THE EFFECTS OF DYNAMIC NEUROMUSCULAR STABILITY EXERCISE ON THE SCOLIOSIS AND PAIN CONTROL IN THE YOUTH BASEBALL PLAYERS

While the presence of dynamic neuromuscular stabilization (DNS) has been provided as an important component of the integrated spinal stabilization and associated abdominal stabilization prior to dynamic movement, no previous study has investigated the spinal mechanical e®ects scoliosis and pain control in youth baseball player with scoliosis. This study compared the e®ects of gymball exercise, with and without DNS core stability exercise, on spine kinematics and pain control in youth baseball player with scoliosis. A total of 28 participants with scoliosis were randomized into gymball exercise, with and without DNS core stability exercise. Clinical outcomes included the Cobb's angle and visual analog scale (VAS). Two-way repeated analysis of variance (ANOVA) was conducted at p < 0 : 05 . Two-way repeated ANOVA showed that gymball with DNS showed superior e®ects, compared to gymball without DNS, on Cobb's angle ( P < 0 : 001 ), but not on VAS ( P < 0 : 837 ). Our results provide novel, promising clinical evidence that DNS improved scoliosis kinematics as well as pain control in youth baseball player with scoliosis.


Introduction
Scoliosis, a three-dimensional transformation of the spine, 1 is de¯ned as a physical condition in which the spine is bent by more than 10 degrees in radiography. 2About 85% of scoliosis patients are diagnosed with unexplained idiopathic scoliosis, which is known to be most prevalent from about 10 years of age to adolescence, when bone growth stops. 3The clinical signs of scoliosis have been thoroughly investigated and well documented, while idiopathic refers to unknown causes. 4][7] In addition, Park (2018) reported that repetitive asymmetrical movements, such as baseball, result in the deformation of the spine structure, and that it is important for baseball players during the growth period to take good care of the spine, considering that the cause of adolescent idiopathic scoliosis occurs until they become adults.Therefore, the scoliosis of growing baseball players is accompanied by various spine problems, such as back pain, as well as their performance as they grow as reviewed in previous study, so especially at that time, the management of scoliosis is considered to be important. 8n the other hand, dynamic neuromuscular stabilization (DNS) is a rehabilitation approach that can be of great help in preventing recurrent thoracolumbar muscle tension injuries. 9,10It is widely known that it can be used in the functional treatment of musculo-skeletal system syndrome, where patients feel pain, but that it is also used to increase exercise capacity as a di®erent e®ect.The DNS approach is based on a model of developmental kinematics. 11DNS contains innate motor patterns or programs that can develop a newborn baby-like ideal posture, functional joint centration, and optimal breathing and movement. 12The main goal of the DNS approach is to restore the physiological motor patterns de¯ned in developmental kinematics.Also, optimal trunk stabilization is a basic prerequisite for the ideal qualitative movement of all activities, including sports activities. 10The role of intraabdominal pressure control and the integrated stabilizing system of the spine in relation to functional spinal stability is to generate the torque required for joint motion through the stability of the spine and dynamic co-activation muscles. 9In other words, the DNS exercise can be said to be helpful in the functional activity of the spine based on stabilization of the spine during exercise.However, it is known that the DNS exercise helps improve the function of the spine, and it is judged that the studies conducted on sports players are still insu±cient.Therefore, the purpose of this study is to provide meaningful data for the maintenance of growing players by investigating the e®ects of the DNS exercise on scoliosis in players with scoliosis among the youth baseball players in republic of Korea during the growth stage, who mainly move unilaterally.We hypothesized that DNS exercise would produce greater changes in the scoliosis angle and pain scale than gymball exercise alone in youth baseball players in republic of Korea.

Plan of study
In this study, 28 patients with the Cobb's angle of 10 or more and the Visual Analog Scale (VAS) of low back pain were selected through scoliosis examination among 192 male baseball players from 14 (junior high school students) to 18 (high school students) years old living in Busan (Fig. 3).Their physical characteristics are shown in Table 1.

