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Shinshiro Mineta,1 Takayuki Inami,2 Raldy Mariano,3 Norikazu Hirose4 1Graduate School of Sport Sciences, 2Institute of Physical Education, Keio University, Hiyoshi, Yokohama, 3Graduate School of Asia-Pacific Studies, Waseda University, Shinjuku, Tokyo, 4Faculty of Sport Sciences, Waseda University, Higashifushimi, Nishitokyo, Japan Introduction: Center of pressure (COP) is a sudden displacement at the time of a lateral ankle sprain (LAS). It has been suggested that the distribution of plantar pressure and the quantity of COP displacement are important for assessing the risk of LAS. Therefore, we evaluated the plantar pressure during a single-leg balance test with eyes closed (SLB-C) to identify the factors and characteristics of plantar pressure in people with repeated cases of LAS.Methods: We recruited 22 collegiate athletes and divided them into an instability group (IG; n=11) and a control group (CG; n=11). We measured the distribution of plantar pressure and lower extremity muscle activity during a SLB-C along with static alignment and isometric ankle strength.Results: The fibularis longus (FL) activity was significantly lower in the IG than in the CG. The lateral plantar pressure (LPP)/medial plantar pressure (MPP) ratio was also higher in the IG than in the CG. In addition, the LPP/MPP ratio was correlated with the tibialis anterior (TA)/FL ratio.Conclusion: These results suggest that increased lateral plantar pressure is related to decreased FL activity and increased TA/FL ratio. Keywords: chronic ankle instability, ankle sprain, postural stability, soccer, prevention

Márcio Rabelo Mota,1,2 Renata Aparecida Elias Dantas,1,2 Iransé Oliveira-Silva,2 Marcelo Magalhães Sales,2,3 Rafael da Costa Sotero,2 Patrícia Espíndola Mota Venâncio,2 Jairo Teixeira Júnior,2 Sandro Nobre Chaves,4 Filipe Dinato de Lima4 1College of Education and Health Sciences, University Center of Brasília – UniCEUB, Brasília, 2College of Physical Education, UniEVANGÉLICA, Anápolis, Goiás, 3College of Physical Education, Universidade Estadual de Goiás - UEG, Quirinópolis, Goiás, 4College of Physical Education, University of Brasília – UnB, Brasília, Brazil Purpose: The aim of this study was to investigate the effect of self-paced active recovery (AR) and passive recovery (PR) on blood lactate removal following a 200 m freestyle swimming trial. Patients and methods: Fourteen young swimmers (with a training frequency of 6–8 sessions per week) performed two maximal 200 m freestyle trials followed by 15 minutes of different recovery methods, on separate days. Recovery was performed with 15 minutes of passive rest or 5 minutes of passive rest and 10 minutes of self-paced AR. Performance variables (trial velocity and time), recovery variables (distance covered and AR velocity), and physiological variables (blood lactate production, blood lactate removal, and removal velocity) were assessed and compared. Results: There was no difference between trial times in both conditions (PR: 125.86±7.92 s; AR: 125.71±8.21 s; p=0.752). AR velocity was 69.10±3.02% of 200 m freestyle trial velocity in AR. Blood lactate production was not different between conditions (PR: 8.82±2.47 mmol L−1; AR: 7.85±2.05 mmol L−1; p=0.069). However, blood lactate removal was higher in AR (PR: 1.76&plusm

Pamela J Lang,1,2 Dai Sugimoto,1–3 Lyle J Micheli1–3 1Division of Sports Medicine, Department of Orthopedics, Boston Children’s Hospital, 2Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA, 3The Micheli Center for Sports Injury Prevention, Waltham, MA, USA Abstract: As more children and adolescents participate in competitive organized sports, there has been an increase in the reported incidence of anterior cruciate ligament (ACL) injuries in these age groups. ACL injuries in skeletally immature athletes present a challenge, as reconstruction must preserve the physis of the distal femur and of the proximal tibia to avoid growth disturbances. Historically, a skeletally immature athlete with an ACL injury was treated with a brace and activity modification until skeletal maturity, with ACL reconstruction being performed at that time in the “non-copers” who experienced instability. More recently, evidence has shown that delayed reconstruction may lead to increased damage to the meniscus and articular cartilage. As a result, early reconstruction is favored to protect the meniscus and allow continued physical activity. While adolescents at or those near skeletal maturity may be treated with standard reconstruction techniques, they may result in growth disturbances in younger athletes with significant growth remaining. In response to the growing need for ACL reconstruction techniques in skeletally immature individuals, physeal-sparing and physeal-respecting reconstruction techniques have been developed. In addition to the advancements in surgical technique, ACL injury prevention has also gained attention. This growing interest in ACL prevention is in part related to the high risk of ACL re-tear, either of the ACL graft or of the contralateral ACL, in children and adolescents. Recent reports indicate that well-designed neuromuscular training programs may reduce the risk of primary and subsequent ACL injuri

