Formulation of School Board Policies for the South Bend Public Schools

The purpose of this study is to develop a set of written school board policies for and with the cooperation of the Board of Directors of the South Bend, Washington, School District 118. Board authorization was given to investigate and write a permanent set of policies for action by the board

Error and Anomaly Detection for Intra-Participant Time-Series Data

Identification of errors or anomalous values, collectively considered outliers, assists in exploring data or through removing outliers improves the statistical analysis. In biomechanics, outlier detection methods have explored the ‘shape’ of the entire cycles, although exploring fewer points using a ‘moving-window’ may be advantageous. Hence, the aim was to develop a moving-window based method for detecting trials with outliers in intra-participant time-series data. The test data were the angles and displacements for the strides or cycles (mean 38 cycles) from treadmill running, with outliers detected through two-stages. Stage-1 was a one-dimensional (spatial) outlier detection at each time-point, where any data-value of a scaled median-absolute-deviation away from the median at that time-point led to removing that cycle. Stage-2 was a two-dimensional (spatial-temporal) outlier detection of a moving-window-standard-deviation (mwSD) across cycles and across the moving-window size (size of ± 0, 1, 2 or 3 time-points), where any data-value greater than the scaled mwSD led to removing that cycle. Scaling was performed using the t-statistic for three significance levels of 0.01, 0.001 or 0.0001. Fewer cycles were removed with smaller scaling and smaller window size. Appropriate settings were stage-1 scaling of 0.0001 (mean 3.5 cycles removed) and stage-2 scaling of 0.01 with a moving-window size of 1 (mean 2.6 cycles removed). Settings in the supplied Matlab code should be customised to each data set, and trials with outliers assessed to justify whether to retain or remove those trials. The method provides an effective method to identify trials with outliers in intra-participant time-series data

WHEN DO KINETIC CHANGES PLACE GREATEST RISK FOR NON-CONTACT ACL INJURY DURING THE STANCE PHASE OF FOOTBALL CUTTING MANEUVERS IN MATCH PLAY CONDITIONS?

This research aimed to determine when kinetic changes place greatest risk for noncontact ACL (anterior cruciate ligament) injury during football cutting in match play. Fourteen professional football players undertook three trials of a straight line run and sidestep cutting at 30° and 60° with standardised velocity on an approved football surface. Two types of standardised studded football boots were utilised. Using inverse dynamics analyses, an eight camera gait analysis system synchronised with a force platform, determination of knee joint moments, joint forces and flexion angles were undertaken. Magnitudes and timings were compared with critical limits for ACL injury. 33- 50% of stance during cutting was associated with increased risk of ACL injury with peak valgus and internal rotational moments and anterior joint forces. Knee flexion above 30° at 22%-77% of stance appears protective. By ensuring knee control by training techniques, ACL injury risk could be reduced

MECHANICAL SIMILARITIES OF HIGH BAR PROGRESSIONS

The purpose of this study was 10 develop a method to rank selected progressions for learning the longswing on high bar. Video recordings of four male international gymnasts performing the longswing and four associated progressions were quantified using 2D DLT techniques. Root mean square differences (RMSD) for hip and shoulder angular displacements and velocities facilitated grouping of the progressions based on overall level of agreement. The progression that was most similar to the 'target' skill was the 'chalked bar pendulum swing', whilst the least similar was the same skill without hip and shoulder 'action'. The method provided a useful means to quantify and rank progressions based on kinematic similarity to the longswing

RELATIONSHIP OF SIMULTANEOUS HIP AND KNEE KINETIC & KINEMATIC MAGNITUDES AND TIMINGS ON POTENTIAL ACL INJURY RISK DURING FOOTBALL MATCH PLAY CUTTING MANEUVERS

