Cumulative Trauma Disorders Research Papers (original) (raw)

Prospective studies on overuse injuries and their impact on athletic training among youth team sports are scarce. The purpose of this study was to investigate the incidence, severity and player related risk factors of overuse injuries among young (12–20 years) basketball and floorball players. A total of 387 players participated in a 3-year prospective study. Each player completed a baseline questionnaire regarding their background information. Overuse injuries that prevented players to fully or partly participate in their regular training were collected. In all, 204 overuse injuries were registered (injury incidence 1.51 injuries/1 000 h of exposure; 95% CI 1.35–1.78). Most of the injuries involved the knee (35%) and lower back (21%), and were classified as severe (44%). Injury incidence was 1.51 (95% CI 1.2–1.82) and 1.61 (95% CI 1.32–1.91) in basketball and floorball, respectively. Incidence was significantly higher among female compared with male players (incidence rate ratio 1....

- by
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- Mechanical Engineering, Sports Medicine, Adolescent, Finland

Greater insight into sports and work performance of athletes with patellar tendinopathy (PT) will help establish the severity of this common overuse injury. Primary aim of this study is to investigate the impact of PT on sports and work performance. Seventy seven active athletes with PT (50 males; age 28.1 ± 8.2 years; Victorian Institute of Sports Assessment Patella 56.4 ± 12.3) participated in this survey. Sports performance, work ability and work productivity were assessed using the Oslo Sports Trauma Research Center overuse injury questionnaire, the single-item Work Ability Index and the Quantity and Quality questionnaire, respectively. Reduced sports performance was reported by 55% of the participants; 16% reported reduced work ability and 36% decreased work productivity, with 23% and 58%, respectively, for physically demanding work. This study shows that the impact of PT on sports and work performance is substantial and stresses the importance of developing preventive measures.

- by Ron Diercks
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- Mechanical Engineering, Sports Medicine, Medicine, Tendinopathy

Background: The popularity of running is still growing and, as participation increases, the incidence of running-related injuries will also rise. Iliotibial band syndrome (ITBS) is the most common injury of the lateral side of the knee in runners, with an incidence estimated to be between 5% and 14%. In order to facilitate the evidence-based management of ITBS in runners, more needs to be learned about the aetiology, diagnosis and treatment of this injury. Objective: This article provides a systematic review of the literature on the aetiology, diagnosis and treatment of ITBS in runners. Search strategy: The Cochrane Library, MEDLINE, EMBASE, CINAHL, Web of Science, and reference lists were searched for relevant articles. Selection criteria: Systematic reviews, clinical trials or observational studies involving adult runners (>18 years) that focused on the aetiology, diagnosis and/or treatment of ITBS were included and articles not written in English, French, German or Dutch were excluded. Data collection and analysis: Two reviewers independently screened search results, assessed methodological quality and extracted data. The sum of all positive ratings divided by the maximum score was the percentage quality score (QS). Only studies with a QS higher than 60% were included in the analysis. The following data were extracted: study design; number and characteristics of participants; diagnostic criteria for ITBS; exposure/treatment characteristics; analyses/outcome variables of the study; and setting and theoretical perspective on ITBS.

- by Anton De Wijer
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- Mechanical Engineering, Sports Medicine, Running, Exercise therapy

Injury to the ulnar collateral ligament (UCL) of the elbow causes significant disability in the throwing athlete. The most significant symptom is medial elbow pain. It is occasionally accompanied by ulnar nerve paresthesias. Throwers usually notice a decrement in their velocity and/or control. 2,3 In high school baseball, most UCL injuries become apparent in a single throw, in which a popping or tearing sensation in the elbow is accompanied by immediate medial elbow pain. The microtrauma leading up to this injury, however, is usually accumulated over a season or more. Evidence of this microtrauma can often be seen on radiographs that show healed avulsion fractures of the sublime tubercle of the ulna or ossification within the UCL. We have seen, based on experience at our institution, a dramatic increase in baseball players who require UCL surgery. Most alarming is the fact that there has been a 50% increase in the proportion of surgeries performed on high school players. Between 1988 and 1994, the senior author (JRA) performed UCL reconstruction or repair on 85 baseball players. 3 Of this group, 8% (7/85) were high school players. Between 1995 and mid-2003, the senior author performed UCL reconstruction or repair on 609 baseball players, of whom 13% (77/609) were high school players.

