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Fuminori Takayama,1,2 Atsushi Aoyagi,3 Keigo Takahashi,2,3 Yoshiharu Nabekura1 1Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba-shi, Ibaraki, Japan; 2Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, Japan; 3Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba-shi, Ibaraki, Japan Purpose: Individual variations in response of C-reactive protein (CRP) to acute strenuous exercise are less well known. The purpose of this study was to investigate the relationship between running economy and systemic inflammation following a marathon. Materials and methods: Sixteen college recreational runners participated in this study. To measure maximal oxygen uptake and running economy, the treadmill running test was performed 1–2 weeks before the marathon race. Running economy was defined as oxygen cost (mL/kg/km) at submaximal running. CRP and muscle damage markers (creatine kinase and lactate dehydrogenase) were measured before and 1, 2, and 3 days after the race. Results: All subjects completed the race in 4 hours 7 minutes 43 seconds±44 minute 29 seconds [mean±SD]. The marathon running significantly increased CRP and muscle damage markers. The levels of inflammation and muscle damage peaked after 1 day and remained high throughout the 3-day recovery period compared to that before the race. Spearman correlation analysis showed that the change in CRP level was significantly positively correlated with oxygen cost (r=0.619, P=0.011) but not maximal oxygen uptake. There was no significant relationship in responses between muscle damage markers and CRP. Conclusion: These findings suggest that running economy is related to postmarathon race CRP response. Further study to clarify the cause of the relationship and clinical significance of transient increase in CRP is necessary. Keywords: inflammation, oxygen consumption, C-reactive protein, muscle damage

Spencer W Sullivan,1,2 Niles A Fleet,3 Vanessa A Brooks,3 Jennifer Bido,2 Benedict U Nwachukwu,2 Peter H Brubaker1 1Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC, 27106, USA; 2Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, NY, 10021, USA; 3Department of Sports Medicine, Wake Forest University, Winston-Salem, NC, 27106, USACorrespondence: Spencer W Sullivan 1109 Crowne Oaks Circle, Winston Salem, NC, 27106, USATel +1 317 775 2626Fax +1 646 885 8252Email spencer.sullivan44@gmail.comBackground: Bilateral leg power is being increasingly investigated as a proxy for the recovery of muscle performance after injury. Functional tests like the single leg hop for distance (SLHD) and single leg vertical jump (SLVJ) are often used to determine symmetry and return to play (RTP) readiness. As an injury predictor, leg power is accurately measured with the Keiser Air420 seated leg press.Purpose: To measure and analyze lower leg asymmetry in healthy collegiate athletes across each test battery.Methods: Eighty-eight healthy student-athletes (44 males, 44 females) across 14 varsity teams at Wake Forest University performed the SLHD, SLVJ, and the Keiser. Horizontal and vertical displacement were measured via the SLHD and SLVJ, respectively. Peak power was recorded via the Keiser Air420 leg press. Pearson correlations and repeated measures ANOVA were used to calculate associations and compare bilateral asymmetry indices (BAI) and raw scores.Results: There was a significant effect on each test’s raw BAI (P < 0.01). The mean absolute BAI were 5.42 ± 4.9%, 6.64 ± 4.9% and 5.36 ± 4.7% for the SLHD, SLVJ and Keiser, respectively. The SLVJ and Keiser (dominant leg r = 0.832, nondominant leg r = 0.826) were more highly correlated than the SLHD and Keiser (dominant leg r = 0.645, nondominant leg r = 0.687), all of which were statistically significant (P < 0.01).Conclusion: At the 90th percentile, healthy collegiate athletes attained < 15% BAI. We recommend the implementation of a battery of tests to determine normative lower limb asymmetry. A battery of functional tests may present different asymmetry indices as opposed the 10% reference asymmetry.Keywords: lower leg, power testing, functional testing, limb symmetry, athlete, return to play

Andrew Kompel,1 Prashanth H Haran,1 Akira M Murakami,1 Lars Engebretsen,2– 4 Mohamed Jarraya,1,5 Frank Roemer,1,6,* Ali Guermazi1,7,* 1Department of Radiology, Boston University School of Medicine, Boston, MA, USA; 2Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland; 3Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway; 4Department of Orthopedic Surgery, Oslo University Hospital, University of Oslo, Oslo, Norway; 5Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA; 6Department of Radiology, Friedrich-Alexander University Erlangen-Nürnberg, & Universitätsklinikum Erlangen, Erlangen, Germany; 7Department of Radiology, VA Boston Health System, Boston, MA, USA*These authors contributed equally to this workCorrespondence: Andrew KompelDepartment of Radiology, Boston University School of Medicine, 820 Harrison Avenue, FGH Building 3rd Floor, Boston, MA, 02118, USATel +1 617 638-6610Fax +1 617 638-6616Email Andrew.Kompel@bmc.orgPurpose: Describe the frequency and severity of knee ligament sprains diagnosed by MRI in athletes participating at the 2016 Summer Olympic Games, their association with certain sports and assess correlations with additional knee structural injury.Patients and Methods: All knee MRIs performed in the Olympic Village and polyclinics during the 2016 Olympics were retrospectively, blindly reviewed for ligament sprains and associated knee injuries. In addition to the absence or presence of these abnormalities, athletes were stratified by age, gender and sport.Results: 11,274 athletes participated in the 2016 Olympic Games: 113 athletes received at least one knee MRI with some having bilateral or repeat MRI on the same knee. Anterior cruciate and medial collateral ligament (ACL/MCL) sprains were most common, accounting for 32 of the 43 sprains (74.4%). Wrestling (10), hockey (7), athletics (7), and judo (5) accounted for over half of ligament sprains. ACL sprains showed a significant positive correlation with medial, lateral meniscal tears and bone contusions. The positive correlation between posterior cruciate ligament (PCL) sprains with MCL/lateral collateral ligament sprain, and popliteus tendon tear was statistically significant with 50% of total PCL sprains occurring in hockey. When athletes were stratified by gender, ligament sprains had a similar occurrence and distribution between men and women.Conclusion: Knee ligament sprains, at the Rio 2016 Games, were most common in wrestling, hockey, athletics and judo with ACL and MCL sprains most frequent. Meniscal tears and bone contusions occurred often with ACL sprains. PCL sprains tended to be multi-ligamentous injuries. Sustained ligament sprains had similar occurrence between genders, while men had a peak incidence of sprains at a younger age and women at an older age.Keywords: Olympics, knee, ligament, sprain, MRI

