Ankle brace is commonly used to treat and prevent ankle sprain. Its main aim is to restrict supina tion of the ankle. However, some braces restrict ankle dorsiflexion and plantar flexion. In addition, loosening and loss of restriction after exercise have also been reported. The purpose of this study was to reveal if thin-type ankle brace for ankle sprain restricts ankle dorsiflexion and plantar flexion and its effect of exercise. Five male adults (average age of 30.8±5.2 years) were included in the study. Dorsiflexion and plantar flexion of subjectsʼright ankle was measured before and after wearing the brace, and before and after exercises. Exercises consisted of perform ing 20 times of calf raise, full squat, maximum vertical jump, and 5-minute running on a treadmill. Measurement was performed thrice, and their average was statistically analyzed between with and without the brace, and be fore and after each exercise. The results showed that there was no significant difference between all measured an gles of with and without the brace and before and after each exercise. Thin-type ankle brace for ankle sprain have been reported to restrict supination. Considering our results, this brace does not restrict ankle dorsiflexion and plantar flexion.

This study examined the impact of the COVID-19 pandemic on menʼs ice hockey in Kanagawa pre fecture. We investigated the number and type of penalties and injuries that occurred in menʼs ice hockey league games in Kanagawa between September 2018 and March 2023. In total, data from 734 games were analyzed, and data were compared between seasons. The average number of penalties per game was 5.93 in the 2018-2019 sea son, 5.66 in the 2019-2020 season, 4.96 in 2020-2021, and 4.40 in 2021-2022, 4.64 in the 2022-2023 season, indicating that the number of penalties decreased during the COVID-19 pandemic. However, the number of penalties involv ing the stick increased. Injuries during games also increased during the COVID-19 pandemic, from 0 in the 2018-2019 (175 games) and 2019-2020 (191 games) seasons to 1 case in the 2020-2021 (73 games) season, 6 cases in the 2021-2022 (119 games) season and 2 cases in the 2022-2023 (176 games) season. The increased number of injuries observed may have been due to the closure of ice rinks by the state of emergency, which restricted on-ice training.As players avoided contact to prevent the spread of COVID-19, penalties caused by contact play decreased,whereas those involving sticks increased.

Our study aimed to investigate characteristics of jump distance and body size of 85 asymptomatic elementary school baseball players with abnormal humeral medial epicondyles. The following parameters were recorded: age, body size, bilateral forward jump distance, bilateral single forward, and lateral jump. Elbow injuries were classified based on physical examination findings of throwing pain and tenderness at the medial elbow joint and ultrasonographic findings. The distance jumped values were normalized by height. Participants with humeral medial epicondylar fragmentation, no tenderness, and subjective pain were classified as abnormal. Healthy group comprised those with no elbow pain or ultrasonographic findings. The two groups were compared using unpaired t-test. Abnormal and healthy groups comprised 15 and 62 participants, respectively. Bilateral single lateral jump distance of the abnormal group was significantly smaller than that of the healthy group. Age and body size of the injury group were significantly larger than those of the healthy group. Our study showed that the abnormal group had decreased bilateral single lateral jump and increased age and body sizes compared to those of the healthy group.

(Objective) Growth-related bone disorders in boysʼsports injuries are known to occur frequently dur ing growth spurt, and growth phase (phase) s are used to categorize the timing of sports disorder（SD）s. On the other hand, the relationship between fatigue fractures and growth phases is not clear. We examined the occur rence of SDs based on body composition.

(Methods) 151 boys and 123 girls, aged 9 to 18 years, who engaged in sports activities at least 5 days per week,were included. The incidence of 306 SDs that occurred were reviewed.

(Results) EDs were observed most frequently in phase II among boys (26 cases) and those who developed EDs had significantly lower height and lean body mass. In girls, only 8 cases of Eds were reported. FFs were most com mon in phase III (20 boys and 18 girls, respectively).

(Discussion) EDs were more common in boys before their peak growth period, while in girls, a low BMI was con sidered a risk factor for FFs, but there was no inferiority in the physique of the affected individuals. In boys, The results suggest that increased skeletal muscle may contribute to the development of FFs in boys.

The purpose of this study was to investigate the relationship between self-estimated values and landing errors in the single leg hop for distance (SHD). Self-estimated values and hop distance were measured for 63 healthy adults. The participants were classified into two groups: those who were able to achieve a stable landing (group A), and those who were not (group B). In addition to the self-estimated values, knee flexion and extension muscle strength, age, height, and weight were included in the analysis as factors that may potentially affect postural stability during landing. Statistical analyses were performed using the Mann-Whitney U test, independent ttest, logistic regression analysis, and ROC analysis. The significance level was set at 5%. The results showed that the mean self-estimated value (standardized by height) was significantly higher for group B (102.8±19.0) compared to the corresponding value for group A (74.4±16.8). Of the potentially influential factors, the only one identified as a predictor of landing stability was the self-estimated value, with a cut-off value of 87.1%. If the SHD selfestimated value exceeds 87.1%, a landing error may occur.