Experimental design
Scoliosis was evaluated through X-ray imaging by a certi¯ed radiologist who was expert in scoliosis evaluation at the Radiology Department in Busan, and players evaluated with the medical opinion of specialists on scoliosis examination were selected as subjects for the study.They were divided into two groups: 14 people who received a trunk stabilization exercise with a gym ball and 14 people who received both the trunk stabilization exercise with a gym ball and DNS exercise, and each group performed the experiment 3 times a week for 8 weeks.The exercise programs are as shown in Fig. 1 and Table 2.

X-ray Cobb's angle inspection
In order to ¯nd the Cobb's angle, as shown in Fig. 2, the distal vertebrae tilted toward the most concave of the spinal curve should be determined at the upper and lower levels of the curve, then one line needs to be drawn at the top of the upper end spine and the other line at the bottom of the lower end spine, and then draw lines orthogonal to each line to cross them. 2 Scoliosis was examined through X-ray (DK II525R-Korea) as above, and each score represents an angle.Cobb's angle obtained through this is also the size of the curve.

Visual analog scale test
Hawksley (2000)'s method, widely used as a pain scale, was used to measure the visual analog scale (VAS). 13In case of pain, subjective pain is recorded using a visual pain scale, and the 10 cm straight line was used set to be 0 point for no pain and 10 point for severe pain.

Statistical analysis
Results were expressed as means and standard deviations.SPSS for Windows (25.0, SPSS, Chicago, IL, USA) was used to conduct statistical analyses.The Kolmogorov-Smirnov test was used to con¯rm normal data distribution; hence, parametric analyses were performed.Two-way repeated Analysis of Variance (ANOVA) was   used to compare the di®erence in the dependent variables, such as Cobb's and VAS scale ( ¼ 0:05).

Cobb's angle
The ANOVA analysis showed signi¯cant decrease in Cobb's angle between the GSD and GS groups (p < 0:001), indicating that the GSD group was superior in the reduction of scoliosis angle than GS group (Table 3).

VAS score
The ANOVA analysis showed no signi¯cant di®erence in VAS score between GSD and GS groups (p ¼ 0:837), that the GS group was superior in the reduction of pain than GSD group (Table 4).

