USING A BREAKPOINT TO DETERMINE THE OPTIMAL CUT-OFF FREQUENCY

The aims of this study were to compare methods of determining the optimal cut-off frequency (CFopt) for a Butterworth filter. CFopt were determined for leg displacement data for treadmill running through residual analysis using regression (RA0reg), integral of the power spectral density (PSD), and both these methods analysed through a new ‘breakpoint’ method. RA0reg did not correlate with other methods suggesting poor concurrent validity. The ‘breakpoint’ method correlated significantly between several methods. CFopt was least for anterio-posterior and highest for vertical directions for all methods (p\u3c0.05). Settings for RA0reg and PSD can have substantial effects on CFopt, but the ‘breakpoint’ is not affected as much by the settings. Future research should attempt to standardise settings and explore the criterion validity of the methods to determine CFopt

The clubhead and hand planes in golf draw and fade shots.

Swing planes in golf have become a popular area of research. Cochran and Stobbs (1968) examined the motion of the clubhead and hands qualitatively. Subsequent quantitative analyses have included investigations of the planarity of the whole club (Coleman & Anderson, 2007) and clubhead (Shin, Casebolt, Lambert, Kim, & Kwon, 2008). The aim of this study was to investigate the motion of the clubhead and hands in the downswing quantitatively, and to compare these motions for the fade and draw (as suggested by Coleman and Anderson, 2007). In conclusion, both the clubhead and hand planes in the late downswing were found to differ significantly in relation to the target line between the draw and fade shots. Greater differences were found between golfers, rather than between shots, in the relationship between the clubhead and hand motion during the downswing. Nevertheless, further detailed analysis is warranted of how the motions around impact – especially the clubface orientation – differ between the two types of shot

The clubhead swing plane in golf draw and fade shots

It has become popular to characterise a golf shot in terms of a ‘swing plane’. However Coleman and Anderson (2007) showed that the motion of the whole club in the downswing could not be represented by a single plane in all players. Shin et al. (2008) found that the clubhead motion was consistently planar between the club being horizontal in the downswing and follow-through. Coleman and Anderson (2007) also suggested that the club plane might differ between draw and fade shots. The purpose of this study was to compare draw and fade shots, with a focus on the clubhead motion in the late downswing. The late downswing clubhead plane differs between a draw and a fade shot, even when differences in address angles are accounted for

QUANTIFYING COORDINATION IN KINEMATIC DATA: A RUNNING EXAMPLE

To compare methods of quantifying coordination, one healthy male participant was filmed in three dimensions at 120 Hz whilst running at 3.8 m/s. The knee and hip angles and angular velocities of the left stride, normalised to 100 data points, were analysed using continuous relative phase (CRP) and cross correlations (CC). The phase planes were normalised to -1 and +1, and the component phase angles (I) for each segment calculated with the range O°<

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

Patient-oriented and performance-based outcomes after knee autologous chondrocyte implantation: a timeline for the first year of recovery