Wolf Petersen,1 Ingo Rembitzki,2 Christian Liebau3 1Department of Orthopaedic and Trauma Surgery, Martin Luther Hospital, Grunewald, Berlin; 2German Sport University Cologne, 3Asklepios Clinic, Bad Harzburg, Germany Abstract: Patellofemoral pain (PFP) is a frequent cause of anterior knee pain in athletes, which affects patients with and without structural patellofemoral joint (PFJ) damage. Most younger patients do not have any structural changes to the PFJ, such as an increased Q angle and a cartilage damage. This clinical entity is known as patellofemoral pain syndrome (PFPS). Older patients usually present with signs of patellofemoral osteoarthritis (PFOA). A key factor in PFPS development is dynamic valgus of the lower extremity, which leads to lateral patellar maltracking. Causes of dynamic valgus include weak hip muscles and rearfoot eversion with pes pronatus valgus. These factors can also be observed in patients with PFOA. The available evidence suggests that patients with PFP are best managed with a tailored, multimodal, nonoperative treatment program that includes short-term pain relief with nonsteroidal anti-inflammatory drugs (NSAIDs), passive correction of patellar maltracking with medially directed tape or braces, correction of the dynamic valgus with exercise programs that target the muscles of the lower extremity, hip, and trunk, and the use of foot orthoses in patients with additional foot abnormalities. Keywords: anterior knee pain, dynamic valgus, hip strength, rearfoot eversion, single leg squat, hip strength&nbsp

Markus Posch,1 Martin Burtscher,1 Alois Schranz,2 Katja Tecklenburg,2 Kenneth Helle,2 Gerhard Ruedl1 1Department of Sport Science, University of Innsbruck, Innsbruck, Austria; 2Medalp Sportclinic, Imst, Austria Background and purpose: The ability to successfully self-release the ski binding can prevent skiing-related injuries of the lower extremities. Failure of binding release associated with a knee injury is significantly higher among females compared to males. The International Standards Organization ISO 11088 standard for binding setting values allows a lowering by 15% upon request of the skier. Thus, the aim of this study was to evaluate the impact of lowered ski binding settings by 15% on the outcome of the self-release test among female recreational skiers. Materials and methods: In this randomized single-blinded study, a cohort of 20 females (24.5±2.7 years) performed the self-release test in the laboratory thrice with each leg under two conditions: 1) with an actual ISO 11088 setting and 2) with a setting lowered by 15%. For each attempt, torques calculated via the force plate were normalized to torques measured by a binding adjustment system (relative release torque, RRT). Results: Among 240 trials in total, more females were significantly able to self-release their ski bindings with lowered binding settings when compared to their actual ISO settings (53% vs 9%, p<0.001). Thirteen females (65%) were able to release their bindings at least once with both legs with lowered binding settings compared to only three females (15%) with their actual binding settings (p<0.001). Mean RRT of all failure of binding release trials significantly differed between lowered and actual binding settings (58.6%±22.2% vs 50.5%±20.4%, p=0.003). Conclusion: Four times more females were able to self-release their ski bindings at least once with both legs with a 15% lowered binding setting compared to their normal ISO 11088 se

Yoshinao Nakagawa,1 Masaaki Hattori2 1Human Performance Lab, Otaru University, Otaru, Hokkaido, 2Department of Community Development, Tokai University, Sapporo, Japan Abstract: The present study used magnetic resonance spectroscopy (1H-MRS) to examine quantitative differences in intramyocellular lipid (IMCL) contents in various muscle types at rest for individual athletes from different sport disciplines. Five groups consisting of sprinters, alpine skiers, cross-country skiers, endurance runners and untrained healthy male subjects volunteered for this study. Data were acquired using 1H-MRS from the tibialis anterior (TA), medial gastrocnemius (MG) and soleus (SOL) muscles. No significant difference was found in the cross-sectional area (CSA) of the TA, MG and SOL muscles, whereas the CSA of subcutaneous fat was significantly lower (p<0.01) for each athlete group compared with untrained subjects. In both TA and MG, IMCL concentrations in endurance runners were significantly higher than those of alpine skiers (p<0.01), sprinters (p<0.01) and untrained subjects (p<0.05). The IMCL concentrations in TA and MG of cross-country skiers were significantly higher than those of alpine skiers (p<0.05) and sprinters (TA, p<0.01; MG, p<0.05). There was no significant difference in the IMCL concentrations of TA and MG between alpine skiers or sprinters and untrained subjects. The IMCL concentration in SOL was significantly greater in endurance runners and showed no difference in cross-country skiers compared with that in alpine skiers and sprinters. There was no significant difference in the IMCL concentration of SOL between athletes and untrained subjects. These results suggest that differences in IMCL contents stored in various muscle types for athletes at rest are associated with the muscle cellular adaptation for differences in the type of exercise training and/or muscle fiber composition. Keywords: IMCL, alpine ski, skeletal mu

