Muscular Balance, Core Stability, and Injury Prevention에 대하여

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Muscular Balance, Core Stability,달리기 선수의 부상.pdf

 Weakness or lack of sufficient coordination in core musculature can lead to less efficient movements, compensatory movement patterns, strain, overuse, and injury. This article discusses the importance of muscle balance and core stability for injury prevention and for improving a distance runner’s efficiency and performance. It includes a detailed series of core exercises that can be incorporated gradually into a runner’s training program. 

- 코어근육의 약화나 협응성부족은 충분하지 못한 움직임을 야기하여 보상움직임 패턴, 근육손상, 과사용 그리고 손상을 일으킴. 이 논문은 손상방지와 마라톤 선수의 충분한 기능을 위해 근육균형과 코어안정성의 중요성에 대해 논의함. 

The program starts with restoration of normal muscle length and mobility to correct any muscle imbalances. Next, fundamental lumbo-pelvic stability exercises are introduced which teach the athlete to activate the deeper core musculature. When this has been mastered, advanced lumbopelvic stability exercises on the physioball are added for greater challenge  used to stimulate the subcortex and provides a basis for functional movement exercises that promote balance, coordination, precision, and skill acquisition. The ultimate goal of core stabilization is to train ‘‘movements’’ and ‘‘positions’’ rather than muscles. Exercises are most effective when they mirror the demands of the athlete’s sport.

- 운동프로그램은 정상근육길이의 회복과 근육균형의 교정을 위한 움직임으로 시작함. 다음으로 필수적인 요추골반 안정성운동법이 소개되는데 이는 깊은 코어근육 활성화를 가르침. 이것을 완전히 익혔을때, 짐볼위에서 진보된 요추골반안정성 운동이 추가되는데, 이는 뇌를 자극하고 기능적 움직임 을 위한 기초를 제공하여 균형성, 협응성, 정확하고 스킬 회복을 위한 것임. 코어 안정화의 궁극적인 목표는 근육보다는 움직임과 위치능력을 트레이닝하는 것임. 

 The role of the core 코어의 역할

In essence, the ‘‘core’’ can be viewed as a box with the abdominals in the front, paraspinals and gluteals in the back, the diaphragm as the roof, and the pelvic floor and hip girdle musculature as the bottom [1]. Within this box are 29 pairs of muscles that help to stabilize the spine, pelvis, and kinetic chain during functional movements. 

- 근본적으로 코어는 앞쪽으로 복부근육, 등쪽으로 부척추근육, 둔근, 천정쪽으로 횡격막근육, 바닥쪽으로 골반저 근육이 만드는 박스와 같은 개념. 

- 이 박스내에 29쌍의 근육들이 척추, 골반을 안정화하여 기능적 움직임을 하는 동안 운동사슬을 만듬. 

When the system works efficiently, the result is appropriate distribution of forces; optimal control and efficiency of movement; adequate absorption of ground-impact forces; and an absence of excessive compressive, translation, or shearing forces on the joints of the kinetic chain. This efficiency requires an integration of the myofascial, articular, and neural systems, which, in turn, requires optimal functioning of the muscles, including the muscles’ ability to contract in a coordinated manner and with sufficient motor control and neuromodulation so the joints receive adequate compression through the articular structures. 

- 이 박스 시스템이 충분하게 기능할때, 그 결과는 임의 배분이 적절하고 움직임의 적절한 조절과 능률이 최적화됨. 지면반발력을 잘 흡수하고, 과도한 압박력, 평행이동력, 전단력을 제거해 줌. 이 능률은 근막, 관절, 신경시스템의 통합이 필요함. 

- 근육의 최적의 기능 발휘를 위해 충분한 운동조절능력과 협응성 방법으로 근수축하는 능력이 필요하고, 신경조절능력은 관절이 적절한 압박력을 받게 하는 것임. 

This model supports an integrated model of joint function [2] and leads to optimal length-tension ratios and optimal force coupling of the muscles. Additionally, this model sets the stage for optimal postural alignment, normal movement patterns, and a minimal potential for joint dysfunction. Biomechanical studies showed clearly that joint dysfunction anywhere from the spine to the feet can lead to compromise elsewhere in the kinetic chain [3] .