- by Glenn S Fleisig
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- Mechanical Engineering, Biomedical Engineering, Baseball, Treatment Outcome

To evaluate the ability of ultrasonography to predict eventual symptoms in an at-risk population, 52 elite junior basketball players' patellar tendons were studied at baseline and again 16 months later. The group consisted of 10 study tendons (ultrasonographically hypoechoic at baseline) and 42 control tendons (ultrasonographically normal at baseline). By design, all tendons were asymptomatic at baseline. No differences were noted between subjects and controls at baseline for age, height, weight, training hours, and vertical jump. Functional (P < 0.01) and symptomatic outcome (P < 0.05) were poorer for subjects' tendons than for controls. Relative risk for developing symptoms of jumper's knee was 4.2 times greater in case tendons than in control tendons. Men were more likely to develop ultrasonographic changes than women (P < 0.025), and they also had significantly increased training hours per week (P < 0.01) in the study period. Half (50%) of abnormal tendon...

- by Zoltan Kiss
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- Ultrasound, Adolescent, Prospective studies, Basketball
- by John O'Byrne
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- Rheumatology, Magnetic Resonance Imaging, Quality of life, Dancing

Studies regarding ankle and foot overuse injuries are quite diverse in research methodology, data reporting, and outcomes. The aims of this systematic review were to analyze the methodology of published studies regarding ankle and foot overuse injuries in different sports disciplines and to summarize epidemiological data of ankle and foot overuse injuries. Four electronic databases, PubMed (MEDLINE), EMBASE, CINAHL, and SPORTDiscus(®) were systematically searched up to June 2011. A total of 89 articles on 23 sports disciplines were included in this review. Soccer, running, and gymnastics were the most frequently studied sports. Achilles tendinopathy, plantar fasciitis, and stress fracture were the most frequently studied injuries. Study design and reporting methods were heterogeneous. Most studies suffered from a weak methodology and poor reporting. The most common weaknesses were lack of a clear case definition, describing assessment procedures and reporting sample characteristics....

- by R dekker
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- Soccer, Running, Tendinopathy, Gymnastics

Epicondylitis is a common disorder of the arm, yet the role of individual-and work-related factors has not been addressed in a population study. The aims of this study were to estimate the prevalence of lateral and medial epicondylitis and to investigate their risk factors. The target population of this study comprised a representative sample of people aged 30-64 years residing in Finland during 2000-2001. Of the 5,871 subjects, 4,783 (81.5%) were included in this study. The prevalence of definite lateral epicondylitis was 1.3%, and that of medial epicondylitis was 0.4%. The prevalence did not differ between men and women and was highest in subjects aged 45-54 years. Current smoking (adjusted odds ratio (OR) ¼ 3.4, 95% confidence interval (CI): 1.4, 8.3) and former smoking (OR ¼ 3.0, 95% CI: 1.3, 6.6) were associated with definite lateral epicondylitis. An interaction (p ¼ 0.002) was found between repetitive movements of the arms and forceful activities for the risk of possible or definite lateral epicondylitis (for both repetitive and forceful activities vs. no such activity: OR ¼ 5.6, 95% CI: 1.9, 16.5). Smoking, obesity, repetitive movements, and forceful activities independently of each other showed significant associations with medial epicondylitis. Epicondylitis is relatively common among working-age individuals in the general population. Physical load factors, smoking, and obesity are strong determinants of epicondylitis.