Dan Gordon,1 Sarah Wightman,2 Itay Basevitch,1 James Johnstone,1 Carolina Espejo-Sanchez,1 Chelsea Beckford,1 Mariette Boal,1 Adrian Scruton,1 Mike Ferrandino,1 Viviane Merzbach1 1Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, 2The Flying Runner, Cambridge, UK Purpose: The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5–3 h, 3–3.5 h, 3.5–4 h, 4–4.5 h and >4.5 h).Materials and methods: A total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm), with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1), lactate turn point (LT2) and running economy (RE). Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of VO2max. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data.Results: Training frequency was shown to be significantly greater for the 2.5–3 h group compared to the 3.5–4 h runners (P < 0.001) and >4.5 h group (P = 0.004), while distance per session (km⋅session–1) was significantly greater for the 2.5–3 h group (16.1 ± 4.2) compared to the 3.5–4 h group (15.5 ± 5.2; P = 0.01) and >4.5 h group (10.3 ± 2.6; P = 0.001). Race speed correlated with LT1 (r = 0.791)

Ashim Aggarwal,1 Jeffrey J Heslop,1 Rebecca R Wigant,1 Suneetha Venkatapuram,1 Stephanie J Hillis,1 Alan R Parr,1 Hakan Oral,2 Timir S Baman11Cardiology Department, University of Illinois College of Medicine at Peoria and OSF Saint Francis Medical Center, Peoria, IL, USA; 2Cardiac Arrhythmia Service, University of Michigan, Ann Arbor, MI, USAAlthough low-to-moderate intensity exercise has been shown to result in decreased cardiovascular morbidity and mortality, limited data suggest that there may be an association between atrial fibrillation (AF) and trained endurance athletes.1 The aim of our study was to prospectively evaluate moderately trained athletes for the occurrence of occult AF.

Pantelis Theodoros Nikolaidis,1 Beat Knechtle2,3 1Exercise Physiology Laboratory, Attiki, Greece; 2Gesundheitszentrum St. Gallen, St. Gallen, 3Institute of Primary Care, University of Zurich, Zurich, Switzerland Abstract: Pacing strategies in marathon runners have previously been examined, especially with regard to age and performance level separately. However, less information about the age × performance interaction on pacing in age-group runners exists. The aim of the present study was to examine whether runners with similar race time and at different age differ for pacing. Data (women, n=117,595; men, n=180,487) from the “New York City Marathon” between 2006 and 2016 were analyzed. A between–within subjects analysis of variance showed a large main effect of split on race speed (p<0.001, η2=0.538) with the fastest speed in the 5–10 km split and the slowest in the 35–40 km. A small sex × split interaction on race speed was found (p<0.001, η2=0.035) with men showing larger increase in speed at 5 km and women at 25 km and 40 km (end spurt). An age-group × performance group interaction on Δspeed was shown for both sexes at 5 km, 10 km, 15 km, 20 km, 25 km, 30 km, 35 km, and 40 km (p<0.001, 0.001≤η2≤0.004), where athletes in older age-groups presented a relatively more even pace compared with athletes in younger age-groups, a trend that was more remarkable in the relatively slow performance groups. So far, the present study is the first one to observe an age × performance interaction on pacing; ie, older runners pace differently (smaller changes) than younger runners with similar race time. These findings are of great practical interest for coaches working with marathon runners of different age, but similar race time. Keywords: running, master athlete, endurance, aerobic capacity, fatigue, gender, race time

