Video measurement of linear displacement along an oblique line using the cross-ratio

The purpose of this study was to rediscover the cross-ratio and assess its effectiveness for measuring linear displacement when the image plane is not parallel to the object plane. In the laboratory a fixed, 4m object length was reconstructed with a mean absolute error of 2.6mm (s.d. = 1.6mm, maximum = 4.9mm). In the field, two cameras filmed a fixed, 8m object length with a mean absolute error of 13mm (s.d. = 5mm, maximum = 20mm). The method is very accessible to non-specialists in projective geometry and the results are both valid and reliable

Perceptual, mechanical and electromyographic responses to different relative loads in the parallel squat

The effectiveness of the OMNI-RES (0-10) and the electromyographic signal for monitoring changes in the movement velocity was examined during a set to muscular failure using different percentages of one repetition maximum (1RM) in the parallel squat exercise (PSQ). Twelve males (26.3 ± 5.8 years) were evaluated on eight separate days with 48 hours of rest between sessions. After determining the 1RM value, participants underwent seven tests until achieving muscular failure with the following percentage ranges: 30 to 90%. An optical rotary encoder measured mean accelerative velocity (MAV) and the OMNI-RES (0-10) scale was used to express the Rating of Perceived Exertion (RPE) after every repetition of each set. Additionally, the normalized root mean square (RMS) signal of the surface electromyography (N-EMG) was calculated for the vastus medialis muscle. The RPE expressed after the first repetition and when the maximum value of MAV was achieved along the sets was lower (p 0.8) than the RPE that corresponded to a 10% drop in MAV and at failure. Additionally, the initial RPE was useful to distinguish different loading zones by anchoring the OMNI-RES value to the magnitude of the relative load (<60%, 60 to <70% or ≤ 70% 1RM). Similar patterns were observed using the N-EMG. In conclusion, apart from differentiating between relative loads during a set to failure in the PSQ, the RPE and the N-EMG can both reflect changes associated with the initial, maximal, 10% drop in movement velocity and the muscular failure

THE IDENTIFICATION OF IMPULSES IN 3-D RECONSTRUCTED DATA USING RECURSIVE FILTERS ON THE ORIGINALLY DIGITIZED 2-D IMAGE DATA

INTRODUCTION: Reconstructed three-dimensional (3-D) data is usually processed using either a low-pass Butterworth filter or quintic spline, though neither gives an implicit indication that the processed data is more accurate than the original data. This study investigated the effect of processing the original twodimensional (2-D) data before reconstruction, a technique commonly applied in the communications industry (e.g., the removal of noise prior to amplification). Reconstruction of the 3-D data can be considered successful when the condition of coplanarity is met (i.e., the lines from each centre of projection pass through their respective image points and intersect at the object point). The 3-D data is considered to be more accurate if the lines converge after processing (i.e. the residual error of the reconstructed points was reduced) and less accurate if the lines diverge. The independent application of a recursive filter in both forward and backward directions to the 2-D data enables the detection of a discontinuity. Each original 2- D data set can then be considered as two different data sets whose paths intersect at the discontinuity caused by an impulse. The timing of the impulse can be calculated from the extrapolated curves even if it was not explicitly captured on film. METHOD: Two cameras were located so that their optical axes were approximately orthogonal to each other and a 3-D volume was calibrated to generate the linear transformation parameters. A bouncing ball was then filmed within the calibrated volume, digitized and then passed through a Kalman filter in both the forward and backward directions to determine the timing of the impulse, (i.e., when the ball hit the ground). RESULTS: Two cameras provide four image co-ordinates and thus four equations with three unknowns so the 3-D object space co-ordinates were calculated using least squares estimation. To ensure only random noise was removed, the processed 2-D signal must have the same total energy as the original 2-D signal, even if the energy density spectrum has altered and the filter was deemed to be effective if the residual error of the reconstruction was reduced. Using this method, it was possible to identify when the impulse forces occurred, for both image sets, independently. CONCLUSIONS: This technique breaks a signal down into a series of discontinuous signals, each discontinuity indicating the application of an impulse to the original measured data. With proper camera placement any impulse can be observed independently in both the 2-D images so the impulses can also be used to synchronize previously unsynchronized data