- by R. Shiri
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- Obesity, Finland, Diabetes mellitus, Smoking
- by Mark Batt
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- Engineering, Mechanical Engineering, Education, Magnetic Resonance Imaging

- by Anton De Wijer
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- Mechanical Engineering, Sports Medicine, Running, Exercise therapy
- by Laura Punnett and +1
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- Nursing, Research Design, Research, Prospective studies

Objective: To examine hip abductor strength in longdistance runners with iliotibial band syndrome (ITBS), comparing their injured-limb strength to their nonaffected limb and to the limbs of a control group of healthy long-distance runners; and to determine whether correction of strength deficits in the hip abductors of the affected runners through a rehabilitation program correlates with a successful return to running.

- by Ajit Chaudhari
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- Running, Adolescent, Tibia, United States
- by Matt Wallden
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- Complementary and Alternative Medicine, Yoga, Massage, Pregnancy

Objectives: Shoulder disorders in the occupational environment have been widely studied, but the quality of research and methodology applied vary. Little has been done to ascertain whether shoulder pain in female repetitive workers is due to any verifiable pathology, or to compare findings with the general population. Therefore, we decided to evaluate the prevalence of self-reported shoulder pain in a group of female supermarket cashiers and in the general female population using a standardized questionnaire. Shoulder pain prevalence was then compared to imaging findings in order to assess specific and non-specific pain prevalence. Material and Methods: 196 cashiers and 302 controls filled in a standardized shoulder questionnaire and underwent an imaging examination of a shoulder. Results: The prevalence of shoulder pain was significantly higher in the group of cashiers (46.4%) than in the general population (25.5%) (OR = 1.821; 95% CI: 1.426-2.325). Specific pain prevalence was higher among the controls (19.5%) than among the cashiers (13.2%). Conclusions: The more frequent reports of shoulder pain in the supermarket cashiers are not correlated with a higher prevalence of imaging abnormalities. The causes of these more frequent complaints should be probably sought in the psycho-social and occupational environment.

- by Valerio Sansone
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- Italy, Commerce, Risk factors, SHOULDER PAIN

The objectives of this study were to investigate the rate of cumulative trauma disorders (CTDs) in the upper body and to describe the associations of such disorders with ergonomic parameters in a group of data entry operators. A total of 173 data entry operators volunteered to take part in the study. Questionnaires were used to investigate their medical history. Diagnoses of CTDs were made with clinical tests. A visual posture analysis of the workers and an ergonomic analysis of workstations and workload were used to reveal risk factors. Neck and shoulder pain, extensor tendonitis of the wrists and De Quervain's disease were common in the study population. An assessment of risk factors showed that leaning wrists on the keyboard, hard keystrokes, extreme wrist joint and thumb positions and working in poor ergonomic design were correlated to pain and development of CTDs.

- by Mufit Akyuz
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- Electromyography, Risk factors, Posture, Occupational

In recent years the popularity of disabled sports and competition among disabled athletes has grown considerably. With this rise in exposure of, and participation in wheelchair sports comes an increase in related stressors, including musculoskeletal load. External mechanical loading may increase the risk of shoulder complaints. The objective of this literature review was to 1) identify and describe the prevalence and/or incidence of shoulder complaints in wheelchair athletes in the literature, to 2) examine the factors and underlying mechanisms that could be potentially involved, and 3) provide some insights into the development of preventative measures. A literature search was conducted using PubMed, Scopus and Embase databases, to identify relevant published articles. All articles in the English language that contained any type of shoulder complaint in relation with a wheelchair sports player, at any level of status (recreational to elite), of any sport, were included. Articles we...

- by Riemer Vegter
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- Multidisciplinary, Sports, Shoulder, Wheelchairs
- by Nicola Petrone
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- Engineering, Education, Biomechanics, Injury Prevention

Ballet is a highly demanding activity that requires a unique balance of athleticism and artistry. Participation in ballet declines with age because of a variety of factors, with injury frequently implicated." There are numerous epidemiologic studies of dance injuries, with injury incidence of 40% to 80% depending on the level of parti~ipation,~, 34, 44 and a lifetime incidence of up to 90% for all Many studies document injury patterns, with the lower leg, foot, and ankle making up roughly 40%, and the knee and hip each about 20%, of injuries.34, 36