- 이 모델은 관절기능의 통합모델을 지지하고 적절한 길이-장력비율과 적절한 근육의 짝힘을 유도함. 게다가 이 모델은 적절한 자세조절, 정상 움직임 패턴 그리고 관절기능부전을 위한 최소한의 잠재력을 위한 것임. 생체역학 연구에서는 명백히 제시하는데, 관절기능부전은 운동사슬에서 척추에서 발까지 약화를 야기한다고 함. 

The first stage in developing a stable core is to develop the abdominal muscles. Richardson and coworkers [1]  discovered that there are two different types of muscles fibers (slow-twitch and fast-twitch) that comprise the abdominal muscles; because of this different fiber composition, different exercise regimens are required to train the abdominal muscles properly.

- 안정적인 코어를 발달시키기 위한 첫번째 단계는 복부근육을 트레이닝하는 것임. 연구자들은 서로 다른 두 근육섬유(지근과 속근)이 있는데 이는 복부근육을 포함하.ㅁ 이 서로 다른 근육조성때문에 서로다른 운동법이 복부근육을 적절하게 트레이닝하기 위해 필요함. 

코어에서 지근의 역할

Slow-twitch fibers primarily make up the local muscle system- the muscles of the deeper abdominal muscle layers. These muscles are closer to the center of rotation of the spinal segments and, with their shorter muscle lengths, are ideal for controlling intersegmental motion, maintaining mechanical stiffness of the spine, and are best suited to respond to changes in posture and extrinsic loads. 

- 지근섬유는 일차적으로 국소적 근육시스템-깊은 복부근육층의 근육들을 만듬. 이 근육들은 짧은 근육길이를 가진 근육으로 척추분절의 회전 중심에 가까움. 이는 국소분절움직임 조절을 위해 이상적이고, 척추의 역학적 단단함을 유지하기에 적절하고, 자세와 외부 부하에서 변화에 반응하기에 가장 적절함.

The key muscles of this system include the transversus abdominus, multifidi, internal oblique, deep transversospinalis,  and pelvic floor muscles. McGill [4]  described a ‘‘hoop’’ around the abdomen that consists of the abdominal fascia anteriorly, the lumbodorsal fascia posteriorly, and the transverse abdominis and internal obliques muscles laterally. In combination with the intra-abdominal pressure mechanism, activation of this system serves to tension the hoop and provide a stabilizing corset to the spine.

- 이 시스템의 주요근육은 복횡근, 다열근, 내복사근, 심부척추근육, 골반적근육을 포함함. 맥길은 복부주위의 hoop(굴렁쇠)라고 묘사하여 앞쪽으로 복부근막, 뒤쪽으로 lumbodorsal 근막, 옆쪽으로 복횡근과 내복사근이 있다고 함.  복내압 기전과 함께 이 시스템의 활성화는  hoop에 장력을 제공하고 척추에 안정성 코르셋을 제공함. 

코어에서 속근의 역할

Fast-twitch fibers, conversely, primarily make up the global muscle system (superficial or outer-layer muscles). These muscles possess long levers and large moment arms that are capable of producing large outputs of torque, with an emphasis on speed, power, and larger arcs of movement [5] .

- 속근은 반대로 큰근육 시스템이 주근육임. 이 근육들은 긴 지레를 포함하고 큰 지레팔을 가지고 있어서 큰 토크를 생성하여 스피드, 힘, 움직임의 큰 아크를 가짐. 

The main muscles in this layer are the erector spinae, external oblique, and  rectus abdominis muscles- the muscles that are strengthened by traditional back and abdominal exercises and that assist with gross spinal movements.

- 이 근육들은 척추기립근, 외복사근, 복직근-이 근육은 전통적인 등과 복부근육 운동으로 강화하고 이는 큰 척추움직임을 도움. 

Hodges and Richardson [6,7]  showed that it is not simply that deep-layer abdominal muscles are recruited during stabilization of the spine, but it is how they are recruited that is important. The transverse abdominus, the innermost of the four abdominal muscles, has fibers that run horizontally (except for the most inferior fibers, which run in line with the internal oblique muscle).  

