The association between subjective anti-doping knowledge and objective knowledge among Japanese university athletes: a cross-sectional study.

Introduction: This study aimed to assess the association between subjective anti-doping knowledge (subjective ADK) and objective anti-doping knowledge (objective ADK) among Japanese university athletes, framed within the context of the Theory of Planned Behavior (TPB). Methods: Eligible participants were 486 university athletes [320 men (65.8%), 166 women; mean age of 18.9 ± 1.0 years]. The participants categorized themselves in terms of the quality of their anti-doping knowledge. This assessment resulted in an independent variable coded as "(1) substantial lack of adequate knowledge," "(2) some lack of adequate knowledge," "(3) fair amount of knowledge" or "(4) good amount of knowledge." Objective ADK was assessed using the Athlete Learning Program about Health and Anti-Doping (ALPHA) test, a set of questions derived from the ALPHA-a former World Anti-Doping Agency e-learning program. The test comprises 12 questions (four choices each; passing index: ≧10 points or 80% correct answer rate). ANCOVA was conducted using subjective ADK as an independent variable and ALPHA scores as a dependent variable, adjusting for confounding factors (anti-doping experience). Results: The ALPHA corrected answer rate across subjective ADK levels for the group were 73.10% for "(1) substantial lack of adequate knowledge," 71.97% for "(2) some lack of adequate knowledge," 75.18% for "(3) fair amount of knowledge" and 72.86% for "(4) good amount of knowledge." Comparison between different levels of subjective ADK revealed no significant differences in ALPHA score considering the main effects or any of their interactions. Discussion: The present results revealed that Japanese university athletes' subjective ADK did not match their objective ADK. In the context of the TPB, there may be limitations in the perceived behavioral control in anti-doping knowledge. Even if athletes view doping as a wrongful act and have formed attitudes and subjective norms to comply with the rules, the results suggest that errors may occur in the composition of behavioral intentions due to a lack of knowledge. This could lead to the possibility of facing the risk of unintentional anti-doping rule violations. It highlights the need for targeted educational interventions to align subjective ADK of athletes with their objective ADK.

Risk Factors for Concussion in Under 18, Under 22 and Professional Men's Rugby Union: A Video Analysis of 14,809 Tackles.

OBJECTIVE: This study aimed to identify the risk factors for tackle-related concussion observed in matches involving under (U) 18, U 22 and professional men's Rugby Union players through video analysis. STUDY DESIGN: Descriptive epidemiology study. METHODS: Twenty Rugby Union matches each for high school (U18), university/college (U22) and professional (Elite) were randomly selected from 202 matches in the 2018/2019 season. Both one-on-one and tackles involving multiple tacklers were analyzed for the 60 matches. The 28 categorical and continuous variables (e.g., tackle characteristics and duration before the tackle) were applied as risk factors to a least absolute shrinkage and selection operator (Lasso) regression analysis. To identify high-risk situations, a simulation model with coefficients obtained from the Lasso regression was used. Statistical analysis was conducted according to tackle direction. RESULTS: A total of 14,809 tackles and 41 concussions involving 1800 players were included in the analyses. The incidence rate of concussions (injuries/1000 tackles) was greater in Elite players (4.0) compared with U18 (1.9) and U22 (2.4) players. The factors most highly associated with concussions were head-in-front tackles (where the tackler's head is placed forward, impeding a ball carrier's forward movements, 11.26/1000 tackles), and were more often observed among U18 players. A simulation model predicted that the highest risk tackle situation in Elite players was a head-in-front, side-on tackle below the hip of the ball carrier (predicted incidence rate 18.07/1000 tackles). CONCLUSION: The risk factors associated with concussion need to be assessed cautiously. Avoiding head-in-front, side-on tackles to the lower extremities of a ball carrier should be considered to reduce injury risks.

The Accuracy of Ankle Eccentric Torque Control Explains Dynamic Postural Control During the Y-Balance Test.

