1. Introduction
The creation of optimal learning environments that will allow players to improve their performance and motor skills acquisition at early stages is a key factor for a proper personal and athletic development [
1,
2]. Therefore, coaches and sport organizations should design child sports based on robust theoretical frameworks that understand the complexity of learning functional skills [
2,
3]. “Nonlinear pedagogy” (NLP), based on concepts from an ecological dynamics perspective, understand this complexity, due to the learning process rarely following a linear behavior progression [
4], because each player uses different problem-solving strategies [
1]. Moreover, the development and acquisition of functional motor skills respond to a process of self-organization to form stable patterns when the performer and environment interact [
2,
5,
6,
7].
According to Newell’s [
6] constraints model, NLP elaborate five key principles for designing adequate environments to facilitate learning [
2,
4,
5]: “representative learning design”; “developing relevant information-movement couplings”; “manipulation of constraints” (task, performer and environment constraints); “reducing conscious control of movement”; and “providing functional variability”. Thus, a meaningful learning design must occur in a real-sport context, which affords the optimal learning opportunities and manipulates the key constraints, influencing the performer’s intention to explore functional movements in problem-solving, while also focusing their attention on the effect of the action [
8]. To do this, several studies pointed out the “manipulation of constraints” principle, and especially the task constraints, which is the most powerful principle for designing adequate learning environments, given their significance in learning [
2,
5,
6]. Modifying the task constraints, such as the play rules, rules of the league, sport equipment, playing space, etc., could lead to the acquisition of certain functional movement patterns and decision-making, promoting variability and creativity [
4,
5,
6,
7]. Hence, NLP offers a pedagogical guideline to design optimal competitions, which improves the learning process [
6,
9,
10].
The concept “scaling junior sport”, based on the aforementioned concepts, seeks to implement junior sport according to players’ characteristics and needs, and not just adapt the adult game to the young players, through the manipulation of the task constraints (ball size, court size, etc.) [
11,
12,
13]. In this sense, some studies have been carried out in recent years in collective sports, such as soccer [
13,
14,
15,
16], basketball [
17], handball [
18], volleyball [
19], field hockey [
20], cricket [
21] or rugby [
22]. Whereas in racquet sports, most of the research was performed in tennis, to create or redesign the best environment and competition possible for junior tennis players [
12]. Most of the studies have assessed the effect of reducing the net height [
12,
23,
24,
25,
26,
27], court size [
12,
23,
24,
26,
27], playing with small racquets [
28] or a low-compression ball [
12,
28,
29] on child players during match-play. Results of these studies showed that the scaling of equipment and playing area improve the players’ match performance, engagement, enjoyment and the development of desirable movement patterns related to motor variability. However, in badminton, the research has focused to analyze the following aspects: technical and tactical [
30], physiological [
31,
32] or performance analysis [
33,
34,
35,
36] in elite and junior elite players, and not so much in scaling the equipment and play space for junior players. Although, some associations and federations, such as the Spanish Badminton Federation [
37], in a similar way to the tennis 10’s program developed by the International Tennis Federation, do structure badminton competitions for junior players, to manipulate key task constraints. In particular, a badminton junior program called “minibadminton” (MB) was developed, which is divided into three stages: under-9 (under 9 years old), under-11 (under 11 years old) and under-13 (under 13 years old) [
37]. The MB program is characterized by significantly reducing the net height and court dimension at the first stage of MB (under-9) and increasing it progressively until the adult sports version.