Yasuharu Nagano,1 Yui Shimada,2 Naoki Sasaki,1 Masaki Shibata1 1Faculty of Physical Education, Japan Women’s College of Physical Education, Tokyo, Japan; 2Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, Tokyo, JapanCorrespondence: Yasuharu NaganoFaculty of Physical Education, Japan Women’s College of Physical Education, 8-19-1, Kitakarasuyama, Setagaya, Tokyo, 157-8565, JapanTel +81-3-3300-5437Fax +81-3-3300-5437Email nagano.yasuharu@jwcpe.ac.jpIntroduction: The purpose of this prospective cohort study was to investigate the prevalence and burden of “any physical complaint” in college female basketball athletes using a daily questionnaire.Methods: Fifty-four female college basketball players were recruited and followed up for 135 days using the Oslo Sports Trauma Research Centre questionnaire.Results: The questionnaire response rate was 96.4% (95% confidence interval: 95.7– 97.1). The average daily prevalenceof any problem was 44.4%, whereas that of substantial problems was 16.0%. The anatomical areas found to be most frequently affected by physical problems were the ankle (average daily prevalence: 14.5%, 95% confidence interval: 13.4– 15.7), lower back (14.4%, 95% confidence interval: 13.7– 15.2), and knee (9.6%, 95% confidence interval: 9.0– 10.2). The cumulative severity score, calculated by summing severity scores and dividing by number of respondents, showed that ankle, knee, and lower back problems exhibited greater relative burden.Discussion: Injuries common in basketball athletes, such as ankle sprain, anterior cruciate ligament injury, overuse knee pain, and low-back pain, are reflected in the present data.Keywords: epidemiology, sports injuries, overuse injuries, ankle, knee

Dominik Szymski,1 Leonard Achenbach,2,3 Martin Siebentritt,4 Karola Simoni,5 Norbert Kuner,5 Christian Pfeifer,1 Werner Krutsch,1,6 Volker Alt,1 Rainer Meffert,2 Kai Fehske2 1Department of Trauma Surgery, University Medical Centre Regensburg, Regensburg, Germany; 2Department of Trauma-, Hand-, Plastic- and Reconstructive Surgery, University Wuerzburg, Wuerzburg, Germany; 3Department of Orthopaedics, Koenig-Ludwig-Haus, University Wuerzburg, Wuerzburg, Germany; 4Department for Anesthesiology and Operative Intensive Care, Bayreuth, Germany; 5General Medicine and Dermatology, Medical Center for General Medicine, Dermatology, Paediatrics and Internal Medicine, Costa Calma Fuerteventura, Costa Calma, Spain; 6Sports-Orthopedics, SportDocs Franken, Nuremberg, GermanyCorrespondence: Kai FehskeDepartment of Trauma-, Hand-, Plastic- and Reconstructive Surgery, University Wuerzburg, Wuerzburg, GermanyTel +49 931 201 37001Fax +49 931 201 37009Email kai.fehske@ukw.deIntroduction/Background: Surfing, wind surfing and kite surfing enjoy a growing popularity with a large number of athletes worldwide. The aim of this study was to identify and compare the injury profiles and compare the injury profiles of these three extreme water sports.Materials and Methods: These data for this retrospective cohort study were collected through an online standardised questionnaire during the 2017– 18 season. The questionnaire included questions about anthropometry, skill level, injury diagnosis, injury mechanism, environmental conditions and training regimes.Results: The 626 athletes included reported 2584 injuries. On average, each athlete sustained 4.12 injuries during the season. The most frequent injury location was in the lower extremity, in particular the foot, with 49 (16.4%) injuries in surfing, 344 (18.3%) in wind surfing and 79 (19.7%) in kite surfing. Surfing demonstrated a particularly high rate of head injuries (n = 37; 12.4%). Other frequent injury types were skin lesions (up to 42.1%) and contusions (up to 40.5%). The most common injury across all surfing sports was skin lesions of the foot (wind surfing: 11.7%; kite surfing: 13.2%; surfing: 12.7%). In surfing, skin lesions of the head were frequently observed (n = 24; 8.0%). In surfing, a ‘too large wave’ (n = 18; 24.7%) was main cause of the injury, while in wind surfing (n = 189; 34.5%) and kite surfing (n = 65; 36.7%) ‘own incompetence’ led to the most injuries.Conclusion: This unique study compares injury epidemiology and mechanism in the three most popular surfing sports: wind surfing, kite surfing and surfing. Overall, injuries were sustained mainly in the lower extremity, while surfing also demonstrated a high rate of head injuries.Keywords: water sports, injury, training, ankle, foot, epidemiology