Background: The Y-Balance Test (YBT), especially the posteromedial (PM) reach direction (PM-YBT), is able to identify dynamic postural control deficits in those who have ankle instability. However, there still exists a need to understand how sensorimotor function at the ankle explains the performance during the PM-YBT. Hypothesis/Purpose: The purpose of this study was to determine whether the ability to accurately control eccentric ankle torque explained PM-YBT performance. It was hypothesized that eccentric dorsiflexion/plantarflexion torque control would be positively related to the maximum reach distance (MRD) of PM-YBT. Study Design: Cross-sectional study. Methods: Twelve healthy subjects performed the PM-YBT, maximum voluntary isometric contractions (MVIC) for both dorsiflexion and plantarflexion muscle strength, and then the torque control testing of the ankle. The torque control testing provided a target torque level on a screen in front of the subject and passive rotations of the ankle joint in the sagittal plane at 10 deg/sec between plantarflexion to dorsiflexion. Subjects were then instructed to eccentrically contract the dorsiflexors and plantar flexors to generate torque while the ankle joint rotated. The accuracy of torque control during eccentric dorsiflexion and plantarflexion by calculating absolute errors, the area between the target torque and the produced torque were evaluated. Tibialis anterior and soleus muscle activities were simultaneously recorded during testing. A step-wise linear regression model was used to determine the best model predicted the MRD of the PM-YBT (PM-MRD). Results: A step-wise linear regression developed a model explaining only eccentric dorsiflexion torque control predicted higher PM-MRD score (R2 = 44%, F1,10 = 7.94, ß = -0.67, p = 0.02). Conclusion: The accuracy of torque control during eccentric dorsiflexion predicts better performance in the PM-YBT. Level of Evidence: 3b.

Cross-cultural adaptation, validity, reliability and responsiveness of the Japanese version of the Victorian Institute of sports assessment for patellar tendinopathy (VISA-P-J).

BACKGROUND: This study aimed to translate, adapt, and test the psychometric properties of the Japanese version of the Victorian Institute of sports assessment for patellar tendinopathy (VISA-P-J). METHODS: This prospective cohort study registered 43 participants ≥ 18 years old with a history of painful symptoms in the inferior pole of the patella to the proximal patellar tendon lasting ≥ 1 month for patellar tendinopathy. Pain in daily life and during sports activities, symptom classification, and patient global impression of change were assessed at the baseline, 1 week, and 12 weeks. The psychometric properties, test-retest reliability, standard error of measurement, internal consistency criterion validity, construct validity, responsiveness, and interpretability, of the VISA-P-J were calculated according to the COSMIN. RESULTS: The two-way random-effects, absolute agreement intraclass correlation coefficient for test-retest reliability of VISA-P-J was 0.87 (95% confidence interval: 0.78, 0.93), and the standard error of measurement of VISA-P-J was 0.89. The Cronbach's alpha for internal consistency of VISA-P-J was 0.81. A correlation between VISA-P-J and Roel's classification, Visual Analog Scale for pain (VAS)-Active Daily Living, and VAS-Sports (r = - 0.52, r = - 0.66, r = - 0.86, p < 0.01, respectively) was observed for criterion validity. All hypotheses of the hypothesis-testing method to evaluate construct validity and responsiveness of VISA-P-J were substantiated. The minimal clinically important difference of VISA-P-J was 7 points. CONCLUSION: We demonstrated that the VISA-P-J was a reliable, valid, and responsive assessment method for individuals with chronic pain in the patellar tendon.

Effect of Isokinetic Training with Blood Flow Restriction During Rest Interval Versus Exercise on Muscle Strength, Hypertrophy, and Perception: A Pilot Study.

Objectives: This study aimed to determine the effects of high-intensity isokinetic training with blood flow restriction during rest interval between set (rBFR) versus during exercise (eBFR) on muscle hypertrophy and increasing muscle strength and determine whether BFR-induced exercise pain is suppressed by rBFR. Materials and Methods: Fourteen arms (7 participants) were recruited for the study. We conducted the following interventions for each arm: eBFR (n=4), rBFR (n=5), and exercise only (CON, n=5). The participants performed elbow flexion training with a BIODEX device twice weekly for 8 weeks. This study training consisted of total four sets; each was performed until <50% peak torque was achieved twice consecutively. BFR pressure was set at 120 mmHg. Elbow flexor peak torque during concentric contraction (CC), isometric contraction (IM), and muscle cross-sectional area (CSA) were measured before and after the intervention. Numerical rating scale scores used to assess pain during exercise were determined during training. Results: Peak torque at the CC increased in the rBFR (p<0.05) and IM increased in the rBFR and CON (p<0.05), while CSA increased in the rBFR and CON (p<0.001). The pain during exercise was severe in the eBFR and moderate in the rBFR and CON. Conclusions: This study's showed that high-intensity isokinetic training with rBFR did not have a synergistic effect on increasing muscle strength and muscle size. Additionally, high-intensity isokinetic training with BFR when it may be best not to perform it during exercise, because it was induces severe pain and may inhibit increases in muscle strength.

