ABSTRACT
Previous study reported that baseball pitchers had a decreased shoulder internal rotation (IR) range of motion after pitching. However, whether the decreased range of motion associated with pitching is caused by tightness of the posterior shoulder has not been clarified yet. The joint stiffness in the passive torque can be compared with posterior shoulder tightness before and after pitching. Hence, this study aimed to compare shoulder IR stiffness based on passive torque before and after pitching in baseball pitcher. Eleven health male collage baseball pitchers were recruited. Passive torque during IR (max IR, peak torque and stiffness) of dominant and non-dominant arms was measured using an isokinetic dynamometer. Measurements were taken before, after, and post 24 hours after pitching (105 pitches). It was observed that after pitching, max IR and peak torque were significantly decreased compared to those before pitching. However, there was no difference in the stiffness of passive torque among three measurements. In conclusion, healthy college baseball pitchers have a decreased IR range of motion after pitching. However, this result is not due to posterior shoulder tissue tightness, but because of altered stretch tolerance.
ABSTRACT
The purpose of this study was to describe the incidence, severity, and burden of injuries in Japanese male collegiate rugby union players. Initially, 170 male collegiate rugby union players from one university club were registered in this epidemiological surveillance study. The occurrence of injuries was recorded by a team medical staff during the 2017–2021 playing seasons. The incidence of injuries was 6.87 injuries/1000 h. This incidence was significantly higher during matches (100.37 injuries/1000 h) than that during training (3.63 injuries/1000 h). The severity of injuries was 31.0 days, and there were no significant differences between matches and training, or forwards and backs. The burden of injuries was 213.1 days/1000 h. This burden was significantly higher during matches (2887.8 days/1000 h) compared to training (120.1 days/1000 h). Matches had higher incidence of ankle sprain/ligament injuries (15.80 injuries/1000 h) and concussion (15.36 injuries/1000 h). The most common injury site was the ankle (1.24 injuries/1000 h). However, the greatest severity and burden were observed for knee injuries (severity: 59.1 days, burden: 48.6 days/1000 h). Furthermore, the greatest burden of injury type was knee sprain/ligament injuries (39.4 days/1000 h). In addition, the incidence of acromioclavicular joint injury was significantly higher in forwards, whereas hamstring strain was significantly higher in backs. The common injury mechanisms identified were being tackled (16.0%) and tackling (14.7%), followed by overuse (12.1%). In order to improve the player welfare of the Japanese collegiate rugby union players, it is necessary to work on the prevention strategy considering the injury profile.
ABSTRACT
The Star Excursion Balance Test (SEBT) is a dynamic balance test used for the screening of injuries in the fields of sports; however, we do not clearly understand what factors of the SEBT are associated with the occurrence of injury. We hypothesized that the trunk movement would be a key factor related with the maximum reach distance (MRD) of the SEBT. The purpose of this study was to examine the relationship of the MRD during the SEBT with trunk lean angles and ankle flexibility. We recruited 19 healthy male athletes (age: 21±0.8 years, height: 170.2 ± 6.6 cm, weight: 65.2 ± 6.9 kg) and measured the MRD of the SEBT including anterior, posteromedial and posterolateral directions, the trunk lean angles at MRD, and the maximum ankle dorsi-flexion angle (DFA). The trunk lean angles were measured with the Direct Linear Transformation (DLT) method. The DFA was measured by the weight-bearing-lunge-test. We used Pearson’s correlation coefficient. There were positive correlations between the anterior-MRD and DFA; the posteromedial-MRD and the lateral trunk angle; the posterolateral-MRD and the forward trunk angle (r =.58, r =.47, r =.62, p<0.05, respectively). For future study, we need to consider the trunk movement and to focus on other factors such as muscle strength, muscle activities, center of mass, and center of pressure, which contribute to the MRD of the SEBT.
ABSTRACT
The purpose of this study was to investigate the effects of <i>Lactobacillus gasseri</i> OLL2809 (MG2809) intake on salivary secretory immunoglobulin A (SIgA) secretion and incidence of upper-respiratory tract infection (URTI) symptoms among college rugby athletes. Sixty-seven subjects were assigned to a MG2809 group (n = 33) or a placebo group (n = 34) using a double-blind procedure. Each subject took MG2809 or placebo tablets for 9 weeks. Resting saliva samples were collected before (0 week) and after 2, 4, 6, 8, and 9 weeks of the MG2809 intakes. A log of URTI symptoms was kept every day during the study period. Our results showed that salivary SIgA level was significantly increased at 6 weeks in the MG2809 group (p < 0.05), although the placebo group did not show significant change. The duration of URTI symptoms episode in the MG2809 group was significantly shorter than that in the placebo (p < 0.05). These results suggest that regular intake of MG2809 may enhance oral immune function mediated by SIgA and reduce the risk of URTI in athletes.