Emily M Wittrup,1 Lucas A Fox,1 Katherine M Breedlove,2,3 Allyssa K Memmini,1 Steven P Broglio1 1Concussion Center, University of Michigan, Ann Arbor, MI, USA; 2Center for Clinical Spectroscopy, Brigham and Women’s Hospital, Boston, MA, USA; 3Department of Radiology, Harvard Medical School, Boston, MA, USACorrespondence: Emily M WittrupConcussion Center, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI 48109, USATel +1 810-986-5105Fax +1 734-936-1925Email ewittrup@umich.eduIntroduction: Increased risk of musculoskeletal (MSK) injury post-concussion has been reported in collegiate athletes, yet it is unknown if professional football athletes are at the same risk of secondary injury. The objective of this study was to determine if the risk of MSK injury in National Football League (NFL) athletes increases after concussion.Methods: NFL injury reports from 2013 to 2017 were collected from public websites. Concussed athletes (n=91) were equally matched to a non-injured control and an athlete with an incident of musculoskeletal (MSK) injury.Results: Following their return to sport, concussed athletes were 2.35 times more likely to have a subsequent MSK injury relative to non-injured controls (95% CI: 2.35 [1.25, 4.44], P = 0.01), but were no more likely than athletes with an incident MSK injury (P = 0.55). Likewise, athletes with an incident MSK injury were no more likely to have a subsequent MSK injury than controls (P = 0.08).Discussion: Increased odds of MSK injury in the 12-week period following a concussion in professional football athletes warrants future research on the acute effects of concussion and the relationship to MSK injury risk.Keywords: mild traumatic brain injury, musculoskeletal injury, return to play, NFL, professional American football

Purpose The factors associated with low back pain (LBP) and the relationship between LBP and ball velocity during kicking motion of adolescent soccer players remain largely unknown. This study aims to clarify the relationship between increasing ball velocity and LBP in adolescent soccer players. Participants and Methods Adolescent soccer players were divided into two groups according to the presence and absence of LBP (LBP group, n=38 and NBP (no back pain) group, n=29, respectively). Real-time kick motion was measured using a three-dimensional motion analysis system and the angle of the lumbar spine, hip, and center of mass (COM) were calculated. Regression analysis was used to identify factors associated with ball velocity and LBP. In addition, Pearson’s correlation coefficients were determined between the angle of the lumbar spine and hip, and ball velocity and position of COM in the extracted phase from regression analysis. Results The major factor associated with increasing ball velocity was the rotation angle of both hips (Adjusted R2=0.244) and vertical position of COM during kicking (Adjusted R2=0.262). Furthermore, the factors associated with LBP were the flexion angle of kick-side hip (OR=1.126) and abduction angle of both hips (kick-side OR=1.124; support-side OR=0.872). The factors for ball velocity and LBP were related to the maximum hip extension phase. In the hip extension phase of kicking, compared with the NBP group, the LBP group showed lesser extension and external rotation of the kick-side hip angle. In the hip flexion phase of kicking, the ball velocity was correlated with vertical (r=0.56)/anterior (r=0.46) position of COM in the NBP group. Conclusion To compensate for this restricted hip motion, the LBP group could extend and rotate their lumbar spine, which may likely cause stress to this region., Video abstract Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/dgg9fhFb124

Babak Vahdatpour, Fahimeh Momeni, Ali Tahmasebi, Parisa Taheri Department of Physical Medicine and Rehabilitation, Isfahan University of Medical Sciences, Isfahan, IranCorrespondence: Parisa TaheriIsfahan University of Medical Sciences, School of Medicine, Department of Physical Medicine and Rehabilitation, Hezar-Jarib Avenue, Isfahan, IranEmail Prs_taheri@yahoo.comIntroduction: Trigger finger disorder is a sudden release or locking of a finger during flexion or extension. Regarding the complications and disadvantages mentioned for the methods used in the treatment of trigger finger disorder, the aim of this study was to investigate the effect of extracorporeal shock wave therapy in the treatment of patients with trigger finger.Methods: This study was an interventional study recruiting 19 patients with trigger finger disorder. Evaluation of pain severity, severity of triggering, and functional impact of triggering was carried out using the Visual Analogue Scale, Trigger Finger Score suggested by Quinnell, and Quick-Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, respectively, before intervention, immediately after intervention, and in 6 and 18 weeks after intervention. Each patient was treated with extracorporeal shock wave therapy in three sessions with a 1-week interval. Data were analyzed in Statistical Package for the Social Sciences (SPSS) software using ANOVA to monitor changes in pain severity, severity of triggering, and functional impact of triggering during follow-ups.Results: There were statistically significant differences with regard to reduction of the pain severity, severity of triggering, and functional impact of triggering before intervention, immediately after intervention, and in 6 and 18weeks after intervention (P< 0.01). However, the effect of extracorporeal shock wave therapy on reducing severity of triggering immediately after intervention did not yield a statistically significant difference compared to before intervention (P> 0.01).Conclusion: It seems that extracorporeal shock wave therapy leads to a reduction in pain severity, severity of triggering, and functional impact of triggering. These effects persisted until the 18th week after the intervention. It is recommended to use extracorporeal shock wave therapy in terms of a non-invasive intervention with no significant complications for patients with trigger finger.Keywords: extracorporeal shock wave therapy, trigger finger, pain severity, severity of triggering, functional impact of triggering

