Acute anterior shoulder dislocation is the commonest type of shoulder dislocation. Subsequently, the shoulder is less stable and more susceptible to re-dislocation, especially in active young adults. 

A search in the Cochrane Musculoskeletal Injuries (1996-2003) to compare surgical versus non-surgical treatment for acute anterior dislocation of the shoulder involved  a total of 239 young (mainly aged around 22 years) active and mainly male people, all of whom had had a primary (first time) traumatic anterior shoulder dislocation.

Pooled results from all five trials showed that subsequent instability, either redislocation or subluxation, was statistically significantly less frequent in the surgical group. This result remained statistically significant for the three trials reported in full. Half (17/33) of the conservatively treated patients with shoulder instability in these three trials opted for subsequent surgery. The results were more favourable, usually statistically significantly so, in the surgically treated group. Aside from a septic joint in a surgically treated patient, there were no other treatment complications reported.

There was no information on shoulder pain, long-term complications such as osteoarthritis or on service utilisation and resource use. The conclusions were that the limited evidence available supports primary surgery for young adults, usually male, engaged in highly demanding physical activities who have sustained their first acute traumatic shoulder dislocation. There is no evidence available to determine whether non-surgical treatment should not remain the prime treatment option for other categories of patients. (Handoll, H H G. Almaiyah, M A. Rangan, A.: Surgical versus non-surgical treatment for acute anterior shoulder dislocation. Cochrane Database of Systematic Reviews. (1):CD004325, 2004) 

This following study suggests that the subscapularis muscle is the main active stabilizer when the humerus is abducted and externally rotated. Conservative treatment of anterior shoulder instability therefore aims at strengthening this muscle. Ten human shoulders specimens were loaded with an anterior dislocating force and the effect of different subscapularis tensions on humeral translation was measured with the Motion Analysis system, for the abducted and externally rotated arm and neutral positions. Also, lines of action of the subscapularis segments were measured on a 3D epoxy model.

It was found that shoulders in which the humeral head migrated antero-superiorly under an external antero-inferior load were observed to dislocate under simulated active subscapularis tension in both positions. In contrast, shoulders in which the head migrated antero-inferiorly remained stable. Twice as many specimens dislocated in the abducted - externally rotated position than in the neutral position. The change in line of action of the subscapularis may account for this change.  

The conclusion was that exercises alone are unlikely to be adequate for all patients with anterior instability symptoms. Passive motion pattern of the humeral head might serve as an indicator as to whether the effect of strengthening the subscapularis might stabilize a shoulder without further operation. Development of a clinical test based on these findings might differentiate the non-operative from operative candidates among patients presenting with anterior instability of the shoulder. (Werner, C M L. Favre, P. Gerber, C.: The role of the subscapularis in preventing anterior glenohumeral subluxation in the abducted, externally rotated position of the arm.Clinical Biomechanics. 22(5):495-501, 2007 Jun). 

The shoulder tends to dislocate up and to the front with the arm away from the body with the thumb up (as in overhead activities).  The subscapularis and latissimus dorsi guards the shoulder during this upward movement to prevent the shoulder from dislocation.  These muscles cannot be allowed to get too tight.   Subscapularis and latissimus dorsi can be isometrically exercised just by holding for 10 secs, 10 times with the arm and elbow at side of the body rotated inward so that the thumb and palm are facing the back of the body. Latissimus dorsi can be exercised by tensing it isometrically for 10 secs, 10 times by having the arm in extension (30° shoulder backward movement with the arm close to the side of the body).  

People with recurrent shoulder dislocations should not do push up activities which can dislocate the shoulder even more.  eToims® is ideal for selectively exercising these muscles and all other shoulder girdle and scapular muscles in order to strengthen those muscles which are weak and relax those muscles which are too tight.

