Coordination in gait: Demonstration of a spectral approach

Many important notions in Life Sciences are linked with the idea of cycles, periodicity, fluctuations and transitions. The aim of this paper is to use spectral analysis in a unique way to study and quantify whole body coordination during gait. A participant walked at 3 km/h and ran at 15 km/h on a treadmill for 2 minutes. Position of the approximate center of rotation of the toe, ankle, knee, hip, shoulder, elbow and wrist, and heel, PSIS and head were collected at 100 Hz using CODAmotion analysis system. Fast Fourier Transform was performed on x-coordinate data of the 1) knee marker; 2) 4 markers attached to the free lower limb (toe, ankle, heel and knee); 3) left and right free lower limbs; 4) whole body (all markers). Gait is described by a largely harmonic and resonant oscillator that operates unilateral free limbs at the stride frequency, and axial regions at the step frequency. Running is described by a more harmonic and resonant oscillating structure than walking, with a 3 times higher Q factor and 47% lower Inharmonicity Index. This method is presented as a way to capture global dynamics of our complex multi-segment system, and presents a novel application of spectral analysis to study coordination in multiple oscillators

Changes in joint kinetics during learning the longswing on high bar

Biomechanics helps us understand the association between technique changes and performance improvement during learning. The aim of this research was to investigate joint kinetic characteristics of technique during learning of the longswing on the high bar. Twelve male, novice participants took part in the learning study. During swing attempts in 8 weekly testing sessions, kinematic data were collected. Inverse dynamics analysis was performed from known zero forces at the toes to quantify joint moments and power at the hips and shoulders. Key biomechanical constraints that limited performance outcome were identified based on changes in joint kinetics during learning. These constraints were the ability to perform a large shoulder power and to overcome passive kinetics acting during the downswing. Constraints to action at the level of joint kinetics differentially challenge learners and therefore could underpin more individual, specific learning interventions. Functional phases, defined by maximum hyperextension to flexion of the hips and maximum flexion to extension of the shoulders, did not describe the key joint kinetics of the hip and shoulder for novices. The functional phases may serve however to identify novices that were unable to overcome the passive kinetic constraint

Biomechanical energetic analysis of technique during learning the longswing on high bar

Biomechanical energetic analysis of technique can be performed to identify limits or constraints to performance outcome at the level of joint work, and to assess the mechanical efficiency of techniques. The aim of this study was to investigate the biomechanical energetic processes during learning the longswing on the high bar. Twelve male, novice participants took part in a training study. Kinematic and kinetics data were collected during swing attempts in eight weekly testing sessions. Inverse dynamics analysis was performed from known zero forces at the toes. Joint work, total energy, and bar energy were calculated. Biomechanical constraints to action, that is, limits to novice performance, were identified as “total work” and “shoulder work”. The most biomechanically efficient technique was associated with an onset of the hip functional phase and joint work that occurred between 10–45° before the bottom of the swing. The learning of gross motor skills is realised through the establishment of a set of techniques with task specific biomechanical constraints. Knowledge of the biomechanical constraints to action associated with more effective and efficient techniques will be useful for both assessing learning and establishing effective learning interventions

Physical Activity Levels in Children with Sensory problems: Cross-sectional Analyses from the Millennium Cohort Study

Background: Hearing and vision impairments/problems are associated with increased risk of premature mortality in adulthood. One potential pathway explaining this association is reduced levels of physical activity. Reductions in activity levels due to sensory impairments may commence earlier in life; however, associations between sensory impairments/problems and activity levels in childhood are not well understood. Objective: The objective of this study was to examine associations between hearing and vision problems and objectively measured activity levels in a representative sample of British children. Methods: Data were drawn from sweep 4 of the Millennium Cohort Study, a prospective cohort study among children aged 7. Child hearing and vision problems were reported by parents in a postal survey. Children were also invited to have their physical activity measured objectively via accelerometry. A total of 6410 children had valid accelerometry data accompanied by complete survey data on the variables of interest. The main outcomes were objectively measured moderate-to-vigorous physical activity, steps and sedentary time. Adjusted linear regression was used to examine associations between vision and hearing problems and objectively measured activity levels. Results: In this sample of 7-year old children, 16.7% (n = 1068) had a reported vision problem and 11.6% (n = 745) had a hearing problem. Reported vision problems in both eyes, but not one eye, was associated with 2 fewer minutes of moderate-to-vigorous physical activity per day (B = −2.1 95% Confidence Intervals [CI] −3.9 to −0.4) and almost 200 fewer steps per day (B = −198.4 95% CI, −398.4 to 1.6). Hearing problems were not associated with activity levels in either one or both ears. Conclusion: Children with visual problems affecting both eyes, but not one eye, are likely to have lower levels of physical activity. Strategies to promote physical activity in children with visual problems are warranted

Bidirectional causal control in the dynamics of handstand balance

The aim of this study was to identify motor control solutions associated with the ability to maintain handstand balance. Using a novel approach, we investigated the dynamical interactions between centre of pressure (CoP) and centre of mass (CoM) motion. A gymnastics cohort was divided into a ‘less skilled’ group, who held handstands for 4–6 s, and a ‘more skilled’ group, who held handstands in excess of 10 s. CoP–CoM causality was investigated in anterior–posterior (AP) and medio-lateral (ML) directions, in addition to time–space, time–frequency and Hurst Exponent (H) analyses. Lower AP CoP to CoM causal drive and lower H values (> 0.6) indicated the more skilled gymnasts were less reliant on CoP mechanics to drive CoM motion. More skilled performance demonstrated greater adaptability through use of reactive, as opposed to anticipatory, control strategies. Skilled performers additionally exploited mechanical advantages in ML (e.g. a wider base of support), compared to the less skilled athletes. A multiple regression analysis revealed H and frequency domain measures to be better predictors of handstand balance duration than time–space domain measures. The study findings highlight the advantage of an adaptable motor control system with a directional profile, and provide new insight into the clear, measurable footprint of CoP on the dynamics of CoM