Fourteen professional male football players undertook straight line run and sidestep cutting at 30° and 60° with standardised approach velocity on an approved football surface using standardised studded football boots. The relationship of simultaneous hip and knee kinetic and kinematic magnitudes and timings on potential non-contact ACL (anterior cruciate ligament) injury using inverse dynamics analyses by an eight camera gait analysis system synchronised with a force platform were determined. Early peak cutting hip abduction and internal rotation moments at 13-32% of stance and high hip abduction angles are related to later peak knee valgus moments and internal rotation moment values at 30-46% that can influence ACL injury. Early stance large hip abduction angles and valgus moments early should be targeted in injury training prevention

ANGULAR MOMENTUM IN THE STRAIGHT TKATCHEV ON HIGH BAR

Angular momentum in the straddle Tkatchev was reported as part of a study by Arampatzis and Brüggemann, (2001). The Tkatchev is an interesting skill as it requires the gymnast to reverse the direction of rotation between the bar circling action (the longswing) and the flight phase from release until regrasp

MUSCULOSKELETAL WORK IN HIGH BAR PROGRESSIONS

This study explained and assessed the similarity in joint kinetic profiles between the longswing (LS) and four progressions. Video recordings of four male gymnasts performing the LS and four progressions were quantified using 2D DLT techniques on an instrumented high bar. Inverse dynamic analyses quantified the muscle moments and work done at hips and shoulders. RMSD analysis between the work during the LS and progressions was used to group the progressions based on overall level of similarity to the LS. The least similar progression was the looped bar pendulum swing, whilst the most similar was the bent knee LS. This study has identified that progressions can be classified into those that are similar in terms of physical demand or movement pattern. This study raises the question should progressions be selected based on its kinetic or kinematic similarity to the target skill

A SIMPLE OUTLIER DETECTION METHOD FOR INTRA-SUBJECT TIME-SERIES DATA

Removal of outliers assists in improving the statistical representations of the general finding. Currently no simple method is advocated for detecting outliers in time-series data obtained in biomechanics. The aim was to demonstrate a 2-stage method for detecting outliers. The test data were the ankle and knee angles for the strides (n=41±2.8) from treadmill running (n=6). Stage 1 was an outlier detection of >±3.3SD from the mean at each time-point, and removing any stride with an outlier. Stage 2, with padding of k=3 points and mean-detrending, was a moving window SD for all strides across ±k data points, and removing strides with any point >±2.58SD. After removal of 5.2±3 (stage 1) and 2.0±1.4 (stage 2) strides, the mean was unchanged and the SD reduced (

HIP AND SHOULDER COORDINATION DURING THE HANDSPRING FRONT SOMERSAULT ON THE VAULTING "HORSE" AND "TABLE"

The purpose of this study was to establish inter-segmental co-ordination (ISC) during a handspring front somersault performed on the old vaulting horse and new table. Four male international level gymnasts were filmed in 3D performing five trials on separate occasions. ISC of the hip and shoulder joint in three phases (board contact; flight; vault contact) was assessed using continuous relative phase (CRP). CRP variability (CRPsd) and root mean square difference (RMSD) between the old and new vault CRP profiles were also calculated. Small differences existed at key moments (e.g. both board touch downs=155), but the RMSD in the CRP profiles were large (e.g. board contact phase= 27 ). Larger variability on the table than the horse (e.g. CRPsd during vault contact 26% greater) suggests a less stable co-ordination pattern requiring further investigations into devising learning drills for the table

KINETIC ANALYSIS OF TOE-ON TKACHEV ON UNEVEN BARS

The purpose of this study was to explain the mechanics of the Toe-on Tkachev on Uneven Bars, and to identify how the release conditions were created. 3D video based data and inverse dynamics were used to analyze five different Toe-on Tkachevs recorded at the 2007 World Championships. Digitising and DLT techniques were combined with customised inertia modelling as input to standard inverse dynamics. Data were normalised to eliminate influences of height and mass. Hip action was characterised by a single large input which peaked close to the horizontal on the upswing, followed by a smaller negative shoulder power contribution as release was approached. The dominant role of positive hip extension was highlighted as a major factor contributing to the creation of the final body orientation and desirable release conditions