VIDEO MEASUREMENT OF LINEAR DISPLACEMENT ALONG AN OBLIQUE LINE USING THE CROSS-RATIO

The purpose of this study was to rediscover the cross-ratio and assess its effectiveness for measuring linear displacement when the image plane is not parallel to the object plane. In the laboratory a fixed, 4m object length was reconstructed with a mean absolute error of 2.6mm (s.d. = 1.6mm, maximum = 4.9mm). In the field, two cameras filmed a fixed, 8m object length with a mean absolute error of 13mm (s.d. = 5mm, maximum = 20mm). The method is very accessible to non-specialists in projective geometry and the results are both valid and reliable

The effects of a sports specific maximal strength and conditioning training on critical velocity, anaerobic running distance and 5-km race performance

Purpose: To investigate the effects of a sports specific maximal 6-week strength and conditioning program on Critical Velocity (CV), anaerobic running distance (ARD) and 5-km time trial performance (TT). Methods: 16 moderately trained, recreational endurance runners were tested for CV, ARD and TT performances on three separate occasions (baseline, mid and post study). Design: Participants were randomly allocated into a strength and conditioning group (S&C; n=8) and a comparison, endurance training only group (EO; n=8). During the first phase of the study (6 weeks), the S&C group performed a concurrent maximal strength and endurance training, whilst the EO group performed an endurance only training. After the re-test of all variables (mid study) both groups subsequently, during phase two, performed another 6 weeks of endurance only training which was followed by post study tests. Results: No significant change for CV was identified in either groups. The S&C group demonstrated a significant decrease for ARD values after the first and second phase of the study. TT performances were significantly different in the S&C group after the intervention with a performance improvement of 3.62%. This performance increase returned close to baseline after the 6-week endurance only training. Conclusion: combining a 6-week resistance training program with endurance training significantly improves 5-km time trial performance. Removing strength training results in some loss of those performance improvements

A systematic scoping review on the evidence behind debriefing practices for the wellbeing/emotional outcomes of healthcare workers

IntroductionDebriefings give healthcare workers voice through the opportunity to discuss unanticipated or difficult events and recommend changes. The typical goal of routine debriefings has been to improve clinical outcomes by learning through discussion and reflection of events and then transferring that learning into clinical practice. However, little research has investigated the effects of debriefings on the emotional experiences and well-being of healthcare workers. There is some evidence that debriefings are a multi-faceted and cost-effective intervention for minimising negative health outcomes, but their use is inconsistent and they are infrequently adopted with the specific intention of giving healthcare workers a voice. The purpose of this systematic scoping review is therefore to assess the scope of existing evidence on debriefing practices for the well-being and emotional outcomes of healthcare workers.MethodsFollowing screening, 184 papers were synthesised through keyword mapping and exploratory trend identification.ResultsThe body of evidence reviewed were clustered geographically, but diverse on many other criteria of interest including the types of evidence produced, debriefing models and practices, and outcomes captured.DiscussionThe current review provides a clear map of our existing understanding and highlights the need for more systematic, collaborative and rigorous bodies of evidence to determine the potential of debriefing to support the emotional outcomes of those working within healthcare.Systematic Review Registrationhttps://osf.io/za6rj.</jats:sec

A systematic scoping review on the evidence behind debriefing practices for the well-being/emotional outcomes of healthcare workers

Debriefings give healthcare workers voice through the opportunity to discuss unanticipated or difficult events and recommend changes. The typical goal of routine debriefings has been to improve clinical outcomes by learning through discussion and reflection of events and then transferring that learning into clinical practice. However, little research has investigated the effects of debriefings on the emotional experiences and well-being of healthcare workers. There is some evidence that debriefings are a multi-faceted and cost-effective intervention for minimising negative health outcomes, but their use is inconsistent and they are infrequently adopted with the specific intention of giving healthcare workers a voice. The purpose of this systematic scoping review is therefore to assess the scope of existing evidence on debriefing practices for the well-being and emotional outcomes of healthcare workers. Following screening, 184 papers were synthesised through keyword mapping and exploratory trend identification. The body of evidence reviewed were clustered geographically, but diverse on many other criteria of interest including the types of evidence produced, debriefing models and practices, and outcomes captured. The current review provides a clear map of our existing understanding and highlights the need for more systematic, collaborative and rigorous bodies of evidence to determine the potential of debriefing to support the emotional outcomes of those working within healthcare