- by Nancy Kadel
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- Mechanical Engineering, Dancing, Human Body, Cumulative Trauma Disorders

Objective: To investigate shoulder pain incidence rates and selected risk factors for shoulder pain in competitive swimmers. Design: 12-month prospective cohort study. Setting: Five swimming clubs in Melbourne, Australia. Participants: 74 (37 M, 37 F) competitive swimmers ranging in age from 11 to 27 years and performing at least five swim sessions per week. Assessment of risk factors: Swimmers completed a baseline questionnaire regarding demographics, anthropometric features, swimming characteristics and training and injury history. Active shoulder internal (IR) and external rotation (ER) range of motion and passive joint laxity were measured. Main outcome measurements: Shoulder pain was self-reported over 12 months with significant interfering shoulder pain (SIP) defined as pain interfering (causing cessation or modification) with training or competition, or progression in training. A significant shoulder injury (SSI) was any SIP episode lasting for at least 2 weeks. Results: 28/74 (38%) participants reported SIP while 17/74 (23%) reported SSI. Exposure-adjusted incidence rates were 0.3 injuries and 0.2 injuries per 1000 swim km for SIP and SSI, respectively. Swimmers with both high and low ER range were at 8.1 (1.5, 42.0) and 12.5 (2.5, 62.4) times greater risk of sustaining a subsequent SIP, respectively and 35.4 (2.8, 441.4) and 32.5 (2.7, 389.6) times greater risk of sustaining a SSI, respectively than those with mid-range ER. Similarly swimmers with a history of shoulder pain were 4.1 (95% CI: 1.3, 13.3) and 11.3 (95% CI: 2.6, 48. 4) times more likely to sustain a SIP and SSI, respectively.

- by Henry Wajswelner
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- Australia, Adolescent, Swimming, Prospective studies

Verletzungen des Skelettmuskels gehören mit 10-55% zu den häufigsten Sportverletzungen überhaupt [7, 22, 32]. Sie können aufgrund von außen einwirkender Gewalt (Traumen) oder durch verschiedene innere Ursachen (Stoffwechsel, Vorschädigung etc.) hervorgerufen werden. Dabei kommt es zu einem Missverhältnis zwischen Belastung und Belastbarkeit, was posttraumatisch innerhalb eines bestimmten Regenerationszeitraums (Stunden bis Wochen) zu einer Funktionseinschränkung der Muskulatur führt.

The purpose of this study was to determine the biomechanical and anthropometric factors contributing to elbow valgus torque during pitching. Video data of 14 youth pitchers throwing fastballs were used to calculate shoulder and elbow kinematics and kinetics. Peak elbow valgus torque averaged 18 Nm and occurred just before maximal shoulder external rotation. The magnitude of valgus torque was most closely correlated with the thrower's weight. When subject weight and height were controlled for, maximum shoulder abduction torque and maximum shoulder internal rotation torque were most strongly associated with elbow valgus torque, accounting for 85% of its variance (P <.001). When only kinematic variables were considered, maximum shoulder external rotation accounted for 33% of the variance in valgus torque. Given that the biomechanical variables correlated with peak valgus torque are not easily modifiable, limiting the number of innings pitched is likely the best way to reduce elb...

- by Michelle Sabick
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- Kinetics, Baseball, Anthropometry, Child

The purpose of this study was to examine the nature, extent and severity of sports injuries in young female players in European team handball and to identify the etiological factors involved in the injuries. Twenty-two teams with 217 players, aged 16-18 years, participated in the study. A very high injury incidence during games was observed, with 40.7 injuries/ 1000 hours of game. Backplayers had the highest incidence (54.8/1000 hours), which is five times higher than any previously recorded injury incidence in players in European team handball. We found that 92.9% of injuries were traumatic and 7.1% were from overuse. One-hundred and twenty-four of the 21 1 injuries were traumatic injuries of the lower extremities. Of these 63 (51%) were without contact with an opponent. The study confirmed that European team handball is a sport that has a very high injury rate, especially regarding young female players. Field position and earlier injuries are major risk factors, with an earlier injury being the single highest risk factor and with backplayers having a significantly higher number of injuries than players in other field positions.

