Early Sport Specialization Trends and Injuries in Former High School Athletes Specialized in Sports

Purpose

Determining the effects of early specialization in a specific sport is difficult. Therefore, it is necessary to investigate its effects based on the type of sports. The purpose of this study was to investigate the proportion of participants who had been participating in a single sport, in individual or team sports from an early age and to compared the prevalence of acute and overuse injuries among these participants.

Methods

A total of 1377 adult participants (team sports = 700, individual sports = 637) retrospectively completed a questionnaire assessing sports participation from elementary school to high school and injury history (acute and overuse) at high school age. The proportions of the specialized / nonspecialized groups per sport type were compared, and differences in acute or overuse injury prevalence were examined.

Results

The proportion of the specialized group participants who continued to play the same single sport from elementary school age to high school age was greater in team sports (33.6%) than that in individual sports (19.2%) (p < 0.01). The specialized group participating in team sports had a greater prevalence of overuse injury at high school age than the nonspecialized group (p < 0.05) who previously participated in several sports. However, the prevalence of overuse injury at high school did not significantly differ between the specialized and nonspecialized groups participating in individual sports.

Conclusion

More children who continued to play only one sport from elementary school age to high school age played in team sports in Japan. They also had a higher prevalence of overuse injuries when they were at high school age. It is necessary to consider the environment to play multi sports before high school age, especially in team sports.

Association of sports sampling and training frequency with injury among school-age athletes in Japan

BACKGROUND

This study evaluated the status of sports participation and training frequency during school years to identify related factors for injuries in the general Japanese population.

METHODS

A total of 1,533 adult participants (762 males, 771 females) retrospectively completed a questionnaire assessing sports participation (single/multisport), training frequency (weekly days of sports participation), and injury history (acute and overuse) at each stage of school (elementary, junior high, and high school).

RESULTS

In total, 41.1% of participants reported playing multiple sports in elementary school; this rate decreased to 17.4% in junior high school and 8.9% in high school. Weekly days of sports participation were associated with almost all injuries at each age. Participants who still played multiple sports in junior high school had fewer overuse injuries in junior high school and high school (P = 0.017; odds ratio (OR) = 0.69; 95% confidence interval (CI) = 0.51-0.94; P = 0.006, OR = 0.66, 95% CI, 0.49-0.89, respectively). The ratio for sports sampling differed between elementary school and older ages. This trend was associated with the prevalence of overuse injuries.

CONCLUSION

Promoting sports sampling through junior high school ages and controlling the training frequency may decrease the occurrence of injuries in young athletes.

Association of Sports Participation and Training Frequency with Injury in Japanese Students Majoring in Physical Education: A Retrospective Analysis

Objectives: This study evaluated prior sports participation and training frequency during elementary to high school and their association with acute and overuse injuries in Japanese college students currently majoring in physical education.Methods: This retrospective study included 292 students who completed questionnaires that assessed their type of sport participation (single sport or multiple sports), training frequency (number of days per week), and injury history (acute and overuse) during the elementary, junior high, and high school periods.Results: In total, 47.9% (95% confidence interval [CI]: 38.2–57.7) of elementary school-aged athletes played multiple sports; this decreased to 22.3% (95% CI: 14.1–30.4) in junior high school and 5.5% (95% CI: 1.0–9.9) in high school. There was a significant difference in the training frequency between those who had overuse injuries and not in elementary (p < 0.05), and junior high school (p < 0.05).Conclusions: The results of this study suggest that participating in multiple sports through junior high school may lead to improved sports levels (i.e., participation in higher levels of competition). In addition, appropriate management of training frequency may help reduce the incidence of overuse injuries.

Neuromuscular responses of the hamstring and lumbopelvic muscles during unanticipated trunk perturbations

Hamstring strain often occurs when an opponent unanticipatedly perturbs an athlete's movements. We examined the neuromuscular responses of hamstring and trunk muscles during unanticipated trunk perturbations in athletes with and without a history of hamstring strain injury. Male college athletes (11 with a history of a unilateral hamstring injury and 10 without prior injury) knelt while wearing a chest harness attached to a cable that was pulled backward. They were instructed to resist the force isometrically and maintain their position when the perturbations were applied. The pressure was released with or without a cue (CUE or NoCUE). We measured trunk acceleration, three-dimensional kinematic data, and surface electromyography (EMG) signals of the erector spinae, internal oblique, gluteus maximus, biceps femoris long head, and semitendinosus muscles. Maximum trunk acceleration and displacement were greater with NoCUE in both groups (p < 0.05). EMG amplitude did not differ after perturbation of any investigated muscle. The injured group demonstrated a delayed onset of the gluteus maximus and erector spinae muscles in NoCUE versus CUE stimuli (p < 0.05). Athletes with a history of hamstring strain injury exhibited a reduced neuromuscular coordination of the lumbopelvic muscles in response to unanticipated trunk movement.