Hauke Horstmann, 1 Pascal Medico, 2 Florian Lasch, 3 Werner Krutsch, 4 Thomas Sanjay Weber-Spickschen 2 1Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany; 2Institute of Sports Medicine, Hannover Medical School, Hannover 30625, Germany; 3Institute for Biometry, Hannover Medical School, Hannover 30625, Germany; 4Trauma Department, University of Regensburg, Regensburg 93053, GermanyCorrespondence: Hauke HorstmannDiakovere – Annastift, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Street 1-7, Hannover 30625, GermanyTel +49 5115354568Email hauke.horstmann@diakovere.deContext: Isokinetic testing is used as a standard tool in measuring strength in professional athletes. It is often used to evaluate improvement during rehabilitation. The disadvantages of isokinetic testing include its costs, the fact that it is not portable, and its risk of injury, which makes it not suitable for early postoperative rehabilitation.Hypothesis: The aim of this study was to investigate the relationship between the results of the isokinetic testing and the measurements of an application-based knee-training device.Study Design: Exploratory diagnostic study.Methods: In this monocentric study, 100 subjects performed an isokinetic maximum strength examination and an assessment on the application-based knee-training device in a randomized order. The isokinetic testing was based on the Swiss Olympic protocol with 3 sets of 5 repetitions of maximum strength testing for flexion and extension. The subjects consisted of 50 healthy professional athletes and 50 healthy recreational athletes, half male and half female, between the ages of 18 to 30 years old.Results: No medical or technical issues were reported. The analysis of the relationship between application-based knee-training device and extension showed a Pearson correlation coefficient of r=0.667 for the left knee and r=0.604 for the right knee. For flexion, the Pearson correlation coefficient was r=0.640 for the left side and r=0.673 for the right side. When strength measured by the application-based knee-training device was adjusted for height and weight of the subjects, the Pearson correlation was even stronger (extension left: r=0.727, right: r=0.689; flexion left: r=0.641, right: r=0.711).Conclusion: The study shows a moderate to high correlation between isokinetic testing and the application-based knee-training device. These results suggest that the application-based knee-training device is effective for early strength rehabilitation without the risk of injury.Keywords: knee, isokinetic, app-based rehabilitation, exergame

Okba Selmi,1,2 Ibrahim Ouergui,1 Danielle E Levitt,3,4 Pantelis T Nikolaidis,5 Beat Knechtle,6 Anissa Bouassida1 1Research Unit, Sportive Performance and Physical Rehabilitation, High Institute of Sports and Physical Education of Kef, University of Jendouba, Kef, Tunisia; 2High Institute of Sports and Physical Education, Ksar Said, University of Manouba, Tunis, Tunisia; 3Applied Physiology Laboratory, University of North Texas, Denton, TX, USA; 4Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, USA; 5Exercise Physiology Laboratory, Nikaia, Greece; 6Institute of Primary Care, University of Zurich, Zurich, SwitzerlandCorrespondence: Beat KnechtleInstitute of Primary Care, University of Zurich Medbase St. Gallen Am Vadianplatz, Vadianstrasse 26, St. Gallen 9001, SwitzerlandTel +41 71 226 93 00Fax +41 71 226 93 01Email beat.knechtle@hispeed.chIntroduction: High-intensity interval training (HIIT) and small-sided games (SSG) have been applied and tested for athletes in order to enhance the soccer performance. For this reason, this experimental study aimed to compare the effects of SSGs and HIIT on power, physiological responses and perceived enjoyment.Materials and Methods: Sixteen youth soccer players (age, 17.5± 0.6 years, mean±standard deviation; height, 178.2± 6.4 cm; body mass, 70.4± 5.4 kg; body fat, 10.6± 0.8%) completed one session each of HIIT and SSG on separate days with 1 week between sessions. Each sessionlasted 25 mins (4x4mins work with 3mins of passive recovery in-between). SSGs consisted of 4 versus 4 player games on a 25× 35 m pitch, and HIIT consisted of intermittent 15-s runs at 110% maximal aerobic speed separated by 15 s of passive recovery. Psychological responses following each protocol were assessed using the Physical Activity Enjoyment Scale (PACES). Heart rate (HR) was continuously recorded, rating of perceived exertion (RPE) and lactate concentration [La] were measured after each training session. Lower body muscular power was assessed using the 5-jump test relative to leg length (5JT-relative) before and after each training session, where greater average distance per stride over five sequential jumping strides indicated greater muscular power.Results: HIIT and SSG showed no significant difference in HR, RPE and [La] responses (p=0.70, ES=0.11; p=0.61, ES=0.08 and p=0.38, ES=0.21, respectively). 5JT-relative decreased significantly for SSG and HIIT (p< 0.05, ES=0.50 and p< 0.05, ES=0.40, respectively). PACES score was greater in SSG compared to HIIT (ES=5.35, p< 0.001).Conclusion: HIIT and SSG sessions induced similar physiological responses; however, SSGs induced a higher enjoyment level than HIIT. Coaches could choose between these training modalities according to the objective of their training session, considering the enjoyment-related advantages of SSGs.Keywords: aerobic fitness, psychology, motivation, soccer, athletes

