank test) and how it contributes to the dynamic stability of posture (using SEBT) among padel players in Jeddah Saudi Arabia.

Study Design and Sample Size A cross-sectional study was planned with total of 30 padel players from six different padel centers in Jeddah, Saudi Arabia. A power analysis was done using G power indicated that sample size of 30 participants would be enough in order to measure the medium effect size (d = 0.50) with 80% power at alpha level of 0.05. All the 30 participants were selected by simple random sampling using random number table. The equal number of males (n = 15) and females (n = 15) were chosen for this study. The method was repeated until number of males and females were equal. Age of recruited players was above 18 years (with an average age of 25.73±4.46 years).   Eligibility Criteria for Recruitment of Participants in Study Participants included in this study must be healthy adults, with age above 18 years and should have at least six months of padel training experience. Additionally, participants must have had no injuries in the past six months without any history of cardiac problems or neurological disorders. All those individuals who have less than six months of padel training experience and a history of any primary disease like cardiac, musculoskeletal, or neurological issues were excluded from the study.   Outcome Measurement Following outcomes will be measured by pre-designed physical examination form which consists of three sections:   Demographic details and leg length measurement for both right-side and left-side, to facilitate standardized reach distances during SEBT. The equation to normalize the standardization of the results is:   Where, Excursion distance: Measured distance of reach (in centimetres), Stance Limb Length (LL): Length of the stance limb (in centimetres), Normalized Reach Distance (%): Reach distance expressed as a percentage of the stance limb length.   This methodology was in accordance with the study conducted by Gribble et al. [5] and Alshehre et al. [12] which demonstrated the use of normalized SEBT reach distances to identify limb asymmetries in healthy and injured populations. Similarly, Appiah-Dwomoh et al. [13] has also used this method for sample size calculation while investigating star excursion balance test in young athletes with back pain.   Core Stability Participants were explained about the test in detail. The plank test was performed in prone position with both the elbows at 90̊ with ground and shoulder in flexed position. Trunk was asked to lift above the ground aligning itself with the position of shoulders and feet. Both shoulder and feet were wide apart (Figure 1). The basic plank test has high validity as well as good test-retest reliability. Participants were asked to hold plank position for as long as possible with an intermittent rest of 2 minutes in between all the three attempts. Core strength was tested using the plank hold in the prone position and the average of three attempts was calculated. As previous studies have already demonstrated higher interrater and intra-rater reliability (ICC>0.9) of plank’s test in assessing core endurance, hence it has been used in the current study for its proven statistical evidence [14].   Figure 1: Participant od study performing plank test   Dynamic Stability SEBT assessed participants reach distance in eight different directions namely; anterior, anteromedial, medial, posteromedial, posterior, posterolateral, lateral and anterolateral; measuring dynamic postural stability in all three planes frontal, transverse, sagittal. During the test, participants were asked to stand in the center of the grid. Participant were asked to maintain single leg stance on one leg while reaching as far as possible with the contralateral leg (Figure 2). Reach distance was recorded for nearest 0.5 cm in each direction. Participants completed test in three attempts for each leg and final scores were calculated based on average of these three trials for all the eight directions. SEBT has good construct validity as well as good test-retest reliability. Selection of SEBT test to measure dynamic stability was due to its proven reliability and validity by previous studies. Range for interrater and intra-rater reliability for this test was between 0.81 to 0.96, refarming reproducibility of this test. Also, Hertel et al. [15], used this test to identify chronic ankle instability showing SEBT relevance for postural stability evaluation (5,15,16).     Figure 2: Participant of study performing SEBT     Protocol of the Study and Ethical Approval Following Figure 3 explains the protocol of this study:     Figure 3: Flowchart of protocol of the study   Ethical Approval This study has been approved by Local Research Ethics Committee (LREC) at FoM & KAU, King Abdulaziz University (Reference No. 282-24).   Procedure for Data Collection Anthropometric measurements were taken initially followed by plank test and SEBT during the visits to all six centers of study and test data was collected under guidance of an expert. Furthermore, to minimize observer bias during data collection procedure, the observers were specifically trained for standardized data collection methods where we also implemented blinding at all stages possible (Figure 4).       Figure 4: Procedure of the study   Data was collected using physical examination form with three sections:   Participants information and leg length measurement Plank tests results: Time taken to complete each test for three times SEBT test parameters using standardized data recoding form of this test   Data Management and Statistical Analysis Data collection was then managed using MS Excel. This data was then analyzed through Statistical Package for Social Science (SPSS) software version. Demographic characteristics were calculated using descriptive statistics and summarized in form of Mean±standard deviation and range. Study data was assessed for normality using Shapiro-Wilk test (data significant for test). Independent t-test was performed to compare both the genders. Pearson’s correlation analysis was performed to investigate relationship between core strength and dynamic postural stability. Value for significance was accepted at p<0.05. Furthermore, the findings of this study have been reported based on STROBE Checklist which has been considered standard tool for reporting observational studies [17].