Chronic ankle instability (CAI) causes impairment in proprioception, such as ankle joint position sense and plantar cutaneous sensation. Although plantar vibration stimulation may be effective as a means of en hancing proprioception, its efficacy remains ambiguous. This study aimed to clarify the immediate effects of plan tar vibration stimulation on healthy athletes and athletes with CAI. Eight healthy and eight CAI athletes partici pated in this study, and their joint position sense and cutaneous sensation were evaluated before and after the in tervention of plantar vibration stimulation or non-intervention, designed as a cross-over study. There were no sig nificant differences between the healthy group and the CAI group in both joint position and plantar cutaneous sensation. Also, there were no statistically significant changes in either group before or after the intervention. One possible explanation for the absence of differences between the healthy and CAI groups could be attributed to a high Foot and Ankle Ability Measure score. Neither group exhibited any changes in joint position or plantar cuta neous sensation following the vibration intervention. The frequency and amplitude of the vibration stimulation af fecting proprioceptors may be different, and the joint position and plantar cutaneous sensation of CAI groups may be comparable with those of healthy participants.

We aimed to determine the usefulness of release push test (RPT) in detecting shoulder pain in baseball players with throwing shoulder injury. Fifty-five baseball players with throwing shoulder injury were recruited. RPT entailed pushing the examinerʼs hand while simulating the hand position of releasing the ball during throwing. Full can, empty can test, hyper-external rotation test (HERT), Neer impingement sign, Hawkins impingement sign, and OʼBrien test were also performed. All tests were considered positive if shoulder pain was provoked during the test. The RPT positivity rate was 51%, which was the highest among all the tests. Ten patients had only RPT positive during the examination; it had the highest single positivity which was also seen with HERT. The players with RPT positivity reported significantly more shoulder pain after the cocking phase of throwing compared to players with HERT positivity who reported more shoulder pain in the cocking phase. This study suggested that RPT may be a useful pain provocation test to assess the start or change in strength of throwing because it showed high positivity rate and could detect specific pain in players with throwing shoulder injury.

Fifty-one elementary school students who were diagnosed with fresh lumbar spondylolysis using MRI between March 2015 and March 2022 were enrolled. Study 1 included 10 patients in the early grade group and 41 patients in the late grade group. The patientsʼcharacteristics at disease onset (sex, presence or absence of spina bifida occulta (SBO) in the affected vertebra, vertebral level, unilaterality or bilaterality of lesions, presence of a contralateral terminal stage, and disease stage) were compared between the two groups. Study 2 included 34 patients in whom the success or failure of bone union was confirmed. The bone union rates in both groups were compared, and factors that affected bone union in the entire study cohort were examined.

In study 1, the proportion of patients with SBO, those with bilateral lesions, and those with advanced stages was significantly higher in the early grade group than in the late grade group. In study 2, the bone union rate was significantly lower in the early grade group than in the late grade group. Multivariate analysis revealed that in all the enrolled patients, advanced disease stage were factors that affected bone union.

This study aimed to determine the period to return to sports after hamstring injury, muscle strength, and flexibility at the time to return to sports compared by injury type.

The participants were 33 patients who were diagnosed with a hamstring injury based on magnetic resonance imaging findings and followed up until returning to sports.

According to the Japan Institute of Sports Science classification, they were classified into Type I (muscle fiber injury) and Type II (tear of the tendon plate).

The evaluation variables included the period from examination to sports beginning (sports beginning period),period from examination to returning to sports (sports returning period), isokinetic knee flexion muscle strength (180̊/sec, 60̊/sec), Straight Leg Rising (SLR), and Active Knee Extension Test (AKET) at the time to begin sports.

Type I was significantly shorter than Type II in both the sports beginning and returning periods (p＜0.05,p＜0.01).

There were no significant differences in isokinetic knee flexion muscle strength, SLR, and AKET between the two groups.

The time to return to sports after hamstring injury differed depending on the injury type. Furthermore, muscle strength and flexibility improved regardless of the injury type.

The characteristics of fresh lumbar spondylolysis at multiple levels were developed and compared with single-level spondylolysis.

Fresh lumbar spondylolysis was diagnosed in 530 patients between March 2015 and March 2022.

The subjects were divided into two groups: those with multiple-level spondylolysis (multiple group) and those with single-level spondylolysis (single group).

The survey items included age, gender, time from pain awareness to consultation (disease duration), time from pain awareness to checkup (checkup duration), sports events, side of lamina, vertebral level, disease stage, and bone union rate.

The number of patients in the multiple group was 44 (8.5%), and that of the single group was 486 (91.5%).

Age was significantly higher in the multiple group (p＜0.01).

