Sports training is one of the most outstanding fields that has undergone remarkable scientific development in recent decades as a result of the systematic integration between various movement sciences, especially physiology, biomechanics and motor learning, since this integration has contributed to deepening the understanding of the mechanisms of sports performance and the precise analysis of its neurological components. muscular and mechanical, with the aim of achieving the highest levels of achievement. The throwing events in the Iraqi Athletics Federation are those that require a high level of neuromuscular organization, due to their explosive kinetic nature that is based on the transfer of force through a continuous chain of movement that starts from the lower limbs, through the torso to the upper limb. especially the shoulder joint as a key axis to direct the final force and precision of performance. The advanced achievement in the effectiveness of gravity bending is not achieved randomly, but is based on scientific training programs that take into account the age characteristics of young people and work to develop their physical and skill capacities according to correct biomechanical fundamentals, which ensure saving effort and increasing performance effectiveness. Therefore, the importance of neuromuscular synergy exercises has emerged as a training technique that seeks to improve coordination between the central nervous system and the muscular system, improving the efficiency of neural excitation, synchronizing the contraction of the working and corresponding muscles, and reducing unnecessary activity of the countermuscles. which leads to greater motor fluidity and the sequence of force production. The regulation of muscle electrical activity, which is normally measured by neuromuscular activity indicators, reflects the efficiency of nerve recruitment and the number of motor units involved in performance, which is directly related to important biomechanical characteristics such as the speed of launching the tool, the angles of the joints at the time of release, the moment of application of the force and the trajectory of movement. It improves the stability of the shoulder joint during performance, reducing the likelihood of injury and increasing performance efficiency. The scientific planning of training at this stage is not limited to the development of the elements of strength and speed separately, but also focuses on integrating them into a functional kinetic context that simulates the requirements of competitive performance and in line with the optimal biomechanical properties of weight bearing. From this point of view, the importance of the research lies in studying the efficacy of neuromuscular synergy exercises to regulate the electrical activity of the shoulder muscles, and to analyze the reflection of this in some biomechanical variables and the level of achievement among juniors, with the aim of supporting coaches with scientific foundations that contribute to the development of training programs and the improvement of the level of performance according to precise objective foundations.

Research Problem 

Despite the great scientific progress in modern methods of sports training, especially in the field of integration between neurological, muscular and biomechanical aspects, the adoption of neuromuscular synergy exercises in the training of junior weightlifting athletes remains limited, as the researcher points out that there is a traditional approach to the development of strength elements in general without sufficient attention to regulating electrical activity of the working muscles, especially the shoulder muscles, which are a key axis for producing and directing the final force during the pushing phase. Through field experience in shooting events, a relatively low level of digital achievement was observed among juniors, as well as a clear gap between local levels and their global counterparts, indicating that there is a deficiency in some physical and functional variables related to performance specificity.

Research Objectives 

• Preparing neuromuscular coordination exercises for the shoulder muscles among junior shot putters

• Identifying the impact of neuromuscular coordination exercises in regulating the electrical activity of the working shoulder muscles during performance

• Revealing the reflection of regulating the electrical activity of muscles on some biomechanical characteristics of technical performance

• Identifying the effect of neuromuscular coordination exercises in developing the level of shot put achievement among juniors

Research Hypotheses 

• There are statistically significant differences between the pre- and post-tests in the electromyography indicators of the shoulder muscles among the experimental group members, in favor of the post-tests

• There are statistically significant differences between the pre- and post-tests in some biomechanical characteristics of technical performance

• There are statistically significant differences between the pre- and post-tests in the level of shot put achievement among juniors, in favor of the post-tests

Research Approach

The researcher adopted the experimental approach for its suitability to the nature of the research problem and its objectives, by using the one-group design with pre- and post-measurements, as it is one of the appropriate designs to study the effect of the independent variable in causing change in the dependent variables within a specific sample [1-3]. The research sample was selected from junior shot putters, and they were subjected to pre-measurements that included electromyography indicators of the working shoulder muscles during performance, and some biomechanical characteristics related to the push phase, in addition to measuring the digital achievement level.