- 호저스와 리처드슨은 심부층 복부근육이 척추의 안정성동안 동원되는 것이 단순하지 않음을 보여줌. 하지만 그들이 어떻게 동원되는지는 매우 중요함. 복횡근은 4개의 복근중 가장 안쪽의 근육으로 평행하게 배열됨. 

The transverse abdominus and the multifidi are considered ‘‘stabilizing muscles’’ (muscles that are modulated continually by the central nervous system and  provide feedback about joint position), whereas the global and larger torque producing muscles control acceleration and deceleration. 

- 복횡근과 다열근은 안정성 근육으로 고려됨. 이 근육은 중추신경 시스템에 의해서 연속적으로 근육이 조절되고, 관절위치에 대하여 피드백을 제공함. 반면에 큰근육과 큰 토크를 야기하는 근육은 가속과 감속을 조절함. 

The investigators found that the cocontraction of the deeper-layer transverse abdominus and multifidi muscle groups occurs before any movement of the limbs. They noted that the transverse abdominus is active 30 milliseconds before movement of the shoulder and 110 milliseconds before leg movement; this neuromuscular stabilization may be delayed in individuals who have low back pain. It is believed that these muscles anticipate dynamic forces that may affect the lumbar spine and act to stabilize the spine before movement. 

- 탐구자들은 심층 복횡근과 다열근의 동시수축은 팔이 움직이기 전에 일어난다고 보고함. 그들은 복횡근이 어깨의 움직임이 일어나기 전 30ms에 활성화하고, 하지 움직임 전 110milisecond에 활성화한다고 보고함. 이러한 신경근 안정성은 하부요통을 가진 환자에서는 지연될 수 있음. 

- 움직임 전에 척추이 안정성이 작용하고 요추에 영항을 줄 수 있는 동적인 힘은 이 근육들이 참여한다고 믿어짐. 

In agreement with this, Hides and colleagues [8]  documented that patients who sustained a low back injury had difficulty recruiting their transverse abdominus and multifidi muscles early enough to stabilize the spine before movement.  For a more detailed discussion on the theoretic basis for core strengthening, the reader is referred to a recent review article by Akuthota and Nadler [9] .

- 지속적인 허리통증 환자는 복횡근과 다열근 동원이 어려워 움직이기 전에 충분히 안정화 하기 힘들다고 연구결과가 나옴. 

- 좀더 자세한 토의를 위해 코어강화를 위해 오쿠토타와 나들러 논문을 리뷰함. 

 Muscle imbalances

Stability work should be started only after the athlete has achieved good mobility, because adequate muscle length and extensibility are crucial to proper joint function and efficiency. Also required is a proper relationship between the prime movers, synergists, and stabilizers. 

- 안정성 작업은 운동선수가 좋은 움직임을 달성하기 위해 반드시 시작해야 함. 왜냐하면 적적한 근육길이와 신장성은 관절의 기능과 능률에 매우 중요하기 때문임. 또한 필요한 것은 안정성 근육, 협력근육, 주동근사이의 적절한 관계성임. 

A prime mover is the muscle that provides most of the force during a desired body movement. Stabilizers and synergists are muscles that assist in the motion by means of control or neutralizing forces. Proper timing and coordinated effort of these muscles is paramount to the runner, and the functional exercises included here stress these relationships.

- 주동근은 원하는 인체 움직임동안 힘의 대부분을 제공하는 근육임. 안성화근육과 협력근은 힘을 중립화하거나 조절하는 움직임에 도움을 주는 근육임. 이러한 근육의 적절한 타이밍과 협력은 달리기에 가장 중요함. 그리고 기능적 운동은 ....

A thorough eval‎uation of the muscular system should include an assessment of the muscles for overactivity, shortening, weakness, inhibition, and quality of motion. This is accomplished best by using muscle-length tests, strength tests, and tests for the efficiency of basic movement patterns and neuromuscular control. A thorough postural observation and videotaping of the athlete’s running gait will help in assessing and identifying any movement imbalances.