- by Niels Wedderkopp and +1
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- Adolescent, Medicine, Sports, Denmark

- by Lucas van der Woude
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- Multidisciplinary, Sports, Shoulder, Wheelchairs

Symptoms of jumper's knee (patellar tendinosis) are not easily quantitated and this may explain why there are no evidence-based guidelines for managing the condition. A simple, practical questionnaire-based index of severity would facilitate jumper's knee research and subsequently, clinical management. Thus we devised and tested the Victorian Institute of Sport Assessment (VISA scale) questionnaire. The brief questionnaire assesses (i) symptoms, (ii) simple tests of function and (iii) ability to undertake physical activity. Six of the eight questions are scored on a visual analogue scale from 0-10 with 10 representing optimal health. The maximal VISA score for an asymptomatic, fully performing individual is 100 points and the theoretical minimum is 0 points.

- by Gil Rodas
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- Exercise therapy, Massage, Cryotherapy, Tendinopathy

This paper reviews the literature concerning the use of surface electromyography (sEMG) for the study of the neck musculature in response to work and workplace design during light work and semi-static tasks. The paper also draws upon basic research and biomechanical modeling in order to provide methodological recommendations for the use of surface electromyography in this region of the body and to identify areas which require further investigation. The paper includes review and discussion of electrode site location, methods of normalization, data reliability, and factors that can affect sEMG signals from this region, including noise, physiologic artifact, stress, visual deficiencies, and pain. General guidance for maximum exertions with the neck musculature, for sEMG normalization or other purposes, is also included.

- by Sharon Joines
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- Electromyography, Cumulative Trauma Disorders, Basic Research, Electrodes

Lower extremity overuse injuries are associated with gluteus medius (GMed) weakness. Understanding the activation of muscles about the hip during strengthening exercises is important for rehabilitation. To compare the electromyographic activity produced by the gluteus medius (GMed), tensor fascia latae (TFL), anterior hip flexors (AHF), and gluteus maximus (GMax) during 3 hip-strengthening exercises: hip abduction (ABD), hip abduction with external rotation (ABD-ER), and clamshell (CLAM) exercises. Controlled laboratory study. Laboratory. Twenty healthy runners (9 men, 11 women; age = 25.45 ± 5.80 years, height = 1.71 ± 0.07 m, mass = 64.43 ± 7.75 kg) participated. A weight equal to 5% body mass was affixed to the ankle for the ABD and ABD-ER exercises, and an equivalent load was affixed for the CLAM exercise. A pressure biofeedback unit was placed beneath the trunk to provide positional feedback. Surface electromyography (root mean square normalized to maximal voluntary isometric c...

- by Wendy Huddleston
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- Skeletal muscle biology, Running, Resistance Training, Athletic Training

ENT/phoniatrics specialists are frequently the primary reference persons for patients who have problems with the professional use of their voice. Singers show the highest risk factors for voice disorders among all professional voice users. The treatment and care of singers requires specific knowledge and competence of the physician, as well as a treatment setting adapted to the needs of this special group of patients, whose existence depends on the use of their voice. To some extent, evidence based concepts can be taken into account when treating professional singers. In cases for which no concepts have yet been developed and evaluated, recourse to clinical experience is necessary. In the present paper, current concepts for the treatment of singers are discussed on the basis of scientific publications and on long-standing experience of consultations in musician's medicine and ENT, under the aspects of diagnosis, therapy as well as prevention, taking into account the most frequen...

- by Matthias Echternach
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- Music, Treatment, Risk assessment, Phonation

Iliotibial band friction syndrome (ITBFS) is a common injury of the lateral aspect of the knee particularly in runners, cyclists and endurance sports. A number of authors suggest that ITBFS responds well to conservative treatment, however, much of this opinion appears anecdotal and not supported by evidence within the literature. The purpose of this paper is to provide a systematic review of the literature pertaining to the conservative treatment of ITBFS.