Research Sample

The research sample chosen by the researcher included junior shot putters under the age of 17 years, who are regular in training, totaling 6 players, as the sample represented 100% of the original population for this category. They were selected purposively for their consistency with the research requirements in terms of training age and regularity in training units. For the purpose of ensuring the homogeneity of the sample and verifying the condition of normal distribution in the variables under study, the researcher used the skewness coefficient to test the normality of the distribution, as the values falling within the statistically acceptable limits were considered an indicator that the sample is characterized by a normal distribution, as shown in Table 1, which allows the adoption of appropriate statistical treatments to extract results accurately and objectively.

Table 1: Shows the Homogeneity of the Research Sample 

Methods of Data Collection, Devices, and Tools Used in the Research

Methods of Data Collection: (Scientific studies, research, and reports, publications of championship results issued by the International Association of Athletics Federations, technical observation and experimentation, personal interviews, tests, and measurements).

Tools Used in the Research

• Two Japanese-made Casio cameras, with a speed of (240 frames/second) to record movement and analyze biomechanical characteristics during pushing

• Two camera tripods to ensure recording stability

• Weights in the form of belts with different weights (100 g - 1 kg) to apply graduated strength training during neuromuscular coordination

• Four (4) wooden boxes with dimensions (70 cm width × 3 m length × 5 cm height) and inclined at a (15°) angle to design specialized training units

• Phosphorescent markers to define reference points for analyzing the movement of the shoulder and pushing arm

• A metal measuring tape with a length of (20 m)

• Two manual stopwatches and a whistle to organize training times and time intervals

• A Japanese-made Elacta electronic scale to measure the athletes' mass

• A Chinese-made Lenovo 310 laptop computer for data analysis and processing of results

• Electrodes

• Six (6) stabilizing cases to secure the electrodes on the shoulder muscles during training

• Medical alcohol and cotton for cleaning and sterilization

• Ten (10) shot put balls with a legal weight (5 kg) designated for juniors, to be used in training units and measuring the achievement level

Devices Used in the Tests

Dynafoot Device: The Dynafoot is an electronic foot scanner made in France that is one of the modern scientific devices used in sports biomechanics laboratories to analyze the motor performance of athletes. The device consists of several components, including: soles, pressure sensor technology, shock sensor technology, data transmission, power supply, computer communication, and 10m Bluetooth range.

        To obtain accurate data during weight training, the device requires the athlete to enter some basic data before starting the test, including name, age, weight and shoe size, to ensure accurate measurements while moving. After completing the test, the device extracts a number of important biomechanical variables, such as the force applied to the feet, the instantaneous time of pushing, as well as the measurement of the pressure applied to each part of the foot and the period of time from the start of the first foot contact to the end of the pushing phase.

Field Research Procedures

Some Tests Specific to the Shot Put: After reviewing numerous scientific sources, similar previous studies, and taking the opinions of experts in the field of athletics biomechanics, some tests were determined: 

Shot Put Achievement Test (https://www.iaaf.org/home)

• Test Objective: Measuring the best horizontal distance of the shot (achievement)

• Performance Description: The thrower throws the implement within the designated throwing sector, and the player is given 3 attempts per thrower, and the best distance achieved from the 3 attempts is selected

Measurement of Some Biomechanical Variables

All biomechanical variables (the moment of the throw and throw), including instantaneous force, the moment of the correct man, the moment of the push, the instantaneous force, the moment of the throw, the moment of releasing the weight, the instantaneous and momentary moment of the man with the right foot, and the velocity of the throw were extracted from gravity by using the Kinovea analysis software and the dynafoot device.

Exploratory Experiment

The exploratory experiment was conducted for the purpose of verifying the working efficiency of the Dynafoot device on 3/1/2025 at 2:00 PM in the stadium of the College of Physical Education and Sports Sciences in Baghdad, on one player from the research sample. This experiment aimed at several aspects related to analyzing biomechanical performance and the effect of neuromuscular coordination exercises on the electrical activity of the shoulder muscles and the level of shot put achievement among juniors.