- 근육시스템의 측정을 통해 과활성, 짧아짐, 약화, 억제 그리고 움직임의 질을 위한 근육들의 측정을  포함해야 함. 이것은 근육-길이 검사, 근력테스트, 신경근 조절과 움직임 패턴의 능률을 위한 검사를 사용하여 달성함. 

- 자세관찰과 비디오 영상을 통해 스포츠 선수의 달리기는 움직임 불균형을 측정하고 확인하는데 도움이 됨. 

Muscles that are used frequently can shorten and become dominant in a motor pattern. If a muscle predominates in a motor pattern, its antagonist  may become inhibited and cause a muscle imbalance. An example of this is tightness in the iliopsoas muscle- the primary hip flexor that has its origins at the anterolateral aspect of the lumbar vertebral bodies and its transverse processes. 

- 자주사용되는 근육은 짧아질 수 있고, 운동패턴에서 우세할 수 있음. 만약 하나의 근육이 운동패턴에서 우세하다면, 그것의 길항근은 억제될 수 있고. 근육의 불균형이 초래될 수 있음. 이것의 사례는 장요근이 tighteness되면 ...

When the iliopsoas muscle is tight or shortened, it is believed to inhibit the deep abdominals and the primary hip extensor- the gluteus maximus. Inhibition of the gluteus maximus muscles may result in inadequate stabilization of the lumbar spine, with increased anterior shear and extension forces on the lower lumbar vertebrae. 

- 장요근이 짧아질때, 심부 복근과 고관절 신전인 대둔근이 억제된다고 믿어짐. 

- 대둔근의 억제는 요추의 부적절한 안정성을 야기하고 요추에 가해지는 신전력과 전단력이 증가함. 

Muscles are divided into two types: postural and phasic (Box 1 ). Postural muscles are used for standing and walking. Phasic muscles are used for  running; they propel the runner. Although 85% of the gait cycle is spent on one leg when walking [10] , when running, there is a double-float phase during which both legs are off the groundd one at the beginning and one at  the end of swing phase. 

- 근육은 자세유지근과 위상근육을 나뉨. 자세근육은 걷거나 서있는 자세에서 사용되는 근육이고, 위상근육은 달리기에 주로 사용되는 근육임. 보행주기의 85%는 한다리로 서 있는 상태임. 달릴대는 두다리가 지면에서 떨어져 있는 double-float 단계...

Running mechanics demand efficient firing patterns from the postural muscles, whereas phasic muscles do the work of propelling the runner forward. Because postural muscles are being activated constantly in the human body to fight the forces of gravity, they have a tendency to shorten and become tight. In runners, because of training and prolonged use, certain postural muscles are particularly likely to tighten, shorten, and become hypertonic. 

This occurs predominately in muscles that  cross more than one joint [11] . We commonly see this in the gastroc-soleus (predominantly the soleus), rectus femoris, iliopsoas, tensor fascia lata, hamstrings, adductors, quadratus lumborum, piriformis, and sartorius. 

Restricted extensibility of muscles also can lead to decreased circulation and ischemia, which contributes to overuse injury [12] . In comparison, phasic muscles (the more global muscles) typically may remain in an elongated state. It was shown that elongated muscles may lack force in shortened-range test positions [13] . Weak phasic muscles might allow excessive motion to occur at the joints upon which they act. In our experience, common phasic muscles that have a tendency to develop weakness or become inhibited in runners are the tibialis anterior; peronei; vastus medialis; long thigh adductors; and the gluteus maximus, medius, and minimus. 

 Beginning a core strengthening program

The first step in a preventive or performance-enhancing program is to assess which muscles have become tight and shortened. These deficits can be  addressed with stretching exercises and soft tissue mobilization techniques. Following this, the clinician should seek to activate inhibited, or strengthen any weak, muscle groups. The challenge for the clinician is to design an individualized program that addresses these imbalances.

Preliminary stretches for shortened, predominant muscles should include proprioceptive neuromuscular facilitation–type or contract-relax stretches that strive for isometric contraction, followed by end-range stretching. These are effective techniques for maintaining muscle length and joint mobility. Active Release Techniques [12] , (a specialized method for soft tissue mobilization) when used in conjunction with stretching techniques, have shown great promise in restoring muscle length and soft tissue extensibility.

