Topics of Study in Under-18 Padel Categories: A Systematic Review

1. Introduction

Padel has achieved a significant popular interest due to its social and competitive nature [1], leading to an increase in both competitive players [2] and research in various domains [3]. Key research areas include game analysis, psychological factors, physical and physiological profiles of players, and teaching methodologies [3].

In this context, researchers conduct theoretical studies aimed at reporting advances in specific areas of knowledge. Numerous theoretical studies on padel have been undertaken [4,5,6]. Noteworthy among these are systematic reviews of the characteristics and incidences of padel in Spain [7] and studies related to player movements on the court, temporal structure, and game actions in padel [3,6,8,9].

Other topics explored in theoretical studies include physiological and metabolic responses, physical preparation, injury risk, and rehabilitation in padel [8,10]. Additionally, a systematic review of the TESEO database was conducted to compile doctoral theses on padel [11].

1.1. Analysis of Game Parameters

The analysis of game parameters, particularly game actions, has emerged as the primary research area [6]. Various studies have established an average set duration of 40 minutes [12], with average point durations varying by sex (13.98 seconds for men and 15.49 seconds for women), and a similar number of strokes between sexes (10-11 strokes) [13]. Additionally, these studies have identified that the smash and forehand volley are the strokes with the most winners for men and women, respectively [14], with the volley being the most frequently used stroke for men [15]. These findings allow for the identification of tactical parameters with significant practical applications in training.

1.2. Psychological Analysis

The psychological analysis of players has become the second most researched area [3], due to the impact of competition on the players’ psycho-emotional resources [16]. In this context, there are three main effects of emotional load: cognitive anxiety (negative thoughts, discomfort, and feelings of insecurity caused by the fear of negative social evaluation, failure, and loss of self-esteem [17,18], and somatic anxiety (increased physiological activation caused by nervousness, such as elevated heart rate, respiration, and muscle tension [19,20], which have a negative effect on player performance. Conversely, self-confidence (the athlete’s belief in their ability to perform well in competition [21], has a positive effect on sports performance [22].

1.3. Physiological and Physical Profiles

Similarly, the analysis of the physiological and physical profiles has provided insights into the characteristics of competition and players in other racket sports [23,24]. Internal load parameters, such as heart rate (HR) and oxygen consumption (VO2), are used to quantify competitive efforts [25] and to identify the limits of cardiovascular function [26]. In padel, both HR [27,28] and VO2 [27,29] are influenced by the level of play and sex among senior players. Additionally, physical characteristics such as strength (maximal, vertical, and horizontal) and changes in direction, as well as player height, differ between men’s and women’s players in amateur and professional categories [29,30,31], potentially affecting playing styles based on these characteristics and demands.

1.4. Teaching Methodologies

Furthermore, the analysis of teaching methodologies in various sports disciplines aims to understand the impact of different teaching styles on the educational process of players, particularly children and young beginners [32,33]. In padel, the use of videos for students in formative cycles has been shown to aid in study, comprehension, motivation, and reinforcement of learning [34]. Additionally, a multi-methodological teaching approach by coaches, incorporating demonstrations and error corrections (group or individual) [35], as well as designing tasks that are adaptive, varied, innovative, and challenging for beginners [36], can enhance learning at these levels of play among senior players.

A review of the scientific literature indicates that theoretical studies have been conducted on various areas of knowledge in padel. However, there is still a need to better analyze existing knowledge in youth categories and minors (under 18). Despite its importance, given that 12.5% of federative licenses in Spain belong to minors [2], there is a lack of systematic revisions in this field. Therefore, the objective of this study was to conduct a systematic review of the existing literature on padel among players in youth categories (under 18) and to develop a classification of the main fields of study in this research topic.

2. Materials and Methods

2.1. Study Design

The study was conducted based on the principles of systematic review as outlined by Cartwright-Hatton [37].The information search was carried out using three sport science specialized databases: Web of Science, Scopus and PubMed. Keywords used included: padel AND (Young OR youth OR boys OR girls OR children OR kids OR under OR U12 OR U14 OR U16 OR U18 OR junior* OR menor* OR niños OR jóvenes). The final search was conducted on December 20, 2023, encompassing all research up to that date.

