Application of the coaching biomechanics interface: Which technique should I choose?

The under somersault (Felge) is one of the key family of skills on the parallel bars in men’s artistic gymnastics. At the highest level of competition two distinct techniques, termed here “deep pike” and “hips close”, are used to perform the skill. The aim of the present study was to determine the relative performance benefits of each technique in order to provide coaches with information to facilitate technique selection and gymnast preparation. A combination of kinematic analysis of Olympic performances and technique optimisation using computer simulation modelling, was used to address this aim. The kinematic analysis found that both techniques had similar performance outcomes in terms of generating horizontal and vertical velocity at release, confirming that both techniques were fit for purpose. Results from the optimisation study found that the “deep pike” had an advantage in generating vertical velocity, due to more time to perform work, and being more forgiving in terms of generating a larger release window for acceptable performance, whilst the “hips close” technique was associated with requiring less effort (sum of joint torques squared). As the “deep pike” requires more effort and a larger range of hip flexibility, choosing this technique will have implications for gymnast preparation. </p

Elbow joint variability for different hand positions of the round off in gymnastics

The aim of the present study was to conduct within-gymnast analyses of biological movement variability in impact forces, elbow joint kinematics and kinetics of expert gymnasts in the execution of the round-off with different hand positions. Six international level female gymnasts performed 10 trials of the round-off from a hurdle step to a back-handspring using two hand potions: parallel and T-shape. Two force plates were used to determine ground reaction forces. Eight infrared cameras were employed to collect the kinematic data automatically. Within gymnast variability was calculated using biological coefficient of variation (BCV) discretely for ground reaction force, kinematic and kinetic measures. Variability of the continuous data was quantified using coefficient of multiple correlations (CMC). Group BCV and CMC were calculated and T-test with effect size statistics determined differences between the variability of the two techniques examined in this study. The major observation was a higher level of biological variability in the elbow joint abduction angle and adduction moment of force in the T-shaped hand position. This finding may lead to a reduced repetitive abduction stress and thus protect the elbow joint from overload. Knowledge of the differences in biological variability can inform clinicians and practitioners with effective skill selection.</p

Double knee bend in the power clean

no abstract availabl

Limit cycle dynamics of the gymnastics longswing

The purpose of the study was to examine the macroscopic dynamics of the longswing through a limit cycle analysis of the motion of the center of mass (CM) as a function of skill level. One elite international, five gymnasts able to perform release and regrasp skills, five gymnasts unable to perform release and regrasp skills, and five novice gymnasts each performed four consecutive longswings on a high bar. Kinematic data were collected to facilitate the calculation of the center of mass position of the performer during swinging. Poincare plots were used to explore the limit cycle dynamics of the center of mass movement. The attractor dynamic was very close to a one-dimensional limit cycle for the elite (D=1.18) but higher for the release and regrasp group (D = 1.35 ± 0.06) and non-release and regrasp group (D = 1.37 ± 0.07). The novice dynamic was characterized by a two-dimensional limit cycle (D = 2.49 ± 0.28) that also had more variability and lower determinism. In the frequency domain, Inharmonicity was lower and the Q factor higher as a function of increased skill level. The findings show that the dynamical degrees of freedom of the CM in the skilled performance were reduced compared to those of novices and represented a more efficient and predictive, rather than exploratory, technique

Eight Weeks of Self-Resisted Neck Strength Training Improves Neck Strength in Age-Grade Rugby Union Players: A Pilot Randomized Controlled Trial

