Neuromuscular Training Improves Movement Competency and Physical Performance Measures in 1113-Year-Old Female Netball Athletes

Hopper, Amanda1; Haff, Erin E.1; Barley, Oliver R.1; Joyce, Christopher2; Lloyd, Rhodri S.3; Haff, G. Gregory1

Journal of Strength & Conditioning Research: May 2017 - Volume 31 - Issue 5 - p 1165–1176
doi: 10.1519/JSC.0000000000001794
Original Research

Abstract: Hopper, A, Haff, EE, Barley, OR, Joyce, C, Lloyd, RS, and Haff, GG. Neuromuscular training improves movement competency and physical performance measures in 11–13-year-old female netball athletes. J Strength Cond Res 31(5): 1165–1176, 2017—The purpose of this study was to examine the effects of a neuromuscular training (NMT) program on movement competency and measures of physical performance in youth female netball players. It was hypothesized that significant improvements would be found in movement competency and physical performance measures after the intervention. Twenty-three junior female netball players (age, 12.17 ± 0.94 years; height, 1.63 ± 0.08 m; weight, 51.81 ± 8.45 kg) completed a test battery before and after a 6-week training intervention. Thirteen of these athletes underwent 6 weeks of NMT, which incorporated plyometrics and resistance training. Trained athletes showed significant improvements in 20-m sprint time, 505 agility time, countermovement jump height, and peak power (p ≤ 0.05, g > 0.8). In addition, trained athletes significantly improved their score in the Netball Movement Screening Tool (NMST) (p < 0.05, g > −1.30); while the athletes also demonstrated increased reach in the anterior and posteromedial directions for the right leg and left leg, and in the posterolateral direction for the left leg only in the Star Excursion Balance Test (SEBT) (p < 0.05, g > −0.03). Control subjects did not exhibit any significant changes during the 6-week period. Significant negative correlations were found between improved score on the NMST and decreased 5-, 10-, and 20-m sprint time, and 505 change of direction time (r > 0.4, p ≤ 0.05). Results of the study affirm the hypothesis that a 6-week NMT intervention can improve performance and movement competency in youth netball players.

1Center for Exercise and Sport Science Research, Edith Cowan University, Joondalup, Western Australia, Australia;

2School of Health Sciences, Notre Dame University, Fremantle, Western Australia, Australia; and

3Youth Physical Development Unit, Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, Wales, United Kingdom

Address correspondence to G. Gregory Haff, g.haff@ecu.edu.au.

Article Outline
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Introduction

Neuromuscular training (NMT) programs have been shown to improve physical performance measures and reduce injury risk in youth and adolescent athletes (27,28). Typically, NMT combines fundamental movement skill training with strength and conditioning activities, such as resistance training and plyometric training (28) to improve dynamic joint stability, enhance movement patterns and skills, improve neuromuscular control and increase strength (27). Research has shown that NMT may be particularly important for child and adolescent female athletes as they consistently show decreased levels of strength, power and performance indices, and increases in injury risk in comparison with males (12,26,27). One sport that may benefit from the incorporation of NMT is netball. The sport requires athletes to possess high levels of speed, agility, upper and lower-body strength and power, movement competency, and anaerobic and aerobic endurance (5,8). Netball is also commonly associated with a high incidence of lower limb injuries (11), and is one of the top 5 sports associated with sporting injuries in Australian children (39).

Several studies have shown that NMT programs are effective in improving physical performance measures in youth populations (10,27,29). Myer et al. (27) report that after a 6-week NMT program, 14–16-year-old female athletes across 3 different sports significantly improved sprint time, vertical jump performance, and squat and bench press 1-repetition maximums. Similarly, another study reported that after the completion of an 8-week NMT program by grade 2 children, significant improvements were found in push-ups, curl ups, long jump, single leg hop, and running performance (10). In addition, Noyes et al. (29) report significant improvements in vertical jumping performance after 6 weeks of NMT undertaken by 14–17-year-old female basketball players (29). The well-documented improvements in performance of basketball (29) and volleyball (27) athletes suggest that similar results may be found with netball athletes of a similar age owing to similarities in physical and movement demands inherent to both sports.