Amin Daneshfar,1 Carl Petersen,1 Daniel Gahreman,2 Beat Knechtle3,4 1School of Health Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand; 2College of Health & Human Sciences, Charles Darwin University, Darwin, Australia; 3Institute of Primary Care, University of Zurich, Zurich, Switzerland; 4Medbase St. Gallen Am Vadianplatz, St. Gallen, SwitzerlandCorrespondence: Beat Knechtle Medbase St. Gallen Am Vadianplatz, Vadianstrasse 26, St. Gallen 9001, SwitzerlandTel +41 71 226 93 00Fax +41 71 226 93 01Email beat.knechtle@hispeed.chIntroduction: Power meter is a useful tool for monitoring cyclists’ training and race performance. However, limited data are available regarding BMX racing power output. The aim of this study was to characterise the power production of BMX riders and investigate its potential role on race performance.Methods: Fourteen male riders (age: 20.3 ± 1.5 years, height: 1.75 ± 0.05 m, mass: 70.2 ± 6.4 kg) participated in this study. The tests consist of performing two races apart from 15-min recovery. SRM power meter was used to record power and cadence. Cyclists’ fastest race was used for the data analysis. Heart rate was recorded at 1-s intervals using a Garmin HR chest strap. Lap time was recorded using four pairs of photocells positioned at the start gate, bottom of the start ramp, end of first corner (time cornering), and on the finish line.Results: There was a large correlation between race time and relative peak power (r = − 0.68, p < 0.01) as well as average power with zero value excluded (r = − 0.52, p < 0.01). Race time was also significantly associated with time cornering (r = 0.58, p < 0.01). Peak power (1288.7 ± 62.6 W) was reached in the first 2.34 second of the race. With zero values included, the average power was 355.8 ± 25.4 W, which was about 28% of the peak power, compared to 62% when zero values were excluded (795.6 ± 63.5 W).Conclusion: The post-race analysis of the power data might help the cyclists recognizing the need to apply certain strategies on pedalling rates and power production in certain portions of the BMX track, specially, at the start and around the first corner. BMX coaches must consider designing training programs based on the race intensity and power output zones.Keywords: BMX race, cadence, heart rate, power binning

Purpose This study compared the accessory anteromedial portal (AAMP) and the modified transtibial technique (MTTT)” for single-bundle anterior cruciate ligament (ACL) reconstruction. Patients and methods Sixty active adult patients with ACL tear were randomly assigned into two equal groups who were treated surgically. One group was operated on using AAMP and the other group through MTTT. Both the groups had the same postoperative course and were followed for 1 year after surgery. The follow-up included Lysholm and International Knee Documentation Committee (IKDC) subjective knee evaluation forms, IKDC objective knee examination form, and radiological evaluation. Results were evaluated and compared with each other. Results There was no significant difference in subjective effects or clinical examination between the two groups. Regarding radiological angles, the AAMP had more oblique graft orientation in the coronal plane than the MTTT, but both were found to be more slanted than native ACL. Also, the MTTT had succeeded to place the graft and tunnel more obliquity than the traditional non-anatomic TTT and better than the anatomic ranges despite having the graft inclination of the AAMP higher than the MTTT. The complaints from the patients and subjective scoring were found to be positively related to graft stability. Patients with healthier preoperative subjective state had a smoother postoperative period and better outcome. Conclusion This study offers simple modifications to the transtibial technique to allow near anatomic ACL reconstruction with similar results comparable to the AAMP and with fewer complications., Video abstract

Guy W Nicolette, Jocelyn R Gravlee University of Florida, Gainesville, FL, USA Introduction: Elbow ulnar collateral ligament (UCL) injuries in gymnastics have not been well documented in the literature, in comparison to UCL injuries in baseball. Few studies have examined the mechanism and nonoperative management of this injury, and no studies to date have been published on incidence of injury and return to play recommendations in gymnastics. Patient case review: A literature search was performed using PubMed to review articles from 1980 to 2016 that addressed the biomechanics of UCL injury in baseball and gymnastics, the anatomy of the elbow, injury rates, surgical vs non-surgical management, rehabilitation, and return to play recommendations for the sport of gymnastics. Five female collegiate gymnasts sustained UCL injury over a 3-year period. Electronic medical records for each case were thoroughly reviewed including imaging, surgical and non-surgical management, rehabilitation, and the progressive return to gymnastics. Discussion: Four UCL injuries were confirmed by MRI to be avulsions at the distal insertion of the UCL and one was an avulsion at the proximal origin. While less than half of baseball players can return to competition with conservative management of these types of injuries, four out of five gymnasts were able to return to competition with nonoperative management. One gymnast opted to have reconstruction after a successful competition season. Time to return to play varied seemingly dependent on the severity of UCL injury and event. Conclusion: In our case series, collegiate female gymnasts were able to return to participation with nonoperative treatment of the UCL. Their success in returning to competitive gymnastics may also depend on the event(s) in which they are trying to participate. Strength of Recommendation Taxonomy: C. Keywords: elbow ulnar collateral ligament, gymnastics, gymnast