Acceleration profile of high-impact movements during young football games: a cross-sectional study involving healthy children

Repetitive high-impact movements cause growth-related injuries in children. This study aimed to identify which movements during junior football games require >6 G and >8 G acceleration and the frequency at which they occur. Additionally, we compared the components of acceleration among movements with >8 G resultant acceleration. Eleven young male footballers (10.7 ± 0.4 years) played 8-a-side games while wearing a tri-axial accelerometer on their upper back. The number and frequency of the movements that generated >6 G and >8 G were calculated, and each directive acceleration of the top five items was compared using two-way ANOVA to examine the effect of movements. The frequency of movements that generated >6 G and >8 G acceleration during junior football games was 8.70 case/min and 2.62 case/min, respectively. The top five >8 G movements were braking and pre-braking in shuffle, slowdown, stop, and run/jog items. The vertical acceleration was significantly greater during braking in shuffle than during slowdown, stop, and run/jog and also greater during stop and pre-braking in shuffle than during run/jog movement. This pilot study suggests that decelerated movements mainly provoked high-impact situations and may be key actions for preventing overuse injury in young footballers.

Prevalence and Burden of Physical Problems in Female College Basketball Athletes: A 135-Day Prospective Cohort Study

Introduction

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 prevalence of 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.

An update of the Japanese Oslo Sports Trauma Research Center questionnaires on overuse injuries and health problems

Monitoring the health of athletes is important for their protection, and questionnaires such as those produced by the Oslo Sports Trauma Research Center (OSTRC) are a valuable tool in this process. In 2020, several changes were made to the OSTRC questionnaires (OSTRC-O, OSTRC-H), including changes to the wording, structure, and logic of the original questionnaires. In the present study, the Japanese versions of the OSTRC questionnaires (OSTRC-O.JP, OSTRC-H.JP) were revised to meet the requirements of the updated versions and to analyse new and previously collected data to illustrate the impact of the changes on Japanese athletes. Proposed changes were categorized as minor or more substantial; minor changes were effected to the questionnaire instructions and to the wording of all four questions, and more substantial changes were made to the wording of question 2. The updated questionnaires also included changes to questionnaire logic and answer categories. To assess the consequences of the changes to the wording of question 2, 101 athletes were asked to complete the OSTRC-H.JP, which included both the original and updated versions of question 2, over 10 consecutive weeks. We calculated the number of health problems identified when new gatekeeper logic was and was not applied, using 1585 OSTRC-H.JP responses to assess the consequences of the changes to the questionnaire logic. The kappa coefficient, which measures the level of agreement between the responses to question 2 of the original and updated versions, was high. By applying gatekeeper logic, there was a remarkable reduction in the number of injuries and illnesses among all health problems but less reduction in substantial health problems and time loss health problems. These changes will make it easier for Japanese athletes to complete the questionnaires and improve the quality of collected data.

High-Impact Details of Play and Movements in Female Basketball Game

This study aimed to identify the high-impact details of play and movements with higher acceleration and their frequency during a female basketball match. Trunk acceleration was measured during a simulated basketball game with eight female players. The extracted instance was categorized, which generated at > 6 and 8 G resultant accelerations using a video recording and an accelerometer attached to the players’ trunk, as details of play and movements. The frequency and ratio of the details of play and movements regarding all detected movements were calculated. A total of 1062 and 223 play actions were detected for the resultant acceleration thresholds of > 6 and 8 G, respectively. For these acceleration thresholds, in terms of details of play, positioning on the half-court was the most frequently observed (29.6 and 23.8%, respectively). In terms of movements, deceleration was the most frequently detected movement (21.5 and 23.3%, respectively), followed by landing (7.6 and 15.7%, respectively). Deceleration during positioning on the half-court and defense as well as landing mostly after a shot were detected as high-impact frequent basketball-specific movements. The results also showed that characteristics of movements or playing style and playing position may have an effect on acceleration patterns during a basketball game.

Acceleration Profile of High-Intensity Movements in Basketball Games

Koyama, T, Rikukawa, A, Nagano, Y, Sasaki, S, Ichikawa, H, and Hirose, N. Acceleration profile of high-intensity movements in basketball games. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to elucidate movements that require greater acceleration during basketball games, their occurrence frequency, and compare acceleration components. Eighteen male collegiate basketball players (age: 19.5 ± 0.8 years) were enrolled. Triaxial accelerometer was used to measure acceleration and a synchronized video was recorded. Moments that generated resultant accelerations >4, 6, and 8 G, and their coincided movements were identified. Ratios and frequencies of the extracted movements were calculated and Jonckheere-Terpstra trend test was used to examine which movement rate increased when acceleration threshold increased. In addition, the top 7 movements that generated a resultant acceleration >6 G among the combination of basketball-specific movements were extracted. Their resultant, mediolateral, vertical, and anteroposterior accelerations were identified and compared using one-way analysis of variance. Cohen's d was used to calculate effect sizes. All p < 0.05 were considered statistically significant. The extracted frequencies were 33.6, 9.1, and 2.3 cases per minute for >4 G, >6 G, and >8 G, respectively. As the threshold increased, the rate of deceleration, landing, and physical contact increased. The mediolateral acceleration of physical contact was significantly greater than other movements, whereas the vertical acceleration of landing and deceleration was significantly greater than other movements. Thus, acceleration component analysis was performed to classify movement types. Greater acceleration appeared frequently in movement during defense. It is suggested that many defense movements involve a reaction to the ball and opponent. There are many passive movements during defense and speed changes rapidly. If many passive movements occur when defending, larger physical load is applied, and may lead to fatigue.