However, to our knowledge, there is not much information about the effect of playing in scaled badminton competitions (MB) or under the same conditions as adult badminton (B). Furthermore, only two studies in a physical education context and one in a formal badminton competition have provided information on player learning when playing with scaled equipment and play spaces. The study developed by Nathan et al. [
38] compared the NLP and Linear Pedagogy (LP) models during a badminton competition in students of approximately 13 years. The results showed that NLP improved the students’ game performance in terms of their tactical decision-making, recovery movement to base and skills execution regarding drop shots and smashes, as compared to LP. The second study investigated the effects of practice under Teaching Games for Understanding (TGfU), NLP and LP, indicating that students are more engaged during NPL or TGfU (age ~13 years old) than LP lessons [
39]. Finally, the study conducted by Nor Azmi et al. [
40] assessed the effect of playing in four different conditions, manipulating the racquet (40.0 cm to 35.0 cm), net (1.5 m to 1.2 m) and court size (13.40 m × 6.1 m). Four groups (
n = 40, under-9 players) played in the following conditions: standard racquet, net and court size (SRSC); standard racquet, modified court and net (SRMC); modified racquet, standard court and net (MRSC); and modified racquet court and net (MRMC). This study has found that children’s hitting opportunities (number of strokes) and stroke effectiveness (strokes into designated areas) were higher using MRMC than in other conditions. These studies showed the overall results, so it is difficult to reach solid conclusions.
The key research question that will be tested here is whether MB, manipulating court size and net height, is likely to generate a greater amount and variability of technical and tactical behaviors than B. Therefore, the main purpose of the present study is to investigate the incidence of MB by reducing the court dimensions (from 13.40 m × 5.18 m to 11.88 m × 5.18 m) and net height (from 1.55 m to 1.30 m), also observing the differences with the current under-11 badminton players’ competition (B) in the following technical and tactical variables: (a) service area; (b) stroke effectiveness; (c) kinds of technical strokes; (d) players’ hitting area; (e) shuttle landing area; (f) shuttle flight; and (g) rally length. Hence, it could conceivably be hypothesized that MB will improve the use of different kinds of strokes (especially the “special strokes” classified into the observational instrument) [
41], the stroke effectiveness, and will decrease the rally length, affording an offensive style of playing.
3. Results
Table 2 shows the differences between B and MB in respect of the usage percentage and the stock count technical and tactical according to service area.
The results indicate that there is a probability of 9.964 to find differences in the number of actions in the advantage zone in B compared to MB, with evidence at a Strong qualitative level. In the same way, the number of actions in the deuce zone has a probability of 6.909 to find differences in B with respect to MB, with evidence at a Moderate qualitative level.
The
Table 3 presents the differences between B and MB in terms of the usage percentage and the stock count technical and tactical in accordance with stroke effectiveness.
Data show that, in the percentage, both in B and MB the most determined action is total continuity, followed by error, partial continuity and winner. The results obtained indicate that there is a probability of 14.642 to find differences in the number of actions in total continuity in B compared to MB, with evidence at a Strong qualitative level. It can also be observed a probability of 4.982 to find a high percentage of winners in B with respect to MB, with evidence at a Moderate qualitative level. There are no notable differences in the rest of the variables, which show evidence at an Anecdotal qualitative level.
Table 4 shows the differences between B and MB with regard to the usage percentage and the stock count technical and tactical as depending on the kinds of technical and tactical strokes.
The data reveal that, in the percentage, the most determined strokes in B are forehand clear, followed by forehand service and forehand smash. Thus, in general, the results show a probability of 234.335 (percentage) and 179.109 (number of actions) to find differences in total forehand in B compared to MB, with evidence at an Extreme qualitative level. In the case of total backhand, the results indicate a probability of 234.359 (percentage) and 43.227 (number of actions) to find differences in MB with respect to B, with evidence at an Extreme and Very Strong qualitative level, respectively.
In a more detailed way, it highlights the probability to find differences both in percentage and number of actions in MB compared to B in forehand drop (30,579.697–3094.865), backhand drop (7397.641–601.093) and backhand lob (142.644–111.347), in all cases, with evidence at an Extreme qualitative level. In turn, there is a probability of 35.934 to find differences in the percentage forehand drive in MB in relation to B, with evidence at a Very Strong qualitative level. Likewise, there is a probability to see differences both in the percentage and number of actions in MB with respect to B in special strokes (161.711–72.056), with evidence at an Extreme and Very Strong qualitative level, respectively. The probability to find differences both in percentage (3259.116) and number of actions (531.678) in B concerning to MB in forehand clear should also be emphasized, with evidence at an Extreme qualitative level. Finally, the probability in the percentage (8.023) and number of actions (17.292), to find differences in smash in jump in MB compared to B, should be noted, with evidence at a Moderate and Strong qualitative level, respectively.
