Yasuharu Nagano

Biomechanical characteristics of the knee joint in female athletes during tasks associated with anterior cruciate ligament injury

This study was designed to compare biomechanical characteristics of the knee joint for several athletic tasks to elucidate their effects and to examine what tasks pose a risk for ACL injury. Three athletic tasks were performed by 24 female athletes: single-limb landing, plant and cutting, and both-limb jump landing. Angular displacements of flexion/extension, abduction/adduction, and external/internal tibial rotation were calculated. Angular excursion and the rate of excursion of abduction and internal tibial rotation were also calculated. During plant and cutting, from foot contact, subjects rotated the tibia more rapidly and to a greater degree toward internal tibial rotation. Moreover, excursion of knee abduction is greater than that during single-limb landing. During both-limb jump landing, the knee flexion at foot contact was greater than for either single-limb landing or plant and cutting; peak knee abduction was greater than for either single-limb landing or plant and cutting. In plant and cutting, the risk of ACL injury is increased by greater excursion and more rapid knee abduction than that which occurs in single-limb landing, in addition to greater internal tibial rotation. Although single-limb tasks apparently pose a greater risk for ACL injury than bilateral landings, both-limb landing with greater knee abduction might also risk ACL injury.

Relationship between three-dimensional kinematics of knee and trunk motion during shuttle run cutting

Abstract Female athletes are considered to exhibit knee and trunk motion that is characteristic of anterior cruciate ligament (ACL) injury. The aim of this study was to examine the in vivo motion of the trunk and knee during a cutting manoeuvre and determine the relationship between them. All participants (10 male and 10 female college athletes) performed a shuttle run cutting task with the left limb. Trunk inclination (forward and lateral) and knee joint angles (flexion/extension, abduction/adduction, and internal/external tibial rotation) were calculated. Differences between the sexes and associations between knee motion and trunk inclination were examined. An increase in trunk forward inclination was strongly correlated with an increase in knee flexion angle and moderately correlated with a decrease in the excursion of internal tibial rotation. An increase in right trunk lateral inclination was moderately correlated with an increase in excursion of internal tibial rotation. The results also showed differences between the sexes in trunk forward inclination, lateral inclination, and knee flexion angle, but no such differences in knee abduction or internal tibial rotation. Trunk inclination is related to knee flexion and excursion of internal tibial rotation. Female athletes demonstrate a low trunk forward inclination and knee flexion angle, a posture that resembles that of ACL injury.

Statistical modelling of knee valgus during a continuous jump test

Landing with the knee in a valgus position is recognized as a risk factor for anterior cruciate ligament (ACL) injury. Using linear and non-linear regression analyses, the purpose of this study was to examine the correlation between two-dimensional (2D) knee valgus and three-dimensional (3D) knee kinematics measured during a jump landing task. Twenty-eight female collegiate athletes participated. All participants were required to perform a continuous jump test. The average maximum angles of abduction and internal tibial rotation during landing were measured using the Point Cluster Technique. Average peak knee valgus angle was measured using a 2D approach. Linear and non-linear regression analyses between 2D valgus and 3D knee abduction, and between 2D valgus and 3D internal tibial rotation, were performed. The R 2 value between 2D valgus and 3D knee abduction was significantly different from zero and had a moderate correlation for all models, whereas the R 2 value between 2D valgus and 3D internal tibial rotation was not significantly different from zero. The 2D approach could be used to screen a specific group of individuals for risk of ACL injury; however, using frontal plane 2D analysis of valgus motion to evaluate internal tibial rotation is not advised.

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

Abstract 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.

Evidence of Validity for the Japanese Version of the Foot and Ankle Ability Measure

CONTEXTnThe Foot and Ankle Ability Measure (FAAM) is a valid, reliable, and self-reported outcome instrument for the foot and ankle region.nnnOBJECTIVEnTo provide evidence for translation, cross-cultural adaptation, validity, and reliability of the Japanese version of the FAAM (FAAM-J).nnnDESIGNnCross-sectional study.nnnSETTINGnCollegiate athletic training/sports medicine clinical setting.nnnPATIENTS OR OTHER PARTICIPANTSnEighty-three collegiate athletes.nnnMAIN OUTCOME MEASURE(S)nAll 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.nnnRESULTSnThe 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.nnnCONCLUSIONSnThe 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.

Change in tibial rotation of barefoot versus shod running

Tibial rotation during foot pronation has been proposed as a key factor in running related injuries. Precise analysis of knee motion during running, including the analysis of motion in the coronal plane, is difficult, and the effect of the wearing shoes on tibial rotation during running is unknown. Therefore, we aimed to determine the effect of wearing shoes in reducing tibial rotation during running. Fifteen healthy subjects (nine males, six females) participated in this study; 25 markers were secured on the left lower extremity of each subject. Three-dimensional kinematic data were collected using the MAC3D System (Motion Analysis Co.). The data were processed using the point cluster technique (Andriacchi et al. 1998, J Biomech Eng 120, 743). The subjects were required to run (a) barefoot and (b) while wearing athletic running shoes (Adidas Response Cushion). Tibial motion with respect to the femur was assessed in the stance phase. The internal/external rotation, adduction/abduction and flexion of knee joint were analyzed for a period of 100 ms after foot strike. In both the conditions, all subjects experienced internal tibial rotation after foot strike. During the 100-ms period after foot strike, the shoes reduced the amount of tibial rotation during running (barefoot 16.0 ± 4.1°, shod 13.7 ± 5.3°). The angular change of the knee flexion was increased with running shoe (barefoot 20.8 ± 4.9°, shod 26.5 ± 4.2°). These findings suggest that tibial rotation can be reduced by wearing athletic running shoes.