- by Richard Ellis and +1
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- Manual Therapy, Massage, Systematic review, Clinical Sciences

A pathway-based approach investigating the genes encoding interleukin-1β, interleukin-6 and the interleukin-1 receptor antagonist provides new insight into the genetic susceptibility of Achilles tendinopathy ABSTRACT Objectives Achilles tendinopathy (AT) is a multifactorial condition for which genetic risk factors have been identifi ed. A pathway-based approach was used to investigate genes within the infl ammatory pathway. Methods Functional polymorphisms within IL-1β (−31T→C and −511C→T), IL-1RN (variable number tandem repeat) and IL-6 (−172G→C) were investigated for associations with AT in a South African (SA) and Australian (AUS) case-control studies. A total of 369 (161 SA and 208 AUS) asymptomatic control participants (CON) and 175 (90 SA and 85 AUS) participants with AT (TEN) were genotyped. Allele combinations were constructed using the above polymorphisms in combination with the COL5A1 BstUI RFLP. Results Independently, no associations were observed between any of the polymorphisms tested and risk of TEN. The allele combinations of fi ve polymorphisms were, however, found to have a highly signifi cant relationship with AT (p=0.005), after adjusting for gender and country (SA or AUS). Conclusions Variations within the interleukin genes and the COL5A1 BstUI CC genotype are collectively signifi cantly associated with risk of AT. This research emphasises that a pathway-based genetic association study may be a more effective approach to capture and understand the genetic risk factors underlying the multifactorial conditions, such as AT.

- by Alison September and +1
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- Engineering, Education, British, Tendinopathy

Work-related neck and upper limb disorders (WRNULD) are common problems among office workers who use computers intensively and maintain prolonged static postures. These disorders have often been attributed to result from sustained muscle activity in the neck–shoulder musculature. The present study examined whether symptomatic subjects exhibited the same muscle activity patterns as asymptomatic controls when they performed a prolonged computer

- by Leon Straker
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- Skeletal muscle biology, Motor Control, Manual Therapy, Multivariate Analysis

Dupuytren 's contracture (DC) is a disease of the palniar fascia resulting in thickening rind contracture of fibrous bands on the palmar sugace of the hands arid fingers. For decades, a controversy has e.xisted regarding whether acute traumatic injury or cumulative biomechanical work exposure can contribute to the development of this disorder. To address this controversy, this review considers the following questions: Is there e\idence that DC is associated Lcith I) frequent or repetitive munual work; and 2) hand vibration ? The published literature M."S searched,for studies meeting the following criteria: I) in English or having un Eiiglisli abstract; 2) controlled studies; 3) DC an identified health outcome studied; and 4) the study group exposed to repetitive or frequent manual work. vibration, or acute traumatic injuv. Relevant non-English articles identified through English abstructs were translated. The validity of studies meeting the selection criteria was assessed using a series qf questions adapted from those of Stock 11991: Am J Ind Med 19:87-1071. Studies that met a priori minimum levels of methodologic quality were taken into account to reach conclusions with respect to the above questions. Odds ratios (ORs) and 95% confidence intervals (CIS) were calculated fiw each study. Ten studies met the initial selection criteria. Of these, four studies met the criteria for methodologic quality, one addressing the relationship between manual work and DC, arid three studies of vibration arid DC. No controlled studies of acute trauma and DC were identified. Bennett 1196'2: Br J Ind Med 39:98-100].found the prevalence of DC at a British PVC bagging and packing plant in which workers were exposed to repetitive ntanual work to be 5.