Farzin Halabchi,1,2 Maryam Abolhasani,1,2 Maryam Mirshahi,1,2 Zahra Alizadeh1,2 1Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Sports and Exercise Medicine, Tehran University of Medical Sciences, Tehran, Iran Abstract: Patellofemoral pain (PFP) is a very common problem in athletes who participate in jumping, cutting and pivoting sports. Several risk factors may play a part in the pathogenesis of PFP. Overuse, trauma and intrinsic risk factors are particularly important among athletes. Physical examination has a key role in PFP diagnosis. Furthermore, common risk factors should be investigated, such as hip muscle dysfunction, poor core muscle endurance, muscular tightness, excessive foot pronation and patellar malalignment. Imaging is seldom needed in special cases. Many possible interventions are recommended for PFP management. Due to the multifactorial nature of PFP, the clinical approach should be individualized, and the contribution of different factors should be considered and managed accordingly. In most cases, activity modification and rehabilitation should be tried before any surgical interventions. Keywords: anterior knee pain, sport, rehabilitation, runners’ knee

Max Greenky, Steven B Cohen Department of Orthopedic Surgery, Rothman Institute, Thomas Jefferson University, Philadelphia, PA, USA Abstract: Hamstring injuries are common injuries in all levels of athletics. Hamstring injuries can cause prolonged absence from sports and have a notorious rate of reinjury. Magnetic resonance imaging (MRI) is being increasingly utilized following a hamstring injury. Physicians are being increasingly asked to utilize MRI to predict clinical outcomes, including time frame for return to play and risk of reinjury. In spite of numerous studies in this area, no clear consensus exists. The purpose of this paper is to summarize the literature and evidence regarding the role of MRI in treating hamstring injuries. Keywords: hamstring injury, MRI, return to play

Noppon Taksaudom,1 Natee Tongsiri,2 Amarit Potikul,1 Chawakorn Leampriboon,1 Apichat Tantraworasin,1 Anong Chaiyasri,1 1Cardiovascular and Thoracic Surgery Unit, Department of Surgery, Chiang Mai University Hospital, 2Department of Mathematics, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand Objective: Unique rough-terrain ultra-trail running races have increased in popularity. Concerns regarding the suitability of the candidates make it difficult for organizers to manage safety regulations. The purpose of this study was to identify possible race predictors and assess hemodynamic change after long endurance races.Methods: We studied 228 runners who competed in a 66 km-trail running race. A questionnaire and noninvasive hemodynamic flow assessment including blood pressure, heart rate, stroke volume, stroke volume variation, systemic vascular resistance, cardiac index, and oxygen saturation were used to determine physiologic alterations and to identify finish predictors. One hundred and thirty volunteers completed the questionnaire, 126 participants had a prerace hemodynamic assessment, and 33 of these participants completed a postrace assessment after crossing the finish line. The participants were divided into a finisher group and a nonfinisher group.Results: The average age of all runners was 37 years (range of 24–56 years). Of the 228 ­runners, 163 (71.5%) were male. There were 189 (82.9%) finishers. Univariable analysis indicated that the finish predictors included male gender, longest distance ever run, faster running records, and lower diastolic pressure. Only a lower diastolic pressure was a significant predictor of race finishing (diastolic blood pressure 74–84 mmHg: adjusted odd ratio 3.81; 95% confidence interval [CI]  =1.09–13.27 and diastolic blood pressure <74 mmHg: adjusted odd ratio 7.74; 95% CI =1.57–38.21) using the figure from the multivariable analysis. Among the finish

Jessica L Ford, Kenneth Ildefonso, Megan L Jones, Monna Arvinen-Barrow Department of Kinesiology, Integrative Health Care & Performance Unit, University of Wisconsin-Milwaukee, Milwaukee, WI, USA Abstract: To date, much research has been devoted to understanding how anxiety can affect sport performance, both in practice and in competitive settings. It is well known that sport has the potential for high levels of stress and anxiety, and that practicing and employing a range of psychological strategies can be beneficial in anxiety management. Equally, growing evidence also suggests that anxiety can play a role in sport injury prevention, occurrence, rehabilitation, and the return to sport process. The purpose of this paper is to provide current insights into sport-related anxiety. More specifically, it will provide the reader with definitions and theoretical conceptualizations of sport-related anxiety. This will be followed by making a case for considering the term "performance" to be broader than activities associated with sport-related performance in practice and competition, by including performance activities associated with sport injury prevention, rehabilitation, and the return to sport process. The paper will then highlight the importance of recognizing early signs and symptoms of anxiety, and the potential need for referral. Finally, the conclusions will emphasize the need for appropriate, client-specific, and practitioner competent care for athletes experiencing sport-related anxiety. Keywords: anxiety, sport, performance, injury, sport medicine professional, sport psychology, mental health