Age-related changes in mechanical properties of semitendinosus tendon used for anterior cruciate ligament reconstruction.

BACKGROUND: Hamstring tendons are a popular choice for autografts in anterior cruciate ligament (ACL) reconstruction. However, there is increasing evidence that hamstring tendon autografts carry a high risk of revision and residual instability in young patients. To elucidate the reasons for the inferior outcome of the reconstructed ACL with hamstring tendon autografts in young patients, we investigated the Young's modulus and the extent of cyclic loading-induced slackening of the semitendinosus tendon used for ACL reconstruction across a broad range of ages. METHODS: Twenty-six male patients (aged 17-53 years), who were scheduled for ACL reconstruction surgery using the semitendinosus tendon autograft, participated in this study. The distal portion of the harvested semitendinosus tendon, which was not used to construct the autograft, was used for cyclic tensile testing to calculate the Young's modulus and the extent of slackening (i.e., increase in slack length). RESULTS: Spearman correlation analysis revealed that the Young's modulus of the semitendinosus tendon was positively correlated with the patient's age (ρ = 0.559, P = 0.003). In contrast, the extent of tendon slackening did not correlate with the patient's age. CONCLUSIONS: We demonstrated that the Young's modulus of the semitendinosus tendon increases with age, indicating that the semitendinosus tendon used for ACL reconstruction is compliant in young patients.

Relationship between the level of willingness to learn about anti-doping and objective knowledge among Japanese university athletes: A cross-sectional study.

Previous studies have indicated that athletes' anti-doping knowledge is inadequate. Athletes' willingness to learn about anti-doping (willingness to learn) may influence their anti-doping knowledge, but the actual situation is unclear. This study aimed to determine the relationship between athletes' willingness to learn about anti-doping and their objective measurement knowledge and explore directions for educational interventions. The eligible participants were 971 male and 802 female university athletes. We used the ALPHA test (12 questions/four choices; passing index: ≥10 points/80% correct answer rate) to assess objective anti-doping knowledge. The willingness to learn question was, "Would you like to learn more about anti-doping?" Responses were given on a 4-point scale ranging from 1: strongly disagree to 4: strongly agree. An ANCOVA was conducted with four levels of willingness to learn as the independent variable and ALPHA correct answer rate as the dependent variable, adjusting for confounding factors (years of athletic experience and anti-doping education experience). The percentage of athletes (%) and each ALPHA correct answer rate (%) by the level of willingness to learn was 1: strongly disagree, n = 1.64%, 61.78%; 2: somewhat disagree, n = 13.14%, 62.38%; 3: somewhat agree, n = 62.94%, 64.08%; 4: strongly agree, n = 22.28%, 67.11%. The ALPHA correct answer rates showed significant differences in the main effect by the level of willingness to learn [F (3, 1767) = 2.873, p < 0.05, η2 = 0.01], although the effect size was small, and multiple comparisons showed no significant differences between the levels. The results indicated that the ALPHA correct answer rate did not reach 80% even for the "strongly agree" level of willingness to learn, suggesting that information on anti-doping may be inadequate. The need to provide sufficient educational content to improve knowledge was evident.

Effects of Various Numbers of Runs on the Success of Hamstring Injury Prevention Program in Sprinters.