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Work related neck disorders are common problems in office workers, especially among those who are intensive computer users. This study estimated the one-year prevalence of neck pain among office workers and to determine which physical, psychological and individual factors are associated with these prevalences. Five hundred and twelve office workers were studied. Information was collected by an online questionnaire. Self-reported neck pain during the preceding 12 months was regarded as a dependent variable, whereas different individual, work-related physical and psychosocial factors were studied as independent variables.

The 12 month prevalences of neck pain in office workers was 45.5%. Women had an almost two-fold risk compared with men . Persons older than 30 years have 2.61 times more chance of having neck pain than younger individuals. Being physically active decreases the likelihood of having neck pain. Significant associations were found between neck pain and often holding the neck in a forward bent posture for a prolonged time, often sitting for a prolonged time and often making the same movements per minute. Mental tiredness at the end of the workday and shortage of personnel are significantly associated with neck pain.

The results of this study indicate that physical and psychosocial work factors, as well as individual variables, are associated with the frequency of neck pain. These association patterns suggest also opportunities for intervention strategies in order to stimulate an ergonomic work place setting and increase a positive psychosocial work environment. (Cagnie B. Danneels L. Van Tiggelen D. De Loose V. Cambier D. Individual and work related risk factors for neck pain among office workers: a cross sectional study. European Spine Journal. 16(5):679-86, 2007 May).  

Sitting at work for more than 95% of the working time seems to be a risk factor for neck pain and there is a trend for a positive relation between neck flexion (more than 20 degrees) and neck pain. No clear relation was found between neck rotation and neck pain. (Ariens GA. Bongers PM. Douwes M. Miedema MC. Hoogendoorn WE. van der Wal G. Bouter LM. van Mechelen W. Are neck flexion, neck rotation, and sitting at work risk factors for neck pain? Results of a prospective cohort study. Occupational & Environmental Medicine. 58(3):200-7, 2001 Mar). 

Some evidence for a positive relationship between neck pain and the following work-related risk factors: neck flexion, arm force, arm posture, duration of sitting, twisting or bending of the trunk, hand-arm vibration, and workplace design. (Ariens GA. van Mechelen W. Bongers PM. Bouter LM. van der Wal G. Physical risk factors for neck pain. Scandinavian Journal of Work, Environment & Health. 26(1):7-19, 2000 Feb).

Shoulder injuries in tennis players are common because of the repetitive, high-magnitude forces generated around the shoulder during the various tennis strokes. An understanding of the complex sequences of muscle activity in this area may help reduce injury, enhance performance, and assist the rapid rehabilitation of the injured athlete.  

The supraspinatus, infraspinatus, subscapularis, middle deltoid, pectoralis major, latissimus dorsi, biceps brachii, and serratus anterior muscles were studied in six uninjured male Division II collegiate tennis players using dynamic electromyography (EMG) and synchronized high-speed photography.  The tennis serve contains four stages. Three stages characterize the forehand and backhand groundstrokes.

The results indicate that the subscapularis, pectoralis major, and serratus anterior display the greatest activity during the serve and forehand.  The middle deltoid, supraspinatus, and infraspinatus are most active in the acceleration and follow-through stages of the backhand. The biceps brachii increases its activity during cocking and follow-through in the serve with a similar pattern noted in the acceleration and follow-through stages of the forehand and backhand. The serratus anterior demonstrates intense activity in the serve and forehand, thus providing a stable platform for the humeral head and assisting in gleno-humeral-scapulothoracic synchrony.

The tennis serve and forehand and backhand groundstrokes are accomplished by complex sequences of muscle activity that incorporate contributions from the lower extremities and trunk into smooth, coordinated patterns. (Ryu RK. McCormick J. Jobe FW. Moynes DR. Antonelli DJ. An electromyographic analysis of shoulder function in tennis players. American Journal of Sports Medicine. 16(5):481-5, 1988 Sep-Oct.  

Rehabilitation and conditioning programs for tennis players should be structured to restore and optimize the activation sequences (scapular stabilisers before rotator cuff), task specific functions (serratus anterior as a retractor of the scapula, lower trapezius as a scapular stabilizer in the elevated rotating arm) and duration of activation of these muscles. (Kibler WB. Chandler TJ. Shapiro R. Conuel M. Muscle activation in coupled scapulohumeral motions in the high performance tennis serve. British Journal of Sports Medicine. 41(11):745-9, 2007 Nov).