Jill Thein-Nissenbaum,1 Erin Hammer2 1Department of Family Medicine, University of Wisconsin-Madison, Madison, WI, USA; 2Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, WI, USA Abstract: Since the passage of Title IX in 1972, female sports participation has dramatically increased. The benefits of physical activity, including decreased risk for heart disease and diabetes as well as improved body image and self-esteem, far outweigh the risks. However, a select population of adolescent and young adult females may experience symptoms related to the female athlete triad (Triad), which refers to the interrelatedness of energy availability, menstrual function, and bone mineral density (BMD). These conditions often manifest clinically as disordered eating behaviors, menstrual irregularity, and stress fractures; an individual may suffer from 1 or all of the Triad components simultaneously. Because of the complex nature of the Triad, treatment is challenging and requires a multidisciplinary approach. Team members often include a physician, psychologist or psychiatrist, nutritionist or dietitian, physical therapist, athletic trainer, coach, family members, and most importantly, the patient. A thorough physical examination by a primary care physician is essential to identify all organs/systems that may be impacted by Triad-related conditions. Laboratory tests, assessment of bone density, nutritional assessment, and behavior health evaluation guide the management of the female athlete with Triad-related conditions. Treatment of the Triad includes adequate caloric consumption to restore a positive energy balance; this is often the first step in successful management of the Triad. In addition, determining the cause of menstrual dysfunction (MD) and resumption of menses is very important. Nonpharmacologic interventions are the first choice; pharmacologic treatment for MD is reserved only for those patients with symptoms of estrogen d

Lisa Müller,1 Carolin Hildebrandt,1,2 Erich Müller,3 Renate Oberhoffer,2 Christian Raschner1 1Department of Sport Science, University of Innsbruck, Innsbruck, Austria; 2Department of Sport and Health Science, Preventative Pediatrics, Technical University of Munich, Munich, Germany; 3Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria Background: Studies on injuries and illnesses involving youth ski racers younger than 15 years are lacking in the literature. The aim of this study was prospectively to assess the incidence, prevalence, and severity of traumatic and overuse injuries, as well as illnesses of elite youth ski racers with regard to sex, biological maturity status, and relative age.Subjects and methods: A prospective, longitudinal cohort design was used to monitor the anthropometrics, training characteristics, traumatic and overuse injuries, and illnesses of 82 elite youth ski racers (51 males, 31 females, age 9–14 years) over 2 consecutive years. The exact training exposure (skiing and athletic) was recorded. Relative age and estimated biological maturity status were assessed.Results: Relatively low injury incidence or prevalence (traumatic, 0.86/1,000 hours of training; overuse, 0.28/1,000 hours) and comparably high illness prevalence (2.4/athlete) were reported. The knee was the most commonly affected body part (traumatic injuries 36.5%, overuse injuries 82%). A high number of bone fractures were revealed (46%), while no stress fractures occurred; 66% of the illnesses were respiratory tract infections. No differences were found between males and females, the differing maturity groups, or relative age quartiles. Early-maturing athletes had comparably low traumatic and overuse-injury rates. Relatively younger athletes had low traumatic injury rates.Conclusion: The injury-prevention measures implemented in the training process of youth ski racers seem to contribute to a low incidence of injury. B

Natalie C Rollick,1 Yohei Ono,1,2 Hafeez M Kurji,3 Atiba A Nelson,1 Richard S Boorman,1 Gail M Thornton,1,4 Ian KY Lo1 1Department of Surgery, Section of Orthopaedic Surgery, McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada; 2Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan; 3College of Medicine, University of Saskatchewan, Saskatoon, SK, 4Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada Abstract: The most common surgical techniques for the treatment of recurrent anterior shoulder instability include the arthroscopic Bankart repair, the open Bankart repair and the open Latarjet procedure. The purpose of this study was to evaluate and compare the long-term outcomes following these procedures. A systematic review of modern procedures with a minimum follow-up of 5 years was completed. The objective outcome measures evaluated were post-operative dislocation and instability rate, the Rowe score, radiographic arthritis and complications. Twenty-eight studies with a total of 1652 repairs were analyzed. The estimated re-dislocation rate was 15.1% following arthroscopic Bankart repair, 7.7% following open Bankart repair and 2.7% following Latarjet repair, with the comparison between arthroscopic Bankart and open Latarjet reaching statistical significance (p<0.001). The rates of subjective instability and radiographic arthritis were consistently high across groups, with no statistical difference between groups. Estimated complication rates were statistically higher in the open Latarjet repair (9.4%) than in the arthroscopic Bankart (0%; p=0.002). The open Latarjet procedure yields the most reliable method of stabilization but the highest complication rate. There are uniformly high rates of post-operative subjective instability symptoms and radiographic arthritis at 5 years regardless of procedure choice. Keywords: Bankart, Latarjet, lon