Studies have not adequately addressed the influence of fatigue, which is considered a major risk factor for hamstring injuries. Therefore, this study aimed to clarify how a muscle fatigue condition affects the success of hamstring injury prevention programs in sprinters. The study subjects were 613 collegiate male sprinters. They employed submaximal/maximal running for a large number of runs and supramaximal running for a small number of runs in daily training. The hamstring injury prevention program had become the most effective strategy in the past 24 seasons of track and field for preventing hamstring injuries. The number of sprinters who experienced hamstring injuries in three periods over the 24 seasons was recorded. The incidents of hamstring injuries during supramaximal running per athlete-seasons were 137.9, 60.6, and 6.7 for Periods I, II, and III, respectively, showing a significant decline (p < 0.01). Furthermore, the incidents of hamstring injuries during submaximal and maximal running per season showed no significant change. The results of this study indicate that by inducing muscle fatigue, a small number of runs makes hamstring injury prevention programs effective.

Effect of low-intensity exercise with blood flow restriction during rest intervals on muscle function and perception.

PURPOSE: We assessed the effects of low-intensity exercise with blood flow restriction (BFR) during rest intervals on recovery of muscle function and pain during exercise and rest intervals. METHODS: Participants were 10 males and study arms of the participants were randomly assigned into three conditions; low-intensity exercise with BFR during rest intervals (rBFR), low-intensity exercise with BFR during exercise (eBFR) and low-intensity exercise only (EO). The exercise task was elbow flexion until repetition failure at 30% of 1 RM and cuff pressure was 120 mmHg. The maximum voluntary isometric contraction (MVIC) and the muscle endurance (ME) were measured pre, post, 1, 24 and 48 h after the exercise. Pain during exercise and rest intervals were evaluated using the Numerical Rating Scale. RESULTS: MVIC and ME significantly decreased after exercise in all conditions. Pain during exercise was lower in rBFR (4.2 ± 2.9) (p = 0.007) and EO (4.4 ± 2.7) (p = 0.014) conditions compared to eBFR condition (6.7 ± 1.7), but the pain during rest intervals was more intense in rBFR condition (5.2 ± 1.6) compared to eBFR (1.5 ± 1.4) and EO (1.7 ± 1.2) conditions (p < 0.001). CONCLUSION: We discovered that recovery of muscle function was the same as BFR during rest intervals and BFR during exercise. Also, our results suggested that BFR itself may cause the perception of pain. Future studies are thus required to investigate the optimal dosage focusing on the pressure volume and intensity used in BFR during intervals.

Lifestyle Changes and Baseball Activity among Youth Baseball Players before and during the First COVID-19 Pandemic in Japan.

This cross-sectional study aimed to clarify the changes in lifestyle and baseball activity before and during the COVID-19 pandemic among youth baseball players. Participants were 99 youth baseball players (ages 9.6 ± 1.5 years, height 137.8 ± 9.4 cm, weight 35.3 ± 12.4 kg) in Japan. They completed an online survey between April 6 and 20, 2021, on their demographic characteristics, lifestyle (recreational screen, sleep, and study times), and baseball activity (frequency of team practice time and voluntary exercise-related baseball) at two-time points: before the pandemic (before March 2020) and during the state of emergency declared in Japan (from April to May 2020). The changes in outcomes between the two-time points were evaluated for significance. Recreational screen time and sleeping time during the state of emergency were significantly increased compared to those before the pandemic (p < 0.001). The frequency of team practice time on weekends during the state of emergency was significantly reduced, and voluntary exercise-related baseball was significantly increased compared to that before the pandemic (p < 0.01). We found that the COVID-19 pandemic changed behaviors concerning activities and exercise among youth baseball players and recommended that such behavioral changes be carefully monitored.

Yields of mesenchymal stromal cells from synovial fluid reflect those from synovium in patients with rheumatoid arthritis.