Table 5 presents the differences between B and MB in terms of the usage percentage and the stock count technical and tactical in consideration of player hitting area.
Overall, the obtained results show a probability of 13.631 to find differences in number of hitting actions in the deuce zone in B compared to MB, with evidence at a Strong qualitative level. In relation to the court area, there is a probability to find differences in MB with respect to B in hitting percentage in the service zone (1380.579) and close to the net (35.667), with evidence at an Extreme and Strong qualitative level, respectively. On the other hand, there is a probability, both in percentage (603,088.64) and in number of actions (183,255.439), to hit the inside court in B in relation to MB, either way with evidence at an Extreme qualitative level. In more detail, there is a probability in the percentage (400.784) and in the number of actions (390.436) to hit in the baseline and sideline in MB compared to B, with evidence at an Extreme qualitative level. In turn, there is a probability to find differences in MB compared to B in the percentage of hitting in the service area, more precisely, in the advantage zone (80.777), deuce zone (11.691) and close to the net in deuce zone (10.887), with evidence at a Very Strong (service area advantage zone) and Strong qualitative level.
Table 6 shows the mean and standard deviation, as well as the
p-value of the usage percentage and the stock count technical and tactical in B and MB according to shuttle landing area.
In general, the results in
Table 6 indicate that there is a probability of finding differences in errors in the percentage (264.660) and number of actions (3.094) that are not in the net in MB compared to B, with evidence at an Extreme and Moderate qualitative level, respectively. In such a way, there is a probability in the percentage (264.660) and number of actions (236.083) to find differences in net errors in B with respect to MB, with evidence at an Extreme qualitative level. The probability in the percentage (98.766) and number of actions (45.035) in shuttle landing area (inside court) in B with regard to MB should also be emphasized, with evidence at a Very Strong qualitative level.
Table 7 presents the mean and standard deviation, as well as the
p-value of the usage percentage and the stock count technical and tactical in B and MB in accordance with shuttle flight.
The results in
Table 7 bring to light that, in percentage, both in B and MB, the most determined shuttle flight is the crossed one, followed by the straight one and others. It should also be taken into consideration that there is a probability of 14.364 to find differences in the number of actions that are crossed flights in B regarding to MB, with evidence at a Strong qualitative level. In addition, there is a probability of 9.389 to find differences in the percentage in other flights in MB concerning B, with evidence at a Strong qualitative level.
Table 8 shows the mean and standard deviation, as well as the
p-value, of the usage percentage and the stock count technical and tactical in B and MB according to rally.
Table 8 results reveal that, in percentage, both in B and MB, the most frequent rally range is 2–5, followed by 6–9, 1 and, lastly, +9. It should be noted that there is evidence at an Anecdotal qualitative level of different rally duration options, both from the point of view of the percentage and the number of actions.
4. Discussion
The main purpose of the present research was to examine the incidence of MB by reducing the court dimensions (from 13.40 m × 5.18 m to 11.8 m × 5.18 m) and net height (from 1.55 m to 1.30 m), and observing the differences with the current under-11 badminton players’ competition (B) in the following technical and tactical variables: (a) service area; (b) stroke effectiveness; (c) kinds of technical strokes; (d) players’ hitting area; (e) shuttle landing area; (f) shuttle flight; and (g) rally length. Considering other similar studies on junior tennis [
25,
27,
59], scaling task constraints (reducing net height and court size) in a real-game context for under-11 badminton players seems to promote optimal learning opportunities. Hence, MB encourage players to seek new offensive play patterns by hitting different kind of strokes that enhance their behavioral variability, even if their effectiveness does not improve. Furthermore, according to the ideas and concepts developed by Torrents et al. [
60], MB could help the acquisition of motor creativity, by affording a degree of freedom related to the increase of hitting variability and reducing conscious awareness in a real-game context using proper task constraints. Overall, MB appears to be beneficial for optimal children’s sport and personal development according to NLP principles and “scaling junior sport”.