Careful inspection of the scientific literature reveals that female athletes are at a higher risk of sports-related injury in comparison with males (14,27). One possible explanation for this discrepancy is the decreased neuromuscular control females experience after maturation (15). Poor neuromuscular control can lead to poor movement patterns and predispose female athletes to an increased risk of injury (14,23). Movement screening tools are commonly performed to assess movement capabilities, identify musculoskeletal and strength deficits, and predict potential injury risk in athletes (33). The Netball Movement Screening Tool (NMST) was developed specifically to replicate the movement patterns pertinent to netball to identify injury risk (33). The screen incorporates 4 components (a) the Movement Competency Screen (MCS), (b) jump components, (c) the Star Excursion Balance Test (SEBT), and (d) the active straight leg raise (ASLR). Although various movement screens were developed to assess an athlete's risk of injury (33,38), recent research suggests that they may be largely ineffective in predicting injury (1). For example, a recent meta-analysis on movement screens suggests that the Functional Movement Screen (FMS) may not be predictive of injury risk in active adults (9). Although there may be limited utility of movement screens for prediction of injury, there is evidence to suggest that movement screens such as the FMS may have a relationship to performance measures in adolescent athletes. For example, Lloyd et al. (23) revealed significant relationships between FMS scores, reactive agility, and reactive strength index intraclass correlation coefficient alpha (ICCα = 0.4–0.7) in 11–16-year-old male soccer athletes. Furthermore, another study found that younger than 16-year-old rugby union players who scored lower on a movement screen had slower sprint times, scored lower on the Yo-Yo test, and jumped lower in a vertical jumping task (31), thus indicating movement competency could be related to performance in youth populations.

Research shows that movement competency can be enhanced after exposure to NMT interventions; for example, Klusemann et al. (18) conducted a 6-week fully supervised resistance training program to junior basketball athletes, which resulted in improvements in FMS scores. In addition, there were improvements in countermovement jump (CMJ) and agility performance after the 6-week training period (18). These findings suggest that when junior athletes engage in supervised training, significant improvements in movement competency and markers of sports performance capacity can occur simultaneously. Similarly, McLoad et al. (25) conducted a 6-week NMT program for high school female basketball players, which resulted in a significant decrease in errors in the Balance Error Scoring System (BESS) as well as significant improvements in the SEBT. Improvements in balance and stability could potentially lead to improved athletic performance and reduced injury risk (25). As in basketball, balance and stability are also particularly important in netball because of the foot work rule of the game requiring athletes to decelerate, stabilize, and balance when receiving the ball to avoid a step violation (40).

Therefore, the aim of this study was to determine whether NMT was effective in improving physical performance indices and movement competency in female youth netball players. Based on previous research (10,18,25,27,29), it is hypothesized that the training intervention will increase sprinting speed and agility, improve vertical jumping height, and improve movement competency scores in junior netball players.

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Methods

Experimental Approach to the Problem

This study used a 6-week NMT program comprising 3 training sessions per week completed on nonconsecutive days, lasting approximately 60 minutes. All participants partook in a 1-week familiarization program before undertaking baseline testing. After baseline testing, participants were randomly assigned into either an experimental or control group (CG). After the 6-week intervention, all subjects completed the after testing sessions. The CG only participated in the baseline and after intervention testing sessions and undertook no NMT intervention during the course of the study. All participants were instructed to continue with their normal netball training and games throughout the data collection period. All participants had their sprinting and change of direction speed, CMJ, and NMST performance assessed. A summary of the testing schedule is presented in Figure 1.

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Subjects

A total of 23 junior female netball players (age, 12.17 ± 0.94 years; height, 1.63 ± 0.08 m; weight, 51.81 ± 8.45 kg) with no NMT experience were recruited to participate in the study. Age, height, and weight data across participants are presented in Table 1, with no significant differences found between control and experimental groups (EGs) between the baseline or after testing sessions (p > 0.05). Participants were selected on the following criteria; currently participating in competitive netball, no previous history of lower limb injuries, and no history of resistance training. Written parental consent and participant assent were provided before initiating the study in accordance with the Edith Cowan University Human Research Ethics Committee guidelines.