Background:Greater neck strength is associated with fewer head and neck injuries. Neck-strengthening programs are commonly burdensome, requiring specialist equipment or significant time commitment, which are barriers to implementation.Hypothesis:Completing a neck-strengthening program will increase isometric neck strength in age-group rugby players.Study Design:A pilot randomized controlled exercise intervention study.Level of Evidence:Level 2.Methods:Twenty-eight U18 (under 18) male regional age-group rugby union players were randomized (intervention n =15/control n = 13). An 8-week exercise program was supervised during preseason at the regional training center. Control players continued their “normal practice,” which did not include neck-specific strengthening exercises. The 3-times weekly trainer-led intervention program involved a series of 15-second self-resisted contractions, where players pushed maximally against their own head, in forward, backward, left, and right directions.Outcome Measure:Peak isometric neck strength (force N) into neck flexion, extension, and left and right side flexion was measured using a handheld dynamometer.Results:Postintervention between-group mean differences (MDs) in isometric neck strength change were adjusted for baseline strength and favored the intervention for total neck strength (effect size [ES] = 1.2, MD ± 95% CI = 155.9 ± 101.9 N, P = 0.004) and for neck strength into extension (ES = 1.0, MD ± 95% CI = 59.9 ± 45.4 N, P = 0.01), left side flexion (ES = 0.7, MD ± 95% CI = 27.5 ± 26.9 N, P = 0.05), and right side flexion (ES = 1.3, MD ± 95% CI = 50.5 ± 34.4 N, P = 0.006).Conclusion:This resource-efficient neck-strengthening program has few barriers to implementation and provides a clear benefit in U18 players’ neck strength. While the present study focused on adolescent rugby players, the program may be appropriate across all sports where head and neck injuries are of concern and resources are limited.Clinical Relevance:Greater neck strength is associated with fewer head and neck injuries, including concussion. Performing this neck exercise program independently, or as part of a whole-body program like Activate, an interactive guide for players and coaches, could contribute to lower sports-related head and neck injuries.</div

sj-docx-1-sph-10.1177_19417381211044736 – Supplemental material for Eight Weeks of Self-Resisted Neck Strength Training Improves Neck Strength in Age-Grade Rugby Union Players: A Pilot Randomized Controlled Trial

Supplemental material, sj-docx-1-sph-10.1177_19417381211044736 for Eight Weeks of Self-Resisted Neck Strength Training Improves Neck Strength in Age-Grade Rugby Union Players: A Pilot Randomized Controlled Trial by Matthew J. Attwood, Lewis-Jon W. Hudd, Simon P. Roberts, Gareth Irwin and Keith A. Stokes in Sports Health: A Multidisciplinary Approach</p

Additional file 2: of NUP98 – a novel predictor of response to anthracycline-based chemotherapy in triple negative breast cancer

Figure S1. (A) Kaplan Meier plot of overall survival of TNBC patients from in-house datasets dichotomised based on NUP98 gene expression above (high) and below the median (low). (B) Kaplan Meier plot of overall survival stratified based on absent (0), low (1) or high (2) NUP98 IHC expression in the TNBC TMA with matched gene expression. (C) Kaplan Meier plot of overall survival stratified based on absent (0), low (1) or high (2) NUP98 IHC expression in the 2nd TNBC TMA. (D) Kaplan Meier plot of overall survival stratified based on presence or absence of NUP96. (PPTX 170 kb

Additional file 3: of NUP98 – a novel predictor of response to anthracycline-based chemotherapy in triple negative breast cancer

Figure S2. (A) Kaplan Meier plot of overall survival dichotomised based on NUP88 gene expression above (high) and below the median (low) in the in-house TNBC gene expression dataset.(B) Box and whisker plot of NUP43 gene expression in good and poor outcome samples in the in-house TNBC gene expression dataset. (C) Kaplan Meier plot of relapse free survival dichotomised based on NUP43 gene expression above (high) and below the median (low) in the in-house TNBC gene expression dataset. (PPTX 156 kb

Additional file 1: of NUP98 – a novel predictor of response to anthracycline-based chemotherapy in triple negative breast cancer

Table S1. Clinical and pathological data of patient samples within the 2nd TNBC cohort. Table S2. Contingency table of NUP98 expression (dichotomised based on NUP98 expression above (high) and below the median (low)) and pathological response in publicly available neo-adjuvant datasets (GSE6861, GSE22093 and GSE20271). (PPTX 69 kb