Hiroaki Hobara, Satoru Hashizume, Yoshiyuki Kobayashi Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan Abstract: During human movement, the leg can be represented as a mechanical spring, with its stiffness potentially contributing to sports performance and injury prevention. Although many individuals perform athletic activities with joint stabilizers, little is known about the effects of prophylactic lower extremity braces on leg stiffness. The objective of this study was to investigate the effect of ankle and/or knee braces on leg stiffness measured during one-legged ­hopping at a range of frequencies. Thirteen male participants performed one-legged hopping with their dominant leg at frequencies of 2.2, 2.6, and 3.0 Hz. All participants were randomly tested under the following four brace conditions: 1) no brace (control), 2) prophylactic ankle brace, 3) prophylactic knee brace, and 4) prophylactic ankle and knee braces. Based on a spring–mass model, leg stiffness was calculated using data from an accelerometer. It was found that leg stiffness increased with increasing hopping frequency for each brace condition. However, there were no significant differences in leg stiffness among the four brace conditions at the three hopping frequencies. Since some level of leg stiffness is needed for optimal athletic performance and training, these results suggest that ankle and knee braces do not significantly interfere with dynamic hopping activities. Keywords: spring–mass model, injury prevention, compensatory strategy

Matthew J Jordan,1 Per Aagaard,2 Walter Herzog1 1Human Performance Laboratory, The University of Calgary, Calgary, AB, Canada; 2Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense M, Denmark Abstract: The purpose of the present review was to: 1) provide an overview of the current understanding on the epidemiology, etiology, risk factors, and prevention methods for anterior cruciate ligament (ACL) injury in alpine ski racing; and 2) provide an overview of what is known pertaining to ACL reinjury and return to sport after ACL injury in alpine ski racing. Given that most of the scientific studies on ACL injuries in alpine ski racing have been descriptive, and that very few studies contributed higher level scientific evidence, a nonsystematic narrative review was employed. Three scholarly databases were searched for articles on ACL injury or knee injury in alpine ski racing. Studies were classified according to their relevance in relation to epidemiology, etiology, risk factors, and return to sport/reinjury prevention. Alpine ski racers (skiers) were found to be at high risk for knee injuries, and ACL tears were the most frequent diagnosis. Three primary ACL injury mechanism were identified that involved tibial internal rotation and anteriorly directed shear forces from ski equipment and the environment. While trunk muscle strength imbalance and genetics were found to be predictive of ACL injuries in development-level skiers, there was limited scientific data on ACL injury risk factors among elite skiers. Based on expert opinion, research on injury risk factors should focus on equipment design, course settings/speed, and athlete factors (eg, fitness). While skiers seem to make a successful recovery following ACL injury, there may be persistent neuromuscular deficits. Future research efforts should be directed toward prospective studies on ACL injury/reinjury prevention in both male and female

Anna Åkerberg,1,2 Anne Söderlund,2 Maria Lindén1 1School of Innovation, Design and Engineering, 2School of Health, Care and Social Welfare, Mälardalen University, Västerås, Sweden Background: Different kinds of physical activity (PA) self-monitoring technologies are used today to monitor and motivate PA behavior change. The user focus is essential in the development process of this technology, including potential future users such as representatives from the group of non-users. There is also a need to study whether there are differences between the groups of users and non-users. The aims of this study were to investigate possible differences between users and non-users regarding their opinions about PA self-monitoring technologies and to investigate differences in demographic variables between the groups. Materials and methods: Participants were randomly selected from seven municipalities in central Sweden. In total, 107 adults responded to the Physical Activity Products Questionnaire, which consisted of 22 questions. Results: Significant differences between the users and non-users were shown for six of the 20 measurement-related items: measures accurately (p=0.007), measures with high precision (p=0.024), measures distance (p=0.020), measures speed (p=0.003), shows minutes of activity (p=0.004), and shows geographical position (p=0.000). Significant differences between the users and non-users were also found for two of the 29 encouragement items: measures accurately (p=0.001) and has long-term memory (p=0.019). Significant differences between the groups were also shown for level of education (p=0.030) and level of physical exercise (p=0.037). Conclusion: With a few exceptions, the users and the non-users in this study had similar opinions about PA self-monitoring technologies. Because this study showed significant differences regarding level of education and level of physical exercise, these demographic vari