All participants completed a modified Pubertal Maturation Observational Scale (PMOS) that is used to classify participants into maturational categories: prepubertal, midpubertal, and postpubertal as previously used in the literature (15). All participants completed the Physical Activity Readiness Questionnaire (PAR-Q) before commencement of the study. Finally, participants were randomly divided into either the EG (n = 13) or CG (n = 10). Analysis of the PMOS revealed that there was no significant difference in maturational categories between the EG and CG (p > 0.05).

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Testing Procedures

Height was measured to the nearest 0.1 cm with the use of a stadiometer (ECOMED; New South Wales, Australia), whereas weight was measured to the nearest 0.1 kg on an electronic scale (Tanita Australia Inc., Kewdale, Western Australia, Australia). Both sessions also included a battery of performance and movement competency tests. Countermovement jump, 20-m sprint, and 505 netball agility tests were used to assess the athlete's neuromuscular performance, and the NMST was used to assess the participant's movement competency. The order of testing was constant for both testing sessions with the movement competency testing occurring first, followed by the physical performance measures.

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Countermovement Jump Test

The participant's CMJ height (centimeter) was measured using a Vertec (Yardstick II; SWIFT, Queensland, Australia). Participants performed a CMJ in accordance with the procedures outlined by Nuzzo et al. (30). Participants were instructed to take-off from a self-selected jump stance and jump for maximum height. Participants were given 3 warm-up trials, followed by 3 maximal effort trials with a 60-second intertrial rest interval (32). The highest vertical jump obtained was used for analysis.

The vertical displacements determined in this study were used to estimate a peak power value with the use of the Sayer et al. (36) equation:

This equation was selected because it has previously been shown to be an accurate estimator of peak power output during vertical jumping (13,36).

The validity of the Vertec as a tool for determining vertical jump displacement has previously been reported to be a valid tool for the assessment of anaerobic power (4,16,20,30). The reliability of the assessment of vertical jump displacement using the Vertec has previously been reported to be excellent (ICCα = 0.94) (30). Analysis of vertical jumping scores in this study demonstrated a high degree of reliability as indicated by an ICCα = 0.89.

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Twenty-meter Sprint Test

Sprinting speed (seconds) was assessed using the 20-m sprint test as outlined by Netball Australia guidelines for testing netball athletes (42). Wireless infrared timing gates (Swift, QLD) were set at distances of 5, 10, and 20 m and used to record the athletes' velocity and ability to accelerate from a static position. Participants performed 3 warm-up sprints at 50, 70, and 90% respectively. Participants then performed 2 maximal effort sprints. All sprint trials were separated by a 2-minute rest period to ensure that the participants had adequate recovery between sprints, as recommended by the national netball protocols (42). Only the fastest 20-m sprint time was used for analysis. Five-meter, 10-, and 20-m sprint time and sprint velocity were recorded for analysis. Previous authors have shown high reliability of using infrared timing gates to assess sprint speed (coefficient of variation [CV] = 1.00–1.13%) (44). Analysis of 20-m sprint scores in this study demonstrated excellent reliability (ICCα = 0.97).

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505 Agility Test

The 505 agility test was used to assess the participants' ability to decelerate, change direction, and accelerate as outlined by Netball Australia (42). A distance of 15 m was measured with distances of 0 and 15 m marked with masking tape and cones as directed by the national netball protocols (42). Wireless infrared timing gates (SWIFT) were used to quantify the change of direction speed (seconds) of each athlete. Athletes were instructed to perform the change of direction element of the test with the preferred foot (42). All participants completed 2 warm-up trials at 50 and 70% of maximal effort. Participants then completed 3 maximal effort trials with the fastest time being recorded for analysis. All 5-0-5 change of direction trials were separated by 2 minutes to ensure adequate recovery and maximize performance (42). Previous authors have reported high reliability and good within-subject variation of the 505 agility test with CV values ranging from 1.95 to 2.40% (41). The reliability of the 505 agility test has also previously been examined in netball players; results revealing ICCα of 0.96–0.97 for the stationary start (2). Analysis of 505 scores for this study showed similarly high between-trial reliability (ICCα of 0.92).