Differences in high trunk acceleration during single-leg landing after an overhead stroke between junior and adolescent badminton athletes

The magnitude of trunk acceleration reflects the ground reaction force. This study compared the frequency of high trunk accelerations during single-leg landing after an overhead stroke between junior and adolescent badminton players, and examined the difference in each directive magnitude according to age and landing leg. Thirty-eight female badminton players (17 junior and 21 adolescent athletes) played two singles games while wearing a tri-axial accelerometer on their upper back. The frequency and 95% confidence interval (CI) of single-leg landings that generated >4-G resultant acceleration, and each directive magnitude were calculated. A two-factorial analysis of variance (factor 1: group, factor 2: landing leg) was performed to determine the effects of age and different landing patterns. Frequency of single-leg landings following an overhead stroke in the adolescent athletes (mean, 1.71 cases/min; 95% CI, 1.59-1.83 cases/min) was higher than that in the junior athletes (mean, 1.13 cases/min; 95% CI, 1.01-1.25 cases/min). The adolescent athletes exhibited greater mediolateral acceleration in the movement towards racket-hand leg and anteroposterior acceleration in the movement towards the opposite leg than the junior athletes. This cross-sectional study suggests that the frequency and movement pattern associated with high-load landing in badminton games differ between junior and adolescent athletes.

P3644Plaque progression from normal vessel wall to fibroatheroma: lessons from over 5-year follow-up optical coherence tomography study

Background

Progression of atherosclerosis is a non-uniform process characterized by coexistence of normal vessel wall (NVW) and advanced fibroatheroma within the same cross-section (Figure). Plaque progression from NVW to fibroatheroma usually takes years, that has never been investigated in human.

Purpose

To investigate the incidence and related factors associated with atherosclerotic progression from NVW to fibroatheroma using long-term serial optical coherence tomography (OCT) follow-up data over 5 years.

Methods

We enrolled 47 vessels in 30 patients who had undergone serial OCT imaging over 5 years (average: 6.8 years). Baseline and follow-up OCT images were matched for longitudinal and circumferential location and OCT cross-sections that had NVW >30 degrees were enrolled. NVW was defined as vessel wall having OCT-detectable three-layer structure with intimal thickening ≤300μm. Cross-sections were diagnosed as +Progression when NVW in the cross-section reduced by >30 degrees during >5-year follow-up.

Results

In the present study, atherogenic progression from NVW to fibroatheroma was observed only in 37.2% of the enrolled cross-sections. On the other hand, despite an average long-term follow-up period of 6.8 years, the extent of NVW was maintained in 62.8% of cross-sections. The incidence of microchannel in adjacent fibroatheroma within the same cross-section (23.6% vs. 13.1%, p=0.023), eccentric plaque distribution (21.7% vs. 11.4%, p=0.019), and concave shape (6.6% vs. 0%, p=0.001) at baseline was significantly higher in cross-sections with +Progression than those without Progression. Average intimal thickness of NVW (187.2±64.9μm vs. 170.7±68.6μm; p=0.048) at baseline was significantly thicker in cross-sections with +Progression than those without. Multivariate analysis demonstrated that the presence of microchannel, eccentric plaque distribution and thicker average intimal thickness of NVW at baseline were independently associated with plaque progression during the follow-up.

Atheroma progression

Conclusion

The presence of microchannel in adjacent fibroatheroma, eccentric plaque distribution, and thicker intimal thickening of NVW were potentially associated with plaque progression from NVW to fibroatheroma.

P5508Impact of CD14++CD16+ monocytes on coronary plaque vulnerability assessed by optical coherence tomography in coronary artery disease patients

Background

Diabetes mellitus has been known as an important factor of coronary artery disease (CAD) progression despite of widespread with lipid-lowering therapy. Although we have reported that large glucose fluctuation is associated with the development of cardiovascular disease in both diabetes mellitus (DM) and non-DM patients, the underlying mechanisms remain unclear.

Monocytes play a key role for atherosclerotic plaque formation. Monocytes in human peripheral blood are divided into three subsets: CD14++CD16− monocytes, CD14++CD16+ monocytes, and CD14+CD16++ monocytes. The CD14++CD16+ monocyte subset has recently received attention because it is reported to be associated with future cardiovascular events such as acute myocardial infarction. However, their impact on coronary plaque vulnerability in coronary artery disease (CAD) patients with or without DM remains unclear.

Purpose

The aim of this study was to investigate the impact of CD14++CD16+ monocyte levels on coronary plaque vulnerability and glucose fluctuation in stable CAD patients with well-regulated lipid levels.