2.2. Inclusion and Exclusion Criteria

The selection of articles for the review was based on the following inclusion criteria: (a) sample of padel players under 18 years of age; (b) original studies; (c) variables related to methodology, teaching, and performance, especially game parameters, health, physiological, and physical aspects; (d) studies published in scientific journals (indexed in JCR, Scimago SJR, or meeting at least 30 Latindex criteria); (e) book chapters. Excluded were (a) abstracts, conference communications, and systematic reviews; (b) variations of padel such as individual padel, adapted padel, and wheelchair padel; (c) samples of padel players over 18 years of age. Articles written in English and Spanish were included.

2.3. Identification and Selection of Studies

The process for searching the studies to be analyzed followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method. The identification of potential studies to include was based on six phases [38,39]: (i) searching for original studies in the databases, (ii) removing duplicate studies, (iii) first screening phase based on title and abstract, (iv) second screening phase based on the full text of the article, (v) forward searching (references cited in the included studies), and (vi) backward searching (citations of the included studies).

2.4. Literature Search and Selection

Figure 1 presents the PRISMA flow diagram illustrating the studies obtained during the search process. The keywords used in the initial search identified a total of 62 articles. After analyzing the titles and abstracts, 41 studies were discarded due to duplication and insufficient indexing to meet the inclusion criteria. The second screening, based on the full text, excluded 5 articles because the results mixed under-18 and senior players. Ultimately, 16 studies were included in the review for analysis.

2.5. Risk of Bias in Included Studies

The quality assessment of the articles was performed using the Cochrane Risk of Bias Tool (CROB). It consists of six domains with the following scoring: high risk, low risk and unclear risk [40]. The methodological quality was described in the Table 1 and Figure 2. Overall, all studies were dominated by “low risk of bias” in the proposed quality criteria. Only the criterion Blinding of participants and personnel (Performance bias) showed some concerns.

3. Results

The most frequently analyzed topic was gameplay parameters (n=6), followed by physical characteristics (n=5), physiological, psychological, and teaching parameters (n=3) (Table 2). The articles were published between 2011 and 2023. Of the included studies, 58.82% were published in Journal Citation Report (JCR) journals. Table 3 presents a summary of each study included in the review, indicating the sample, variables, and most relevant results.

4. Discussion

The aim of this study was to conduct a systematic review of the existing literature on padel among young players (under 18) and to develop a classification of the main fields of study in this research topic. Following the methodology for search and selection of studies, a total of 16 articles were included. They focused on the following fields of study: teaching methodologies, psychological characteristics, physiological parameters, physical characteristics, and gameplay parameters.

4.1. Teaching Methodologies

During the formative and initial stage, an effective teaching methodology is crucial for acquiring the necessary knowledge for learning. According to Prieto-Bermejo & Renes-López [47], any teaching style can improve the knowledge of players in initiation stages around the age of eight. However, these authors suggest that a search-based methodology (learning in variable game situations) significantly enhances performance in baseline-to-baseline and baseline-to-net situations compared to a traditional methodology (repetition-based exercises and automatization of decontextualized actions). Additionally, the materials used in the teaching process are crucial for the student’s training. Firstly, adapting the court size from 20x10 meters to 10x6 meters increases the execution of wall shots, volleys, and overhead shots [44]. Secondly, while modifying the pressure of the balls does not affect temporal, physiological, or specific game actions, using lower pressure balls for beginners around 10 years old promotes a more enjoyable, comfortable environment and facilitates game development [48]. Therefore, in initiation stages with younger players, a search-based teaching methodology combined with modified instructional materials (court dimensions, net and racket size, and ball pressure) can lead to greater learning at these ages and levels, enhancing the educational process of the players. Additionally, Díaz-García et al. [51] indicated that exposing elite players to an external stimulus during training (e.g., a session with a professional player) increases motivation (intrinsic and extrinsic), fatigue, mental load, and physiological variables. Therefore, implementing a reward system adapted to the players’ level and age to generate appropriate demands may be an interesting approach to increase engagement and performance improvement.