- by Susan R. Stock
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- Vibration, Causality, Medicine, Public health systems and services research
- by Ulrich Fredberg
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- Pain, Skeletal muscle biology, Differential Diagnosis, Rupture
- by Todd Ellenbecker and +2
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- Sports Medicine, Kinetics, Adolescent, Rotator cuff
- by Ruth Solomon
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- Mechanical Engineering, Dancing, Adolescent, Dance

It has been speculated that repetitive patterns of movement will lead to specific patterns in fascia contraction, which, if it exceeds a specific limit, will lead to injury. Therapists working in the athletic environment are challenged to find ways not only to assess and measure fascia dysfunction, but also to restore functional strength by manipulating the fascia back to its neutral position. The 'Bunkie' test was developed over a period of 12 years to measure the function of the specific fascia lines in athletes. Numerous athletes from various sports were assessed and treated. Results have shown over the years that this test can be used successfully to find the cause of and treat injuries and to determine the progress of treatment in elite and recreational athletes.

- by Benita Kropman and +1
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- Sports Medicine, Complementary and Alternative Medicine, Fascia, Cumulative Trauma Disorders
- by Angelo Cacchio and +1
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- Engineering, Education, Psychometrics, Adolescent

Sports medicine practitioners have begun to realise that factors proximal to the site of the injury, such as hip muscle weakness, may play a role in lower extremity injury potential. The purpose of this review is to describe current theories and various levels of evidence supporting hip muscle strengthening and/or weakness and lower extremity athletic injuries. Studies describing normal running mechanics, as well as relationships between hip muscle weakness and lower extremity athletic injuries, are described. Some common examples of hip muscle testing, as well as strengthening and rehabilitation exercises, are displayed.

- by Thomas Thieman
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- Running, Adolescent, Clinical, Analysis of Variance

The effects of tennis racket grip size on the forces exerted by muscles affecting lateral 23 epicondylalgia (LE) were assessed in this study. Grip forces and joint moments applied on the 24 wrist were quantified under three different handle size conditions, with and without induced 25 muscle fatigue for intermediate and advanced players. The obtained experimental results were 26 then used as input data of a biomechanical model of the hand. This simulation aimed to 27 quantify the impact of grip strength modulation obtained in the experiment on the wrist 28 extensor muscle forces. Our results show that there is an optimal grip diameter size defined as 29 the handle inducing a reduced grip force during the stroke, in both fatigued and non-fatigued 30

- by E. Berton
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- Skeletal muscle biology, Tennis, Computer Simulation, Young Adult

Objective: The primary goal of this study was to use the Strain Index (SI) to assess the risk of developing upper extremity musculoskeletal disorders in a television (TV) manufacturing industry and evaluate the effectiveness of an educational intervention. Methods: The project was designed and implemented in two stages. In first stage, the SI score was calculated and the Nordic Musculoskeletal Questionnaire (NMQ) was completed. Following this, hazardous jobs were identified and existing risk factors in these jobs were studied. Based on these data, an educational intervention was designed and implemented. In the second stage, three months after implementing the interventions, the SI score was re-calculated and the Nordic Musculoskeletal Questionnaire (NMQ) completed again. Participants: 80 assembly workers of an Iranian TV manufacturing industry were randomly selected using simple random sampling approach. Results: The results showed that the SI score had a good correlation with the symptoms of musculoskeletal disorders. It was also observed that the difference between prevalence of signs and symptoms of musculoskeletal disorders, before and after intervention, was significantly reduced. Conclusions: A well conducted implementation of an interventional program with total participation of all stakeholders can lead to a decrease in musculoskeletal disorders.

- by Majid Motamedzade and +1
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- Mechanical Engineering, Psychology, Health Education, Television

• Youth sport participation offers many benefits including the development of self-esteem, peer socialization, and general fitness. • However, an emphasis on competitive success, often driven by goals of elite-level travel team selection, collegiate scholarships, Olympic and National team membership, and even professional contracts, has seemingly become widespread. • This has resulted in increased pressure to begin highintensity training at young ages. • Such an excessive focus on early intensive training and competition at young ages rather than skill development can lead to overuse injury and burnout.