Methods

This prospective observational study included 50 consecutive patients with CAD (DM [n=22], Non-DM [n=28]), receiving lipid-lowering therapy and undergoing coronary angiography and optical coherence tomography (OCT). Patients were divided into 3 tertiles according to the CD14++CD16+ monocyte percentages assessed by flow cytometry. Standard OCT parameters including lipid arc, lipid length, fibrous cap thickness (FCT) on lipid rich plaque, were assessed for 97 angiographically intermediate lesions (diameter stenosis: 30–70%). The presence of thin-cap fibroatheroma (TCFA), defined as a thin fibrous cap (<65μm) overlying a lipid-rich plaque (>90°), was also assessed. Daily glucose fluctuation assessed by using continuous glucose monitoring system was analyzed by measuring the mean amplitude of glycemic excursion (MAGE).

Results

CD14++CD16+ monocytes negatively correlated with FCT on lipid rich plaque (r=0.508, p<0.01) (Figure. 1). The presence of thin-cap fibroatheroma (TCFA) was increased stepwise according to the tertile of CD14++CD16+ monocytes (0 [tertile 1] vs. 5 [tertile 2] vs. 10 [tertile 3], p<0.01). CD14++CD16+ monocytes were a significant determinant of TCFA (OR 1.279, p=0.001). Although CD14++CD16+ monocytes were not significantly correlated with MAGE in DM patients (r=0.259, p=0.244), a significant relationship was found between CD14++CD16+ monocytes and MAGE in non-DM patients (r=0.477, p=0.018) (Figure 2).

Conclusions

CD14++CD16+ monocytes were associated with coronary plaque vulnerability in CAD patients with well-regulated lipid levels both in DM and non-DM patients. Cross-talk between glucose fluctuation and CD14++CD16+ monocytes may enhance plaque vulnerability, particularly in non-DM patients. CD14++CD16+ monocytes could be a possible therapeutic target for coronary plaque stabilization.

Hamstring muscles' function deficit during overground sprinting in track and field athletes with a history of strain injury

In this study, we aimed to clarify the characteristics of neuromuscular function, kinetics, and kinematics of the lower extremity during sprinting in track and field athletes with a history of strain injury. Ten male college sprinters with a history of unilateral hamstring injury performed maximum effort sprint on an athletic track. The electromyographic (EMG) activity of the long head of the biceps femoris (BFlh) and gluteus maximus (Gmax) muscles and three-dimensional kinematic data were recorded. Bilateral comparisons were performed for the EMG activities, pelvic anterior tilt angle, hip and knee joint angles and torques, and the musculotendon length of BFlh. The activity of BFlh in the previously injured limb was significantly lower than that in the uninjured limb during the late-swing phase of sprinting (p < 0.05). However, the EMG activity of Gmax was not significantly different between the previously injured and uninjured limbs. Furthermore, during the late-swing phase, a significantly more flexed knee angle (p < 0.05) and a decrease in BFlh muscle length (p < 0.05) were noted in the injured limb. It was concluded that previously injured hamstring muscles demonstrate functional deficits during the late swing phase of sprinting in comparison with the uninjured contralateral muscles.

A retrospective study of mechanisms of anterior cruciate ligament injuries in high school basketball, handball, judo, soccer, and volleyball

The purpose of this study was to analyze the mechanism of anterior cruciate ligament (ACL) injuries among male and female high school students across several different sports to understand ACL injury trends.A total of 1000 cases involving high school students who suffered ACL injuries during school activities (soccer, basketball, volleyball, handball, and judo) and who received insurance benefits through the Injury and Accident Mutual Aid Benefit System, were included to clarify the various mechanisms of ACL injuries. The mechanism of ACL injury was divided into contact and non-contact injuries. Contact injuries were further divided into direct and indirect contact injuries. Non-contact ACL injuries were also further divided into landing injuries, which involved jump-landing movements, and cutting and stopping injuries, which involved movement with a change of direction and deceleration.Overall, 99.0% of judo ACL injuries were categorized as contact ACL injuries. With regards to ball sports, the number of non-contact ACL injuries among basketball, volleyball, and handball players was significantly higher than the number of contact injuries (67.0%, 86.5%, and 68.5% respectively). With regards to female soccer and basketball players, the number of indirect ACL injuries was higher than direct injuries (72.2% and 76.7%, respectively).Volleyball was associated with a higher rate of non-contact injuries. Soccer, basketball, and handball were associated with more or similar rates of indirect and non-contact injuries than direct injuries. Judo was associated with a higher rate of contact injuries.