The yield of primary synovial mesenchymal stromal cells (MSCs) from synovium of patients with rheumatoid arthritis (RA) is highly variable, but cell transplantation therapy with autologous synovial MSCs requires accurate prediction of the synovial MSC yield per synovium weight. Here, we determined whether the yield of synovial fluid MSCs might predict the ultimate yield of primary MSCs from the synovium of RA knees. Synovial fluid and synovium were harvested during total knee arthroplasty from the knee joints of 10 patients with RA. Synovial fluid (1.5 mL) was diluted fourfold and plated equally into six 60 cm2 dishes. Nucleated cells from digested synovium were similarly plated at 1 × 104 cells in 6 dishes. All dishes were cultured for 14 days and analyzed for MSC yields and properties, including in vitro chondrogenesis. The cultured synovial cell number was correlated with the cultured synovial fluid cell number (n = 10, R2 = 0.64, p < 0.01). Synovial fluid cells formed cell colonies and showed MSC-like surface epitopes and multi-differentiation potential. However, the cartilage pellet weight indicated a greater chondrogenic potential of the synovial MSCs (n = 8). The primary MSC yields from synovial fluid and synovium were correlated, indicating that the synovial fluid MSC yield can predict the ultimate synovial MSC yield.

Remnant preservation provides good clinical outcomes after anterior cruciate ligament reconstruction.

PURPOSE: To evaluate the association of remnant preservation (RP) and non-RP (NRP) with patient-reported outcome measures and subsequent graft rupture at a minimum 2-year follow-up after anterior cruciate ligament (ACL) reconstruction. METHODS: Patients in this retrospective study underwent primary isolated ACL reconstruction by the RP or NRP technique with a four- to five-strand hamstring tendon graft. Multivariate linear or logistic regression and Cox regression analyses were performed to compare the physical and psychological outcomes by the International Knee Documentation Committee subjective knee form (IKDC-SKF) and the Japanese Anterior Cruciate Ligament questionnaire 25 (JACL-25), respectively; satisfaction rate; and prognosticators of graft rupture. RESULTS: In total, 120 patients (mean age, 30.6 ± 12.7 years; 54 RP, 66 NRP) with a mean follow-up of 3.2 ± 1.6 years were enrolled in this study. At the latest postoperative follow-up, the RP group showed a mean IKDC-SKF score of 92.3 ± 8.5 and mean JACL-25 score of 13.2 ± 11.2, while these scores in the NRP group were 86.4 ± 12.2 and 24.4 ± 19.5, respectively (P = 0.016 and 0.007, respectively). No significant differences were found in the return-to-sports rate (RP vs. NRP, 79.5% vs. 67.5%) or satisfaction rate (RP vs. NRP, 89.2% vs. 74.4%) (n.s.); however, a significant difference was found in the rate of return to the preinjury sports level (RP vs. NRP, 64.1% vs. 37.5%; P = 0.014). The graft rupture rate was significantly higher in the NRP than RP group (9/66 vs. 1/54; hazard ratio 9.29; 95% confidence interval 1.04-82.81). Younger age (≤ 18 years) was the other important risk factor for graft rupture (hazard ratio 8.67; 95% confidence interval 2.02-37.13). CONCLUSION: Patients who underwent ACL reconstruction with the RP technique obtained somewhat better physical and psychological results than those who underwent ACL reconstruction with the NRP technique. With respect to clinical relevance, patients treated with the RP technique may obtain better outcomes in terms of graft rupture and return to the preinjury sports level than those treated with the NRP technique, but with no differences in overall return to sports or satisfaction. LEVEL OF EVIDENCE: IV.

Effects of a wearable device and functional wear on spinal alignment and jump performance.

BACKGROUND/OBJECTIVE: To elucidate the effects of walking exercise using a wearable device and functional wear on spinal alignment and jump performance. METHODS: In total, 27 female college soccer players were randomly divided into two groups: trunk solution (TS) and compression garments (CGs). Spinal alignment, jump performance, and electromyography activity during the jump performance of the two groups were measured after a 20-min walking exercise. The values for each group were compared t pre- and post-intervention. RESULTS: The flexibility of the lower thoracic vertebrae in spinal alignment was increased during extension in the TS group. However, the post-value of the abdominal external oblique muscle during a countermovement jump (CMJ) was significantly lower than its pre-value (p < 0.05). In addition, even though spinal alignment was not affected in the CG group, post-values of the jump height during squat jump and CMJ were significantly higher than their pre-values (p < 0.05). Furthermore, the post-value of the biceps femoris during the countermovement jump with arm was significantly lower than its pre-value (p < 0.05). CONCLUSION: Our study suggested that walking exercise using TS may increase the range of motion of the lower thoracic vertebrae in athletes and reduce the muscular activity of the vastus lateralis during CMJ. Additionally, although spinal aliment is not affected, the jump height may increase using CGs.

