Measurement of three-dimensional hand kinematics during swimming with a motion capture system: a feasibility study

Current trends in swimming biomechanics are focused on accurate measurements. Nowadays, reliable calibration methods have been proposed to reach an accuracy of about 1 mm on rigid structure. But the question remains about the final accuracy for three-dimensional hand kinematics measurement during the underwater phase of front crawl swimming. Furthermore, most research is based on manual tracking with two or more cameras. In this paper we propose a protocol to acquire three-dimensional hand kinematics when swimming in a specific pool with a motion analysis system behind windows. Results highlight the benefits of using such a system in terms of accuracy and feasibility: the time allowed for post-processing is ten times lower and the quantified improved accuracy is better than with manual tracking.     

Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk

Abstract

Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement.

Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact.

With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009).

Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs.     

The Western Primary School 'Quiet Room' Project

There has been a great deal of interest recently in the development of more 'nurturing' environments in mainstream primary schools. This interest has been reflected in a series of articles published in the pages of this journal. In this paper, Angus King, headteacher of Western Primary School, a performance management consultant, a threshold assessor and a teacher trainer, with Zara Chantler, Key Stage 1 leader and SENCo at Western, describe the Western 'Quiet Room' project, set up in 1999 as a response to the needs of pupils experiencing social, emotional and behavioural problems. The Quiet Room was designed to provide a nurturing environment in a dedicated space away from the classroom. In this way, argue King and Chantler, a child's emotional needs can be explored, on a one–to–one basis where appropriate, in a safe and supportive setting. The results to date are positive and there is real potential for the scheme to be extended.