4.2. Psychological Characteristics

Psychological characteristics can vary according to age and sex. Generally, padel players exhibit higher levels of self-confidence compared to cognitive and somatic anxiety [16,18]. Regarding sex, Rodríguez-Cayetano et al. [18] indicated that both sexes show similar values of cognitive anxiety, somatic anxiety, and self-confidence. Rodríguez-Cayetano et al. [16] confirmed the data on cognitive anxiety and self-confidence but showed differences in somatic anxiety, with boys exhibiting higher values. Therefore, these results suggest that playing padel generates greater self-confidence in players compared to somatic anxiety, related to physical problems, or cognitive anxiety, linked to negative thoughts and worries. This effect is similar in both sexes except for somatic anxiety, which requires further investigation for validation. Furthermore, Rodríguez-Cayetano et al. [16] found a correlation between the variables, indicating that higher self-confidence is associated with lower anxiety levels, while higher somatic anxiety is associated with higher cognitive anxiety. In relation to age, younger players present better values of self-confidence, cognitive anxiety, and somatic anxiety [16]. Therefore, these data suggest that as players age, they may experience lower self-confidence and higher levels of anxiety. Finally, compared to other racket sports like tennis, male padel players exhibit higher levels of self-confidence but also higher levels of somatic and cognitive anxiety, while female padel players exhibit better levels of self-confidence and cognitive anxiety compared to tennis players [16].

4.3. Physiological Parameters

In terms of physiological parameters, competition results in male players having a VO2 of 24.06±6.95 mL/kg/min (43.73±11.04% of VO2max obtained in the laboratory), a maximum heart rate (HRmax) of 169.72±18.41 bpm (18% lower than HRmax in the laboratory), and an average heart rate (HRavg) of 73.99±4.65% of HRmax in the laboratory [41]. The values reported by [42] are similar, indicating minimum heart rate (HRmin) values of 95.45 bpm, HRavg of 141.23 bpm, and HRmax of 175.24 bpm in the first set. In relation to sexes and age differences, boys have higher VO2max values compared to girls, and younger players (U14 vs. U16) have higher VO2max values in both sexes [53]. Finally, padel is considered a moderate-intensity sport located at the anaerobic threshold (VT2) [41].

4.4. Physical Characteristics

Regarding the physical characteristics of the players, results presented by Courel-Ibáñez & Llorca-Miralles [50] show higher values in height (172.8 vs 158 cm), weight (70.2 vs 54.7 kg), and body mass index (23.3 vs 21.7) in boys compared to girls, who, in turn, have a higher body fat percentage (24.1 vs 16.1%). The physical conditions of padel players show differences related to strength (vertical, horizontal, and throwing), direction changes, distance covered, and flexibility according to sexes. Regarding vertical strength, boys have higher jump heights than girls [50,53]. Regarding throwing strength and agility, there are discrepancies among the results. On the one hand, the data presented by Courel-Ibáñez & Llorca-Miralles [50] indicate that in players with an average age of 14, values for the medicine ball throw (dominant arm, non-dominant arm, and overhead) are similar in both sexes. On the other hand, Sánchez-Alcaraz, Orozco-Ballesta, et al. [46] show that boys have higher values in the overhead throw, while girls achieve better results in agility. Data related to horizontal strength show that in shorter distances (10m), girls achieve better results, whereas in longer distances (20m), boys perform better [46]. These authors also add a positive correlation between linear speed and change of direction (COD) but a negative correlation between linear speed and strength. Lastly, in the study by Pradas et al. [53], it was observed that jump height, maximum oxygen consumption, distance covered, and flexibility variables are influenced by age in both sexes, with older players showing higher values (U16 vs. U14). The results show differences in the data proposed by the studies across various variables, indicating a need for further research on these physical capacities to establish standard values for use with players, allowing coaches to assess physical condition and adapt training accordingly.

4.5. Health-Related Physical Parameters

Regarding health-related physical parameters during padel practice in young players, Delgado-García et al. [52] and [53] indicated that padel practice does not generate asymmetries in lower limbs; however, it does generate asymmetries in upper limbs, which are not affected by maturity status [52]. Finally, injuries are a critical aspect of sports practice, with Castillo-Lozano & Casuso-Holgado [43] indicating that the most common injuries in padel for minors are low back pain (23.30%), knee sprain, plantar fasciitis, and elbow injuries (10%), wrist, ankle sprain, and shoulder (6.70%). They also indicate that body mass index, laterality, and age variables can explain 7.5-18.5% of injuries.

