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DUK Info Sheet 13 - Muscle Imbalance Explained (4pp).qxp_Layout 1 19/08/2014 10:46 Page 1 13 Muscular Imbalance Explained By Kim Hutt, 2014 Muscles are responsible for maintaining Muscle imbalances in themselves are not BOX 1 posture, creating positions, absorbing painful. However, when they reach the shock, producing heat, protecting the point of affecting joint mechanics or 3 Common Biomechanical body’s internal organs and stabilizing altering movement patterns, they can lead Imbalances and moving joints. Muscles account for to injury and pain. It is worth noting here approximately 40-45% of an average that injuries that are not associated with 1 Turnout – holding turnout in ballet for adult’s body mass. They are comprised of muscle imbalance (for example, if you go prolonged periods without including muscle cells, which are the only human over on your ankle and sprain a ligament), training in internal or neutral rotation cells able to produce active tension. may also affect movement patterns in an can often lead to short and tight This means that muscles are able to attempt to avoid pain, and consequently external rotators in the hip and long shorten, lengthen or maintain the same lead to muscular imbalance. Therefore it and weak internal rotators. length against a resistance. For example, is important to highlight that dancing the leg works against gravity when through any pain can indirectly lead to 2 Some dancers, in an attempt to working in the air or against ground muscle imbalance. In short, muscle develop their chest musculature utilize reaction forces when controlling landings imbalance can be a symptom or a weights and overwork the chest from jumps. cause of many injuries. muscles (pectoralis) without paying attention to the balancing muscles at Safe and healthy movement and function Muscles adapt in response to postures the back (trapezius and rhomboids). in dance relies on effective muscle and repetitive movements. It is anticipated This practice can lead to rounded balance. Muscle balance can refer to the that the body will carry some muscle shoulder with short and tight chest length and strength relationship between imbalances. For example, the muscles in muscles and weakened back muscles. the agonist (the muscle most responsible your quadriceps might be stronger than for a given movement) and antagonist those in your hamstrings. However, when 3 When dancers are standing in a (the muscle opposing that given an imbalance impairs normal and healthy relaxed position, they may “sink or movement). For example, in a grand movement patterns, it can lead to injury. slouch into their hip”. This practice can battement, the muscles at the front of the lengthen and weaken the important hip thigh (quadriceps and hip flexors) are the stabilizers (gluteus medius and agonists and the muscles at the back of minimus). Having a weakness in these the thigh and bottom (hamstring and muscles frequently results in incorrect gluteus maximus) act as the antagonists. lower limb alignment. Muscle balance can also refer to the relationship between contralateral muscles (muscles on the right side versus Faulty movement patterns may begin as biomechanical imbalances and over time left side of the body) or dominant versus turn into neurological imbalances. non dominant limb. Biomechanical Neurological Injuries can occur when the normal function of a movement is impaired by Biomechanical imbalances result from Poor alignment resulting from an imbalance between the length and prolonged postures or repetitive movement biomechanical imbalances can lead strength of muscles working around patterns. Agonist muscles may respond to to neurological muscle imbalances. a joint. Muscle imbalances tend to be these postures or movement patterns by Dancing with faulty alignment for the result of faulty movement patterns, shortening and antagonist muscles may prolonged periods of time can change and can be described as a ‘functional respond by lengthening. Prolonged the proprioceptive feedback to the brain pathology’ (meaning a problem associated postures and repetitive movement patterns about that movement, and that movement with movement). There is a high incidence will also ultimately lead to specific muscular pattern becomes habitual. If repeated of chronic or repeated injuries in dance, weaknesses. The associated joint then over the course of a dancer’s training, which are often due to faulty movement moves in an unhealthy way resulting in it can result in weakening of key muscles. patterns.Therefore, the functional microscopic trauma, which can lead to pain This may lead to the brain acknowledging contributors to injury should always and injury. For some examples of common unhealthy movement patterns as correct. be explored. biomechanical imbalances please see Box 1. DUK Info Sheet 13 - Muscle Imbalance Explained (4pp).qxp_Layout 1 19/08/2014 10:46 Page 2 Local and Global Stabilizers An additional consideration in muscle balance is the functional health of stabilizing and mobilizing muscles. Stabilizing muscles protect the