Investigators have suggested that the greater prevalence of lateral humeral epicondylitis (tennis elbow) in novice tennis players compared to expert players may reflect the novice players' use of faulty mechanics for the backhand stroke.

Experts performed the backhand stroke with the wrist extended (re: neutral alignment of the forearm and hand dorsum), moreover, their wrists moved further into extension at impact. In contrast, novice subjects struck the ball with the wrist flexed while moving their wrists further into flexion.

The wrist motion analysis and EMG data together showed that the novice subjects eccentrically contracted their wrist extensor muscles throughout the stroke. The resulting eccentric (lengthening) contraction of wrist extensor muscles may contribute to lateral TE in novice players. Research evidence indicates that eccentric muscle contraction facilitates muscle fiber injury. (Blackwell JR. Cole KJ. Wrist kinematics differ in expert and novice tennis players performing the backhand stroke: implications for tennis elbow. Journal of Biomechanics. 27(5):509-16, 1994 May). 

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The mechanism of the overhead action in throwing sports and tennis has been studied extensively. This motion is unnatural and highly dynamic, often exceeding the physiological limits of the joint. Owing to overload of various anatomical structures, the shoulder is susceptible to injury. Optimal shoulder function requires good kinetic chain function, optimal stability, and coordination of the scapula in the overhead action. A well balanced action of the rotator cuff muscles and capsular structures is necessary to obtain a stable centre of rotation during the overhead action. (van der Hoeven H. Kibler WB. Shoulder injuries in tennis players. British Journal of Sports Medicine. 40(5):435-40; 2006 May).

Primary risk factor for glenohumeral joint injuries in overhead activity athletes is the imbalance of the external rotator cuff muscles which must contract eccentrically (lengthening contractions) while the internal rotator cuff muscles contract concentrically (shortening contractions).  To reduce such injuries to tennis players, upper extremity strength training program must include increasing the eccentric external rotator cuff total exercise capacity without a subsequent increase in the concentric internal rotator total exercise capacity.  (Niederbracht Y. Shim AL. Sloniger MA. Paternostro-Bayles M. Short TH. Effects of a shoulder injury prevention strength training program on eccentric external rotator muscle strength and glenohumeral joint imbalance in female overhead activity athletes. Journal of Strength & Conditioning Research. 22(1):140-5, 2008 Jan). 

A study was performed to broaden the understanding of muscle function during the tennis volley under different ball placement and speed conditions by examining the activity of selected superficial muscles of the stroking arm and shoulder (flexor carpi radialis, extensor carpi radialis, triceps brachii, deltoids, and pectoralis major) and muscles related to postural support (left and right external oblique, lumbar erector spinae, and gastrocnemius) during the volley. In general, muscle activity increased with increasing ball speed. The extensor carpi radialis was more active than the flexor carpi radialis during both forehand and backhand volleys, suggesting the importance of wrist extension/abduction and grip strength. The increase in EMG levels in the forearm muscles shortly before the ball impact indicated that the subjects did not tighten their grip and wrist until moments before ball impact. Both antero-middle and postero-middle deltoids were active in most stroke phases. However, the roles of the deltoid muscles during a volley cannot be determined without knowing the actions of the other shoulder joint muscles. (Chow JW. Carlton LG. Lim YT. Shim JH. Chae WS. Kuenster AF. Muscle activation during the tennis volley. Medicine & Science in Sports & Exercise. 31(6):846-54, 1999).  

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Computer use can give rise to repetitive strain injuries with resultant pain in the neck, arms, shoulders, forearms, wrists and hands. Additionally, more people are using video games and small keyboards associated with hand-held phone devices that can give rise to pain in the fingers, especially the thumbs, from constant texting.  

