The subjects were 83 athletes who were diagnosed with iliopsoas muscle injury during the period from March 2015 to March 2020. We classified iliopsoas muscle injury into muscle-strain type (MT) and peritendinitis type (PT) based on the MRI signal intensity. Then we investigated the number of patients by type, age, gender ratio, sports event, presence of causal injury and causal movement, duration of disease, presence of complicated injury, and time to return to sports (RTS) based on the medical records retrospectively and compared the two types.

The number of MT was 45, and that of PT was 38. The ratio of men to women was significantly more for MT than PT (p<0.01). Many patients who played soccer had MT, while many participating in track and field had PT. There was a significantly higher presence of a causal injury than its absence with MT (p<0.01), and many cases were caused by running and kicking. The was a significantly higher absence of a causal injury than its presence with PT (p<0.01). The duration of disease and the time to RTS was significantly shorter with MT than PT (p<0.01, p<0.01). There were no significant differences in the age and the presence of complicated injuries.

This study investigated the sprain factor in basketball in terms of three aspects. These were position (guard, forward, center); scene of injury (game, practice, situation); and whether there was contact or not (foot, and areas other than the foot). The aim was to clarify the relationship between the incidence of sprain and the above three variables. Sixty university basketball players participated in this epidemiological survey spanning three sea sons. A total of 33 games were assessed.

With regard to the assessment of single factors, it was found that the forward position, game setting, and foot contact were each associated with the highest number of sprains. Regarding multiple factors: a combination of the guard position, game setting, and foot contact, was linked with the highest incidence of sprains.

Since there was a difference between the single and combined factors, it is suggested that the single factors rather than the combined factors should be further investigated.

The purpose of this study was to compare the leg muscle strength and balance ability in different age groups to improve the health of middle-aged people and seniors.

The subjects were 68 females (20 in their 60s, 40 in their 70s, and 8 in their 80s). Their mean duration of gymnastics experience was 11.7±8.5 years. We measured their height, body weight, isometric knee extension strength (IKES), toe grip strength (TGS), and one-leg standing balance test with eyes opened (OSBT). The results were as follows:

1.There were no significant differences between all age groups in the IKES/BW.

2.In the TGS/BW, there were significant differences between the 60s and 70s, and the 60s and 80s. The TGS/BW of the 80s was approximately 35% lower than that of the 60s.

3.There were significant differences between all age groups in the OSBT, and that of the 80s was approximately 49% lower than that of the 60s.

The IKES of experienced senior gymnasts was not affected by age, but their TGS and OSBT significantly decreased. Therefore, gymnasts should perform toe grip and balance exercises in gymnastic classes and at home to maintain their physical fitness.

(Introduction) This study was aimed to compare health status between senior soccer players and the general population.

(Subjects and Methods) This is a cross-sectional study. The senior soccer players completed a self-administered questionnaire. The results of the health status in the 2016 Comprehensive Survey of Living Conditions (CSLC) of the general population were used. A total of 995 senior soccer players and approximately 688000 individuals from the CSLC were included. The survey items were mainly on injuries and diseases, which are the same items in the CSLC. The age-adjusted standardized prevalence ratio (SPR) was calculated using the indirect method with the CSLC as the reference population.

(Results) The SPRs for each survey item were 0.44, 0.26, and 0.79 for diabetes, obesity, and hypertension, respec tively. Concerning other injuries and diseases, the SPRs were 7.15, 2.84, and 2.46 for injuries and burns, fractures,and arthropathy, respectively.

(Conclusion) Although they showed a high prevalence of trauma, the senior soccer players had low prevalence of lifestyle-related diseases.

The purpose of the present study was to assess the surveillance of male collegiate soccer team injuries for two years based on the FIFA definitions.

Two-year injury surveillance was conducted on teams belonging to the Kanto Collegiate Soccer League using the method recommended by FIFA to investigate (1) the number of injuries, (2) injury rate, (3) injury burden, (4) site of injury, and the risk matrix for each injury site.

The injury rate in this study was 3.45 [2.88-4.02]/1000 ph, which is lower than the J-League and European professional categories, but the injury burden was 79.85 [78.28-83.58]/1000 ph, which is comparable to European professional teams. This is because the subjects have fewer games per year and a lower level of competition, resulting in a lower incidence rate, but injuries are more likely to be severe because medical resources and funding are less than those of professional teams.