Jaewoo Pak,1–3* Jung Hun Lee,1,4* Kwang Seung Park,4 Jeong Ho Jeon,4 Sang Hee Lee4 1Stems Medical Clinic, Gangnamgu, Seoul, Republic of Korea; 2TEDA‑Puhua International Hospital, Tianjin, People’s Republic of China; 3Life Science Institute, Komplek Permata Senayan, Jalan Tentara Pelajar, Jakarta Selatan, Indonesia; 4National Leading Research Laboratory, Department of Biological Sciences, Myongji University, Yongin, Gyeonggido, Republic of Korea *These authors contributed equally to this work Abstract: The menisci of the human knee play an important role in maintaining normal functions to provide stability and nutrition to the articular cartilage, and to absorb shock. Once injured, these important structures have very limited natural healing potential. Unfortunately, the traditional arthroscopic meniscectomy performed on these damaged menisci may predispose the joint toward early development of osteoarthritis. Although a very limited number of studies are available, mesenchymal stem cells (MSCs) have been investigated as an alternative therapeutic modality to repair human knee meniscal tears. This review summarizes the results of published applications of MSCs in human patients, which showed that the patients who received MSCs (autologous adipose tissue-derived stem cells or culture-expanded bone marrow-derived stem cells) presented symptomatic improvements, along with magnetic resonance imaging evidences of the meniscal repair. Keywords: adipose tissue-derived stem cells, bone marrow-derived stem cells, human knee, meniscal tear, articular cartilage, therapeutic modality

Andreas Ivarsson,1 Ulrika Tranaeus,2,3 Urban Johnson,1 Andreas Stenling 4 1Center of Research on Welfare, Health and Sport, School of Health and Welfare, Halmstad University, Halmstad, 2Performance and Training Unit, The Swedish School of Sport and Health Sciences (GIH), 3Musculoskeletal & Sports Injury Epidemiology Center, IMM, Karolinska Institutet, Stockholm, 4Department of Psychology, Umeå University, Umeå, Sweden Abstract: Previous research offers evidence that psychological factors influence an injured athlete during the rehabilitation process. Our first objective was to conduct a systematic review and meta-analysis of the results from all published studies that examined the relationships among negative affective responses after sport injuries, rehabilitation adherence, and return to play (RTP). The second objective was to use a meta-analytic path analysis to investigate whether an indirect effect existed between negative affective responses and RTP through rehabilitation adherence. This literature review resulted in seven studies providing 14 effect sizes. The results from the meta-analysis showed that negative affective responses had a negative effect on successful RTP, whereas rehabilitation adherence had a positive effect on RTP. The results from the meta-analytic path analysis showed a weak and nonsignificant indirect effect of negative affective responses on RTP via rehabilitation adherence. These results underline the importance of providing supportive environments for injured athletes to increase the chances of successful RTP via a decrease in negative affective responses and increase in rehabilitation adherence. Keywords: affective responses, rehabilitation behaviors, return to play, sport injuries

Vini Simas,1 Wayne Hing,1 Rodney Pope,1 Mike Climstein1,2 1Water-Based Research Unit, Faculty of Health Sciences and Medicine, Bond Institute of Health and Sport, Bond University, Gold Coast, QLD, 2Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia Background: Age-related bone loss is a major health concern. Only exercises associated with high-impact and mechanical loading have been linked to a positive effect on bone turnover; however, these types of exercises may not always be appropriate for middle-aged and older adults due to physical decline or chronic disorders such as osteoarthritis. Water-based exercise (WBE) has been shown to affect different components of physical fitness, has lower risks of traumatic fracture, and applies less stress to joints. However, the effects of WBE on bone health are unclear.Objective: This study aimed to explore whether WBE is effective in preventing age-related bone deterioration in middle-aged and older adults.Methods: A search of relevant databases and the references of identified studies was performed. Critical narrative synthesis and meta-analyses were conducted.Results: Eleven studies, involving 629 participants, met all inclusion criteria. All participants were postmenopausal women. Eight studies compared WBE to a sedentary control group, and four studies had land-based exercise (LBE) participants as a comparison group. Meta-analyses revealed significant differences between WBE and control group in favor of WBE for changes in bone mineral density (BMD) at the lumbar spine (mean difference [MD] 0.03 g/cm2; 95% confidence interval [CI]: 0.01 to 0.05) and femoral neck (MD 0.04 g/cm2; 95% CI: 0.02 to 0.07). Significant differences were also revealed between WBE and LBE in favor of LBE for changes in lumbar spine BMD (MD −0.04 g/cm2; 95% CI: −0.06 to −0.02). However, there was no significant differe

