The aim of the present study was to investigate if the presence of anterior cruciate ligament (ACL) injury risk factors depicted in the laboratory would reflect at-risk patterns in football-specific field data. Twenty-four female footballers (14.9 ± 0.9 year) performed unanticipated cutting maneuvers in a laboratory setting and on the football pitch during football-specific exercises (F-EX) and games (F-GAME). Knee joint moments were collected in the laboratory and grouped using hierarchical agglomerative clustering. The clusters were used to investigate the kinematics collected on field through wearable sensors. Three clusters emerged: Cluster 1 presented the lowest knee moments; Cluster 2 presented high knee extension but low knee abduction and rotation moments; Cluster 3 presented the highest knee abduction, extension, and external rotation moments. In F-EX, greater knee abduction angles were found in Cluster 2 and 3 compared to Cluster 1 (p = 0.007). Cluster 2 showed the lowest knee and hip flexion angles (p < 0.013). Cluster 3 showed the greatest hip external rotation angles (p = 0.006). In F-GAME, Cluster 3 presented the greatest knee external rotation and lowest knee flexion angles (p = 0.003). Clinically relevant differences towards ACL injury identified in the laboratory reflected at-risk patterns only in part when cutting on the field: in the field, low-risk players exhibited similar kinematic patterns as the high-risk players. Therefore, in-lab injury risk screening may lack ecological validity.
MULTIFILE
In wheelchair sports, the use of Inertial Measurement Units (IMUs) has proven to be one of the most accessible ways for ambulatory measurement of wheelchair kinematics. A three-IMU configuration, with one IMU attached to the wheelchair frame and two IMUs on each wheel axle, has previously shown accurate results and is considered optimal for accuracy. Configurations with fewer sensors reduce costs and could enhance usability, but may be less accurate. The aim of this study was to quantify the decline in accuracy for measuring wheelchair kinematics with a stepwise sensor reduction. Ten differently skilled participants performed a series of wheelchair sport specific tests while their performance was simultaneously measured with IMUs and an optical motion capture system which served as reference. Subsequently, both a one-IMU and a two-IMU configuration were validated and the accuracy of the two approaches was compared for linear and angular wheelchair velocity. Results revealed that the one-IMU approach show a mean absolute error (MAE) of 0.10 m/s for absolute linear velocity and a MAE of 8.1◦/s for wheelchair angular velocity when compared with the reference system. The twoIMU approach showed similar differences for absolute linear wheelchair velocity (MAE 0.10 m/s), and smaller differences for angular velocity (MAE 3.0◦/s). Overall, a lower number of IMUs used in the configuration resulted in a lower accuracy of wheelchair kinematics. Based on the results of this study, choices regarding the number of IMUs can be made depending on the aim, required accuracy and resources available.
Background. Deviant shoulder girdle movement is suggested as an eminent factor in the etiology of shoulder pain. Reliable measurements of shoulder girdle kinematics are a prerequisite for optimizing clinical management strategies. Purpose. The purpose of this study was to evaluate the reliability, measurement error, and internal consistency of measurements with performance-based clinical tests for shoulder girdle kinematics and positioning in patients with shoulder pain. Data Sources. The MEDLINE, Embase, CINAHL, and SPORTDiscus databases were systematically searched from inception to August 2015. Study Selection. Articles published in Dutch, English, or German were included if they involved the evaluation of at least one of the measurement properties of interest. Data Extraction. Two reviewers independently evaluated the methodological quality per studied measurement property with the 4-point-rating scale of the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) checklist, extracted data, and assessed the adequacy of the measurement properties. Data Synthesis. Forty studies comprising more than 30 clinical tests were included. Actual reported measurements of the tests were categorized into: (1) positional measurement methods, (2) measurement methods to determine dynamic characteristics, and (3) tests to diagnose impairments of shoulder girdle function. Best evidence synthesis of the tests was performed per measurement for each measurement property. Limitations. All studies had significant limitations, including incongruence between test description and actual reported measurements and a lack of reporting on minimal important change. In general, the methodological quality of the selected studies was fair to poor. Conclusions. High-quality evidence indicates that measurements obtained with the Modified Scapular Assistance Test are not reliable for clinical use. Sound recommendations for the use of other tests could not be made due to inadequate evidence. Across studies, diversity in description, performance, and interpretation of similar tests was present, and different criteria were used to establish similar diagnoses, mostly without taking into account a clinically meaningful context. Consequently, these tests lack face validity, which hampers their clinical use. Further research on validity and how to integrate a clinically meaningful context of movement into clinical tests is warranted.
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