Athletes also can do self-mobilization with the use of a foam roll. One example of this technique, which targets the iliotibial band, is shown in Fig. 1 . Middle-distance runners have unique and specific training programs that demand strength, power, and endurance. These runners place terrific demands for balance and precise functioning of structures all the way from the core to the feet. Specific exercises for the runner should progress from mobility to stability, reflexive motor patterning, acquiring the skills of fundamental movement patterns, and finally, progressive strengthening.  

These sequences may not be applicable to all athletes; therefore, the key is to analyze the individual in each exercise category and then to tailor an exercise regimen that will best suit that runner’s needs. For example, it was shown that runners who are prone to iliotibial band syndrome often have weakness in their hip abductors that predisposes them to increased stress on the iliotibial band [14] . Thus, a preventative training program for runners who have this syndrome must target the hip abductors, particularly the posterior aspect of the gluteus medius that assists external rotation or in decelerating adduction of the hip. Other muscles that prove weak or inhibited on eval‎uation also should be strengthened on a case-by-case basis.

 The stages of core training

Warm-up

Before beginning the basic core strengthening exercises, the athlete should warm-up the spine with the Cat-Camel motion (Fig. 2).

Fundamental lumbo-pelvic stability

The purposes of the fundamental core stabilization exercises are to gain stability, but more importantly, to gain coordination and timing of the deep abdominal wall musculature. It is extremely important to do these basic exercises correctly because they are the foundation of all other core exercises and movement patterns. These basic exercises emphasize maintaining the lumbar spine in a neutral position (which is the midrange position between  lumbar extension and flexion.) This alignment allows for the natural curvature of the spine. All of these exercises are best done with light loads and high repetitions.

This first stage of core stability training begins with the athlete learning to stabilize the abdominal wall. Proper activation of these muscles is considered crucial in the first stages of a core stability program, before progressing to more dynamic and multiplanar activities. 

We recommend the abdominal bracing technique as described by McGill (Fig. 3 ) [4] . The exercise program should progress sequentially through the initial fundamental movements as detailed in Figs. 4 through 8 . These fundamental exercises are to be performed three times a week to maximize results. The athlete begins with two sets of 15 repetitions and progresses to three sets of

15 to 20 repetitions to develop fully the requisite muscle endurance for

higher level performance. Initially, these exercises are taught in a supine,

hook-lying position or an all-fours quadruped position. The athlete can

progress to more functional standing exercises as control is developed.

Important concepts that are taught at this stage include not tilting the pelvis

or flattening the spine. We also emphasize normal rhythmic breathing.  Advanced lumbo-pelvic stability

Once the athlete demonstrates good stability with all static core exercises,

they can be replaced with more advanced exercises as detailed in Figs. 9

through 14. The use of the physioball requires the athlete to work on

proprioception and higher level core stabilization. These exercises should be

performed two to three times weekly to maximize results. Again, the athlete

begins with one or two sets of 15 repetitions and progresses to three sets of

15 to 20 repetitions. Quality is more important than quantity. Make sure

that the lumbar spine does not go into extension or the cervical/thoracic

spine into flexion and maintain the spine in perfect alignment.

As the athlete progresses through a core exercise program, the emphasis

always should be on correct postural alignment as athletes challenge

themselves with a variety of movement patterns in the three planes of

movement: sagittal, frontal, and transverse. Although runners move

predominately in the sagittal plane, there still is body movement in the

transverse and frontal planes that must be controlled adequately by the

neuromuscular system. During midstance of the running gait cycle, the foot

and ankle unlock to allow absorption of ground reaction forces. During this

phase, the body is challenged most to control excessive or aberrant motion

in the frontal and transverse planes. Functional exercises on one leg are used

to best simulate the neuromuscular demands of running. The athlete is

trained with increasingly challenging functional patterns, with continued

emphasis on postural control and core stabilization. The ultimate goal of

core stabilization is to train ‘‘movements’’ and ‘‘positions,’’ rather than  Development of balance and motor control

The following movements require reflexive control. The athlete can

accomplish this control by using the numerous proprioceptors in the soles of

the feet and the exteroceptors of the skin, and by activating the neck

muscles; these are highly contributory to postural regulation. This sensorymotor

stimulation is an attempt to provide the subcortex with a basis for

movement that is progressively more challenging. It involves exercises that

stimulate balance, coordination, precision, and skill acquisition.