It is well established that autologous chondrocyte implantation (ACI) can require extended recovery postoperatively; however, little information exists to provide clinicians and patients with a timeline for anticipated function during the first year after ACI. Objective: To document the recovery of functional performance of activities of daily living after ACI. Patients: ACI patients (n = 48, 29 male 35.1 ± 8.0 y). Intervention: All patients completed functional tests (weight-bearing squat, walk-across, sit-to-stand, step-up/over, and forward lunge) using the NeuroCom long force plate (Clackamas, OR) and completed patient-reported outcome measures (International Knee Documentation Committee Subjective Knee Evaluation Form, Lysholm, Western Ontario and McMaster Osteoarthritis Index WOMAC, and 36-Item Short-Form Health Survey) preoperatively and 3, 6, and 12 mo postoperatively. Main Outcome Measures: A covariance pattern model was used to compare performance and self-reported outcome across time and provide a timeline for functional recovery after ACI. Results: Participants demonstrated significant improvement in walk-across stride length from baseline (42.0% ± 8.9% height) at 6 (46.8% ± 8.1%) and 12 mo (46.6% ± 7.6%). Weight bearing on the involved limb during squatting at 30°, 60°, and 90° was significantly less at 3 mo than presurgery. Step-up/over time was significantly slower at 3 mo (1.67 ± 0.69 s) than at baseline (1.49 ± 0.33 s), 6 mo (1.51 ± 0.36 s), and 12 mo (1.40 ± 0.26 s). Step-up/over lift-up index was increased from baseline (41.0% ± 11.3% body weight BW) at 3 (45.0% ± 11.7% BW), 6 (47.0% ± 11.3% BW), and 12 mo (47.3% ± 11.6% BW). Forward-lunge time was decreased at 3 mo (1.51 ± 0.44 s) compared with baseline (1.39 ± 0.43 s), 6 mo (1.32 ± 0.05 s), and 12 mo (1.27 ± 0.06). Similarly, forward-lunge impact force was decreased at 3 mo (22.2% ± 1.4% BW) compared with baseline (25.4% ± 1.5% BW). The WOMAC demonstrated significant improvements at 3 mo. All patient-reported outcomes were improved from baseline at 6 and 12 mo postsurgery. Conclusions: Patients' perceptions of improvements may outpace physical changes in function. Decreased function for at least the first 3 mo after ACI should be anticipated, and improvement in performance of tasks requiring weight-bearing knee flexion, such as squatting, going down stairs, or lunging, may not occur for a year or more after surgery

LONGITUDINAL MANIPULATUION OF THE KINEMATIC CHAIN USING A REDUCING BIOFEEDBACK SCHEDULE

Feedback has been shown to be an influential component in skill development, yet this has not been assessed longitudinally in a complex motor skill. Novices (n=32) were introduced to a lunge touch task. Visual biofeedback were given on the timing and magnitude of rear leg kinematics. Results showed that those who received feedback adapted their movement patterns by developing extension velocity magnitudes (40.0%, 24.8% and 28.9% increases for the hip, knee and ankle respectively). The changes were retained across 26 weeks, with a reducing visit schedule of feedback. These results demonstrate that knowledge of performance based biofeedback interventions alone are effective in developing whole limb contributions in an explosive task, and that a reducing visit schedule negates dependence on feedback

MANIPULATION OF THE KINEMATIC CHAlN USING VISUAL BIOFEEDBACK

Feedback has been shown to be an influential component in skill development, yet this has not been assessed in movements involving an explosive proximal to distal sequencing pattern. Novices (n=14) were introduced to a lunge touch task. Visual biofeedback were given on the timing and magnitude of rear leg kinematics. Results showed that those who received feedback adapted their movement patterns by developing extension velocity magnitudes in a summative pattern (pre v post, mean f SD peak ankle angular velocity: biofeedback; 479 * 181 v 889 k 11 7, control; 468 k 106 v 477 f 84 deg.s7), resulting in greater horizontal impulse (mean ? SD: biofeedback; 1.17 ? 0.60 v 1.7 & 0.89, control; 1.33 & 0.33 v 1-48? 0.33 M-s-kg7). The changes were retained after six weeks. These results demonstrate that knowledge of performance based biofeedback interventions alone are effective in developing whole limb contributions in an explosive task

USE OF THE KINEMATIC CHAIN IN THE FENCING ATTACKING LUNGE

Proximal to distal sequencing has been demonstrated in a variety of movements as an optimal solution to generating maximal propulsion. This study aimed to identify whether the kinematic chain is used in the fencing attacking lunge. Six novice and four expert fencers completed attacking lunge movements. Kinematic data were captured, and joint angular velocities compared. The expert group demonstrated a proximal to distal sequence in the rear leg which was not as evident in the novices, resulting in a significantly greater ankle extension velocity (564 ± 132 °.s-1 expert versus 273 ± 184 °.s-1 novice;