Knee kinematics and kinetics during shuttle run cutting: Comparison of the assessments performed with and without the point cluster technique

The differences between the assessments performed with and without the point cluster technique (PCT) for knee joint motions during the high-risk movements associated with non-contact anterior cruciate ligament (ACL) injuries have not been reported. This study aims to examine the differences between PCT and non-PCT assessments for knee joint angles and moments during shuttle run cutting. Fourteen high school athletes performed a maximal effort shuttle run cutting task. Motion data were collected by an 8-camera motion analysis system at 200 Hz, and ground reaction force data were recorded using a force plate at 1000 Hz. In both PCT and non-PCT approaches, the knee joint angles were calculated using Euler angle rotations, and the knee joint moments were obtained by solving the Newton-Euler equations using an inverse dynamics technique. For the extension/flexion angle, good agreement was measured between PCT and non-PCT assessments. The abduction angle obtained in the non-PCT assessment was smaller than that obtained with the PCT. An internal rotation angle was obtained in the PCT assessment, whereas a small external rotation angle was obtained in the non-PCT assessment. For the knee joint moments, good agreement between PCT and non-PCT assessments was observed for all the components. The differences in the knee joint angles were attributed in part to the differences in the position of the medial femoral epicondyle. The results suggest that the ACL injury risk during shuttle run cutting is estimated lower in the non-PCT assessment than in the PCT assessment.

Prevention of anterior cruciate ligament injuries in female basketball players in japan: an intervention study over four seasons

Background Female basketball players are at a higher risk of anterior cruciate ligament (ACL) injury than male players. Therefore, prevention of ACL injury in the former group is essential. Objective To assess the effect of an injury prevention training program on the incidence of ACL injuries in female basketball players. Design Prospective intervention study. Setting Top-level league in Japan. Participants Players from 12 top-league teams. The control season (2006–2007) included 158 players; the first intervention season (2007–2008), 168 players; the second intervention season (2008–2009), 174 players; and the third intervention season (2009–2010), 162 players. Interventions From the middle of the 2007–2008 season, a 3-step injury prevention program was initiated. The program focused on strength, balance, jump-landing techniques, and basketball skills. Subjects were instructed to perform exercises in a neutral position and to avoid lumbar lordosis, rear axial weight bearing, hip adduction, and knee valgus. Main outcome measurements Number and rate of ACL injuries during the four seasons and compliance with the program. Injury incidences were given in terms of per 1000 player-hours (PH). Results Seven non-contact ACL injuries were noted during the control season (0.059/1000 PH); 4, during the first intervention season (0.031/1000 PH); 10, during the second intervention season (0.073/1000 PH); and 2, during the third intervention season (0.016/1000 PH). During the second intervention season, the rate of ACL injuries in the teams that complied with the program was 0.053/1000 PH, while the rate in the teams that did not comply was 0.099/1000 PH. During the third intervention season, the rate of ACL injuries in the teams that complied was 0.011/1000 PH, while the rate in the teams that did not comply was 0.032/1000 PH. Conclusion The results show that the injury prevention program tended to decrease the frequency of ACL injuries.

Influence of Lower Limb Clinical Physical Measurements of Female Athletes on Knee Motion During Continuous Jump Testing

Objectives: To assess the relationship between dynamic knee motion in female athletes during landing after jumping and lower limb clinical physical measurements, considered risk factors for anterior cruciate ligament (ACL) injury. We proposed that (1) knee valgus and flexion angles during landing are correlated with clinical physical measurements; (2) combining these measurements enables prediction of the knee valgus and flexion angles during landing. Methods: Sixty-one female collegiate basketball athletes performed a continuous jump test; the peak knee valgus and flexion angles were measured. The Q-angle, the ranges of motion (ROMs) of hip internal rotation (IR) and external rotation (ER), as well as ankle dorsiflexion (DF), navicular drop, leg-heel alignment, and balance ability as assessed by the Star Excursion Balance Test (SEBT) were measured. Stepwise linear regression analyses were used to assess whether these factors can predict the peak knee valgus or flexion angle. Results: Increased ROM of hip IR and navicular drop predicted 7.9% of the peak knee valgus angle variance. Increased ROMs of ankle DF and hip IR, navicular drop, and anterior balance predicted 29.0% of the peak knee flexion angle variance. The knee valgus and flexion angles during the continuous jump test were slightly correlated with clinical physical measurements. Conclusions: Proximal and distal joint alignment and balance ability influence knee motion during landing. The relationship between knee motion during landing and these factors is weak; therefore, lower limb movement during landing is almost independent of clinical physical measurements, and knee movement should be evaluated by itself.