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Pre-Tests

After completing the exploratory experiment and addressing all the obstacles and difficulties that appeared during it, the two researchers conducted the pre-tests for the sample members, which began on 4/1/2025. The prepared tests were applied to all six throwers included in the sample, where each thrower was given three attempts to perform the shot put according to the training protocol, and the best achievement for each player was selected to be used in the statistical analysis processes, which ensures the accuracy of the results and the objectivity of evaluating the effect of neuromuscular coordination exercises on the electrical activity of the shoulder muscles, biomechanical characteristics, and the achievement level among juniors.

Main Experiment

The researcher adopted the prepared training methodology and applied it to the research sample during the special preparation period for sample members on 5/1/2025 at the stadium of the College of Physical Education for Sports Sciences in Baghdad, where the training curriculum included the sample and use of the prepared exercises.

The Training Curriculum and Exercises Used in the Research

The training curriculum specific to the study was prepared after reviewing specialized scientific sources and consulting experts in the field of sports training and biomechanics, aiming to develop neuromuscular coordination exercises to ensure improving the regulation of the electrical activity of shoulder muscles and enhancing biomechanical characteristics during the shot put among juniors. The main part of the training unit took a duration ranging between 50–60 minutes, excluding the warm-up time; the application of the proposed curriculum continued for 12 weeks, adhering to the fundamental training principle based on the gradual increase of the training load in the units, by controlling the intensity, rest, and volume, and adopting the principle of variation to ensure the effectiveness of the prepared exercises. The training plan consisted of 36 training units, during which the focus was on the main part of the unit for three days a week, with exercises dedicated to enhancing instantaneous power and speed-strength. The practical exercises according to the proposed curriculum included the following: 

• Muscle Strength Exercises: Performing light weight-lifting exercises to strengthen the working muscles during pushing, while weighting the arms with 3% of the relative weight, starting with pushing from a stationary position, then moving to pushing with sequential steps to enhance muscular coordination and kinetic fluidity

• Exercises for Transferring Force from the Lower to Upper Limbs: Executing throws on a wooden box inclined at a 15° angle and with dimensions (70 cm width × 3 m length), while weighting the legs with 3% of the weight to enhance the transfer of force from the lower limbs to the shoulder and arm

• Implement Exercises Specific to the Shot Put: Practicing throwing using the shot put implement (5 kg) with a focus on the correct kinetic sequence and joint angles, to achieve the maximum possible force within the optimal biomechanical characteristics

• Develop Neuromuscular Synergy: Perform the movements first slowly to teach the correct contractions, then gradually accelerate to improve coordination between the working and auxiliary muscles during the throw

• Monitoring Performance Time and Force Distribution: Controlling the application time and performance speed, while monitoring force distribution on the feet and shoulder to ensure efficient energy transfer from the bottom upwards and achieving the best digital achievement.

        The curriculum relies on measuring the maximum intensity for each player to determine training load levels, with the application of the variable intensity training method between high and low within the units to ensure a gradual development in strength and muscular coordination, which enhances the effectiveness of the exercises on the electrical activity of muscles, biomechanical characteristics, and the achievement level among juniors.

Post-Tests

After completing the application of the training program to the sample, the researcher conducted the post-tests for the sample members on 15/3/2021, and the two researchers were keen on providing the same conditions in which the pre-tests were conducted in terms of place, time, tools, method of test execution, and score calculation, and with the presence of the same auxiliary team from the pre-tests.

Statistical Methods

The researchers used the Statistical Package for the Social Sciences (SPSS) system [4-8].

Presentation, Analysis, and Discussion of Results: 

Presentation of the Results of Differences in Some Biomechanical Variables and Shot Put Achievement for the Pre- and Post-Tests: Table 2 Shows the statistical parameters of the results of differences in some biomechanical variables and shot put achievement for the pre- and post-tests among the members of the research sample Degree of Freedom = 5.

The results of the study showed a significant improvement in biomechanical variables and in the level of performance among young people after applying the training curriculum for neuromuscular synergy exercises. The launch velocity increased significantly from 11.95±0.60 m/s before application to 12.80±0.52 m/s afterwards T = 2.666, p = 0.045, indicating a greater ability to transfer force during the pushing phase [8-9]. In addition, the instantaneous force at the last thrust step of the right foot increased from 1817.12±141.43 N to 2230.0±231.82 N, and the instantaneous force at the moment of abandoning the weight of the left foot increased from 1660.8±107.12 N to 2062.7±212.8 N, with strong statistical significance (p<0.01). Research has shown that instant strength training enhances the excitation of high-threshold motor units, which increases the force produced during explosive movements.