Following section is divided into four parts, namely; Participant characteristics, Comparative analysis of dynamic stability and core strength between categories of gender, Relationship between Plank Test and SEBT to assess correlation between dynamic stability and core strength and summary of overall analysis.   Participant Characteristics A total of 30 participants recruited in the study, out of which 15 were females and 15 were males. Most of the participants were right side dominant (86.7%) compared to left side dominancy (13.3%). Equal number of males and females were recruited ensuring unbiased and fair analysis of outcomes variables (Table 1, 2).   Table 1: Distribution of participants by sex and dominant side Variable Category Frequency Percent Sex Female 15 50 Male 15 50 Dominant side Left 4 13.3 Right 26 86.7     Table 2: Characteristics of study participants Variable Mean Std. Deviation Age (years) 25.73 4.46 Weight (kg) 62.57 13.45 Height (cm) 168.23 10.21 BMI (kg/m^2) 21.93 3.23 RT leg length (cm) 92.2 6.02 LF leg length (cm) 92.2 5.94 Years and months of experience 4.14 3.14 Hours per week 7.63 6.51   From Figure 5, it can be observed that leg length measurements were equal in both the legs. According to BMI, there were few participants in overweight category however, mean BMI identified to be 21.53 reinforces that most of them were healthy. Maximum weight identified was 95 kg which may have altered the outcome of BMI in particular.       Figure 5: Range of minimum and maximum values of demographic characteristics of participants   Comparative Analysis of Dynamic Stability and Core Strength Between the Genders This overall analysis highlights that with a sample size of 30 padel players (both male and female), dynamic stability based on reach distance remains were relatively similar, although males tend to show slightly better stability dynamics than females. The overall difference however, remained non-significant (p>0.05).   Comparative Analysis Based on SEBT Between the Two Genders to Understand Variation in Dynamic Stability Recruited participants were asked to undertake distance reach test for both dominant and non-dominant leg sides in different directions. Test was performed using SEBT tool and analyzed using SPSS software. Findings of the tests were summarized in Table 3 and in form of box plots in Figure 2. Overall results indicated that although males have higher reach distance (in both dominant and non-dominant leg sides) in all eight directions compared to females, however, results were found to be statistically insignificant (p>0.05).   Anteromedial direction shows reach distance for both males (72.31±8.58) and females (72.06±5.59) to be nearly same, with only marginal difference of 0.25 units between them (males>females). Also, when mean reach distance was compared between them, analysis showed that for dominant leg, it was maximum in posterolateral direction in males (86.54±9.69) and posterior direction in females (83.89±9.05). When non-dominant leg side was compared, it was found to be maximum posterior direction (85.69±9.21) in males and posterolateral direction (82.51±10.60) in females. However, mean difference (ranged between -0.249 to -5.904) was found to be statistically non-significant (p>0.05; ranged between 0.066 to 0.926) in all the eight directions among both the genders for both dominant and non-dominant leg sides.   Comparison Based on Plank Tests Between the Two Genders When comparison was performed based on plank test time between male and female participants, it was observed that plank time was slightly more for males (115.53 secs) than that of females (109.13 secs). However, mean difference (-6.400) between them, for all the directions remained statistically non-significant (p-value = 0.772). This reflects the influence of training for core strengthening more profoundly over differences in gender.   Following Figure 6, represents overall comparison between the two genders for both dominant and non-dominant leg side through box plots. On comparing males and females, median scores variability in between the categories was insignificant. Outliners in the box plot highlights that, though variability in SEBT scores exists in few directions like medial and posteromedial, it can be attributed to wider interquartile range (IQR). Plot areas under plank tests shows that females have slightly larger spread pointing out the variability as observed. Overall analysis show consistency in performance by both the gender category in dynamic stability and core strength. Therefore, we accept null hypothesis which suggest no significant association between categories of gender in core muscle strength and or dynamic stability among padel players in Jeddah, Saudi Arabia.       