Movements with greater trunk accelerations and their properties during badminton games

This study aimed to elucidate the movements requiring greater trunk accelerations and its frequencies during badminton games, and compare the acceleration components among such movements. Trunk acceleration was measured using a triaxial accelerometer during badminton games. The moments that generated >4 G resultant acceleration were extracted, and movements consistent with the extracted moments were identified. We calculated the extracted movement ratio and frequency and compared the resultant, mediolateral, vertical and anteroposterior accelerations between the top five extracted movements. There were 1,342 movements that generated >4 G [mean, 7.72 (95% confidence interval, 7.31-8.14) cases/min]. The top five movements were lunging during underhand strokes with the dominant hand side leg, landing after overhand strokes on the dominant and non-dominant hand side leg, and cutting from a split step using the dominant and non-dominant hand side leg. Landing on the dominant hand side leg had a greater resultant acceleration than the other movements and had the greatest impact during the badminton game. Lunging during underhand strokes on the dominant hand side leg had greater mediolateral acceleration than the other movements. These results reflected the properties of badminton.

Loading differences in single-leg landing in the forehand- and backhand-side courts after an overhead stroke in badminton: A novel tri-axial accelerometer research

Anterior cruciate ligament (ACL) injuries in badminton commonly occur during single-leg landing after an overhead stroke in the backhand-side court. This study compared differences in trunk acceleration and kinematic variables during single-leg landing in the forehand- and backhand-side courts after an overhead stroke. Eighteen female junior badminton players performed two singles games while wearing a tri-axial accelerometer. The moment that over 4g of resultant acceleration was generated was determined using synchronised video cameras. Trunk lateral inclination and hip abduction angles at the point of landing with over 4g of resultant acceleration were analysed. Mediolateral acceleration in the backhand-side court was greater than that in the opposite-side court (p < 0.001, ES = 0.840). Both trunk lateral angles were larger than those previously reported in injured participants and the hip abduction angle in the backhand-side court was larger than that in the forehand-side court (p < 0.001, ES = 2.357). The lateral and vertical acceleration in the backhand-side court showed moderate-to-strong correlations with the trunk and hip angles. The mediolateral physical demand and high-risk posture in the backhand-side court may be associated with a higher incidence of knee injuries during badminton games.

Risk assessment of the onset of Osgood-Schlatter disease using kinetic analysis of various motions in sports

BACKGROUND

Some studies have listed motions that may cause Osgood-Schlatter disease, but none have quantitatively assessed the load on the tibial tubercle by such motions.

PURPOSES

To quantitatively identify the load on the tibial tubercle through a biomechanical approach using various motions that may cause Osgood-Schlatter disease, and to compare the load between different motions.

METHODS

Eight healthy male subjects were included. They conducted 4 types of kicks with a soccer ball, 2 types of runs, 2 types of squats, 2 types of jump landings, 2 types of stops, 1 type of turn, and 1 type of cutting motion. The angular impulse was calculated for knee extension moments ≥1.0 Nm/kg, ≥1.5 Nm/kg, ≥2.0 Nm/kg, and ≥2.5 Nm/kg. After analysis of variance, the post-hoc test was used to perform pairwise comparisons between all groups.

RESULTS/CONCLUSIONS

The motion with the highest mean angular impulse of knee extension moment ≥1.0 Nm/kg was the single-leg landing after a jump, and that with the second highest mean was the cutting motion. At ≥1.5 Nm/kg, ≥2.0 Nm/kg, and ≥2.5 Nm/kg, the cutting motion was the highest, followed by the jump with a single-leg landing. They have a large load, and are associated with a higher risk of developing Osgood-Schlatter disease. The mean angular impulse of the 2 types of runs was small at all the indicators.

CLINICAL RELEVANCE

Motions with a high risk of developing Osgood-Schlatter disease and low-risk motions can be assessed in further detail if future studies can quantify the load and number of repetitions that may cause Osgood-Schlatter disease while considering age and the development stage. Scheduled training regimens that balance load on the tibial tubercle with low-load motions after a training day of many load-intensive motions may prevent athletes from developing Osgood-Schlatter disease and increase their participation in sports.

Anterior cruciate ligament injury: Identifying information sources and risk factor awareness among the general population

INTRODUCTION

Raising awareness on a disorder is important for its prevention and for promoting public health. However, for sports injuries like the anterior cruciate ligament (ACL) injury no studies have investigated the awareness on risk factors for injury and possible preventative measures in the general population. The sources of information among the population are also unclear. The purpose of the present study was to identify these aspects of public awareness about the ACL injury.

MATERIALS AND METHODS

A questionnaire was randomly distributed among the general population registered with a web based questionnaire supplier, to recruit 900 participants who were aware about the ACL injury. The questionnaire consisted of two parts: Question 1 asked them about their sources of information regarding the ACL injury; Question 2 asked them about the risk factors for ACL injury. Multivariate logistic regression was used to determine the information sources that provide a good understanding of the risk factors.

RESULTS AND DISCUSSION

The leading source of information for ACL injury was television (57.0%). However, the results of logistic regression analysis revealed that television was not an effective medium to create awareness about the risk factors, among the general population. Instead "Lecture by a coach", "Classroom session on Health", and "Newspaper" were significantly more effective in creating a good awareness of the risk factors (p < 0.001).

Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting

This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.