Validation and defining the minimal clinically important difference of the Japanese version of the IKDC Subjective Knee Form.

BACKGROUND: This study aimed to validate and determine the minimal clinically important difference (MCID) in the Japanese version of the International Knee Documentation Committee Subjective Knee Form (Japanese IKDC-SKF) for patients with anterior cruciate ligament (ACL) injuries. METHODS: This prospective study was performed using the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) guideline to assess the measurement properties of reliability, responsiveness, validity, and interpretability of the Japanese IKDC-SKF. RESULTS: A total of 152 patients were enrolled in the study. The Japanese IKDC-SKF had excellent internal consistency [Cronbach's alpha (95% confidence interval, CI) was 0.90 (0.88-0.92), and the test-retest reliability [intraclass correlation coefficient, ICC2,1 (95% CI)] was 0.97 (0.94-0.98). The content validity (r), which was interpretable between the Japanese IKDC-SKF and the Japanese Anterior Cruciate Ligament questionnaire 25 was -0.87 (P < 0.001). The construct validity for the IKDC-SKF was 86% (six of seven hypotheses were consistent with the results), also indicating high validity. Responsiveness of the Japanese IKDC-SKF was confirmed, with an acceptable area under the curve of 0.81 and a large effect size (Cohen's d of 0.8). There were no floor or ceiling effects. The MCID for the Japanese IKDC-SKF for ACL injury was 10.7. CONCLUSIONS: Our results indicate that the Japanese version of the IKDC-SKF is a reliable, valid, and responsive measurement instrument with which to evaluate the physical function of patients with ACL injuries.

Reliability assessment of the functional movement screen for predicting injury risk in Japanese college soccer players.

[Purpose] This study aimed to assess the reliability of the Functional Movement Screen and explore whether this evaluation tool can predict the risks of personal injuries in Japanese soccer players. [Participants and Methods] Seventy-five Japanese college soccer players who participated in our 1 year prospective cohort study underwent a Functional Movement Screen assessment. Demographic data, athletic characteristics, and types and frequency of injuries sustained, were analyzed with the assessment results. [Results] There was no significant difference in the mean Functional Movement Screen composite scores between genders. Although the Functional Movement Screen showed excellent inter-rater reliability (0.92), low overall internal consistency (0.35) was observed. A maximum score of 3 in straight leg raise occurred in 94% of the females and was considered a ceiling effect. None of the cut-off point scores of the Functional Movement Screen were associated with the number of overall injuries, lower limb injuries, and traumatic injuries, or time to return to play. The Functional Movement Screen composite score of ≤15 represented the maximum sensitivity of 76.92% and specificity of 34.78% with 0.56 in the area under the curve. [Conclusion] Functional Movement Screen composite scores do not have sufficient sensitivity and specificity for predicting injuries in Japanese college soccer players.

Spectator medicine at an international mega sports event: Rugby World Cup 2019 in Japan.

BACKGROUND: The Rugby World Cup (RWC) is one of the biggest international mega sports events in the world. This study was conducted to identify and evaluate the volume, nature, and severity of spectator medical care in the stadiums of 12 venues across Japan during RWC 2019. METHOD: This was a retrospective review of medical records from spectator medical rooms of 45 official matches of RWC 2019 between September 20 and November 2, 2019. All patients in the stadium who visited the spectator medical room and were transferred to a hospital were included. The wet bulb globe temperature (WBGT) value at the kick-off time of each match, the number of visits to the spectator medical room, and the number of transfers to a hospital were reviewed and analyzed. The patient presentation rate (PPR) was calculated per 10,000 attendees. Severity categories were defined as mild or severe. Mild cases were considered non-life threatening requiring minimal medical intervention, and severe cases required transport to a hospital. RESULT: The total number of visits to the spectator medical room was 449 with a PPR of 2.63. Most cases (91.5%) were mild in severity. The PPR was significantly higher for the matches held with a WBGT over 25 °C than for the matches under 21 °C (PPR 4.27 vs 2.04, p = 0.04). Thirty-eight cases were transferred to a hospital by ambulance; the PPR was 0.22. The most common reasons for transfer to the hospital were heat illness and fracture/dislocation, at a rate of 15.8% each. The incidence rate of cardiopulmonary arrest per 10,000 attendees was 0.0059 during RWC 2019. CONCLUSION: Preparation and provision of appropriate medical service for spectators is a key factor for mass-gathering events. During RWC 2019, the majority (91.5%) of patients who sought medical attention did so for minor complaints, which were easily assessed and managed. On the other hand, a higher WBGT situation contributes significantly to an increased PPR (< 21 versus > 25, 2.04 versus 4.27, p = 0.04). Careful medical preparation, management, and development of public education programs for higher WBGT situations will be required in the future for similar international mega sports events.