Attractor dynamics of elite performance: the high bar longswing

Combining biomechanics and motor control, the aim of this study was to investigate the limit cycle dynamics during the high bar longswing across the UK elite gymnastics pathway age groupings. Senior, junior and development gymnasts (N = 30) performed three sets of eight consecutive longswings on the high bar. The centre of mass motion was examined through Poincaré plots and recurrence quantification analysis exploring the limit cycle dynamics of the longswing. Close to one-dimensional limit cycles were displayed for the senior (correlation dimension (CD) = 1.17 ± .08), junior (CD = 1.26 ± .08) and development gymnasts (CD = 1.33 ± .14). Senior elite gymnasts displayed increased recurrence characteristics in addition to longer longswing duration (p < .01) and lower radial angular velocity of the mass centre (p < .01). All groups of gymnasts had highly recurrent and predictable limit cycle characteristics. The findings of this research support the postulation that the further practice, experience and individual development associated with the senior gymnasts contribute to the refinement of the longswing from a nonlinear dynamics perspective. These findings support the idea of functional task decomposition informing the understanding of skill and influencing coaches’ decisions around skill development and physical preparation

Using formative research to develop the healthy eating component of the CHANGE! school-based curriculum intervention

Background: Childhood obesity is a significant public health concern. Many intervention studies have attempted to combat childhood obesity, often in the absence of formative or preparatory work. This study describes the healthy eating component of the formative phase of the Children’s Health Activity and Nutrition: Get Educated! (CHANGE!) project. The aim of the present study was to gather qualitative focus group and interview data regarding healthy eating particularly in relation to enabling and influencing factors, barriers and knowledge in children and adults (parents and teachers) from schools within the CHANGE! programme to provide populationspecific evidence to inform the subsequent intervention design. Methods: Semi-structured focus group interviews were conducted with children, parents and teachers across 11 primary schools in the Wigan borough of North West England. Sixty children (N = 24 boys), 33 parents (N = 4 male) and 10 teachers (N = 4 male) participated in the study. Interview questions were structured around the PRECEDE phases of the PRECEDE-PROCEED model. Interviews were transcribed verbatim and analysed using the pen-profiling technique. Results: The pen-profiles revealed that children’s knowledge of healthy eating was generally good, specifically many children were aware that fruit and vegetable consumption was ‘healthy’ (N = 46). Adults’ knowledge was also good, including restricting fatty foods, promoting fruit and vegetable intake, and maintaining a balanced diet. The important role parents play in children’s eating behaviours and food intake was evident. The emerging themes relating to barriers to healthy eating showed that external drivers such as advertising, the preferred sensory experience of “unhealthy” foods, and food being used as a reward may play a role in preventing healthy eating. Conclusions: Data suggest that; knowledge related to diet composition was not a barrier per se to healthy eating, and education showing how to translate knowledge into behavior or action is required. The key themes that emerged through the focus groups and pen-profiling data analysis technique will be used to inform and tailor the healthy eating component of the CHANGE! intervention study. Trial registration: Current Controlled Trials ISRCTN03863885 Keywords: Nutrition, Childhood obesity, Pen-profiles, Health, School

Under-regulated and unaccountable?:Explaining variation in stop and search rates in Scotland, England and Wales

From a position of near parity in 2005/6, by 2012/13 recorded search rates in Scotland exceeded those in England/Wales seven times over. This divergence is intriguing given the demands placed on the police, and the legal capacity to deal with these are broadly similar across the two jurisdictions. The aim of this paper is to unpack this variation. Using a comparative casestudy approach, the paper examines the role of structural ‘top-down’ determinants of policing: substantive powers of search, rules and regulations, and scrutiny. Two arguments are presented. First, we argue that the remarkable rise of stop and search in Scotland has been facilitated by weak regulation and safeguards. Second, we argue that divergence between the two jurisdictions can also be attributed to varying levels of political and public scrutiny, caused, in part, by viewing stop and search almost exclusively through the prism of ‘race’. In Scotland, the significance of these factors is made evident by dint of organisational developments within the last decade; by the introduction of a target driven high-volume approach to stop and search in Strathclyde police force circa 1997 onwards; and the national roll-out of this approach following the single service merger in April 2013. The salient point is that the Strathclyde model was not hindered by legal rules and regulations, nor subject to policy and political challenge; rather a high discretion environment enabled a high-volume approach to stop and search to flourish

Memory-guided force output is associated with self-reported ADHD symptoms in young adults

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed mental health disorder in childhood and persists into adulthood in up to 65 % of cases. ADHD is associated with adverse outcomes such as the ability to gain and maintain employment and is associated with an increased risk for substance abuse obesity workplace injuries and traffic accidents A majority of diagnosed children have motor deficits; however, few studies have examined motor deficits in young adults. This study provides a novel examination of visuomotor control of grip force in young adults with and without ADHD. Participants were instructed to maintain force production over a 20-second trial with and without real-time visual feedback about their performance. The results demonstrated that when visual feedback was available, adults with ADHD produced slightly higher grip force than controls. However, when visual feedback was removed, adults with ADHD had a faster rate of decay of force, which was associated with ADHD symptom severity and trait impulsivity. These findings suggest that there may be important differences in the way that adults with ADHD integrate visual feedback during continuous motor tasks. These may account for some of the motor impairments reported in children with ADHD. These deficits could result from (1) dysfunctional sensory motor integration and/or (2) deficits in short-term visuomotor memory