Figure 6: Difference between males and females in SEBT and plank test   Table 3: Difference between males and females in SEBT and plank test Variable Male Female Mean difference p-value Anterior Dominant 80.35±8.50 76.90±6.26 -3.448 0.216 Non-Dominant 81.63±6.88 76.76±7.05 -4.87 0.066 Anteromedial Dominant 74.23±7.89 72.02±5.05 -2.214 0.368 Non-Dominant 72.31±8.58 72.06±5.59 -0.249 0.926 Medial Dominant 70.51±12.38 67.62±8.58 -2.892 0.463 Non-Dominant 71.64±13.03 68.59±8.91 -3.053 0.46 Posteromedial Dominant 81.94±11.79 76.04±8.66 -5.904 0.129 Non-Dominant 81.41±9.95 78.13±9.07 -3.278 0.354 Posterior Dominant 84.72±8.08 83.89±9.05 -0.827 0.794 Non-Dominant 85.69±9.21 81.15±8.93 -4.536 0.182 Posterolateral Dominant 86.54±9.69 82.84±9.35 -3.696 0.297 Non-Dominant 84.71±8.45 82.51±10.60 -2.205 0.534 Lateral Dominant 80.83±10.25 79.69±8.10 -1.143 0.737 Non-Dominant 80.19±6.34 77.74±7.27 -2.452 0.334 Anterolateral Dominant 81.66±8.91 76.39±7.08 -5.272 0.084 Non-Dominant 80.79±5.15 77.49±7.83 -3.297 0.184 Plank Test time (sec) 115.53±53.21 109.13±65.92 -6.4 0.772     Relationship Between Plank Test and SEBT among Padel Players Based Dominant and Non-dominant Side Table 4, reflects the nature and type of relationship between dominant and non-dominant leg sides in different direction in padel players. Overall findings show “anterior reach” of dominant leg side to be statistically significant at 0.026 (p-value), suggesting anterior reach on dominant side performs better core strength association with anterior reach direction in participants on dominant leg side.     Table 4: Correlation between plank test and SEBT Variable Correlation (r) p-value Anterior Dominant 0.407 0.026 Non-Dominant 0.229 0.223 Anteromedial Dominant 0.198 0.294 Non-Dominant 0.29 0.12 Medial Dominant 0.106 0.576 Non-Dominant 0.078 0.683 Posteromedial Dominant 0.04 0.833 Non-Dominant 0.095 0.618 Posterior Dominant 0.202 0.283 Non-Dominant 0.018 0.923 Posterolateral Dominant 0.358 0.052 Non-Dominant 0.184 0.331 Lateral Dominant 0.301 0.107 Non-Dominant 0.194 0.305 Anterolateral Dominant 0.338 0.067 Non-Dominant 0.206 0.275 r: Pearson’s correlation coefficient, Significant at p<0.05     Dominant Side Leg Category It was observed from Table 4, that there exists weak to moderate positive correlation (coefficient correlation (r) ranges between 0.106 to 0.338) between plank test and SEBT across different directions with no statistical significance (p-value ranged between 0.067 to 0.833) except anterior reach. Nature of relationship between the two test variables for anterior reach showed significance at p = 0.026, suggesting its importance in padel players. Analysis of result indicates that in case of posterolateral and anterolateral reach, correlation between plank test and SEBT was moderate positive at (r) = 0.358 and 0.338, respectively, however, statistical significance despite being closer to the set value of p<0.05, largely remained non-significant (p = 0.052 and 0.067, respectively).     Non-Dominant Side Leg Category On analyzing both the categories of leg sides, plank test and SEBT showed existence of very weak to very weak positive correlation (r = 0.018 to 0.290) at p-value >0.05, across variable categories in all the eight directions. Thus, reinforcing non-significance between them.   Figure 7, summarizes nature of correlation between plank test and SEBT graphically using scatter plots. It demonstrates linear relationship between the two variables with a slight positive slope indicating nature of relationship between them. It can be observed that with increase in core strength, results in small improvement in dynamic stability. On comparing performance direction wise, it was observed that point clusters were close in case of anterior, anterolateral, posterior and posterolateral, directions indicate moderate positive correlation between variables in dominant and non-dominant side leg category. While for posteromedial, anteromedial and medial directions cluster dots are largely scattered across plot area, indicating weak to very weak positive correlations among variables. Therefore, we accept null hypothesis which suggest no significant association between plank test and SEBT among padel players in Jeddah, Saudi Arabia.   Figure 7: Correlation plot between plank test and SEBT

This study investigated differences between male and female participants assess dynamic stability and core strength association using SEBT and plank test respectively. The overall findings of this study reflects that there was marginal difference between scores of males and females during SEBT where males outperformed females in all the directions (however, remained insignificant) and weak to moderate positive correlation was found among between them (although not significant). This can be attributed to the fact that influence of gender on stability and core strength was marginal due to consistent training of players [11].       The assessment of dynamic stability was performed using SEBT tool which is considered to be useful in determining dynamic stability thereby preventing occurrence of injury and damage to the players [18]. For assessing core strength as such clear indication for any particular tool was not found however, plank tests are widely used methods to examine muscle strength [14,19,20]. Plank enables isometric contraction of core muscles leading to strengthening of even respiratory and abdominal muscles thereby improving endurance in core [20,21]. Thus, sports training with planks also ensures improvement in dynamic stability and efficiency in performance during game [22,23].   