Tongue-palatal contact changes in patients with skeletal mandibular prognathism after sagittal split ramus osteotomy: an electropalatography study

The purpose of this study was to investigate the changes in tongue-palatal contact patterns using electropalatography (EPG) before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Nine clients who underwent SSRO for mandibular setback and seven control subjects were participated in this study. Tongue-palatal contact patterns for /t/, /s/ and /k/ production were investigated using EPG before surgery and 3 months after surgery. The mean value of whole total of palate contact (WT) in the maximum contact frame was examined before and after SSRO. The correlation quantity between the change of center of gravity (COG) value and the amount of mandibular setback was also evaluated. The mean value of WT for /t/ and /s/ significantly increased after SSRO, and the EPG pattern became normal. However, a remarkable change in WT for /k/ was not observed, and the mean value was significantly larger in the SSRO group before and after surgery than in the control group. A negative correlation between COG variation and the amount of mandibular setback for /t/ and positive correlation for /s/ was observed. This study demonstrated that tongue-palatal contact patterns for /t/ and /s/ articulation improved clearly after SSRO. There was a significant correlation between COG variation and the amount of mandibular setback. However, no significant change was detected through perceptual assessment before and after SSRO. Further investigation is needed to determine whether these results will change over time.

Differences in activation properties of the hamstring muscles during overground sprinting

The purpose of this study was to quantify activation of the biceps femoris (BF) and medial hamstring (MH) during overground sprinting. Lower-extremity kinematics and electromyography (EMG) of the BF and MH were recorded in 13 male sprinters performing overground sprinting at maximum effort. Mean EMG activity was calculated in the early stance, late stance, mid-swing, and late-swing phases. Activation of the BF was significantly greater during the early stance phase than the late stance phase (p<0.01). Activation of the BF muscle was significantly lower during the first half of the mid-swing phase than the other phases (p<0.05). The MH had significantly greater EMG activation relative to its recorded maximum values compared to that for the BF during the late stance (p<0.05) and mid-swing (p<0.01) phases. These results indicate that the BF shows high activation before and after foot contact, while the MH shows high activation during the late stance and mid-swing phases. We concluded that the activation properties of the BF and MH muscles differ within the sprinting gait cycle.

Altitudinal flower size variation correlates with local pollinator size in a bumblebee-pollinated herb, Prunella vulgaris L. (Lamiaceae)

The influence of locally different species interactions on trait evolution is a focus of recent evolutionary studies. However, few studies have demonstrated that geographically different pollinator-mediated selection influences geographic variation in floral traits, especially across a narrow geographic range. Here, we hypothesized that floral size variation in the Japanese herb Prunella vulgaris L. (Lamiaceae) is affected by geographically different pollinator sizes reflecting different pollinator assemblages. To evaluate this hypothesis, we posed two questions. (1) Is there a positive correlation between floral length and the proboscis length of pollinators (bumblebees) across altitude in a mountain range? (2) Does the flower-pollinator size match influence female and male plant fitness? We found geographic variation in the assemblage of pollinators of P. vulgaris along an altitudinal gradient, and, as a consequence, the mean pollinator proboscis length also changed altitudinally. The floral corolla length of P. vulgaris also varied along an altitudinal gradient, and this variation strongly correlated with the local pollinator size but did not correlate with altitude itself. Furthermore, we found that the size match between the floral corolla length and bee proboscis length affected female and male plant fitness and the optimal size match (associated with peak fitness) was similar for the female and male fitness. Collectively, these results suggest that pollinator-mediated selection influences spatial variation in the size of P. vulgaris flowers at a fine spatial scale.

The relationships between the center of mass position and the trunk, hip, and knee kinematics in the sagittal plane: a pilot study on field-based video analysis for female soccer players

Athletes with non-contact anterior cruciate ligament tears have common features in the sagittal plane; namely, the body’s center of mass (COM) is located posterior to the base of support, the trunk and knee joints are extended, and the hip angle is flexed. However, the relationships among these variables have not been assessed in field-based movements. This study sought to determine relationships between distances from the COM to the base of support and the trunk, hip, and knee positions in women while playing soccer. Sixty events (29 single-leg landing and 31 single-leg stopping events) were analyzed using two-dimensional video analysis. The relationships among the measurement variables were determined using the Pearson’s product-moment correlation coefficient, and stepwise multiple linear regression models were used to explore the relationships between the COM position and the kinematic variables. The distance from the COM to the base of support displayed a moderate negative relationship with the trunk angle (r = −0.623, p < .0001, r² = 0.388) and a strong positive relationship with the limb angle (r = 0.869, p < .0001, r² = 0.755). The limb, knee, and trunk angles were selected in the best regression model (adjusted r² = 0.953, p < .0001, f² = 20.277). These findings suggest that an increased trunk angle and a decreased limb angle at initial contact are associated with a safer COM position. Neuromuscular training may be useful for controlling the trunk and lower limb positions during dynamic activities.