Platelet-rich plasma (PRP) accelerates murine patellar tendon healing through enhancement of angiogenesis and collagen synthesis.

PURPOSE: Although platelet-rich plasma (PRP) therapy has become an increasingly popular treatment for sports-related injuries, the molecular mechanisms of PRP on tissue healing process remain poorly understood. The aim of the present study was to develop an experimental method quantifying the efficacy of PRP with murine patellar tendon injury model, leading to future elucidation of the mechanisms of PRP on healing processes. METHODS: Full-thickness defects were created in the central third of the murine patellar tendon. The prepared allogenic PRP gel was applied on the defect of the patellar tendon (PRP group), while the remaining mice served as the untreated control group. Mice were sacrificed at 2, 4, 6, 8, and 10 weeks after the operation, with histological sections obtained in each time point (n = 4 / time point / group). Semi-quantitative histological evaluation was performed in accordance with the Bonar score. The variables included in this scoring system were cell morphology, ground substance, collagen arrangement, and vascularity, with higher grades indicating worse tendon structures. In addition, the ratio of the collagen fibers to the entire tendon tissue (FT ratio) was measured using KS400 software as a quantitative histological evaluation. RESULTS: The total Bonar score in the PRP group was significantly lower than in control group. With regard to the variables in the Bonar score, the vascularity score was significantly higher in the PRP group at 2 and 4 weeks, while the collagen arrangement score was significantly lower in the PRP group at 8 weeks. Based on a quantitative evaluation, the recovery speed of the patellar tendon determined by FT ratio was significantly faster in the PRP group than in the control group at 6 and 8 weeks. CONCLUSIONS: We have developed an experimental method for histological and quantitative evaluation of the effects of PRP on tissue healing using murine patellar tendon injury model. The results of this study suggest that the local application of PRP could enhance the tissue-healing process both directly through action on localized cells and indirectly through the recruitment of reparative cells through the blood flow. Further investigations will be needed to confirm the mechanisms of PRP in tissue-healing processes with the development of this experimental model.

Effects of hyperbaric oxygen therapy on recovery acceleration in Japanese professional or semi-professional rugby players with grade 2 medial collateral ligament injury of the knee: A comparative non-randomized study.

INTRODUCTION: The effects of hyperbaric oxygen (HBO2) therapy on sprains, ligament injuries, and muscle strains have been reported in several animal studies. In a dog model of compartment syndrome and in a rat contused skeletal muscle injury model, the significant effects of HBO2 therapy on the reduction of edema and muscle necrosis have been reported. In basic research HBO2 therapy stimulated fibroblast activity to improve the healing process. Because of this it expected that HBO2 therapy might improve focal edema and pain in the acute phase and accelerate the healing of injured tissues in athletes with a medial collateral ligament (MCL) injury of the knee. This study aimed to examine the short-term effects of HBO2 application subjectively, and the long-term effects of HBO2 therapy in Japanese professional or semi-professional rugby players with grade 2 MCL injury of the knee. METHODS: Thirty-two professional or semi-professional rugby players with grade 2 MCL injury of the knee were investigated. First, in the HBO2 group (n=16), HBO2 therapy was performed during the acute phase. Visual analog scales (VASs) immediately before and after HBO2 therapy on the same day were compared. Next, we retrospectively evaluated the time to return to play in the HBO2 (n=16) and non-HBO2 (n=16) groups. RESULTS: VAS scores for pain while walking immediately before and after HBO2 therapy on the same day were 37.4 ± 20.1 (mean ± standard deviation) and 32.4 ± 21.8, respectively (p⟨0.001). The VAS scores for pain while jogging were 50.7 ± 25.6 and 43.9 ± 25.0, respectively (p⟨0.001). The time to return to play was 31.4 ± 12.2 days in the HBO2 group and 42.1 ± 15.8 days in the non-HBO2 group, indicating a significant difference between the groups (p⟨0.05). CONCLUSION: HBO2 therapy may reduce pain and accelerate the return to play in athletes with grade 2 MCL injury of the knee in this non-randomized study.