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Netball Movement Screening Tool

All participants were screened with the NMST (33). This screening tool consists of 4 components, (a) the MCS consisting of 5 tests: bodyweight squat, lunge and twist, bend and pull, single leg squat, and push-up; (b) Jump components composed of 3 jump tests; CMJ, CMJ with a single leg landing, and a broad jump with a single leg landing; (c) the Star Excursion Balance Test (SEBT) assessed anteriorly, posteromedially, and postereolaterally; and (d) the ASLR. These tests were chosen as they reflect movement patterns relevant to netball (33). All components of the NMST were video recorded using a standard 2-dimensional camera (HDR-XR260VE; Sony, North Sydney, Australia), with the participants observed from the frontal and sagittal planes.

Each participant completed 6 repetitions of each of the MCS, jump component tests, and SEBT in all directions; 3 repetitions on each leg were completed for the ASLR as previously used in the literature (33). Screening was completed by qualified strength and conditioning coaches with extensive experience in movement screening youth athletes. Scoring occurred retrospectively and was conducted in the same manner described by Reid et al. (33). Specifically, the MCS, jump components, and ASLR were scored out of 33, and the SEBT was scored separately (33). Two scorers were used to assess the participants' MCS and jump components to ensure reliability in scoring and avoid interobserver bias; with the agreement between 2 scorers assessed using the weighted kappa statistic (19), whereby a score of above 0.81 was considered almost perfect, 0.61–0.80 substantial agreement, 0.41–0.60 moderate agreement, and below 0.40 poor agreement (33), reliability of this movement-screening tool has previously been quantified in the literature demonstrating excellent interrater (ICCα = 0.84) and intrarater (ICCα = 0.96) reliability (33). Analysis of SEBT scores for this study showed excellent between-trial reliability across all directions (ICCα ≥ 0.93).

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Neuromuscular Training Program

The EG trained 3 times per week on nonconsecutive days for approximately 1 hour. All familiarization and training sessions were initiated with the use of a standardized 10-minute dynamic warm-up (Table 2), followed by plyometric exercises, strength training, and finishing with static stretching. All participants went through a comprehensive 1-week familiarization period to ensure familiarity with the types of resistance training and plyometric exercises that were used in the NMT (Table 3). The NMT program composed of 2, 3 week blocks (Table 4 and 5), in which the movement pattern remained the same but the volume and exercise complexity were increased in the second block. Exercises in the strength training sections used barbells, medicine balls, and resistance bands. Warm-up sets of each exercise were completed starting with the lowest weight and incrementally increasing by 1.25-, 2.5-, or 5-kg until working weight was reached, with technical competency prioritized at all times. As the participants increased weight over the 6-week period, more warm-up sets were required.

The OMNI rating of perceived exhaustion (RPE) was used to measure RPE during the strength exercises to determine the training intensity for each session. Specifically, the load lifted was modulated to achieve the prescribed RPE as well as at the discretion of the strength and conditioning coach to insure technical competency. Participants were explained how to use the scale to describe the level of difficulty the exercise exhibits as outlined by Robertson et al. (34). Before the session, participants were given an RPE goal for the session (Table 6), and load was adjusted in accordance with the prescribed RPE. All training sessions were monitored by accredited strength and conditioning coaches (Australian Strength and Conditioning Association) and a certified strength and conditioning specialist (CSCS) to ensure that all exercises were performed safely. If the technique was deemed to be unsafe, appropriate modifications to the training load were made.

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Statistical Analyses

Descriptive statistics were reported for all performance and anthropometric tests. A 2 × 2 (group × time) repeated measures analysis of variance (ANOVA) was used to compare pretest and posttest values for the control and training groups. If significant F values were determined, paired comparisons combined with a Holm's sequential Bonferroni post hoc adjustment were performed to account for type I errors to determine differences. Raw difference scores (postbaseline) were compared with the use of a 1-way ANOVA. Pearson's product moment correlation coefficient was used to determine the relationship between selected variables. Statistical significance was set at p < 0.05. Effect sizes were calculated as Hedges g, because it corrects for small sample biases (7). Effect sizes were considered as trivial, <0.20; small, 0.20–0.50; medium, 0.50–0.8; large, 0.8–1.30; and very large, >1.30 (37). All effect sizes were calculated with 95% confidence intervals (CIs). Intraclass correlation coefficient alpha was calculated to measure between-trial reliability across all measures (17) and were interpreted as follows; ICCα ≤ 0.20 poor, ICCα = 0.21–0.40 fair, ICCα = 0.41–0.60 moderate, ICCα = 0.61–0.80 substantial, and ICCα = 0.81–1.00 almost perfect. All statistical analyses were conducted using SPSS (SPSS 23.0.0.0; SPSS Inc., Chicago, IL, USA).

