Development of the Nine-Ball Skills Test to discriminate elite and high-level amateur golfers

Currently, there is a lack of appropriate skill assessments available for use in golf. The aim of this study was to examine the discriminative validity and the test-retest reliability of the newly developed "Nine-Ball Skills Test". Participants of two ability levels (elite, n = 14; high-level amateur, n = 16) each hit nine golf shots of differing combinations of trajectory (straight, fade, draw) and height (normal, high, low) at an individually determined target area. Each shot was scored on its percent error index from the target and whether it achieved the maximum height as required. Participants completed the test twice using a 5-iron club. The elite group scored significantly higher (P < 0.05) than the amateur group for both the first and second rounds of the test as well as the combined scores. The between-round test-retest reliability was deemed to be not acceptable, thus we propose that the test's protocol should include use of the two rounds as standard. Due to the importance of ball striking and flight control to performance in golf, the Nine-Ball Skills Test is appropriate for providing a measure of this skill component in elite and high-level amateur golfers.     

A social skills group for children

Abstract

An NHS Trust set up groups to teach social skills to children and adolescents using a cognitive behavioural framework. One group of seven children (five boys and two girls) is described. Parents were invited to a parallel parents' group. Each group lasted for 90 minutes and ran weekly for 6 weeks. Extensive liaison with parents and teachers took place before, during and after the group. Analysis of pre- and postgroup questionnaires sent to parents and teachers indicated improved social functioning, outside the group, for most of the children. Parents valued the dialogue with professionals and often felt supported by them for the first time. Therapists' contact with teachers ensured full knowledge of children's behaviour and the transfer of skills to schools. Cognitive behavioural techniques with children under-going group work require intensive liaison to facilitate generalization of skills learnt.     

Exploratory analyses to improve model fit: Errors due to misspecification and a strategy to reduce their occurrence

Two Lagrange multiplier (LM) methods may be used in specification searches for adding parameters to models: one based on univariate LM tests and respecification of the model (LM‐respecified method) and the other based on a partitioning of multivariate LM tests (LM‐incremental method). These methods may result in extraneous parameters being included in models due to either sampling error or the model being misspecified. A 2‐stage specification search may be used to reduce errors due to misspecification. In the 1st stage, parameters are added to models based on LM tests to maximize fit. Second, parameters added in the 1st stage are deleted if they are no longer necessary to maintain model fit. Illustrations are presented to demonstrate that errors due to misspecification occur with the LM‐respecified method and are even more likely with the LM‐incremental approach. These illustrations also show how the deletion stage can help eliminate some of these errors.     

Difference score reliabilities within the RIAS-2 and WISC-V

Many prominent intelligence tests (e.g., Wechsler Intelligence Scale for Children, Fifth Edition [WISC-V] and Reynolds Intellectual Abilities Scale, Second Edition [RIAS-2]) offer methods for computing subtest- and composite-level difference scores. This study uses data provided in the technical manual of the WISC-V and RIAS-2 to calculate reliability coefficients for difference scores. Subtest-level difference score reliabilities range from 0.59 to 0.99 for the RIAS-2 and from 0.53 to 0.87 for the WISC-V. Composite-level difference score reliabilities generally range from 0.23 to 0.95 for the RIAS-2 and from 0.36 to 0.87 for the WISC-V. Emphasis is placed on comparisons recommended by test publishers and a discussion of minimum requirements for interpretation of differences scores is provided.     

The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.