Relationship between the peak time of hamstring stretch and activation during sprinting

The purpose of this study was to investigate the time series relationships between the peak musculotendon length and electromyography (EMG) activation during overground sprinting to clarify the risk of muscle strain injury incidence in each hamstring muscle. Full-body kinematics and EMG of the right biceps femoris long head (BFlh) and semitendinosus (ST) muscles were recorded in 13 male sprinters during overground sprinting at maximum effort. The hamstring musculotendon lengths during sprinting were computed using a three-dimensional musculoskeletal model. The time of the peak musculotendon length, in terms of the percentage of the running gait cycle, was measured and compared with that of the peak EMG activity. The maximum length of the hamstring muscles was noted during the late swing phase of sprinting. The peak musculotendon length was synchronous with the peak EMG activation in the BFlh muscle, while the time of peak musculotendon length in the ST muscle occurred significantly later than the peak level of EMG activation (p < 0.05). These results suggest that the BFlh muscle is exposed to an instantaneous high tensile force during the late swing phase of sprinting, indicating a higher risk for muscle strain injury.

Evidence of validity for the Japanese version of the foot and ankle ability measure

CONTEXT

The Foot and Ankle Ability Measure (FAAM) is a valid, reliable, and self-reported outcome instrument for the foot and ankle region.

OBJECTIVE

To provide evidence for translation, cross-cultural adaptation, validity, and reliability of the Japanese version of the FAAM (FAAM-J).

DESIGN

Cross-sectional study.

SETTING

Collegiate athletic training/sports medicine clinical setting.

PATIENTS OR OTHER PARTICIPANTS

Eighty-three collegiate athletes.

MAIN OUTCOME MEASURE(S)

All participants completed the Activities of Daily Living and Sports subscales of the FAAM-J and the Physical Functioning and Mental Health subscales of the Japanese version of the Short Form-36v2 (SF-36). Also, 19 participants (23%) whose conditions were expected to be stable completed another FAAM-J 2 to 6 days later for test-retest reliability. We analyzed the scores of those subscales for convergent and divergent validity, internal consistency, and test-retest reliability.

RESULTS

The Activities of Daily Living and Sports subscales of the FAAM-J had correlation coefficients of 0.86 and 0.75, respectively, with the Physical Functioning section of the SF-36 for convergent validity. For divergent validity, the correlation coefficients with Mental Health of the SF-36 were 0.29 and 0.27 for each subscale, respectively. Cronbach α for internal consistency was 0.99 for the Activities of Daily Living and 0.98 for the Sports subscale. A 95% confidence interval with a single measure was ±8.1 and ±14.0 points for each subscale. The test-retest reliability measures revealed intraclass correlation coefficient values of 0.87 for the Activities of Daily Living and 0.91 for the Sports subscales with minimal detectable changes of ±6.8 and ±13.7 for the respective subscales.

CONCLUSIONS

The FAAM was successfully translated for a Japanese version, and the FAAM-J was adapted cross-culturally. Thus, the FAAM-J can be used as a self-reported outcome measure for Japanese-speaking individuals; however, the scores must be interpreted with caution, especially when applied to different populations and other types of injury than those included in this study.

Mechanics of the muscles crossing the hip joint during sprint running

We aimed to demonstrate the changes over time in the lengths and forces of the muscles crossing the hip joint during overground sprinting and investigate the relationships between muscle lengths and muscle-tendon unit forces - particularly peak biceps femoris force. We obtained three-dimensional kinematics during 1 running cycle from 8 healthy sprinters sprinting at maximum speed. Muscle lengths and muscle-tendon unit forces were calculated for the iliacus, rectus femoris, gluteus maximus, and biceps femoris muscles of the target leg as well as the contralateral iliacus and rectus femoris. Our results showed that during sprinting, the muscles crossing the hip joint demonstrate a stretch-shortening cycle and 1 or 2 peak forces. The timing of peak biceps femoris force, expressed as a percentage of the running cycle (mean [SD], 80.5 [2.9]%), was synchronous with those of the maximum biceps femoris length (82.8 [1.9]%) and peak forces of the gluteus maximus (83.8 [9.1]%), iliacus (81.1 [5.2]%), and contralateral iliacus (78.5 [5.8]%) and also that of the peak pelvic anterior tilt. The force of the biceps femoris appeared to be influenced by the actions of the muscles crossing the hip joint as well as by the pelvic anterior tilt.

Characterization of water pollution in drainage networks using continuous monitoring data in the Citadel area of Hue City, Vietnam

In the Citadel area of Hue City, drainage systems that include canals and ponds are considerable sources of fecal contaminants to inundated water during the rainy season because canals and ponds receive untreated wastewater. It is important to investigate the characteristics of hydraulics and water pollution in canals and ponds. At the canals and ponds, water sampling was conducted during dry and wet weather periods in order to evaluate fecal contamination and to investigate changes in water pollution caused by runoff inflow. Inundated water was also collected from streets during heavy rainfall. At the canals and ponds, concentrations of Escherichia coli and total coliform exceeded the Vietnamese regulation values for surface water in 23 and 24 out of 27 samples (85 and 89%), respectively. The water samples were categorized based on the characteristics of water pollution using cluster analysis. In the rainy season, continuous monitoring was conducted at the canals and ponds using water depth and electrical conductivity (EC) sensors to investigate the dynamic relationship between water level and water pollution. It is suggested that in the canals, high EC meant water stagnation and low EC signified river water inflow. Therefore, EC might be a good indicator of water flow change in canals.