No significant differences were observed between the two groups in terms of gender or disease duration or checkup duration.

The rate of patients in athletics was 4.9%, the lowest of all sports events, in the multiple group. However, that of jumping event was high.

The rate of bone union was 84.5% in the multiple group and 86.8% in the single group.

The rate of bone union was not significantly different between the two groups.

Multiple level spondylolysis was not a factor in inhibiting bone union.

This study examined the method for quantitative assessment of lumbar segmental stability (LSS) us ing a Pressure Biofeedback Unit (PBU). The subjects were 10 healthy men with no history of low back pain. The task movement consisted of placing the PBU under the lumbar region in the dorsal supine position and instructing the subject to raise and lower the right leg 10 times. This task movement was performed under two conditions:the transversus abdominis muscle (TrA) were not contracted (CON), and TrA were contracted (abdominal draw in maneuver: ADIM). As an index of LSS, the coefficient of variation (CV) of PBU pressure change during two tasks. Surface electromyography (EMG) was used to determine the level of muscle activity (%EMGmax) of the trans versus abdominis-obliquus internus (TrA-OI) muscles. The results that CV values of PBU were significantly lower in the ADIM than in the CON. Moreover, TrA-OI muscle activity was significantly higher in the ADIM, with a muscle activity level of around 30%EMGmax. Based on these results, the method used in this study could be used to quantify LSS. In addition, LSS did not require excessive contraction of the TrA, which could be achieved by main taining contraction at a relatively low effort level.

This study aimed to investigate the characteristics of lumbar lordosis angle and sacral slope angle during trunk extension in ballet dancers. The participants were 13 healthy female ballet dancers (ballet group) and 15 women with no ballet experience (non-ballet group). Lumbar lordosis and sacral slope angle in standing and maximum trunk extension were measured using lateral X-ray images of the lumbar spine. The amount of change in lumbar lordosis and sacral slope angle between standing and maximum trunk extension were calculated and compared between the two groups.

The lumbar lordosis angle in static standing of the ballet group was lower than that of the non-ballet group. The ballet group showed a higher amount of change in lumbar lordosis angle and a lower amount of change in sacral slope angle than those of the non-ballet group. The extent of lumbar lordosis is suggested to increase from the standing to the maximum trunk extension position, which is a characteristic of the spinal motion of ballet dancers.

The purpose of this study was to identify the correlation between angle of the lead leg and ball veloc ity during throwing motion of female professional baseball players. Ball velocity and throwing motion were measured. The correlation between the ball velocity and each angle, the amount of change from FC to the maximum value were examined. A positive correlation was observed between ankle plantar flexion angle and ball velocity in the 14-49% section, and a negative correlation was observed with the amount of change in knee flexion. The hip flexion angle was positively correlated with the ball velocity in almost all sections and the hip adduction angle was 75% or later. In male players with high pitching ability, the knee flexion angle is maintained after FC. On the con trary, in female players who can throw fast ball, the amount of change in knee flexion was reduced by holding the ankle joint in the plantar flexion position after FC and suppressing the forward tilt of the lower leg. It is considered that female players who can throw the ball faster support the lead leg with larger hip flexion and adduction angle after the ball is released.

(Purpose) This study aimed to evaluate the usefulness of the Posterior Lumbar Flexibility test (PLF) in assessing the flexibility of the posterior elements of the body in patients with fresh lumbar spondylolysis.

(Subjects and Methods) This study included 131 patients diagnosed with fresh lumbar spondylolysis using magnetic resonance imaging who visited our clinic between September 2019 and March 2022. The positivity rates of PLF were evaluated at baseline and two months, and the positivity rates of Finger Floor Distance (FFD) and Straight Leg Raising (SLR), which are evaluation tests of the posterior elements of the body (lumbar region and hamstring) were evaluated, and compared with the improvement rate of these tests.

(Results) At baseline, the positivity rates were 69%, 52%, and 67% for PLF, FFD, and SLR, respectively. The positivity rates for each test were significantly lower at two months than at baseline (p ＜0.01). The rate of improvement for PLF was significantly higher than FFD and SLR (p ＜0.01).

(Conclusion) Considering its high positivity rate and improvement rate following rehabilitation, PLF could assess lumbar flexibility independently, especially in lumbar spondylolysis. Therefore, PLF in considered to be useful as on evaluation test for flexibility in patients with lumbar spondylolysis.