Getachew Wassihun Dessalew, Dawit Habte Woldeyes, Belta Asnakew Abegaz Anatomy Unit, Department of Biomedical Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, EthiopiaCorrespondence: Dawit Habte Woldeyes Tel +251 913214906Fax +251 582202025Email dwthabte@gmail.comIntroduction: The key elements of success in a given sports competition have become an area of interest for researchers. The reason for the success of Ethiopian runners was not proved scientifically. This study aimed at documenting the anthropometric parameters of 10,000 meter runners and to find out the association between such parameters and performances.Methods: A descriptive field study was conducted. 32 elite 10,000 meter runners participated. The data were collected while the athletics team was preparing for the world athletics championship. The procedure was repeated three times for each individual. Statistical analysis was performed using SPSS version 18. All the data were presented as mean ± S.D. The Pearson product-moment test was used to determine the correlation between the variables and finishing time. The level of significance for all statistical tests was set at p < 0.05.Results: The experience of male and female athletes showed a negative association with finishing time. However, there was no statistically significant correlation between the age and running time in both sexes. A significant positive association of body weight to running time was observed in both sexes. Body height correlates positively to running time in males (p

Sarah K Perry, Harsh H Buddhadev, Lorraine R Brilla, David N Suprak Department of Health and Human Development, Western Washington University, Bellingham, WA, USACorrespondence: Harsh H BuddhadevDepartment of Health and Human Development, Western Washington University, 201H Carver Academic Facility, MS 9067, 516 High Street, Bellingham, WA 98225, USATel +1 360 650-4115Fax +1 360 650-7447Email harsh.buddhadev@wwu.eduBackground: During ballet, injuries to the Achilles tendon are associated with the take-off phase of various jumps.Research question: The purpose of the study was to assess differences in mechanical demand on the body, specifically atthe ankle, in two single-leg jumps commonly trained in ballet: a saut de chat (SDC) and a temps levé (TL).Methods: Fifteen classically trained female dancers had 16 reflective markers placed on the lower body and each dancer performed each jump three times on a force plate. The marker position data and ground reaction forces (GRF) were captured synchronously at 250 Hz and 1000 Hz, respectively. Peak vertical GRF, mean rate of force development (RFD), peak ankle moment, and peak ankle power were determined and averaged across trials. Paired t-tests were used to determine differences between the SDC and the TL.Results: When compared to the TL, the SDC displayed significantly higher peak vertical GRF (p = 0.003), RFD (p = 0.002), and peak ankle moment and power (p < 0.001). The effect sizes for these differences were large for all variables (Cohen’s d > 0.80).Conclusion: The mechanical demand at the ankle joint is significantly greater for the SDC than the TL.Keywords: achilles tendinopathy, power, moment, rate of force development

Jane E Yardley1–4 1Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada; 2Alberta Diabetes Institute, Edmonton, Canada; 3Augustana Faculty, University of Alberta, Camrose, Canada; 4Women’s and Children’s Research Institute, Edmonton, CanadaCorrespondence: Jane E YardleyAugustana Faculty, University of Alberta, 4901 – 46th Avenue, Camrose, AB T4V 2R3, CanadaTel +1 780 679 1688Fax +1 780 679 1590Email jane.yardley@ualberta.caAbstract: Fear of hypoglycemia is a common barrier to exercise and physical activity for individuals with type 1 diabetes. While some of the earliest studies in this area involved only one or two participants, the link between exercise, exogenous insulin, and hypoglycemia was already clear, with the only suggested management strategies being to decrease insulin dosage and/or consume carbohydrates before and after exercise. Over the past 50 years, a great deal of knowledge has been developed around the impact of different types and intensities of exercise on blood glucose levels in this population. Recent decades have also seen the development of technologies such as continuous glucose monitors, faster-acting insulins and commercially available insulin pumps to allow for the real-time observation of interstitial glucose levels, and more precise adjustments to insulin dosage before, during and after activity. As such, there are now evidence-based exercise and physical activity guidelines for individuals with type 1 diabetes. While the risk of hypoglycemia has not been completely eliminated, therapy recommendations have evolved considerably. This review discusses the evolution of the knowledge and the technology related to type 1 diabetes and exercise that have allowed this evolution to take place.Keywords: exercise, physical activity, blood glucose, insulin, carbohydrate, continuous glucose monitoring