The current study considered gender-based comparison for both dominant and non-dominant leg sides showed that difference between male and females in SEBT mean reach scores (however non-significant). It was found that between the two genders for dominant and non-dominant limbs (for all directions), males have higher reach than females. This can be due to anthropometric differences between males and females [24], muscle mass [3], or anatomical structure of body [18]. This study result was supported by Gribble et al. [5] and Ahmed et al. [25]. Similar results were found on comparing plank time between male and female suggesting comparable capacities of both due to efficient training enhancing athletic agility resulting in superimposed gender based physiological differences [1,26,27]. The dominant and non-dominant leg sides SBET scores also reflected posterior and posterolateral position in male and female. For males, it was posterolateral direction with dominant leg and in females, it was posterior direction with dominant leg having highest reaches during the test. The results indicated reversal reach distance when compared based on non-dominant leg sides, where males have higher reach in posterior direction compared to female who showed better reach for posterolateral direction. This could be attributed to the positions more prominent in padel players like forward lunging or backward lunging [2,4,9,26]. Furthermore, findings mentioned by Gribble and Hertel [28] also supports this observation suggesting that males outperform female in posterolateral direction compared to females [5,16,28]. Similarly, study by Plisky et al. [29], Munro and Herrington [30], Zech et al. [31] also concluded that due to differences in lower limb strength with better hip mobility and trunk stabilization, males tend to favour posterolateral direction (29-31). These studies also highlighted that in case of females, females have wider pelvic structures and greater Q-angle naturally favors posterior movement. Also, study such as Gribble & Hertel [28] also documented that there have been differences in neuromuscular controlling strategies among male and female which led them adept certain specific movements during the play. For males, muscles such as gluteus medius, gluteus maximus and vastus lateralis, strengthens with intensive training periods suggesting different muscle mass distribution than females (possess greater hamstring flexibility and endurance supporting more controlled and less rotational movements) [28].   In addition to this, analysis from this study also indicated that minimum reach distance was observed in both the genders was medial direction. This can be attributed to minimal use of this position while playing padel [4,11,32]. Studies have also shown similar patterns while analyzing other types of sports like basketball, volleyball etc. [6,33-35]. This indicates effects of proper training modules in improving agility and performance in field particularly in those sports where significance of quick directional changes is very important.   Relationship between dynamic stability and core strength shows pronounced significant correlation only in “anterior reach” direction (although positive correlation found in all direction however insignificant) which may be associated with “forward lunging” position during the play. All the other directional movements did not establish association with core strength, thereby suggesting that only certain directions relevant to that sport have added advantage of core strengthening [5,33]. This result was supported by Silver [36] highlighting importance of core strength in neuromuscular control, while quick accelerative or decelerative movements of body [37,38]. Anteriorly leaning forward positions typically require core muscle strength to support stable trunk movement over pelvis while maintaining body’s Center of Gravity (COG) [33,39]. This enables in counterbalancing sagittal plane movement without compromising stable posture [26]. However, our results have shown that it is not true for many other directions. Sports with specific movements, like padel, tennis or badminton, undertakes exhaustive training can also be the reason for variability in considered directions [25,40]. Moreover, many studies have evaluated association of core strength with dynamic stability in different sports, however, study by Firouzjah et al. [10], points out positive effects of core stability training on torque of trunk’s flexors and extensors, enabling efficient control in postural movement in basketball players. Overall, the existing literature on padel sport does not clearly evaluate the correlation between the two variables and hence authors of this study emphasize on conducting more comprehensive studies with larger sample size to generalize the findings. This result was also emphasized by other studies [8,41-43].