Discussion
The present randomized control trial is about the initial demonstration of the e®ects of the GS group and GSD group on the VAS pain scale and the Cobb's angle on thoracic and lumbar spine angle kinematics of youth baseball players.The aim of this study is to compare the e®ects of the DNS exercise on scoliosis in players with scoliosis youth baseball players.It was consistent with our hypothesis that the GSD group (À22%) had reduced Cobb's angles, compared to the case of gym ball exercise (À7%) alone.Most importantly, data on Cobb's angles demonstrated that DNS exercise had contributed to a clinically meaningful reduction in bilateral muscle imbalance and appearance of the spinous process.An analysis on scoliosis revealed more signi¯cant reduction in Cobb's angles (mean di®erence between groups ¼ 15%) in the GSD group compared to the GS group.This previous ¯nding is consistent with Schroth Exercise for adolescents (mean age AE standard deviation ¼ 15:50 AE 1; 79) recovering idiopathic scoliosis, which also shows a reduction in Cobb's angles (21%). 14The DNS exercise is comparable to the Schroth Exercise among various exercises for scoliosis.
Our study found that the VAS scale had been reduced in both groups.Previous study assumed that GS could help reduce the risk of pain.The GS maintained the neutral spine and was suitable for targeting a speci¯c function of local muscles in the early stages of motor programming to improve super¯cial spinal stability.Since the DNS involves the greater movement of the descending diaphragm than that of GS, 15 an e®ective intra-abdominal pressure is generated by the oblique chain.However, the GS is signi¯cantly e®ective for the pain control, compared to GSD.
There is one important underlying mechanism by which the DNS exercise enhances a decrease in pain and physical and social disabilities during daily activities, as evidenced by the VAS data. 16A previous study by Kolar et al. (2014) proved that the abnormal postural activation of the diaphragm and the greater strain in the ventral region of the spine during isometric resistance could be a fundamental mechanism to the extremities of chronic low pain.According to the previous author, the insu±cient postural function of the diaphragm resulted in an implement to the control of thoracic and to the intra-abdominal pressure regulation and integrated spinal stabilizing system.The compensation activity of the super¯cial spine extensor increases the pressure on the spine and causes an abnormal location of the chest or ribs due to the imbalance between upper and lower chest musculature. 10 possible underlying rationale is that the DNS focuses on the thoracic-lumbarhip chain's dynamic stabilization and axial elongation movement control, [17][18][19] whereas a gym ball emphasizes the selective activation of the latissimus dorsi and coactivation of the upper and lower abdominal muscles. 20It has theorized that externally, the ¯rst oblique core chain is automatically stimulated immediately by the shoulder supporting zone interacting with the °oor surface which generates the punctum ¯xum (stable basis) for the pectoralis À À À ipsilateral external oblique, rectus abdominis, contralateral internal oblique connected with transverse abdominis, multi¯dus, encapsulated by thoracolumbar fascia, hip muscles while another (second) oblique chain is facilitated as the ipsilateral hip supporting zone comes in contact with the surface, activating the opposite oblique chain muscles.These ¯rst oblique chains may be connected by the posterior chain muscles to correct and stabilize the cervical-thoracic-lumbar spinal segments during the dynamic hip movement of youth baseball players, producing an externally (negative) stabilizing force movement.The IAP force is internally generated by a deep diaphragm, transvers abdominis, pelvic °oor, multi¯dus frontal and dorsal core chains during inspiration, which then provides a counterforce for the further improvement of the oblique chain.
When rehabilitating youth baseball players, one should not just focus on stretching or mobilizing a tight glenohumeral capsule/joint and on strengthening the local muscles, but one may require to ask the question of \why" the local muscles are being impaired.The movement pattern analysis (e.g.arm elevation or the throwing mechanics) must be performed, for the determining whether the core stability is adequate and/or if a \weak link" in the kinetic chain is present.Such weak links may include poor scapular dynamic stability, impaired lower extremity mobility, stability and/or proprioception, and poor trunk mobility or stability. 21n addition to our results that the gym ball exercise was e®ective for pain control, the DNS exercise was also e®ective for pain and scoliosis control.
Despite the meaningful ¯ndings, this study has limitations that it did not measure the anterior super¯cial, deep chain muscles and intra-abdominal pressure.Therefore, future studies are required to develop sophisticated sensors and MRIs to precisely measure the underlying chain muscle's motor control during dynamic movement.

Conclusion
In this study, we demonstrated the superior e®ects of the GS combined with the DNS on pain control, and of the control of a reduction in the scoliosis from youth baseball I. Park et al.

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players when compared to the gym ball exercise alone.Most importantly, the DNS exercise rapidly improved Cobb's angles and relieved pain with improved cervicalthoracic-lumbar stability.These promising results suggest that the use of exercises for scoliosis alongside the DNS exercise with a gym ball is bene¯cial for scoliosis patients with a core instability.

Table 3 .
Changes of Cobb's angle between GSD and GS group.

Table 4 .
Changes of VAS pain scale between GSD and GS group.Values are Mean AE SD. *p < 0:05, **p < 0:01, ***p < 0:001.GSD ¼ Gym Ball Stability with DNS Exercise Group GS ¼ Gym Ball Stability Exercise Group The E®ects of DNS Exercise on the Scoliosis and Pain Control in the Youth Baseball Players 2140030-7 J. Mech.Med.Biol.Downloaded from www.worldscientific.comby YONSEI UNIVERSITY on 08/10/21.Re-use and distribution is strictly not permitted, except for Open Access articles.