This following cross-sectional study evaluated the presence of pain and musculoskeletal pain syndromes in 791 adolescents to associate them to computer and video game use. The research included a questionnaire and physical examination of the musculoskeletal system. A computer was used by 99% and video games by 58%. Pain was reported by 312 (39.4%) students: 23% complained of back pain, 9% of upper limb pain, 4% of diffuse pain and 4% of pain in the trapezius muscle. A clinical examination was carried out in 359 students, and one or more musculoskeletal pain syndromes were present in 56 students (15.6%): benign joint hypermobility syndrome in 10%, myofascial syndrome in 5%, tendonitis in 2% and fibromyalgia in 1%. (Zapata AL. Moraes AJ. Leone C. Doria-Filho U. Silva CA. Pain and musculoskeletal pain syndromes related to computer and video game use in adolescents. European Journal of Pediatrics. 165(6):408-14, 2006 Jun). 

Another study in college students showed that of those students who use a laptop computer for all computer use, 90.1% reported musculoskeletal complaints.  The majority of female college students in this study reported musculoskeletal discomfort during or after computer use. Although a statistical correlation could not be made, students using laptop computers reported a higher incidence of musculoskeletal symptoms than those using desktop computers. (Hamilton AG. Jacobs K. Orsmond G. The prevalence of computer-related musculoskeletal complaints in female college students. Work. 24(4):387-94, 2005). 

Alternating between resting the forearms on the work surface and on the chairs' armrests could solicit different muscles during computer work, and could be considered as a strategy for preventing musculoskeletal disorders. 

When holding mobile devices for texting purposes, it is best that the head not be in a constant bent-down position, arms and elbows be held at the side of the body, the wrists not cocked up but kept in a slightly bent down position.  The thumb and fingers should not press the keyboard with excessive pressure by keeping them as straight as possible.  Long messages are best not to be typed on these hand-held devices.   The key to prevent repetitive injuries so it does not become chronic pain.  The key to prevention is to rest frequently and often.  Try resting for equal durations as time worked.

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World Anti-Doping Agency (WADA) lists many compounds such as beta-agonists, corticosteroids, and narcotics in addition to others.  Many substances on the list are detrimental for athletic prowess. 

Double-blind trials for amphetamines and other stimulants showed that they can enhance performance in short, explosive activities, such as sprinting. Anabolic steroids have been proved beyond any doubt to increase muscle mass and enhance performance among male athletes in sports that require strength, such as weightlifting and shot-putting; in women, they appear to work for endurance sports as well. History provides more circumstantial evidence: In many sports, the amazing rise in performances came to a halt after the crackdown on anabolic steroids began in earnest in the 1980s, and some records have not been broken since then.

One of the hottest substances of the moment, erythropoietin (EPO), has been tested for performance enhancement in only four double-blind trials, they showed that it increased maximum oxygen uptake and performance, but apparently for short durations only. Data are lacking because rigorous trials are expensive, and there's little incentive to fund them.

The drugs' target population, top athletes, usually can't be recruited into studies because it might ruin their careers. Also, the list of substances and combinations is endless; cyclists once used a cocktail of strychnine, cognac, and cocaine with many side effects.

WADA currently does research to improve detection of human growth hormone, a banned substance that appears to be very popular and is very hard to detect. In healthy people, for instance, an overdose of insulin–another listed substance that few believe does athletes any good–can lead to a fatal drop in blood sugar levels.

WADA wants to protect athletes from any drug they don't need, if only to send a message to their young fans. Practically anything can end up on WADA's list–and that athletes risk ending their careers by taking something that doesn't bring them one bit closer to a gold medal.  (ref: Martin Enserink, Science 1 August 2008:Vol. 321. no. 5889, p. 627)

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The forces produced by an athlete during the support phase of a sprint run are a vital determinant of the outcome of the performance. The purpose of this study was to improve the understanding of sprint technique in well-trained sprinters through the comprehensive analysis of joint kinetics during the support phase of a maximum-velocity sprint.  