These improvements are directly related to the electrical activity of the muscles working during throwing, with the right deltoid registering an increase of 1059. 22±87.55 tribal to 1329.90±214.17 posterior, and the left from 1161.46±235.66 to 1503.0±152.92, while the electrical activity of the right triceps increased from 211.336±36.685 to 307.546±62.654, and the left from 230.29±84.926 to 310.91±44.773, with significant differences (p<0.05). These increases indicate improved regulation and more efficient recruitment of neuroactivation units during explosive movements, which is consistent with research findings linking special training to increased EMG activity during complex athletic movements [10-12] (Table 3).

The apparent differences in the electrical activity of the deltoid and triceps muscles can be explained by the increase in the number of motor units used and their synchronization, which contributes to improving the neuromuscular synergy of the muscles that work during pushing and throwing [13-14]. Studies have shown that specialized training increases the consistency of multimuscle operation, supporting faster and more effective force production [15-16].

These findings are associated with deeper biological mechanisms, including better coordination between neuroactivation and muscle contraction and reduced delays between motor unit activation, resulting in a higher speed of force transmission through joints[17]. This improves our understanding of how neuromuscular synergy exercises reorganize and coordinate neural signals to maximize athletic force production [18].

The inclusion of intensity and intensity/resting control in the curriculum also contributed to increased tolerance of working muscles to intense training load without excessive muscle fatigue, which was consistent with the results of Wang et al. and Suchomel et al. who confirmed that structured training leads to improvements in motor performance, while reducing the risk of injury and improving the response of the central nervous system.

These results give great importance to the use of specialized training that corresponds to the nature of the sports movement to be developed, since they contribute to improving the mechanical and electrical performance characteristics of the muscles, thus improving the level of performance in juniors [19-21]. This confirms that the proposed curriculum did not only involve an increase in the amount of work, but was aimed at improving the quality of neuromuscular action and its coordination with athletic performance requirements [22].

Consequently, the results confirm that neuromuscular synergy exercises contribute to regulating the electrical activity of the shoulder muscles and improving biomechanical properties, which is positively reflected in the level of weight bearing in juniors.

Table 2: Presentation of the Results of Differences in Some Biomechanical Variables and Shot Put Achievement for the Pre- and Post-Tests

Table 3: Statistical Parameters of the EMG Test for the Pre- and Post-Tests 

Conclusions 

• The results of the research showed a significant improvement in the biomechanical variables of weighted push-up performance in juniors, including tool throwing speed, instantaneous force when pushing, and instantaneous pushing time, indicating the efficacy of neuromuscular synergy exercises in improving motor and technical performance

• Muscles that work during weight pushing, such as the deltoid and triceps (triceps), reported higher electrical activity in the post-tests compared to the prefrontal ones, reflecting better regulation of motor units and integrated coordination between muscles during push-ups

• The study demonstrated that focusing on instantaneous power and speed-strength exercises for the working muscles of the shot put contributed to reducing push time and increasing the explosive power of the upper limbs, which positively reflected on the achievement distance of the implement

• The results showed that the progression in the training load, the regulation of rest periods between repetitions, and the use of partial resistance for the limbs during performance contributed to raising the physical performance efficiency of the juniors

• The study confirmed that training specific to the working muscles according to the nature of the shot put movement led to improving correct movement trajectories and increasing the speed of muscle contraction, enhancing the economy of muscular effort and elevating the level of achievement in performance

• It was found that practicing neuromuscular coordination exercises specific to the shot put led to an increase in the number of recruited motor units during performance, which helped in developing instantaneous power and speed-strength, thus improving the ability to execute the athletic movement accurately and smoothly

Recommendations 

• Adopting neuromuscular coordination and specific strength exercises for working muscles regularly within shot put training programs for juniors

• Taking into account the progression in exercise intensity and resistance weights to ensure the development of instantaneous power and speed-strength in a safe and effective manner