ABSTRACT
To examine risk factors for shoulder injuries with or without history of the injuries using the stratification analysis for collegiate rugby players. 71 elite rugby players from one university rugby club joined in the preseason medical screening related to their shoulder joints, including basic demographics, history of injuries, and physical findings at that time. Subsequently, the occurrence of shoulder injuries was recorded during four playing seasons. Analysis was stratified with or without history of the injuries; player without the past history of injury, 47 players; player with the past history of injury, 24 players. As a result of all players with the past history, 13 players sustained the shoulder injuries. Internal rotational range of motion [IR ROM] (OR, 1.5; 95%CI, 1.13-1.96; p=0.004), external rotational range of motion [ER ROM] (OR, 1.9; 95%CI, 1.21-2.87; p=0.005), horizontal flexion range of motion [HF ROM] (OR, 1.3; 95%CI, 1.03-1.64; p=0.025), IR muscle strength (OR, 0.4; 95%CI, 0.20-0.65; p=0.001) and rugby experience (OR, 1.2; 95%CI, 1.02-1.46; p=0.032) were associated with the shoulder injuries. On the other hand, 10 players sustained injuries of the players without the past history of injury. IR muscle strength (OR, 0.3; 95%CI, 0.11-0.72; p=0.008) and rugby experience (OR, 1.4; 95%CI, 1.11-1.66; p=0.003) were associated with the shoulder injuries. This study clearly showed that IR, ER, HF ROM, IR muscle strength and rugby experience were important initial risk factors for shoulder injuries. Moreover, IR muscle strength and rugby experience were important recurrence risk factors for shoulder injuries.
ABSTRACT
The purpose of this study was to investigate the relation between alterations of salivary secretory immunoglobulin A (SIgA) and the occurrence of upper respiratory tract infections (URTI) in rugby football players.We examined the relationship between the onset of URTI and the daily alterations of SIgA levels in 32 male collegiate rugby football players (20.5±1.3 years) during summer training camp for 36 days.Total of 6 in 32 subjects had the appearance of URTI symptoms (18 %). SIgA secretion rate decreased significantly in the middle of training camp compared to the baseline (P＜0.05). Furthermore, SIgA secretion rate during the appearance of URTI (13.7±1.1μg/min) were significantly lower than that without symptoms (19.2±1.4 μg/min, P＜0.01). These results suggest that serial monitoring of SIgA may be useful to assess the risk status of URTI affection in athletes.
ABSTRACT
The aim of this study is to examine the potential of the two-dimensional posture evaluation method as a screening tool for detecting the high-risk population for anterior cruciate ligament injury.Eleven healthy adults participated in this study. They jumped from a 31 cm-high box and landed on their dominant leg. Three-dimensional knee flexion/extension, knee valgus/varus and hip adduction/abduction angle during single-legged landing were calculated. At the same time, the Frontal-plane Knee Displacement index (FKD)-the knee joint position relative to the line between the hip and ankle joint-was measured.FKD reflects the time variation of three-dimensional knee valgus and hip adduction angle very well.Our results suggest that FKD has potential as a screening tool particularly for movement occurring primarily in the frontal-plane.
ABSTRACT
The purpose of this study was to investigate the pathologic changes of jumper's knee before and after jumping and effects of icing after jumping. Sixteen healthy college students and sixteen collegiate volleyball players with jumper's knee were divided into two groups by eight, without icing group and with icing group after jumping exercise. Without icing groups rested for 20 minutes, while with icing groups were treated with ice for 20 minutes after eighty times of jumping. Signal to noise ratio (SNR) and sectional area of patellar tendon with Magnetic Resonance Imaging and the tenderness of patellar tendon with visual analog scale were measured before and after exercise, following with or without icing and 24 and 48 hours later from the treatment. In jumper's knee group, significant increase was found in the SNR, sectional area of patellar tendon, and tenderness of patellar tendon after exercise compared to before exercise. In addition, in jumper's knee with icing group, significant decrease was found in the SNR, sectional area of patellar tendon after icing and 24 and 48 hours after icing, and the tenderness of patellar tendon after icing compared to after exercise. These results suggested that icing was an effective treatment for jumper's knee after exercise.
ABSTRACT
The higher anterior cruciate ligament (ACL) injury rate of females is one of the most sever athletic-related problems today. The purpose of this study is to compare the lower extremity kinematics between male and female during single leg landing.Six male and four female healthy subjects participated in this study. They jumped from a 32 cm high box and landed with the dominant leg. The landing action was filmed with three video cameras. The knee flexion, knee valgus/varus, and hip adduction/abduction angle and angle velocity were calculated.In female subjects, the knee flexion angle and hip adduction angle were greater compared to males. Also, the knee valgus velocity and hip adduction velocity were higher in females.Our results suggest that knee valgus kinematics may be related to hip adduction. It is important to evaluate hip kinematics when considering knee kinematics to prevent knee ligament injuries.