It was found that the knee moment did not contribute substantially to power generation during the latter part of the support phase. This may be explained in part by the specific technical requirements of the maximum-velocity phase of the sprint. However, major periods of power generation of the hip extensors in early stance and of the plantar flexors in late stance were observed. The knee extensors played a negligible role in positive work generation throughout stance. The action of the knee joint during the support phase may therefore have been more of a facilitator for the radial transfer of power from the hip through the ankle on to the track. (Bezodis IN. Kerwin DG. Salo AI. Lower-limb mechanics during the support phase of maximum-velocity sprint running. Medicine & Science in Sports & Exercise. 40(4):707-15, 2008 Apr).  

Another study showed that (1) the difference in leg stiffness between endurance-trained and power-trained athletes is best attributed to increased joint stiffness, and (2) the difference in joint stiffness between the two groups may be attributed to a lack of similarity in the intrinsic stiffness of the muscle-tendon complex rather than in altered neural activity. (Hobara H. Kimura K. Omuro K. Gomi K. Muraoka T. Iso S. Kanosue K. Determinants of difference in leg stiffness between endurance- and power-trained athletes. Journal of Biomechanics. 41(3):506-14, 2008).

This study showed that the ability to produce force quickly, as measured by the time to achieve 60% of maximum voluntary contraction is related to sprinting performance, with the coefficient of determination accounting for 53% of the variance in the data. These data also show that sprinting ability is linked with drop jump performance, especially the drop jump from a height of 30 cm. It is suggested that the above tests may prove useful in preparing and testing the sprinting ability and sprint specific strength levels. (Bissas AI. Havenetidis K. The use of various strength-power tests as predictors of sprint running performance. Journal of Sports Medicine & Physical Fitness. 48(1):49-54, 2008 Mar.)  

In a study to investigate the effects of performing heavy back squats and heavy front squats on the average speed during each 10-m interval of 40-m sprint trials. Heavy back squats produced significantly greater speeds compared with the heavy front squats treatment.  It is suggested that coaches could incorporate heavy back squats into the warm-up procedure of athletes to improve sprinting performance. (Yetter M. Moir GL. The acute effects of heavy back and front squats on speed during forty-meter sprint trials. Journal of Strength & Conditioning Research. 22(1):159-65, 2008).

As you view the Olympics gymnasts perform, do you wonder about their pain problems and what muscles may be prone to injuries and how to minimize injuries? 

Pain is a serious problem in advanced level female artistic gymnasts because it decreases the performance. The pain is due to the high numbers of hours spent in training sessions and may be associated to injuries that have relatively high incidence and severity in these athletes.  

This study investigated the role of a preventive-compensative physical activity program, implemented in the warm-up and the cool-down session of standard training, in the prevention and reduction of the pain syndromes by evaluating thirty elite level female athletes, 10-14 years old, who were followed for 12 weeks during the competition preparation period. Fifteen athletes were trained with preventive-compensative motor program implemented in the ordinary training (intervention group) and fifteen (control group) followed the standard training. All athletes completed a self-administered questionnaire regarding the pain intensity with a Visual Analogue Scale pre- and post- intervention.  The experimental protocol consisted of three steps: the treatment of the shortened muscle chains according to Active Posture Reeducation method, the proprioceptive-coordinative training with wobble board and the mobilization and stretching of back using fitball.

Before intervention, the pain in practicing this sport was reported by 83% of all the athletes. The most common primary pain sites were the ankle and low back; the pain anatomical location was correlated to the training. After intervention, low back pain assessment showed a decrease of pain identified as mild (from 56% to 44%) or moderate (from 33% to 22%) and a disappearance of severe pain (from 11% to 0%). Ankle pain decreased and/or disappeared: the mild pain from 33% to 27%, moderate from 27% to 13% and severe from 13% to 0%. The pain analysis did not show different results in the control group. 

