Abstract
ackground/Objectives:Dominant leg use in badminton may contribute to lower limb asymmetry, potentially affecting performance and injury risk. This study inves- tigated the effects of a 12-week integrated neuromuscular training (NMT) program on sports performance.Methods:Twenty-four well-trained male badminton players (age: 13.5±1.15 years) were randomly assigned to groups based on maturation status (pre-peak height velocity [pre-PHV] and post-peak height velocity [post-PHV];n= 12 each). All par- ticipants completed two NMT sessions weekly. Pre- and post-training assessments included a 20 m sprint, countermovement jump (CMJ), agilityt-text, hexagon test, and Y-balance test. Results:Both groups improved significantly across most tests. The post-PHV group (ES: 0.70–1.35) showed greater improvements in sprinting, CMJ, and agility, while the pre-PHV group (ES: 0.39–1.23) improved more in balance and asymmetry.Conclusions:These results
each). All par- ticipants completed two NMT sessions weekly. Pre- and post-training assessments included a 20 m sprint, countermovement jump (CMJ), agilityt-text, hexagon test, and Y-balance test. Results:Both groups improved significantly across most tests. The post-PHV group (ES: 0.70–1.35) showed greater improvements in sprinting, CMJ, and agility, while the pre-PHV group (ES: 0.39–1.23) improved more in balance and asymmetry.Conclusions:These results underscore the need for age- and maturity-specific training strategies to optimize performance and address asymmetries in youth athletes. Keywords:strength; knee; overhead athlete; core stabilization 1. Introduction Badminton is one of the most widely enjoyed sports worldwide, with approximately 200 million individuals engaging in the activity [1]. The sport involves rapid, multidirec- tional footwork, as well as jumping and lunging movements [2]. Research on adolescent badminton players indicates a notably high incidence of stress fractures in the lower leg following long-term training. The most frequently injured areas include the lower back, knees, hips, and ankles [3]. Over time, badminton players often develop weaker knee flexors, imbalanced muscle strength between flexors and extensors, decreased lower limb stability, and a reduced symmetry index between the dominant and non-dominant sides [4]. Children2025,12, 830 https://doi.org/10.3390/children12070830
Children2025,12, 830 2 of 15 Adolescence is categorized into early adolescence (aged 11–14 years) and late adoles- cence (aged 15–19 years), with the distinction based on chronological age. The peak growth velocity period, also known as the peak height velocity (PHV) or “growth spurt,” typically occurs around ages 10–12 for females and 12–14 for males. For adolescents, the primary goal of neuromuscular training (NMT) is to enhance athletic performance [5]. Integrated NMT exercises usually include strength training, coordination exercises, balance control training, plyometrics, agility, and flexibility [6–10]. These modalities have been empirically shown to improve biomechanical movement patterns and sports performances and reduce injury risk, provided that they are implemented under the supervision of qualified coaches who design and oversee the training programs [11,12]. Recent studies suggest that categorizing athletes by their peak height velocity (PHV)— into pre-PHV and post-PHV groups—may offer a more individualized and effective train- ing approach. For example, a four-week (two sessions per week) multicomponent NMT program significantly improved squat stability and enhanced trunk and hip joint alignment in elite adolescent cricket players categorized by PHV stage [13]. Similarly, a six-week change-of-direction training program, performed twice weekly for 20–25 min per session, led to improvements in jump performance, balance, and sprint ability in both pre- and post- PHV elite adolescent soccer players [14]. Furthermore, an eight-week resistance training intervention in adolescent swimmers showed positive trends in maximal isometric pull-up strength for both pre- and post-PHV groups, with greater improvements observed in post- PHV athletes [15]. These findings suggest that strength and conditioning coaches, as well as sports trainers, should recognize the importance of tailoring training programs according to an athlete’s maturation stage—specifically, the pre-PHV and post-PHV phases [16]. Notably, there is a lack of research on the long-term effects of integrated NMT on youth badminton players across different developmental stages. Only one study focusing on female badminton players (aged 16–19 years) demonstrated that 8 weeks of integrated NMT effectively improved functional movement screening scores, vertical jump, balance ability, strength, and overall athletic performance [17]. Therefore, the aim of this study is to inves- tigate the effects
