Adolescents' perception of the relationship between movement skills, physical activity and sport

Movement skill competence is important to organised youth physical activity participation, but it is unclear how adolescents view this relationship. The primary aim of this study was to explore adolescents’ perception of the relationship between movement skills, physical activity and sport, and whether their perceptions differed according to extent of participation in organised physical activities. We recruited 33 (17 male) Grade 11 and 12 students (aged 16 to 18) from two secondary schools in Australia. Focus groups were allocated according to whether or not students participated in organised physical activity, where ‘organised activity’ was defined as activity which involved regular classes, training or competition, was reasonably structured or formal, or had a teacher, instructor or coach. There were three all-male ‘organised’ groups, one mixed-gender ‘organised’ group and one all-female ‘not-organised’ group. Students were asked about their attitudes towards physical activity and sport, the relationship between childhood skill proficiency and later physical activity and their perceptions of the appropriate time taken to learn movement skills. Group discussions lasted for approximately 50 minutes, were recorded and were then transcribed verbatim. Transcripts were read using a constant comparison method, in which quotes were continually compared to other quotes. A thematic analysis was conducted in which the transcripts were analysed inductively. Participation in organised sport had no bearing on opinions regarding whether lack of childhood skill development would negatively impact latter participation. It did, however, subtly influence opinions regarding whether skill could be successfully acquired later in life. When asked whether not having well-developed skills as a child would negatively impact on participation in sport/physical activity later in life, the response was mixed, but this was not related to their involvement in organised sport or activities. Students who believed early skill proficiency related to subsequent activity thought this was due to skill ability and motivation. An alternate view was that subsequent activity did not need to be based on skill proficiency; also, one’s environment might change, resulting in differing opportunities/constraints. Students felt skills could be learnt at any time in life (dependent on motivation), but that learning skills at a younger age would be easier and that skills learnt later would not be as developed. Fear of failure was identified as a barrier to learning when older. We conclude that motivation towards participation in sport and physical activity is affected by adolescents’ perception of their own movement skill ability. Therefore, developing children’s actual and perceived movement skills may help to increase adolescent physical activity. Since those with intrinsic achievement orientations were not as inclined towards organised activity, we may also need to provide physical activity options that resonate with intrinsic achievement motivations.

Ocean currents influence the genetic structure of an intertidal mollusc in southeastern Australia – implications for predicting the movement of passive dispersers across a marine biogeographic barrier

Major disjunctions among marine communities in southeastern Australia have been well documented, although explanations for biogeographic structuring remain uncertain. Converging ocean currents, environmental gradients, and habitat discontinuities have been hypothesized as likely drivers of structuring in many species, although the extent to which species are affected appears largely dependent on specific life histories and ecologies. Understanding these relationships is critical to the management of native and invasive species, and the preservation of evolutionary processes that shape biodiversity in this region. In this study we test the direct influence of ocean currents on the genetic structure of a passive disperser across a major biogeographic barrier. Donax deltoides (Veneroida: Donacidae) is an intertidal, soft-sediment mollusc and an ideal surrogate for testing this relationship, given its lack of habitat constraints in this region, and its immense dispersal potential driven by year-long spawning and long-lived planktonic larvae. We assessed allele frequencies at 10 polymorphic microsatellite loci across 11 sample locations spanning the barrier region and identified genetic structure consistent with the major ocean currents of southeastern Australia. Analysis of mitochondrial DNA sequence data indicated no evidence of genetic structuring, but signatures of a species range expansion corresponding with historical inundations of the Bassian Isthmus. Our results indicate that ocean currents are likely to be the most influential factor affecting the genetic structure of D. deltoides and a likely physical barrier for passive dispersing marine fauna generally in southeastern Australia.

Movement scaling in children with ADHD-combined type

Objective
The aim of the study was to investigate motor performance in children with ADHD using a size-scaling handwriting task.

Method
In all, 14 male children with ADHD and 14 typically developing (TD) children (age 7-15) wrote 10-mm and 40-mm cursive letter “l.”

Results
Children with ADHD were unable to maintain their writing accurately at 40 mm, falling short by several millimeters; this was not evident in the TD children. Children with ADHD also had slightly faster and more fluent writing than TD children.

Conclusion
It was concluded that children with ADHD have difficulties scaling handwriting movement in the larger 40-mm condition that may reflect poor planning and modulation of movement, despite having faster and more fluent movements.

Brief report: children with ADHA without co-morbid autism do not have impaired motor proficiency on the Movement Assessment Battery for Children

Motor proficiency was investigated in a sample of children with Attention Deficit Hyperactivity Disorder-Combined type (ADHD-CT) without autism. Accounting for the influence of co-morbid autistic symptoms in ADHD motor studies is vital given that motor impairment has been linked to social–communication symptoms in children who have co-morbid ADHD and autistic-like symptoms. Two groups of children aged between 7–14 years were recruited; children with ADHD-CT (n = 16; mean age 10 years, 7 months [SD = 1 year, 10 months]) and a typically developing (n = 16; mean age 10 years, 6 months [SD = 2 years, 6 months]) group. Motor proficiency was measured using the Movement Assessment Battery for Children-2nd Edition, ADHD symptoms were measured using the Conner’s Parent Rating Scale. Children with ADHD-CT who had been screened for co-morbid autism did not display motor difficulties on the MABC-2. Higher levels of inattention, but not hyperactivity or impulsivity were associated with poorer motor performance. These findings provide indirect evidence that the motor problems that children with ADHD experience may be related to co-occurring social responsiveness impairments.

Thirteen-year trends in child and adolescent fundamental movement skills: 1997-2010

Movement patterns of green turtles in Brazilian coastal waters described by satellite tracking and flipper tagging

The movements of 8 green turtles Chelonia mydas in Brazilian coastal waters were tracked using transmitters linked to the Argos system for periods of between 1 and 197 d. These were the first tracking data gathered on juveniles of this species in this important foraging ground. Information was integrated with that collected over a decade using traditional flipper-tagging methods at the same site. Both satellite telemetry and flipper tagging suggested that turtles undertook 1 of 3 general patterns of behaviour: pronounced long range movements (>100 km), moderate range movements (<100 km) or extended residence very close to the capture/release site. There seemed to be a general tendency for the turtles recaptured/tracked further afield to have been among the larger turtles captured. Satellite tracking of 5 turtles which moved from the release site showed that they moved through coastal waters; a factor which is likely to predispose migrating turtles to incidental capture as a result of the prevailing fishing methods in the region. The movements of the 3 turtles who travelled less than 100 km from the release site challenge previous ideas relating to home range in green turtles feeding in sea grass pastures. We hypothesise that there may be a fundamental difference in the pattern of habitat utilisation by larger green turtles depending on whether they are feeding on seagrass or macroalgae. Extended tracking of 2 small turtles which stayed near the release point showed that small juvenile turtles, whilst in residence in a particular feeding ground, can also exhibit high levels of site-fidelity with home ranges of the order of several square kilometers.