Wylker Souza Saraiva,1 Jonato Prestes,1 Silvana Schwerz Funghetto,2 James Wilfred Navalta,3 Ramires Alsamir Tibana,1 Dahan da Cunha Nascimento1,4 1Department of Physical Education, Catholic University of Brasilia (UCB), Brasilia, Brazil; 2Department of Nursing, University of Brasilia (UNB), Brasilia, Brazil; 3Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA; 4Department of Physical Education, Center University of Distrito Federal (UDF), Brasilia, BrazilCorrespondence: Dahan da Cunha NascimentoPrograma de Pós-Graduação Stricto Sensu em Educação Física, Universidade Católica de Brasília, Q.S. 07, Lote 01, EPTC – Bloco G, Distrito Federal, Brasilia 71966-700, BrazilTel/Fax +21/55/61 3356 9350Email dahanc@hotmail.comPurpose: Relative handgrip strength (RHGS), Aged Based on Exercise Stress Testing (A-BEST), and chronological age were evaluated as predictors of impaired mobility in older women.Methods: Participants included 88 older women (mean age 68.13±6.02 years) referred for exercise stress testing. Estimated physiological age was computed based on exercise capacity, chronotropic reserve index, heart rate recovery, and medication that could affect heart rate. RHGS was measured using a validated handgrip hydraulic dynamometer and mobility was evaluated by timed up and go test (TUG-test). A hierarchical multiple regression predicted TUG-test performance from A-BEST, chronological age and RHGS.Results: After adjustment for diabetes, RHGS was the only variable to add significantly to the prediction model (p=0.001). An increase in RHGS of 1 kg/body mass index was associated with a decrease in TUG-test of 0.7 seconds.Conclusion: Relative handgrip strength test was a better predictor of impaired mobility when compared with chronological and physiological age in older women. Moreover, RHGS represents an inexpensive, simple, portable, noninvasive measurement for a clinician when compared with an exercise stress testing.Keywords: muscle strength, biological age, chronological age, older, functional capacity

Pantelis T Nikolaidis,1,2 Elias Villiger,3 Luca P Ardigò,4 Zbigniew Waśkiewicz,5 Thomas Rosemann,3 Beat Knechtle3,6 1Exercise Physiology Laboratory, Nikaia, Greece; 2Exercise Testing Laboratory, Hellenic Air Force Academy, Acharnes, Greece; 3Institute of Primary Care, University of Zurich, Zurich, Switzerland; 4Department of Neurosciences, Biomedicine and Movement Sciences, School of Exercise and Sport Science, University of Verona, Verona, Italy; 5Department of Team Sports, Academy of Physical Education, Katowice, Poland; 6Medbase St. Gallen Am Vadianplatz, St. Gallen, Switzerland Purpose: The age of peak performance (APP) has been studied extensively in various endurance and ultra-endurance sports; however, less information exists in regard to duathlon (ie, Run1, Bike, and Run2). The aim of the present study was to assess the APP of duathletes competing either in a short (ie, 10 km Run1, 50 km Bike, and 5 km Run2) or a long distance (ie, 10 km Run1, 150 km Bike, and 30 km Run2) race. Participants and methods: We analyzed 6,671 participants (women, n=1,037, age 36.6±9.1 years; men, n=5,634, 40.0±10.0 years) in “Powerman Zofingen” from 2003 to 2017. Results: Considering the finishers in 5-year age groups, in the short distance, a small main effect of sex on race time was observed (p

Terje Dalen,1 Ørjan Øverås,1 Roland van den Tillaar,1 Boye Welde,2 Erna Dianne von Heimburg1 1Department of Physical Education and Sport Science, Nord University, Levanger, Norway; 2UiT The Arctic University of Norway, School of Sport Sciences, Alta, Norway Background: The aim of this study was to compare the effect of different soccer-specific maximal actions (Continuous run, Sprint, Sprint with change of direction [Sprint COD], Jump and Shot) upon physiological (oxygen uptake and heart rate) and perceptual (rating of perceived exertion [RPE]) responses and accelerometer load. Materials and methods: Ten moderately to well-trained male soccer players volunteered to serve as subjects in this study. A repeated within-subject design was used in which each subject was tested on five occasions on different days, one test each day, during a period of 2 weeks. Each of the five tests had a distance of 900 m and lasted 5 minutes, thus the mean speed for all five tests was 3 m/s. During the test, oxygen uptake, heart rate and accelerometer load were measured. Immediately after each test, RPE was recorded, and after the test, oxygen uptake was measured for 5 minutes while the subject sat in an upright position on a chair. Results: In the comparison of different soccer-specific maximal actions upon physiological and perceptual responses and accelerometer load, this study found that the total accelerometer load was lowest in Sprint and Sprint COD conditions, although the physiological (oxygen uptake and heart rate) and perceptual (RPE) responses were highest in the respective conditions. The Jump condition experienced lower RPE than Sprint and Sprint COD but achieved the highest accelerometer load. Conclusion: Accelerometer load is not a valid measurement for energy costs or RPE but may function as a complementary tool to investigate the player loads during matches and training. Keywords: soccer, oxygen uptake, rate of perceived exhaustion, repeated sprint, jump, shot