the long-term effects of integrated NMT on youth badminton players across different developmental stages. Only one study focusing on female badminton players (aged 16–19 years) demonstrated that 8 weeks of integrated NMT effectively improved functional movement screening scores, vertical jump, balance ability, strength, and overall athletic performance [17]. Therefore, the aim of this study is to inves- tigate the effects of integrated neuromuscular training on lower body speed, jump, agility, and balance performance in male badminton players with different maturation statuses. 2. Methods 2.1. Experimental Approach to the Problem This study aimed to evaluate the effects of integrated NMT on lower extremity sports performance in pre-PHV and post-PHV male badminton players. A parallel, two-group, stratified randomized controlled design was employed. The intervention lasted 12 weeks, with two sessions per week. All dependent variables were assessed at baseline and after 12 weeks. Following the training period, participants completed sport-specific performance tests, including the 20 m linear sprint, countermovement jump, agilityt-test, hexagon test, and Y-balance test. On all testing days, participants were instructed to refrain from consuming alcohol or caffeine. Measurements were taken at the same time of day to ensure consistency. Additionally, participants were advised to maintain stable hydration, sleep, and nutritional levels throughout the study. 2.2. Participants Twenty-four well-trained male badminton players with a mean age of 13.5±1.15 years participated in this study (body mass 48.93±9.99 kg, body height 160.07±11.26 cm). Participants were separated by maturity offset with 12 pre-PHV and 12 post-PHV athletes. Participants had a mean training background of 4.40±1.40 years and participated, on average, in 8–10 h of badminton training per week. Each participant provided informed
Children2025,12, 830 3 of 15 consent prior to the start of the study. Those who had lower extremity, lower-back, or upper extremity muscle-related injury in the 6 months prior to the start of the study were excluded. In addition, all participants regularly in badminton training sessions. All experiments were conducted in accordance with the Declaration of Helsinki and were approved by the Institutional Review Board of Jen-Ai Hospital (approval number: IRB-108-06). 2.3. Criterion Measures Before the first testing day, all participants attended an introductory session, during which they were fully familiarized with the experimental and testing procedures. 2.4. Anthropometrics To calculate biological age, all participants were measured for chronological age, standing height, sitting height, leg length, body mass, and maturity offset (MO) during baseline testing. These variables were used to calculate the maturity offset following the formula proposed by Mirwald et al. [18]. Negative maturity offset values are defined as pre-PHV, while positive values are defined as post-PHV [19]. 2.5. 20 m Linear Sprint Test A 20 m linear sprint test was conducted using a Smartspeed Pro timing gate system (Fusion Sport, Boulder, CO, USA). In the standing position, the participants sprinted 20 m when they heard the audio cue. Three trials were performed with 2 min of rest between each. The best maximal running time was measured over 0–20 m. Acceleration was measured over 0–10 m. This test has an ICC greater than 0.9, suggesting high test–retest reliability [20]. 2.6. Countermovement Jump The participants stood on a jump mat (Smart Jump,Fusion Sport, Brisbane, Australia) with both hands placed on hips, and were instructed to perform a countermovement to a depth that would elicit the greatest jump height and maintain fully extended lower limbs throughout the flight period. The flight time was used to estimate the jump height by the formula: gt 2 /8, wherehis jump height (m),tis flight time (s), andgis the gravity acceleration (9.81 m·s −2 ) [21]. All participants performed 3 jumps, each separated by 1 min, with the height of each being recorded (centimeters). This test has an ICC greater than 0.9 [22]. 2.7. Agility t-Test
time was used to estimate the jump height by the formula: gt 2 /8, wherehis jump height (m),tis flight time (s), andgis the gravity acceleration (9.81 m·s −2 ) [21]. All participants performed 3 jumps, each separated by 1 min, with the height of each being recorded (centimeters). This test has an ICC greater than 0.9 [22]. 2.7. Agility t-Test The agilityt-test was conducted using a Smartspeed Pro timing gate system (Fusion Sport, Boulder, CO, USA). It was used to determine changes in directions such as right and left sides, forward sprinting, and back-pedaling. The agilityt-test details and procedures are detailed in Pauole et al. [23]. The test–retest reliability of this test was 0.98 [24]. Three trials were performed with a 1 min rest interval between each trial. The fastest time was recorded for data analysis. 2.8. Hexagon Test The test has been used as a measure of agility and foot quickness. The test began with the participants standing on the tape strip placed in the middle of the hexagon, facing forward in the middle of a hexagon measuring 60 cm per side and with each angle being 120 degrees. With feet together and hips facing forward throughout the test sequence, participants double-leg hopped forward and backward in a clockwise manner over each of the 6 sides of the hexagon, completing 3 sequences. This test has an ICC of 0.93 [25]. Three