The purpose of this study was to identify risk factors for throwing shoulder injury. 50 junior high school baseball players were included in the study. Data were collected on baseline information, limb mobility,muscle tightness, and the development of throwing shoulder injury. 1 year after the baseline measurements, the same measurements were taken again, and the subjects were divided into 2 groups according to whether or not they had developed throwing shoulder injury. All data were compared between groups by t-test or Mann Whitneyʼs U test. The variables with p＜0.25 for between-group comparison were used as explanatory variables,and risk factors for throwing shoulder injury were analyzed by logistic regression analysis. 47 patients were in cluded in the analysis, 14 of whom were in the throwing shoulder injury development group. The group with im paired shoulder had significantly restricted non-throwing side HBD (p=0.007), which was a risk factor for impaired shoulder (Odds ratio: 1.201, 95% CI: 1.058-1.374). Tightness of the rectus femoris muscle of the non-throwing lower extremity was found to be a risk factor for the development of throwing shoulder injury.

(Purpose) We analyzed injury reports of team belonging to the university soccer TOP league. (Mate rials) 44 players who were enrolled in the top team in the 2021 season. (Methods) We recorded the exposure time and number of injuries for each player and calculated the injury rate. Injury site, injury type, onset factors, and se verity were investigated by year and month. (Results) The number of injuries was 40, exposure time was 13,543 hours, and injury rate was 2.3/1,000 hours (95% CI: 1.8-3.8). Injury rate changes by month showed the highest in February at 6.4/1,000hours, and the highest in June at 41.3/1,000hours during matches. As a monthly trend, num ber of injuries and injury rate were high in February, June, September and October, and exposure time in the pre vious month tended to be low. As for injury type, sprain/ligament injury occurred most frequently, and muscle rupture occurred less frequently. (Discussion) The injury rate was lower than those of the top leagues in other countries. On the other hand, an increase in the total activity time by month may increase injury rate. Sprain/liga ment injury was the most common type of injury, while muscle rupture was rare, suggesting that it was not af fected by COVID-19.

(Introduction) Anemia is believed to be caused by dilutional anemia in boys due to an increase in cir culating blood volume as height increases, and anemia in girls is attributed to blood loss caused by menstruation. At each phase we observed iron deficiency related to anemia in children playing sports.

(Methods) A total of 349 subjects, 209 boys and 140 girls, aged 9 to 17, who were playing sports, were included in the study. phases were identified from growth records and blood measurements were compared.

(Results) In boys, there was an increase in hemoglobin volume and total testosterone in each phase, but a signifi cant decrease in ferritin in phaseII (p<0.01). In girls, there was also an significant increase in creatinine in phaseIV.

(Discussion) Before menarche in boys and girls, before the maximum annual growth rate, phase II showed in creased hemoglobin levels and no dilutional anemia. What occurred in phase II in boys was iron deficiency due to decreased ferritin. In boys, hemoglobin levels did not decrease due to hematopoietic effects of increased total tes tosterone. In girls, iron deficiency was always present, and the decrease in ferritin in phaseIV was thought to be related to an increase in skeletal muscle.

We present two cases of soccer players with greater trochanteric pain syndrome (GTPS).

Case 1 had a nontraumatic onset triggered by a kicking motion, and Case 2 had a traumatic onset triggered by contusion of the greater trochanter due to a diving motion. However, the pain in Case 2 worsened with long kicks. The injury was on the pivot leg side in both cases. Physical examinations in both cases revealed tenderness on the greater trochanter, pain on hip abduction against resistance, limited hip internal rotation range of motion, trunk muscle weakness, and a positive Ober test. Only Case 2 had muscle weakness of the gluteus medius. Magnetic resonance imaging-short-TI inversion recovery revealed no high signals in the gluteus minimus or gluteus medius tendons, however high signals in the greater trochanteric bursa were observed.

We hypothesized the mechanism of GTPS in these cases as follows. During the kicking motion, the pivot legʼs pelvis was laterally deviated due to muscle weakness of the gluteus medius and trunk (Case1: trunk, Case2: gluteus medius and trunk), and its iliotibial band was stretched. Therefore, hip flexion/extension and internal/external rotation caused friction of the greater trochanteric bursa between the greater trochanter and iliotibial ligament.

The Japan Anti-Doping Agency established a certification system of sports pharmacist (hereafter,SP) in 2009, which certifies pharmacists as professionals with the most up-to-date information on anti-doping guidelines. Despite the fact that the number of certified SP is increasing, few studies examined awareness of SP or the usefulness of SP for athletes and individuals involved in sports. This study used a snowball sampling survey to identify sports trainersʼcurrent awareness for SP in connection with their anti-doping activity.

(Result) Of the respondents, 51.0% had experienced related to anti-doping activity, and 87.8% had experience of receive a question in regard to health problems from athletes. The recognition rate of SP was 85.8%, and high expectation of expertise among SP in terms of anti-doping knowledge for medications and nutritional supplements was revealed. Trainers seek easy access to SP consultation, as well as face-to-face communication.

(Conclusion) This study revealed that trainers were involved in health consultations from athletes and antidoping activity. The recognition rate of SP and expectations of them were high. For more effective usage of SP, accessibility to them should be improved and direct relationships between trainers and SP need to be built.