• Monitoring muscular activity and coordinating performance through periodic evaluation of shot put capability and reducing push time, to adjust training programs according to the individual performance results of each player

• Integrating biomechanical exercises specific to working muscles with the technical training of the shot put to ensure improving movement trajectories and increasing performance effectiveness

• The possibility of applying the exercise curriculum specific to strength and neuromuscular coordination to other power sports that require pushing or throwing heavy implements, taking into consideration the specificity of each movement and athletic implement

1. Hammood, Y.M. et al “Measuring the aggressive behavior of the teams in the Iraqi Premier League in football and its relation to the results and ranking of the league for the 2022-2023 season” Sportske Nauke i Zdravlje vol. 14 no. 2 year, 2024, pp. 127-134

2. Mohammed, K.J. et al “The effect of colorful and varied visual skill exercises on the development of sensory perception and complex skill performance among futsal players” Retos vol. 69 year, 2025, pp. 1226-1239

3. Omar, A.F. et al “The impact of cognitive training on field intelligence growth and some composite skills of advanced football players” Retos vol. 66 year, 2025, pp. 46-58

4. AbdulJabbar, M.A. et al “The effect of mental training mental visualization and attention focus on the accuracy and speed of offensive performance in fencing players” Retos vol. 70 year, 2025, pp. 1097-1113

5. Ali, O. et al “The role of supplements in improving muscular strength and endurance in professional soccer players: a systematic review” American Journal of Social and Humanitarian Research vol. 5 no. 12 year, 2024, pp. 485-497

6. Fayyad, F.H. et al “Building and legalizing a test to measure the level of football agility of young players” Retos vol. 68 year, 2025, pp. 1578-1590

7. Khalaf, Y.A. et al “The effect of sports job burnout on the performance of workers in student activities departments in Iraqi universities” Retos vol. 66 year, 2025, pp. 86-95

8. Behm, D.G. and Sale, D.G. “Neural adaptations” Sports Medicine vol. 15 no. 2 year, 1993, pp. 79-98

9. Kawamori, N. and Haff, G.G. “Power vs strength” Journal of Strength and Conditioning Research vol. 18 no. 2 year, 2004, pp. 305-311

10. Carolan, B. and Cafarelli, E. “EMG analysis” Journal of Applied Physiology vol. 73 no. 4 year, 1992, pp. 1239-1246

11. Moritani, T. and deVries, H.A. “Neural adaptation” Journal of Applied Physiology vol. 46 no. 2 year, 1979, pp. 357-362

12. Bird, S.P. et al “EMG amplitude” Journal of Strength and Conditioning Research vol. 19 no. 3 year, 2005, pp. 567-573

13. Farina, D. et al “EMG variables” Journal of Electromyography and Kinesiology vol. 24 no. 1 year, 2014, pp. 1-5

14. Enoka, R.M. and Duchateau, J. “Neural control” Physiological Reviews vol. 95 no. 4 year, 2015, pp. 1517-1558

15. Behm, D.G. et al “Muscle activation” European Journal of Applied Physiology vol. 86 no. 1 year, 2001, pp. 82-88

16. Häkkinen, K. et al “Neuromuscular adaptations” Journal of Sports Sciences vol. 16 no. 1 year, 1998, pp. 83-92

17. Enoka, R.M. “Neuromechanics of human movement” Human Kinetics, 2008

18. Kernozek, T.W. et al “Muscle recruitment” Journal of Athletic Training vol. 40 no. 1 year, 2005, pp. 23-30

19. O’Sullivan, K. et al “Strength training protocols” Journal of Strength and Conditioning Research vol. 26 no. 8 year, 2012, pp. 2152-2160

20. Baker, D. and Newton, R.U. “Methods to increase power” Strength and Conditioning Journal vol. 30 no. 2 year, 2008, pp. 37-47

21. Hamlyn, N. et al “Strength training” Journal of Sports Medicine vol. 37 no. 9 year, 2007, pp. 725-741

22. Kraemer, W.J. and Ratamess, N.A. “Fundamentals of resistance training” Sports Medicine vol. 34 no. 5 year, 2004, pp. 317-338