Children2025,12, 830 4 of 15 trials were performed with a 1 min rest interval between each trial. The fastest time was recorded for data analysis. 2.9. Y-Balance Test (YBT) The test involved unilateral lower limb reaches in three directions: anterior (A), postero-medial (PM), and postero-lateral (PL). Participants completed three official trials in each direction. During each trial, participants kept their hands on their hips while reaching with the non-stance leg barefoot, ensuring that the stance heel remained in contact with the ground. The maximum reach distance from the three trials in each direction was recorded for analysis, and all reach distances were normalized to the participant’s leg length. A composite score (%) was calculated using the following formula: [(maximum anterior reach distance + maximum posteromedial reach distance + maximum posterolateral reach distance)/(leg length×3)]×100. The test was conducted according to a published protocol and was made nondirectional to calculate the total YBT reach asymmetry. The test–retest reliability of this test was 0.99 [26,27]. 2.10. Training Program Every training session consisted of a 10 min dynamic warm-up. After the dynamic warm-up, participants performed the integrated NMT exercise program focusing on the development of whole-body balance ability, coordination ability, lower extremity strength training, core stability training, plyometric training, acceleration, deceleration, and agility training. The 12-week training program consisted of two 40–60 min sessions per week on nonconsecutive days. The selection of exercises was based on a review of the following articles [9,28–32]. The initial 4 weeks focused primarily on skill acquisition to establish a solid training foundation and refine movement techniques. Participants were advised to maintain strong focus and awareness of their movement quality, with particular attention to core stability and the alignment of the hip and knee relative to the foot, ensuring the knee remained positioned over the toe. After the fourth week, the program will progressively increase the intensity and difficulty of the exercises (Table). (1) Balance and coordination training advanced from static to dynamic single-leg activities and incorporated unstable surfaces (e.g., BOSU balls, rocker boards). From week 5 onward, a 1 kg medicine ball was introduced to challenge postural control
the knee remained positioned over the toe. After the fourth week, the program will progressively increase the intensity and difficulty of the exercises (Table). (1) Balance and coordination training advanced from static to dynamic single-leg activities and incorporated unstable surfaces (e.g., BOSU balls, rocker boards). From week 5 onward, a 1 kg medicine ball was introduced to challenge postural control and enhance perturbation response. Badminton specificity: Single-leg balance with contralateral leg movements mimics the split stance and reactive postures used in badminton footwork recovery and lunging actions. (2) Plyometric training progressed from bilateral to unilateral drills and from low to moderate jump heights. By weeks 9–12, box and depth jumps (20 cm) were introduced. Badminton specificity: Jumping patterns (lateral, forward-backward, single-leg) replicate the explosive take-offs and landings seen during rallies, net play, and smashes. (3) Acceleration, deceleration, and agility training evolved from 4-point to 6-point directional change drills, increasing both complexity and speed. Badminton-specific footwork and ladder drills were incorporated throughout. Badminton specificity: These drills emphasize directional agility and mirror on-court movement patterns such as lunges, recovery steps, and split-step initiations. (4) Strength training began with bodyweight exercises and progressed to include Bulgarian bags loaded with 5–10% of body mass from weeks 5 to 12. Badminton specificity: Unilateral lower-limb strengthening (e.g., split squats, lunges, Romanian deadlifts) supports force production during single-leg take-offs and multidirectional changes. (5) Core stability training increased in complexity by incorporating dynamic limb movements and single-leg variations. Repetitions and movement complexity gradually progressed over 12 weeks. Badminton specificity: Rotational and unilateral core challenges replicate trunk control
Children2025,12, 830 5 of 15 demands during overhead strokes and rapid lateral movements. Coaches implementing these training programs must hold a valid professional certification in athletic or strength and conditioning coaching. Table 1.Description of the multicomponent neuromuscular training (NMT) program. Component/wk Balance, Coordination Plyometrics Training Acceleration, Deceleration, Agility Strength Training Core Stability Training 1–4 (wk) Double- and single-leg balance on unstable surfaces hold Single-leg stand on unstable surfaces with the contralateral leg balancing from 45 ◦ flexion to 45 ◦ extension Double- and single-leg heel–toe raises on unstable surfaces Double- and single-leg balance on unstable surfaces to catch the tennis ball # Each exercise was held in position for 30 s per leg. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Step hold Wall jump Tuck jump Squat jump Lateral jump and hold Bounding drills (single-leg and double-leg) # Each exercise was performed for 10 reps. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Ladder: various patterns (e.g., forward, lateral, side to side, crossover quick steps) Badminton 4-point change of direction # Each exercise was performed for 10 s. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Split squat Front lunges Backward lunge Side lunge Double-legged calf raises on step Single-legged Romanian deadlift # Each exercise was performed for 20 reps (10 each leg or side). Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Plank on elbows Side bridge Double leg bridge Abdominal crunches Back hyperextension on the ground # Each exercise was held in position for 30 s. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. 5–8 (wk) Double- and single-leg balance on unstable surfaces Double- and single-leg heel–toe raises on unstable surfaces Single-leg stand on unstable surfaces with the contralateral leg balancing from 45 ◦ flexion to 45 ◦ extension # Each exercise was held in position for
all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. 5–8 (wk) Double- and single-leg balance on unstable surfaces Double- and single-leg heel–toe raises on unstable surfaces Single-leg stand on unstable surfaces with the contralateral leg balancing from 45 ◦ flexion to 45 ◦ extension # Each exercise was held in position for 30 s per leg. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each, and was performed with a 1 kg medicine ball. Barrier jump side to side Barrier jump forward–backward Broad jump Single tuck jump with a soft landing Scissor Jumps # Each exercise was performed for 10 reps. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Ladder: various patterns (e.g., forward, lateral, side to side, crossover quick steps) Badminton 4-point change of direction # Each exercise was performed for 10 s. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Split squat Front lunge Backward lunge Side lunge Double-legged calf raises on step Single-legged Romanian deadlift # Each exercise with an additional Bulgarian bag (loaded with 5% of body mass) # Each exercise was performed for 20 reps (10 each leg or side). Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Plank on elbows, alternate 1 leg lift Plank on elbows while raising the arm and the opposite leg Side bridge while raising the arm and leg Single leg bridge # Each exercise was performed for 30 reps per leg or side. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. 9–12 (wk) Double- and single-leg front jumps on unstable surfaces Double- and single-leg lateral jumps on unstable surfaces # Each exercise was performed for 20 reps or 10 reps per leg. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each, and was
of 3 sets, resting for 1 min between each. 9–12 (wk) Double- and single-leg front jumps on unstable surfaces Double- and single-leg lateral jumps on unstable surfaces # Each exercise was performed for 20 reps or 10 reps per leg. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each, and was performed with a 1 kg medicine ball # Balance exercises using stability ball, rocker boards, bosu, and medicine ball instrumentation. Triple broad jump Single-leg triple hop Box jumps and depth jumps height of 20 cm # Each exercise was performed for 10 reps. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Ladder: various patterns (e.g., high knees, lateral quick steps) Badminton 6-point change of direction # Each exercise was performed for 10 s. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Split squat Front lunge Backward lunge Side lunge Double-legged calf raises on step Single-legged Romanian deadlift # Each exercise with an additional Bulgarian bag (loaded with 10% of body mass) # Each exercise was performed for 20 reps (10 each leg or side). Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Plank on elbows while raising the arm and the opposite leg Side bridge while raising the arm and leg Plank with Knee to opposite elbow and ups-down side Single leg hip lift # Each exercise was performed for 30 reps per leg or side. Perform all exercises as one set. Complete a total of 3 sets, resting for 1 min between each. Reps = repetitions; s = seconds. 2.11. Statistical Analyses A priori power analyses (G*Power 3.1) indicated that the minimum sample size was 10 participants, which resulted in statistical power values of 0.80 [33]. Descriptive statistics (mean and SD) were calculated for each of the variables. The homogeneity of regression assumption was tested, and the results of Levene’s test of equality indicated that the assumption of homogeneity
2.11. Statistical Analyses A priori power analyses (G*Power 3.1) indicated that the minimum sample size was 10 participants, which resulted in statistical power values of 0.80 [33]. Descriptive statistics (mean and SD) were calculated for each of the variables. The homogeneity of regression assumption was tested, and the results of Levene’s test of equality indicated that the assumption of homogeneity of variance was supported.
Description
The study evaluates the impact of NMT on physical fitness in badminton athletes.