Promoting desirable motor skills is an important aspect in “scaling junior sport” [
12], so examining whether there are imbalances in play patterns is a key aspect in junior sport. Hence, the number of different kinds of strokes was compared, and in both competitions more forehand strokes were hit. However, a greater use of backhands can be observed in MB. These results coincide with the evidence found in other studies, which revealed the proliferation of the backhand stroke when reducing court size [
21,
49]. The emergence of special strokes was also analyzed, noting that it is approximately 167 times more likely to occur in MB than in B, although there was not much difference in the total percentage between B (0.36%) and MB (1.37%). These results coincide with those obtained in tennis [
27] or dance [
61], which showed that creativity processes are related at a theoretical level to motor variability in problem solving [
60].
On the other hand, previous studies [
23,
24,
27,
62] on this topic and NLP [
2] indicated that it is important to design children’s competitions that facilitate an offensive style of playing [
23,
24,
27,
62]. Following this line, the distance reduction between the baseline and the net and the reduction in the net height can explain the increase of strokes executed in the service zone and close to the net (more offensive areas) in MB. Moreover, the players used more hits classified as offensive (forehand and backhand drop and smash in jump) by the Spanish Badminton Federation [
37]. Otherwise, the likelihood of performing forehand clears is higher in B than in MB (BF10 = 3259.11); this result showed that the players adopted a defensive playing style, because it is a very common defensive stroke. Consequently, players use it to avoid taking risks during the game.
Analyzing rally length, similar values were observed between B and MB, in addition to the fact that the players were hitting mainly cross strokes. Two possible explanations for these results may be as follows: the players’ lack of experience to perceive relevant information during match-play to change their play patterns; or excessive use of forehand clear in B, not promoting motor variability. Giménez Egido [
27] found similar results in tennis, while the study conducted by Nor Azmil et al. [
40] regarding badminton found that players increased their rally length by reducing the net height, court size and racket size. These results from two studies may have different meanings: Fitzpatrick et al. [
49] indicated that an improved rally length leads to increased learning; nevertheless, Schimodffer et al. [
62] showed evidence that a longer duration of the rally implies a more defensive playing style. According to NLP [
2], the most desirable is to foster an offensive play style that enhances learning processes at the formative stage. In this line, the category total continuity obtained a higher probability of success in B than in MB. The results confirm our hypotheses, except for the increase in stroke effectiveness. A possible explanation could be that the training tasks are still based on linear models, outside the pedagogical principles of NLP, although the players usually play under MB conditions.
Finally, several studies highlighted that a strong limiting factor for learning is net height in child tennis [
21,
23,
24,
26,
27] and badminton [
40] players. These studies indicate that it is necessary to decrease the net height according to the players’ need and characteristics for optimal development, as a greater number of errors occur when players hit inside the net. In accordance with these studies, the results showed that the percentage of errors made in the net are higher in B due to the net height.
Although this study shows strong evidence, the current study had some limitations: the cross-sectional design provided only the short-term effect of these modified competitions; and the sample was composed of only elite junior players. In the future, it would be interesting to reproduce this study with different players’ characteristic.
According to Giménez-Egido et al. [
23] and Buszard et al. [
11], future research in junior badminton should focus on designing nonlinear competition formats, without relying exclusively on the physical maturity or age of the players; for example, using oversize racquets with slower shuttles in MB conditions. In addition, this type of study should be applied by assessing the psychological factors, such as self-efficacy or satisfaction, that mediate the adequate acquisition of motor and behavioral skills.