joints from harmful forces imposed by the muscles that are more responsible for movement. Stabilizing muscles can be local (close to the joint) or global (further away). The role of the local stabilizers is to help to keep the joint in a neutral (healthy) position. When functioning correctly, these muscles should start working before movement, meaning that they activate in anticipation of the movement about to take place. If there is a muscle imbalance, they lose their ability to do this job effectively. The global stabilizer’s role is to control the joint position throughout its range of movement. However, if the local muscles are not working effectively, the global muscles try to take on the job, exacerbating the imbalance. Mobilizing muscles Mobilizing muscles are responsible for functional movement. They are more superficial than the stabilizing muscles and fatigue easily, therefore they cannot effectively stabilize the joints. When stabilizing muscles become compromised, for example due to pain or injury, the mobilizers have a tendency to become short and tight. They attempt to take on the extra workload, potentially resulting in faulty mechanics that can leave a joint more susceptible to injury. DUK Info Sheet 13 - Muscle Imbalance Explained (4pp).qxp_Layout 1 19/08/2014 10:46 Page 3 Common dance-specific faults of time, can unfortunately lead to shortened and tight muscles. The external The following section will consider some rotator muscles attach on the pelvis and common dance specific faults that may spine. Increased tightness in these be a symptom or consequence of muscle muscles may change pelvic placement, imbalances that predispose dancers which can lead to incorrect joint alignment to injury. and pain. Prevention strategies should include stretching techniques for the hip Knee Alignment external rotators (Figure 2). Ideal knee alignment requires good Pelvic alignment muscle balance and therefore plays a key role in preventing injury in dancers. Common postural and biomechanical When standing in parallel or turned out, faults in dance practice are ‘tucking under’ bending the knee or landing from a jump, caused by a posteriorly tilted pelvis (Figure dancers should take care to ensure that 3) and ‘arched back’, which can be their knees are correctly aligned with their caused by, among other things, an feet and hips. Correct alignment ensures anteriorly tilted pelvis (Figure 4). that the knees are travelling over the centre of the foot and not falling in from Tucking under can lead to short and FIGURE 1 the hip. This alignment is managed in tightened abdominal muscles with long part by the deep external rotator and and weak hip flexors and spinal extensor abductor muscles of the hip joint. muscles. As hip flexors are used in dance Dancers who land with an inward facing for any movement of the leg in front of the knee (Figure 1) may be under-utilising body, weakness may predispose these their deep external rotators and muscles to injury, particularly if they are abductors which can become weak and not conditioned for the repetitive forces exacerbate faulty alignment. placed upon them. If the tucking under has resulted in muscle imbalance, The level of external rotator activation strengthening exercises for the hip flexors required for correct knee alignment can and back extensors alongside stretching depend on the foot position – for example exercises for the abdominal muscles are a parallel position will require a lower level recommended. of activation as compared to a turned out position, which would require a higher level of activation. High levels of activation, if held for prolonged periods FIGURE 2 FIGURE 3 FIGURE 4 DUK Info Sheet 13 - Muscle Imbalance Explained (4pp).qxp_Layout 1 19/08/2014 10:46 Page 4 An anteriorly tilted pelvis (resulting in an on stretching the hip flexors and back • Always avoid aggravating activities ‘arched’ lower back appearance), may be extensor muscles and strengthening the when in pain or injured unless the symptom or the cause of tightness in abdominal muscles. specifically prescribed otherwise by the hip flexors and / or lower back a registered practitioner alongside weakness in the abdominal Whether muscle imbalance is the muscles. Tight hip flexors can reduce the symptom or the cause of an existing or FURTHER READING: amount of turnout available at the hips. previous injury, every effort should be 1 Clippinger, K. (2007) Dance Anatomy Additionally, due to the attachment of the made to address the fault for effective and Kinesiology; Principles and psoas major muscle (an important deep recovery from and avoidance of further exercises for improving technique and hip flexor) to the bones in the spine, injury. Simple guidelines to avoid muscle avoiding common injuries, tightness in this muscle can influence the imbalances should be: Champaign, IL: Human Kinetics. position of the lower spine, predisposing • Throughout your dance training, a dancer to lower back pain and injury. strengthen what you stretch, and 2 Simmel, L. (2009) Dance Medicine in When the pelvis is tilted anteriorly, stretch what you strengthen.