Estimation of tibiofemoral static zero position during dynamic drop landing

OBJECTIVE

The objective is to assess the in vivo knee secondary motions intrinsic to flexion in isolation from actual displacements during a landing activity. For this purpose a "static zero position", which denotes the normal tibiofemoral position to the static flexion angle, was introduced to describe the intrinsic secondary motion.

METHODS

The three-dimensional motion data of the healthy knee were collected from 13 male and 13 female young adults by using an auto motion analysis system and point cluster technique. First, the relationship between flexion and secondary motion in the static state was determined during a single-leg quasistatic squat. The static zero position during a single-leg drop landing was then calculated by substituting the flexion angle into the flexion-secondary relational expression obtained.

RESULTS

After the foot-ground contact, the estimated static zero positions shifted monotonically in valgus, internal rotation, and anterior translation in the case of both the male and female groups. For the time-course change, noticeable differences between the actual displacement and estimated static zero position were found from the foot-ground contact up to 25ms after the contact for the valgus/varus and external/internal rotation, and between 20 and 35ms after the contact for the anterior/posterior translation.

SUMMARY

The static zero position demonstrated relatively modest but not negligible shift in comparison with the actual displacement. The intrinsic tibiofemoral motion, or baseline shift, would be worth taking into account when examining the fundamental function and injury mechanics of the knee during an impulsive activity.

Simulation of Blown-Film Process Taking Account of Cooling-air Effect

Numerical simulation of blown-film process of plastics provides a tool for air ring designs and suitable polymer properties. Although cooling-air plays a key role in the process ability and film properties, there have been few research works taking correct account of the cooling-air effect. Numerical analyses of heat transfer from the surface of molten polymer to cooling-air were conducted using precise turbulence models and then simulations of bubble shape of blown-film process were performed under the air pressure and the thermal boundary conditions estimated from the numerical analyses of cooling-air. The film bubble shape predicted has coincided well with experimental data and it is confirmed that the bubble stability is strongly dominated by characteristics of cooling-air flow and heat transfer near the bubble surface.

A mechanical coil insertion system for endovascular coil embolization of intracranial aneurysms

Like other fields of medicine, robotics and mechanization might be introduced into endovascular coil embolization of intracranial aneurysms for effective treatment. We have already reported that coil insertion force could be smaller and more stable when the coil delivery wire is driven mechanically at a constant speed. Another background is the difficulty in synchronizing operators' minds and hands when two operators control the microcatheter and the coil respectively. We have therefore developed a mechanical coil insertion system enabling a single operator to insert coils at a fixed speed while controlling the microcatheter. Using our new system, the operator manipulated the microcatheter with both hands and drove the coil using foot switches simultaneously. A delivery wire force sensor previously reported was used concurrently, allowing the operator to detect excessive stress on the wire. In vitro coil embolization was performed using three methods: simple mechanical advance of the coil; simple mechanical advance of the coil with microcatheter control; and driving (forward and backward) of the coil using foot switches in addition to microcatheter control. The system worked without any problems, and did not interfere with any procedures. In experimental coil embolization, delivery wire control using the foot switches as well as microcatheter manipulation helped to achieve successful insertion of coils. This system could offer the possibility of developing safer and more efficient coil embolization. Although we aim at total mechanization and automation of procedures in the future, microcatheter manipulation and synchronized delivery wire control are still indispensable using this system.

Ankle-brachial pressure index and mini nutritional assessment in community-dwelling elderly people

BACKGROUND

A low ankle-brachial pressure index (an ABPI value <0.90) is considered predictive of cardiovascular disease, and is widely thought to increase morbidity and mortality in the elderly. However, good nutrition is beneficial both for the health and the ability to resist and recover from the disease.

OBJECTIVE

The aim of the present study was to evaluate the relationship between the ankle-brachial pressure index and the nutritional status of the elderly in a city of Kochi prefecture, Japan.

METHODS

This was a cross-sectional study in which a total of 100 elderly people, both males and females, were screened for ankle-brachial pressure index (ABPI), nutritional status (through the use of the short form of the mini nutritional assessment), activities of daily living, lifestyle, gait speed (10MWT), postural stability (OLST), and functional mobility (TUG).

RESULTS

About 67% of the participants were found to have a normal nutritional status, 27% were at risk of malnutrition, and six percent were classified as malnourished. The mean ABPI of the participants was 1.08±0.10, and three participants had an ABPI lower than 0.90. The ABPI was statistically higher in well nourished participants compared with those at risk of malnutrition or the malnourished. The mean ABPI was significantly higher in non-smokers compared with former smokers. The ABPI was found to correlate negatively with gait speed and with TUG score.

CONCLUSION

Well-nourished elderly had a higher normal ankle-brachial pressure index as compared with the malnourished elderly. This study provides supportive evidence for the necessity of adequate nutrition for elderly people.