- by Holly Benjamin
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- Engineering, Sports Medicine, Education, Risk assessment

Anterior knee pain is a common complain in all ages athletes. It may be caused by a large variety of injuries. There is a continuum of diagnoses and most of the disorders are closely related. Repeated minor trauma and overuse play an important role for the development of lesions in Hoffa&amp;amp;amp;amp;amp;#39;s pad, extensor mechanism, lateral and medial restrain structures or cartilage surface, however usually an increase or change of activity is referred. Although the direct relation of cartilage lesions, especially chondral, and pain is a subject of debate these lesions may be responsible of early osteoarthrosis and can determine athlete&amp;amp;amp;amp;amp;#39;s prognosis. The anatomy and biomechanics of patellofemoral joint is complex and symptoms are often unspecific. Transient patellar dislocation has MR distinct features that provide evidence of prior dislocation and rules our complication. However, anterior knee pain more often is related to overuse and repeated minor trauma. Patella and quadriceps tendon have been also implicated in anterior knee pain, as well as lateral or medial restraint structures and Hoffa&amp;amp;amp;amp;amp;#39;s pad. US and MR are excellent tools for the diagnosis of superficial tendons, the advantage of MR is that permits to rule out other sources of intraarticular derangements. Due to the complex anatomy and biomechanic of patellofemoral joint maltracking is not fully understood; plain films and CT allow the study of malalignment, new CT and MR kinematic studies have promising results but further studies are needed. Our purpose here is to describe how imaging techniques can be helpful in precisely defining the origin of the patient&amp;amp;amp;amp;amp;#39;s complaint and thus improve understanding and management of these injuries.

- by Mario Padron and +1
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- Pain, Dislocations, Differential Diagnosis, Diagnostic Imaging

Background: The prevalence of musculoskeletal pain in the shoulder, arm and hand is high among slaughterhouse workers, allegedly due to the highly repetitive and forceful exposure of these body regions during work. Work disability is a common consequence of these pains. Lowering the physical exposure through ergonomics intervention is the traditional strategy to reduce the workload. An alternative strategy could be to increase physical capacity of the worker through strength training. This study investigates the effect of two contrasting interventions, participatory ergonomics versus strength training on pain and work disability in slaughterhouse workers with chronic pain. Methods/design: 66 slaughterhouse workers were allocated to 10 weeks of (1) strength training of the shoulder, arm and hand muscles for 3 x 10 minutes per week, or (2) participatory ergonomics involving counseling on workstation adjustment and optimal use of work tools (~usual care control group). Inclusion criteria were (1) working at a slaughterhouse for at least 30 hours per week, (2) pain intensity in the shoulder, elbow/forearm, or hand/wrist of at least 3 on a 0-10 VAS scale during the last three months, (3) pain lasting for more than 3 months, (4) frequent pain (at least 3 days per week) (5) at least moderate work disability, (6) no strength training during the last year, (7) no ergonomics instruction during the last year. Perceived pain intensity (VAS scale 0-10) of the shoulder, elbow/forearm and hand/wrist (primary outcome) and Disability of the Arm, Shoulder and Hand (Work module, DASH questionnaire) were measured at baseline and 10-week follow-up. Further, total muscle tenderness score and muscle function were assessed during clinical examination at baseline and follow-up.

- by Roger Persson
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- Research Design, Biomechanics, Occupational Health, Chronic Pain
- by Cynthia Labella and +3
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- Pediatrics, Baseball, Risk assessment, Adolescent

Six different methods to calculate the Strain Index (SI) scores for jobs with multiple forces/tasks were developed. Exposure data of 733 subjects from 12 different worksites were used to calculate these SI scores. Results show that using different SI computation methods could result in different SI scores, hence different risk level classifications. However, some simpler methods generated SI scores were comparable to the more complicated composite SI method. Despite differences in the scores between the six different SI computation methods, Spearman rank-order correlation coefficients of 0.61-0.97 were found between the methods. With some confidence, ergonomic practitioners may use simpler methods, depending on their specificity requirement in job evaluations and available resources. Some SI computation methods may tend to over-estimate job risk levels, while others may tend to under-estimate job risk levels, due to different ways used in obtaining the various SI parameters and computations. r

- by Barbara Silverstein
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- Occupational Health, Risk assessment, Adolescent, TIME