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Results

Twenty-meter Sprint Test

When comparing baseline versus postintervention data, there were significant group × time interactions for 10- and 20-m sprint (p ≤ 0.05) performances. Conversely, there were no significant group × time interactions for 5-m sprint performance (p > 0.05). Based on post hoc analyses, the EG demonstrated large and significant decreases in 10- and 20-m sprint times (p ≤ 0.05, g > −1.2) (Figure 2) in response to the 6-week NMT program.

Similarly, there were no significant group × time interactions for the 5-m sprint velocity (p > 0.05); however there were significant group × time interactions for the 10- and 20-m sprint velocities (p > 0.05). When raw difference scores were examined, the EG demonstrated a significant and large increase in sprint velocity over 10- and 20-m sprint times (p > 0.05, g > 1.20) (Figure 3).

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505 Agility

There was a significant group × time interaction when examining the impact of the experimental and CGs on the 505 change of direction results (p < 0.001). Post hoc analysis revealed that the EG largely and significantly reduced their 505 sprint time (p > 0.05, g = −0.98; 95% CI −1.85 to −0.10), whereas the CG displayed an increase in their times (Figure 4).

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Countermovement Jump Height

When examining the impact of the NMT program on vertical jump performance, there was a significant main effect for time with both groups increasing jump height after the 6-week intervention (p < 0.05). There were no significant group × time effects (p > 0.05). However, when examining raw difference scores, the EG demonstrated a significant and large 0.04-m increase in their vertical jumping height after the 6-week training intervention (p ≤ 0.05, g = 0.84; 95% CI −0.01 to 1.70), whereas the CG only displayed a 0.01 m increase (Figure 5).

Results of the peak power values obtained showed a significant main effect for time (p < 0.001) with both groups increasing peak power after the intervention. Data also revealed a significant group × time interaction, with the EG significantly and largely improving their peak power values after the intervention in comparison with the CG (p < 0.05; g = 1.68; 95% CI = 0.72–2.64).

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The Netball Movement Screening Tool

Kappa scores for each individual test demonstrated substantial to almost perfect agreement between the 2 scorers (K = 0.61–0.99). When comparing the effect of the NMT, intervention on the NMST inclusive of the MCS, jump components, and ASLR, there was a significant group × time interaction (p < 0.001). When examining raw difference scores, the EG displayed a significant and very large improvement in their total NMST score (p < 0.001, g = −2.70; 95% CI = −3.84 to −1.57) (Figure 6 and Table 7).

Raw difference scores on the NMST correlated with the change scores for the 5 m (r = −0.41, p ≤ 0.05), 10 m (r = −0.49, p ≤ 0.05), 20-m sprint times (r = −0.57, p ≤ 0.01), and 505 change of direction time (r = 0.428, p ≤ 0.05). No significant correlations were found between the NMST and vertical jumping height (p ≤ 0.05).

Results of the SEBT showed a significant group × time interaction for the anterior reach and posteromedial reach position for both the right and left legs (p ≤ 0.05). Follow-up tests revealed that the EG anterior and posteromedial reach was significantly further than the CG for both the right and left legs (p ≤ 0.05). Conversely, no significant group × time interaction was found for the posterolateral reach direction for the right leg (p > 0.05). However, a significant group × time interaction was found for the left leg (p ≤ 0.05). Follow-up tests revealed that the EG significantly improved their reach in the posterolateral direction for their left leg only (p ≤ 0.05), whereas the CG decreased their reach (Table 8).