The following exercises should be performed while standing (Figs. 15–

17). We instruct the athlete to control the feet, pelvis, and head consciously,

with the goal of making sure that the feet are aligned properly.

These exercises use a rocker board. A rocker board is a board with

a hemisphere underneath that allows single-plane rocking. (The board was

designed by Dr. Vladimer Janda to promote balance and stability of the

spine, www.optp.com).

Common errors or abnormal compensations to look for when attempting these exercises include increased anterior pelvic tilt, increased lumbar lordosis, increasing internal rotation of the hip, excessive valgus at the knee, and hyperpronation at the foot. Therefore, when teaching these exercises, it  is imperative to instruct the athlete on proper spinal alignment. To aid in this, we recommend initiating the abdominal bracing technique before performing the stepping forward-and-backward motions of any of these

exercises (which train correct weight transfer over the feet). Additionally, it

is important to instruct the athlete on proper gait. The focus here should be

on controlling the initial heel strike in a supinated position on the lateral

edge of the foot, into pronation on the medial aspect of the foot, with flexion

of the first metatarsal head and toes. Continuing proper gait instruction, we

teach a falling-forward position into a lunge (with perfect control). The

athlete then progresses to jumps on one or two legs, assuring that there is no

increased lumbar lordosis or increased valgus moment at the knee. This

stimulates vestibular and cerebellar activity, which, in turn, leads to

automatic postural controld an important part of our training. (Readers

will note the increased muscle activity of the ankles and muscles that control

the lower extremity chain and spine.) The athlete can progress to standing

on one leg, with alternating arm movements.

Various devices are useful to challenge balance progressively, moving the

athlete from conscious to subconscious control of the muscles that are

responsible for postural maintenance and gait. These devices include

a balance board (a whole sphere underneath the board, which creates

multiplanar instability) or a rocker board (a curved surface underneath the

board, which allows single-plane motion). Dynamic foam rollers are an  inexpensive alternative to the boards that also can be used to challenge balance, proprioception, and stability. These include half-rollers and fullsized rollers. Two other items that are invaluable to challenge balance and

core stability and aid proprioceptive training in the standing position are the

Bosu Balance Trainer and the Dyna Disk (these can be used interchangeably).

The Bosu has two functional surfaces that integrate dynamic balance

with sports-specific or functional training: the domed surface is convex, the

other side is flat and can be used for less challenge. The Dyna Disk is an airfilled

plastic disc that can be inflated firmly. It has a smaller diameter than

the Bosu and can be used like the Bosu Trainer because it creates an

increased proprioceptive challenge to the athlete while standing on it. The

Dyna Disk is unstable and does not have a base like the Bosu Trainer.

Functional movement training

 Functional movements require acceleration, deceleration, and dynamic stabilization. Figs. 18 through 24  present an array of functional, diagonal exercises for the trunk and extremities that are essential for runners.

Exercises should be safe, challenging, and stress multiplanar motions. These training exercises encourage functional strength, which depends on the  neuromuscular system’s ability to produce dynamic eccentric, concentric, and isometric contractions during movement patterns.

A functional exercise regimen that is specific to the demands of running includes single-leg drills, three-dimensional lunges, resistive diagonal patterns of the upper and lower extremities, drills that involve plyometrics, and triplanar movement sequences. Athletes can progress through the three planes of motion by performing similar exercises on balance boards, the Dyna Disk, or Bosu-type trainers, after static trunk and core stability have been mastered.

Summary

 This article is intended to provide an understanding of the importance of core musculature to runners and to offer exercises that will help them achieve desired mobility, stability, muscular balance, and neuromuscular control. Please see Table 1  for an example of how to incorporate these exercises into a periodized training program. It is highly recommended, however, that athletes consult a skilled practitioner to address individual needs and maximize results from a program of this nature.

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