Jan H Rosenvinge,1 Jorunn Sundgot-Borgen,2 Gunn Pettersen,3 Marianne Martinsen,4 Annett Victoria Stornæs,2 Anne Marte Pensgaard5 1Department of Psychology, Faculty of Health Sciences, UiT – The Arctic University of Norway, Tromsø, Norway; 2Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway; 3Department of Health and Caring Sciences, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway; 4Department of Mathematics, Natural Sciences, and Physical Education, Inland Norway University of Applied Sciences, Hamar, Norway; 5Department of Coaching and Psychology, Norwegian School of Sports Science, Oslo, Norway Introduction: Psychological distress is increasing among adolescents and clusters with other mental health problems such as eating problems. The aim of this study was to investigate the prevalence of psychological distress among young elite athletes and age-matched controls and whether prevalence figures may be attributed to perfectionism and eating problems. Methods: First-year athletes from all Norwegian elite sport high schools (n=711) and 500 ­students from randomly selected ordinary high schools were eligible for this cross-sectional study. In total, 611 athletes and 355 student controls provided self-report data about psychological distress, perfectionism, and eating problems (ie, body dissatisfaction and a drive for thinness), as well as their physical training/activity. Results: A significantly higher proportion of controls scored above the cutoff point for marked psychological distress. Physical activity above the recommended levels for this age group predicted psychological distress among the controls, while the opposite was found in the student elite athlete sample. In both samples, perfectionistic concerns, ie, concern over mistakes, predicted overall psychological distress. However, among elite athletes, perfectionistic concerns were particularly associated with clinically significant psychological distress. Moreover, the impact of eating problems was negligible. Conclusion: Results from this study highlight the need to target the maladaptive perfectionistic concerns to prevent psychological distress among young athletes as well as among their age-matched nonathlete counterparts. Keywords: psychological distress, competitive athletes, perfectionism

Metin Polat,1 Selcen Korkmaz Eryılmaz,2 Sami Aydoğan3 1School of Physical Education and Sports, Erciyes University, Kayseri, Turkey; 2School of Physical Education and Sports, Cukurova University, Adana, Turkey; 3Department of Physiology, Faculty of Medicine, Erciyes University, Kayseri, Turkey Introduction: In order to ensure that athletes achieve their highest performance levels during competitive seasons, monitoring their long-term performance data is crucial for understanding the impact of ongoing training programs and evaluating training strategies. The present study was thus designed to investigate the variations in body composition, maximal oxygen uptake (VO2max), and gas exchange threshold values of cross-country skiers across training phases throughout a season. Materials and methods: In total, 15 athletes who participate in international cross-country ski competitions voluntarily took part in this study. The athletes underwent incremental treadmill running tests at 3 different time points over a period of 1 year. The first measurements were obtained in July, during the first preparation period; the second measurements were obtained in October, during the second preparation period; and the third measurements were obtained in February, during the competition period. Body weight, body mass index (BMI), body fat (%), as well as VO2max values and gas exchange threshold, measured using V-slope method during the incremental running tests, were assessed at all 3 time points. The collected data were analyzed using SPSS 20 package software. Significant differences between the measurements were assessed using Friedman’s twoway variance analysis with a post hoc option. Results: The athletes’ body weights and BMI measurements at the third point were significantly lower compared with the results of the second measurement (p0.05). Conclusion: VO2max and gas exchange threshold values recorded during the third measurements, the timing of which coincided with the competitive season of the cross-country skiers, did not significantly change, but their incremental running test time and running speed significantly increased while their body weight and BMI significantly decreased. These results indicate that the cross-country skiers developed a tolerance for high-intensity exercise and reached their highest level of athletic performance during the competitive season. Keywords: athletic performance, aerobic capacity, winter sport

Ryan M Weatherwax,1,2 Nigel K Harris,1 Andrew E Kilding,3 Lance C Dalleck2 1Auckland University of Technology, Human Potential Center, Auckland, New Zealand; 2Western State Colorado University, Recreation and Exercise & Sport Science, Gunnison, CO, USA; 3Auckland University of Technology, Sports Performance Research Institute New Zealand, Auckland, New Zealand Background: Even though cardiorespiratory fitness (CRF) training elicits numerous health benefits, not all individuals have positive training responses following a structured CRF intervention. It has been suggested that the technical error (TE), a combination of biological variability and measurement error, should be used to establish specific training responsiveness criteria to gain further insight on the effectiveness of the training program. To date, most training interventions use an absolute change or a TE from previous findings, which do not take into consideration the training site and equipment used to establish training outcomes or the specific cohort being evaluated. The purpose of this investigation was to retrospectively analyze training responsive­ness of two CRF training interventions using two common criteria and a site-specific TE.Methods: Sixteen men and women completed two maximal graded exercise tests and verification bouts to identify maximal oxygen consumption (VO2max) and establish a site-specific TE. The TE was then used to retrospectively analyze training responsiveness in comparison to commonly used criteria: percent change of >0% and >+5.6% in VO2max.Results: The TE was found to be 7.7% for relative VO2max. χ2 testing showed significant differences in all training criteria for each intervention and pooled data from both interventions, except between %Δ >0 and %Δ >+7.7% in one of the investigations. Training nonresponsiveness ranged from 11.5% to 34.6%.Conclusion: Findings from the present study support the utility of site-specific TE criterion to quantify training responsiveness. A similar methodology of establishing a site-specific and even cohort specific TE should be considered to establish when true cardiorespiratory training adaptations occur. Keywords: training responders, training nonresponders, cardiorespiratory fitness, exercise training&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

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 V˙O2max. 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), LT2 (r = 0.721) and distance per session (r = 0.563). Conclusion The data highlight profound differences for key components of marathon running (V˙O2max, LT1, LT2, RE and % V˙O2max) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed., Video abstract