Maria Sommervold, Håvard Østerås Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway Background: Excessively high stresses are applied to the shoulder joint of handball players, mainly caused by overhead throwing. Shoulder pain is a significant problem among junior female team handball players and both male and female top-level team handball players in Norway.Method: A randomized selection was performed among the best female junior teams (J 16) in the Trøndelag region of Norway in the 2014–2015 season. Three teams were randomized to the intervention group and three teams to the control group. Players in the intervention group (n=53) participated in a seven-month, three-times-a-week shoulder-muscle strength-training program, while those in the control group (n=53) participated in a comparable handball training, but did not conduct any specific strength training during the season. Results: A strength-training program had no effect on the prevention of shoulder pain. Overall, the players reported shoulder pain, but graded the pain low on visual analog scale (VAS). Both the intervention group and the control group reported pain under 1 on VAS at baseline and posttest, and there was no significant difference within or between the groups when it came to the intensity of pain reported on VAS. A significant difference (p<0.048) was found between the groups on the sport-specific part of the quick-Disability of the Arm, Shoulder and Hand (DASH) form, but it did not fulfill the minimal demand to change and the players scored it low, something that indicates little functional problems when it comes to team handball. The intervention group was significantly stronger (p<0.008) on the push-ups test compared to the control group on the posttest. The intervention group increased the number of push-ups from 3.1 to 6.4, while the control gro

Anna Cronström,1 Ewa M Roos,2 Eva Ageberg1 1Department of Health Sciences, Lund University, Lund, Sweden; 2Research Unit for Musculoskeletal Function and Physiotherapy, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark Background: In patients with anterior cruciate ligament (ACL) deficiency (ACLD) or reconstruction (ACLR), sensory deficits are commonly assessed as knee kinesthesia using time-consuming laboratory equipment. Portable equipment such as that used for evaluation of vibration sense would be preferable. In contrast to kinesthesia, vibration sense is not well studied in these patients. Objectives: 1) To study the association between kinesthesia and vibration sense to investigate if one sensory measurement can replace the other; and 2) to determine the clinical relevance by investigating associations between the sensory measurements and functional performance and patient-reported outcomes in patients with ACLD or ACLR. Methods: Twenty patients with ACLD and 33 patients with ACLR were assessed with knee kinesthesia, vibration sense, the one-leg hop test for distance, as well as the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Tegner Activity Scale. Results: There were no significant correlations between kinesthesia and vibration sense (r= –0.267, p>0.269) or between the sensory measures and hop performance (r= –0.351, p>0.199). In patients with ACLD, worse knee kinesthesia was associated with worse scores on KOOS subscales pain (r= –0.464, p=0.046) and activities of daily living (r= –0.491, p=0.033), and worse vibration sense was associated with worse scores on KOOS subscale quality of life (r= –0.469, p=0.037) and worse knee confidence (item Q3 from subscale quality of life) (rs=0.436, p=0.054). In patients with ACLR, worse vibration sense was associated with worse scores on KOOS subscales pain (r= &a

Douglas R Pedersen,1 Georges Y El-Khoury,2 Dan R Thedens,3 Mothana Saad-Eldine,1 Phinit Phisitkul,1 Annunziato Amendola4 1Department of Orthopaedics and Rehabilitation, 2Department of Radiology, University of Iowa Hospitals and Clinics, 3Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, 4Department of Orthopaedics and Sports Medicine, Duke University Medical School, Durham, NC, USA Background: Bone contusions are frequently encountered in magnetic resonance imaging (MRI) evaluation of knee anterior cruciate ligament (ACL) injuries. Their role as indicators of injury severity remains unclear, primarily due to indeterminate levels of joint injury forces and to a lack of preinjury imaging.Purpose: The purpose of this study was to 1) quantify bone contusion pathogenesis following traumatic joint injuries using fixed imaging follow-ups, and 2) assess the feasibility of using longitudinal bone contusion volumes as an indicator of knee injury severity.Study design: Prospective sequential MRI follow-ups of a goat cohort exposed to controlled stifle trauma in vivo were compared to parallel clinical MRI follow-ups of a human ACL tear patient series.Methods: Reproducible cartilage impact damage of various energy magnitudes was applied in a survival goat model, coupled with partial resection of anterior portions of medial menisci. Both emulate injury patterns to the knee osteochondral structures commonly encountered in human ACL injury imaging as well as instability from resultant ligament laxity. Longitudinal clinical MRI sequences portrayed stifle bone contusion evolution through 6 months after the inciting event.Results: In the first 2 weeks, biological response variability dominated the whole-joint response with no apparent correlation to trauma severity. Control goats subjected to partial meniscectomy alone exhibited minimal bone response. Thereafter, 0.6 J impact bone contusions portrayed a faster rate of resolution than those induced b