I want to focus on one of the first triathlon studies in particular [1]. In this study, data was gathered from the responses of 95 competitors (75 men, 20 women) in the 1986 Hawaii Ironman Triathlon who completed a training and medical history questionnaire. In this sample, virtually all (91%) sustained at least one soft tissue, overuse injury during the previous year’s training. This trend continues, today. Continue reading
Chris arrived at my office complaining of L lateral knee pain. Based on the initial assessment I performed, I thought it might be ITB Friction Syndrome, but the first thing I did was test his knee for hyper-mobility/instability. Continue reading
The effects of aging on training, recovery, and performance are fairly well-known, and even though each of us is unique in many ways we all have, are currently, or will experience these effects at some point… sooner or later. Our physiological capabilities and the effects of training and recovery change as we age. This is the philosopy behind ‘age-groups’. It would be extremely unlikely for a coach who is in their 20’s or 30’s to be familiar with the capabilities and needs of an athlete who is in their 40’s, 50’s, or 60’s. Continue reading
Hamstring injuries are very common injuries and healing them can be more difficult than you might think. Continue reading
Road biking demands that cyclists subject their low back to prolonged flexed posture, exagerated thoracic kyphosis, neck hyperextension, and close-packed hip/knee angles. Aero positions especially, have some risks associated with them. Two common injuries riders experience are to the hamstring and erector spinae muscle groups, in the form of low back pain. Continue reading
Bottom Line:
“ When dealing with endurance athletes, the truth may be hard to say and even harder to hear: All non-traumatic injuries are training-related. All ‘osis’ conditions are caused by overuse. If you didn’t fall off something or get hit by something, you did something wrong in training.” (Boyle, 2010). Continue reading
In the early 20th century, the SI joint was thought to be the main source of low back pain and was the focus of many scientific investigations. In 1934, a published study by Mixter and Barr on rupture of the intervertebral disc quickly changed the direction of these investigations. Over the next four decades, the SIJ was more or less ignored in favor of the disc as the primary cause of back pain.
Resurgence of interest in the SI joint since the 1970s can be traced to the following: Continue reading
The terms function and functional can be confusing because function can be intrinsic, extrinsic, or even a combination of both. The term ‘functional’ has been used to describe an approach to exercise prescription that tries to reproduce the same movements used in a functional activity. This is an extrinsic viewpoint of function. Janda’s viewpoint of function is intrinsic and relates to the function of ‘structures and systems’. The intrinsic viewpoint of function includes the three processes of physiological, biomechanical, and neuromuscular function. Understanding the underlying functions of these three processes is the key to understanding functional lesions.
Excerpted from: (Page, Frank, Lardner. Assessment and Treatment of Muscle Imbalance, The Janda Approach. 2010, Human Kinetics, Champagne IL.)
Muscle balance is the relative equality of muscle length or strength between an agonist and antagonist. This balance is necessary for normal movement and function as it relates to the reciprocal nature of human movement, which requires opposing muscle groups to be coordinated. Muscle balance may also refer to the strength of contralateral (left vs. right) muscle groups. Muscle imbalance occurs when the length or strength of agonist and antagonist muscles prevents normal function.
Muscles may become unbalanced as a result of adaptation or dysfunction. Such muscle imbalances can be either functional or pathological.
Functional imbalances are more common in athletic/active people and are necessary for function. They occur in response to adaptation for complex movement patterns, and include imbalances in strength or flexibility of antagonistic muscle groups. Because such imbalances are required, they must be managed before they become pathological. Clinicians must recognize when to treat muscle imbalances, given the pathology and demands of the sport.
When muscle imbalance impairs function, it is considered to be pathological. Pathological muscle imbalance is associated with dysfunction and pain, although the cause may not result from an initial traumatic event. Pathological imbalance may also be insidious; many people have muscle imbalances without pain. However, if left unaddressed, pathological muscle imbalance will lead to joint dysfunction, altered movement patterns, and pain.
Some injuries cause muscle imbalance, while others result from muscle imbalance:
There are two schools of thought on muscle imbalance: one believes in a biomechanical cause of muscle imbalance resulting from repetitive movements and posture, the other believes in a neurological predisposition to muscle imbalance.
Both are seen clinically, so clinicians must understand both in order to make an accurate diagnosis and treatment.
Patients may also exhibit hybrid muscle imbalance syndromes with factors of both existing together. This further challenges clinicians as they work to diagnose and treat.
This is the traditional view of muscle imbalance. The biomechanical cause of muscle imbalance is the constant stress that muscles experience due to prolonged postures and repetitive movements.
Sahrmann suggests that repeated movements or sustained postures can lead to adaptations in muscle length, strength, and stiffness. These adaptations are termed ‘muscle impairments’ which can alter the relative participation of synergists and antagonists. Muscle impairment eventually leads to altered movement patterns, which Sarhmann terms ‘movement impairments’.
In movement impairment, the precision of joint motion is altered and abnormally stressed by the muscle impairment. Treatment is directed toward restoration of precise joint motion by creating muscle balance; lengthening the muscles that are short and strengthening the muscles that are weak.
The neurological approach to muscle imbalance recognizes that muscles are predisposed to become imbalanced because of their role in motor function. The neural control unit may alter the muscle recruitment strategy to stabilize joints that are temporarily in dysfunction. This change in recruitment alters muscle balance, movement patterns, and ultimately the motor program.
Janda considered muscle imbalance to be an impaired relationship between muscles prone to tightness or shortness and muscles prone to inhibition or weakness. He noted that predominantly static or postural muscles have a tendency to tighten. In various movements they are activated more than muscles that are predominantly dynamic and phasic in function, which have a tendency to grow weak. These characteristic patterns of muscle imbalance have been found in children as young as 8, indicating that the pattern does not differ among individuals, only the degree of imbalance differs. These patterns of muscle imbalance are systematic and predictable because of the innate function of the sensorimotor system.
Janda believed that muscles, being the most exposed part of the neuromuscular system, provide an excellent window into the function of the sensorimotor system. Muscles are at a fuctional crossroads because they must respond to stimuli from the CNS as well as react to changes in the peripheral joints (PNS).
Natural reflexes influence muscle balance and function, leading to adapatation throughout the body through chain reactions. Changes in one system are reflected by adaptive changes elsewhere in the body. Many chronic musculoskeletal pain conditions result from defective motor learning that prevents the motor system from properly reacting or adapting to different changes in the body. The abnormal recovery of the motor system is then reflected in poor mechanical and reflexive motor performance, creating localized muscle imbalance. This muscle imbalance is a characteristic response of the motor system to maintain homeostasis. Over time, this imbalance becomes centralized in the CNS as a new motor pattern, thus continuing the cycle of pain and dysfunction.
Excerpted from: (Page, Frank, Lardner. Assessment and Treatment of Muscle Imbalance, The Janda Approach. 2010, Human Kinetics, Champagne IL.)
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