In this study, the ankle joint was the most common injury site, and this result is similar to those of several previous studies of Japanese university soccer teams and may be a common problem in this category.

(Objective) Low estradiol has been considered a risk factor for sports injuries, especially fatigue fractures, in female athletes, but in this study, we examined whether androgen deficiency is a risk factor.

(Methods) A study of 105 female athletes aged 8-19 years seen for sports injuries was performed to determine their endocrine status.

(Results) Fatigue fracture occurred in 36 patients and was not significantly different from the 69 patients with other sports disorders in terms of body composition, and endocrine status. In 68 patients (64.8%), the total testosterone was less than 0.19 ng/ml, the 25th percentile of that in healthy girls in the same age group who play sports regularly, but there were no significant differences in energy intake.

(Conclusion) It was thought that most of the growing and adolescent girls seen for sports injuries were with low estradiol, but there were many cases who were postmenarche, including those with fatigue fractures, and many cases with low total testosterone. However, since there were no differences in body composition or energy intake,it was speculated that the low total testosterone may be due to increased energy expenditure through sports.

The purpose of this study was to investigate the ACL injury status and the characteristics of ACL injury by the age and sex of ACL-injured patients in our hospital by grouping them by age into those under 22 years (Group I), those of 23 to 39 years (Group II), and those over 40 years (Group III). A total of 364 patients who underwent ACL reconstruction between January 2017 and September 2020 were included. The survey items were patient demographics, activity level, the sport of injury, injury mechanism, and injury situation. The statistical process used theχ² test and the significance level was set at less than 5%. The age of the subjects was related to greater exposure at a competition level. Concerning the sport of injury, soccer, basketball, and handball showed higher percentages in younger age groups, soccer in males and volleyball in females in all groups, and skiing both in males and females in Group III. Concerning the injury mechanism, females showed a higher percentage of noncontact injuries than males in all groups. As for the injury situation, the older the age, the higher the percentage of injuries outside the game. ACL injuries are considered to occur regardless of regional and facility characteristics.

The aim of this study was to clarify the risk factors for Severʼs disease. Eighty male soccer players aged 8-12 years were included in this study. Data were collected on age, height, body mass, the ankle dorsiflexion range of motion (ROM) with the knee fully extended and 90 degrees flexed, and onset of Severʼs disease. One year after the baseline measurement, an orthopedist diagnosed Severʼs disease, and participants were divided into 2 groups: a Severʼs disease group and a healthy group. All data were compared between the groups with t-test or Mann-Whitneyʼs U test. We analyzed the risk factors for Severʼs disease with logistic regression analysis using variables with P＜0.25 for between-group comparison as explanatory variables. Thirty-six participants were included in the analysis, 11 of whom were in the Severʼs group. There were no significant differences between the groups in age, height, body mass, and ankle dorsiflexion ROM with the knee flexed. The ankle dorsiflexion ROM with the knee extended was significantly higher in the Severʼs disease group (P=0.008), and was a risk factor for Severʼs disease (Odds ratio: 1.193, 95%CI：1.038-1.370). It was revealed that a larger ankle dorsiflexion ROM is a risk factor for Severʼs disease.

The aim of this study was to investigate the relationship between shoulder external rotation (ER) muscle strength in the zero position (zero ER strength) and the thorax position at the shoulderʼs maximum exter nal rotation during the late cocking phase (MER).

A total of 14 healthy adult men participated in this study. Zero ER strength was measured using a handheld dy namometer with the shoulder in the zero position and the elbow in 90̊flexion. A three-dimensional motion capture system was used to assess the thorax angle（anteroposterior tilt angle and lateral tilt angle) at MER and maximum shoulder internal rotation moment (MIRM) and elbow varus moment (MVM). The relationship between zero ER strength and thorax angle and MIRM and MVM were calculated using Spearmanʼs rank correlation coefficient.

The zero ER strength positively correlated with the thorax anterior tilt angle (ρ=0.76, p=0.00015). Additionally,the zero ER strength negatively correlated with MIRM and MVM (ρ=­0.65, p=0.01; ρ=­0.56, p=0.03, respectively).

People with high zero ER strength values may have a large anterior tilt angle of the thorax during the throwing motion.