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Discussion

The main findings of this study were that the 6-week NMT intervention significantly improved sprint and change of direction speed, CMJ height and peak, and movement competency in 11–14-year-old netball players. The CG did not show any significant improvements in any of the physical performance measures or movement competency assessments during the course of the 6-week intervention.

After the completion of the 6-week NMT program, data revealed that the EG performed significantly better than the CG in all physical performance tests. Although the EG decreased their sprint time in response to the training, the CG became significantly slower across the 5, 10, and 20 m distances as noted by the increase in sprint time and decrease in sprint velocity. Although there was no statistical difference in 5-m sprint time, it should be acknowledged that the EG maintained their 5 m sprinting speed after the intervention. These findings are consistent with the work by Myer et al. (27) who reported that adolescent female athletes improved their sprint times in the 9.1 m sprint by 0.07 seconds after a 6-week NMT intervention. A meta-analysis by Rumpf et al. (35) found that plyometric training was the superior training method in improving sprint time in pre- and mid-pubertal male youth, whereas postpubertal males benefited from a combined training method. However, after puberty, sex-differences in muscular strength begin to emerge, with males experiencing natural increases in muscular power, strength, and coordination that are not commonly seen in females (24). Furthermore, the loss of neuromuscular control females experience after puberty (15) may indicate the need for an integrative NMT program inclusive of strength training and plyometric training to improve performance. Results of this study shows that the inclusion of strength training exercises to improve lower-body strength and power may be an important component of improving sprinting performance in youth female athletes. The NMT program used in the study by Myer et al. (27) incorporated strength training exercises as part of the integrated NMT program (i.e., plyometrics, balance, and strength training). The strength training program incorporated back squats, bench presses, lateral pull-downs, shoulder presses, Russian hamstring curls, and various isolation exercises, which were similar to the strength training exercises used in this study. Taken collectively, the work by Myer et al. (1) and the data from this study seem to suggest that strength training, which targets the lower body is an important component of an NMT program that is designed to improve performance in untrained female athletes.

After the NMT program, both the experimental (+0.04 m) and CGs (+0.01 m) improved their vertical jump; however, the EG made a much larger and significantly greater improvement. This finding is in agreement with the work by Myer et al. (27) who reported that adolescent female athletes were able to improve their vertical jump by 0.03 m in response to a 6-week NMT program. Similarly, Chappell et al. (6) found a 0.04 m improvement in vertical jump after an NMT program in college-aged female athletes. Both of these studies incorporated a combination of balance, resistance and plyometric exercises. A key component of the NMT program outlined by Myer et al. (27) is that the resistance training exercises used were all executed under load. Similarly, this study also used a combination of plyometric and resistance training exercises which were performed under load. Based on the work by Myer et al. (27) and the data from this study, it seems that NMT programs which use progressive overload are more effective at improving performance and movement competency as a result of systematically increasing strength levels. It is important to note that Lesinski et al. (21) recently reported that youth athletes exhibit the greatest strength improvements in response to higher training intensities when movement quality and technical competency is upheld. Therefore, the inclusion of a progressive resistance training program to an NMT program may be imperative to improve jumping performance in youth athletes. The data collected in this study reveal that the CG also displayed a small improvement in vertical jump performance (+0.01 m), although this was not statistically significant. One possible explanation for this finding is that all participants were participating in regular netball training throughout the study. As playing netball would require some jumping performance during games and practice, it is likely that this may have contributed to the improvement in vertical jump of 0.01 m over the 6 weeks in the CG. However, results of this study indicate that the inclusion of the NMT program resulted in superior vertical jump improvements when compared with netball training alone, thus suggesting that youth netball players should incorporate NMT as part of their performance programs.

When examining the 5-0-5 change of direction test, the EG was able to largely and significantly decrease their change of direction time after the 6-week NMT intervention, whereas the CG increased their change of direction time. These findings agree with previous research that found youth male soccer athletes were able to significantly decrease their change of direction time after completing a plyometric training program (43). The NMT program used in this study incorporated a small plyometric component with a larger emphasis on resistance training, indicating that the improvements in change of direction speed may have been a combination of both the plyometric and resistance training. Change of direction speed is largely affected by sprinting speed, movement efficiency, and muscular strength (21). The NMT program in this study included resistance training exercises to improve lower-body strength and power with a focus on movement quality and technical efficiency. This may indicate that resistance training may play a bigger role in improving speed than plyometric training in youth female netball athletes.