The results indicated that the performed preventive-compensative training is of value, in a short time perspective, in preventing and reducing the pain syndromes in these athletes.( Mirca M. Eleonora S. Edy B. Marina P. Marco M. Pain syndromes in competitive elite level female artistic gymnasts. role of specific preventive-compensative activity. Italian Journal of Anatomy & Embryology. 113(1):47-54, 2008 Jan-Mar.) 

Scapular muscle performance in elite, young gymnasts is characterized by increased protraction strength and altered muscular balance around the scapula compared with nonathletic adolescents. (Cools AM. Geerooms E. Van den Berghe DF. Cambier DC. Witvrouw EE. Isokinetic scapular muscle performance in young elite gymnasts. Journal of Athletic Training. 42(4):458-63, 2007 Oct-Dec). 

To evaluate a specific segmental muscle training program of the lumbar spine in order to prevent and reduce low back pain in young female teamgym gymnasts. Teamgym is a team sport comprising three events: trampette, tumbling and floor program. In a recent study, it was found that teamgym gymnasts practice and compete despite suffering from back pain. Specific muscle control exercises of the lumbar spine have shown good results in reducing pain intensity and functional disability levels in patients with low back pain. 

Fifty-one gymnasts, with and without LBP, 11-16 years old, from three top-level gymnastics team participated in the study comprising 12 weeks. Every day the gymnasts answered a questionnaire regarding low back pain. After baseline (4 weeks) the intervention group performed a specific segmental muscle training program. Twenty-four gymnasts (47%) reported low back pain during baseline. Nine gymnasts failed to answer the questionnaire every day and the following results are based on 42 gymnasts (intervention group, n = 30, and control group, n=12). Gymnasts in the intervention group reported significantly less number of days with low back pain at completion compared to baseline (P=0.02). Gymnasts in the control group showed no difference in terms of days with low back pain or intensity of low back pain between baseline and completion. Eight gymnasts (out of 15) with LBP in the intervention group became pain free.

Specific segmental muscle control exercises of the lumbar spine may be of value in preventing and reducing low back pain in young teamgym gymnasts.  (Harringe ML. Nordgren JS. Arvidsson I. Werner S. Low back pain in young female gymnasts and the effect of specific segmental muscle control exercises of the lumbar spine: a prospective controlled intervention study. Knee Surgery, Sports Traumatology, Arthroscopy. 15(10):1264-71, 2007 Oct). 

In the floor exercise, a gymnast may receive a general composition score deduction associated with a lack of diverse tumbling sequences. Diversity in tumbling is defined as the ability to tumble both forward and backward, as well as twist and flip. A coach's ability to direct technical and physical training for these skill varieties is enhanced when thorough descriptions of the skills are available.

The aim of this study was to describe and compare muscle activation of the lower extremity in various tumbling sequences characterized by differing body orientations. The stretch-shortening cycle actions during the take-off portion of four different tumbling sequences were analysed and the results compared across muscles and type of take-off (forward vs. backward, twisting vs. non-twisting).

Thirteen female gymnasts performed three trials each of round-off flic-flac to backward layout and to backward layout with longitudinal axis twist, and front flic-flac to forward layout and to forward layout with longitudinal axis twist. Activation onset was assessed as an increase of the EMG of 200% above noise before initial floor contact. The EMG was normalized to peak values for each muscle bilaterally during each take-off.

Results showed that muscle activation characteristics in the pre-activation and impact phase (contact to maximal floor depression) differed between tumbling series. Backward take-offs were characterized by longer contact times, greater relative activity of the gastrocnemius compared with the vastus lateralis during pre-activation, and greater biceps femoris activation during impact compared with forward take-offs. Twisting backward was associated with reduced muscle activity of the twisting limb, while twisting forward was associated with increased muscle activation on the twisting limb. These differential effects related to the specific nature of the take-off indicate that training to enhance the stretch-shortening cycle action in gymnasts must be specific to the orientation requirements of each specific skill. (McNeal JR. Sands WA. Shultz BB. Muscle activation characteristics of tumbling take-offs. Sports Biomechanics. 6(3):375-90, 2007 Sep).

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