4.6. Game Indicators

Game indicators related to temporal parameters indicate that matches played by lower-level players (initiation, regional category) have an average point duration of 7-9 seconds [42,48,49]. On the other hand, advanced-level matches show a point duration of around 7 seconds in boys [41], with these values being lower than those proposed by García-Benítez et al. [45] in the national category, indicating that point duration varies based on age and sexes, ranging from 9-12 seconds in boys and 11 seconds in girls. They also indicate that point duration is longer in older age categories, especially in boys. Therefore, there seem to be discrepancies regarding point duration, but the results suggest that higher-level and older players have longer point durations.

4.7. Game Parameters

Regarding game parameters, a lower number of strokes per point is observed at initiation levels (4 strokes per point) compared to regional (7-9) or national levels (6-8) [42,45,48,49]. Additionally, they are slightly higher in older players (U18 vs U16) [45]. Stroke frequency shows a higher use of forehand, backhand, and wall shots at initiation [49], whereas direct strokes (volleys and smashes) surpass bounce strokes (forehand, backhand) in advanced players [41]. Therefore, the data suggest more backcourt play at initiation level and more net-to-backcourt play in higher-level players. Finally, concerning specific stroke analysis, only Sánchez-Pay et al. [54] have examined this issue focusing on under-18 padel players strokes. These authors indicate that the bandeja is the most used finishing move in both sexes, followed by the off the wall samsh in girls and flat smashes in boys. Similarly, they show more winners with flat smash in girls and topspin smash in boys, more continuity and errors with the bandeja. Regarding stroke direction, the bandeja and topspin smash are mainly cross-court, with flat smash down the line and the off the wall smash similar, but according to sexes, girls execute it more down the line (52.5%), while boys do it more cross-court (65.4%).

4.8. Study Limitations and Future Studies

Research in padel has increased in recent years, covering multiple areas but focusing on professional players. The main limitation of this review has been the limited number of studies exclusively focused on younger players. To our knowledge, only those included in this review that meet the inclusion criteria exist. Likewise, a problem arising from the limited research on young players is the lack of information on the different areas addressed. The results have allowed us to gain an understanding of the various research areas; however, it has not been possible to corroborate the information with more studies to draw more robust conclusions. Therefore, future studies should continue to address the analyzed parameters in younger players to enhance their development as athletes and help them grow appropriately as players.

5. Conclusions

Training during formative ages is crucial for the development of players. Therefore, the obtained results can assist professionals dedicated to coaching young padel players in better understanding the educational process and competition demands. The teaching methodology will help comprehend which teaching styles and tools might be most suitable for players’ learning based on their level and age. To illustrate, while any methodology is beneficial at the outset of training (approximately eight years of age), learning in variable game situations facilitates more effective learning, while also reducing the size of the court from 20x10m to 10x6m and the pressure of the balls. Similarly, at more advanced levels, external stimuli that stimulate the athlete’s motivation enhance performance and learning.

Data concerning psychological parameters can aid coaches in adjusting training sessions according to the competition’s impact on players’ emotional states, since, knowing that higher levels of self-confidence and lower cognitive and somatic anxiety are shown in both sexes, with better values observed in younger players, more specific work should be done for a better control of feelings in competition according to the age of the players and according to the sex due to the higher levels of somatic anxiety shown in boys.

Understanding physiological and physical characteristics, will identify competitive demands and enable their replication in training. On the one hand, understanding that a padel match results in VO2 levels of 24.06±6.95 mL/kg/min and around FCmax and Mean values of 169.72±18.41 and 141.23 p/min respectively, in male players, who also have higher VO2max values than girls, and that younger players have higher VO2max values in both sexes. As for example, boys have a greater height (172.8 vs 158 cm) and more jump height in the CMJ (23.2 vs 9.9 cm) will help coaches and physical trainers of U-18 players to improve the physical preparation and tactical situations of the players, individualizing on the basis of sex and age.

Finally, understanding gameplay parameters enables the identification of competition characteristics concerning temporal parameters (7-9 seconds in lower-level players and 9-12 in national category), the number of strokes (from 4 in initiation level to 6-9 in regional and national level, and slightly higher in older players (U18 vs U16), and specific technical actions (forehand and backhand in initiation and volleys in advance level as most used strokes and bandeja most used to finish the point in both sexes).

This knowledge will facilitate the design of training sessions encompassing psychological, physical, and technical-tactical aspects that simulate specific competition scenarios for younger players.