Reproducibility, responsiveness and validation of the Tampa Scale for Kinesiophobia in patients with ACL injuries.

BACKGROUND AND PURPOSE: Psychological factors including fear of pain, re-injury during movement (kinesiophbia) affect return-to-sport rates after anterior cruciate ligament (ACL) reconstructive surgery. Clinicians often encounter in the daily practice that athletes explain lack of self-confidence or psychological readiness during the sports activity. The Tampa Scale for Kinesiophobia (TSK) has been used to evaluate psychological outcomes in patients with ACL injuries in many countries and translated into Japanese version in 2013. However, no researchers validated its reliability, validity, and responsiveness of TSK for patients with ACL injury up to now. The purpose of this study was to evaluate the measurement properties of the Japanese version of the TSK (TSK-J) in patients with ACL injuries. STUDY DESIGN: Cohort study (Diagnostic); Level of evidence, 2. METHODS: This prospective study was performed in the department of orthopaedic surgery at the university hospital of Juntendo from Sep 2016 and Apr 2017. Patients who diagnosed with ACL injury with or without reconstruction surgery completed several patient-reported outcome measures (PROMs) were included in this study. The COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) guidelines were used to evaluate reliability, validity, responsiveness, and interpretability of the TSK-J. RESULTS: 222 patients were included in this study. The TSK-J for ACL injured patients showed good internal consistency (Cronbach's alpha = 0.79) and excellent test-retest reliability (intra-class correlation coefficient, ICC2,1 = 0.90, 95% CI = 0.81 to 0.95). In addtion, the TSK-J was significantly but moderately correlated with the IKDC-SKF (r = - 0.49, P <0.001), VAS-Sports (r = - 0.48, P <0.001), and JACL-25 (r = 0.48, P <0.001). The effect size (ES) was small with the Cohen's d = - 0.2. The minimal important difference (MID) was - 1.3 points. No significant TSK-J score change was observed over 1-year after ACL reconstruction (r = - 0.12, P <0.001). There were no floor or ceiling effects. CONCLUSIONS: Our study demonstrated that the Japanese version of TSK has good reliability. However, its low validity and responsiveness indicate that it may not the best way to assess psychological factors for patients with ACL injury.

Accelerated Return to Play for Professional Rugby Players After Facial Fractures.

BACKGROUND: Facial fractures may result in a significant time away from competition for professional rugby players. An understanding of the return-to-play times is an integral part of clinical decision making when treating professional athletes. A period of 8 to 12 weeks has been conventionally recommended for returning to collision sports after facial fractures. The conventional time to return to sports of 8 to 12 weeks is usually too long for professional players. However, the time of return to play after such facial fractures in elite athletes has not been well described. PURPOSE: To investigate the return to play after facial fractures in professional rugby players with an accelerated rehabilitation protocol. METHODS: Ten professional rugby players with facial fractures were identified and analyzed. The authors investigated the number of days required to return to training and full-contact play according to the trauma type. The authors also determined the presence or absence of refractures and sequelae. RESULTS: The average age of the patients was 26.9 years. Medial orbital wall fractures were the most represented pattern, followed by orbital floor fractures and zygomatic arch fractures. The players returned to jogging after 9.9 days, to sports-specific training after a mean of 10.8 days, and to full-contact training after 18.3 days. There were no cases of refractures and sequelae. CONCLUSION: Players were able to return to their regular rugby activities, earlier than the time commonly allowed to return to full activity.