After completion of the NMT program, the EG significantly improved their score on the NMST and had a significant increase on their dynamic balance reach distance in the 2 SEBT directions. These results are in accordance with the findings of Klusemann et al. (18) who found that after a resistance training program, junior basketball athletes were able to improve their FMS scores. Based on the work by Klusemann et al. (18) and the data from this study, it seems that when youth athletes exhibit movement deficiencies, the incorporation of an NMT program that includes resistance training seems to be a valuable tool for improving movement competency, which may directly impact performance. Lloyd et al. (23) investigated if a relationship exists between FMS scores and physical performance in youth male soccer athletes. Their findings showed moderate-to-strong (r = 0.4–0.7) correlations between the individual components of the FMS and measures of physical performance inclusive of jumping height, agility, and reactive strength index. Results of this study affirm that a strong correlation exists between movement competency, sprinting, and change of direction speed in youth female netball athletes. Strong negative correlations were found between improved scores on the NMST and decreased times in the 5-, 10-, and 20-m sprint, and 5-0-5 change of direction task. Based on these findings, it seems that an NMT program that focuses on improving movement competency may be associated with improved performance capacity in youth netball athletes. Furthermore, the NMST may be a useful test to predict physical performance capabilities in youth female netball athletes.

The NMST was created specifically to replicate the movement patterns evident in netball and as such included a specific jump component. When examining the jump scores independently, the EG improved their score, whereas the CG decreased their score. These results indicate the NMT program was effective in improving jumping and landing efficiency in youth netball athletes. This improvement in jumping and landing quality may be due to improved motor performance because of neural adaptations from the NMT program. A meta-analysis by Behringer et al. (3) showed that resistance training is a very effective tool for improving motor performance in youth athletes. Specifically, children made greater gains in motor skill performance in comparison with adolescents. Similarly, McLoad et al. (25) also found that after a 6-week NMT program, high school female athletes were able to significantly improve their reach distance on the SEBT. The NMT program used by McLoad et al. (25) placed a large emphasis on strengthening exercises, while also incorporating plyometric, agility, and balance training. This study did not incorporate any specific balance training as part of the NMT program, indicating that the strength components and plyometric training alone were enough to improve dynamic balance without inclusion of specific balance exercises. Thereby, the inclusion of resistance training exercises to improve full body strength seems to be a very important component of NMT programs. Properly designed and implemented NMT programs that focus on improving movement efficiency, motor coordination and neuromuscular control, and thus performance measures are paramount to successful performance netball practice and competition.

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Practical Applications

Netball is a game reliant on rapid acceleration, deceleration, and change of direction in combination with short bouts of sprinting, lateral movements, jumping, landing, lunging, and leaping movements. The game is high intensity in nature and requires athletes to possess among other physical qualities, lower-body power, sprinting, change of direction speed, and strength and technical competency. Completion of an integrative NMT program is important for their athletic development to prepare them for the high-intensity nature of the game and to improve performance in netball practice and competition. This study suggests that acute beneficial adaptations (6 weeks) in CMJ height and peak power output during jumping, sprinting performance, change of direction speed, and movement efficiency in youth female netball athletes were elicited through an NMT program that used progressive resistance training in combination with plyometric training 3 times per week. Because of the decrease in neuromuscular control in female athletes after puberty and heightened injury risk, this training study may also decrease the potential for injury risk in netball by improving neuromuscular control, motor coordination, and dynamic joint stability as indicated by the improvements in the movement screen performed in this study. Given the short-term nature of this study, practitioners are advised that to facilitate long-term adaptation, systematic changes in training prescription are required ideally as part of a long-term athletic development plan (22).

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Acknowledgments

The authors wish to thank the coaches, players, and parents from the clubs involved in the data collection and Carl Woods for his assistance with the movement screen methodology. The results of this study do not constitute and endorsement by the authors or the National Strength and Conditioning Association.

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Keywords:

strength training; resistance training; sport; injury prevention

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