Simone V. Gill

Swagger, Sway, and Sexuality: Judging Sexual Orientation From Body Motion and Morphology

People can accurately judge the sexual orientation of others, but the cues they use have remained elusive. In 3 studies, the authors examined how body shape and motion affect perceived sexual orientation. In 2 studies, participants judged the sexual orientation of computer-generated animations in which body shape and motion were manipulated. Gender-typical combinations (e.g., tubular body moving with shoulder swagger or hourglass body moving with hip sway) were perceived generally to be heterosexual; gender-atypical combinations were perceived generally to be homosexual. These effects were stronger for male targets. Body shape affected perceived sexual orientation of women, but motion affected perceived sexual orientation of both men and women. Study 3 replicated and extended these findings. Participants judged dynamic outlines of real people (men and women, both gay and straight) in which body shape and motion were measured. Again, gender-atypical body motion affected perceived sexual orientation and, importantly, affected accuracy as well.

Obesity, functional mobility and quality of life

Obesity is a health condition that, through a complex interaction of biopsychosocial and environmental factors, is associated with mobility disability. The mobility disability experienced by persons with obesity is associated with reduced health related quality of life (HRQoL) compared to persons without obesity. This paper will review and discuss functional mobility and its relationship to HRQoL for persons living with obesity. This will be done by conducting a review of the literature in the area of obesity and functional mobility and its association with HRQoL. Recommendations to address the known factors that contribute to mobility disability and reduced quality of life are outlined while suggestions for research to contribute to best practice to enable mobility for persons with obesity are made.

Brief communication: A midtarsal (midfoot) break in the human foot

The absence of a midtarsal break has long been regarded as a derived feature of the human foot. Humans possess a rigid midfoot that acts as an efficient lever during the propulsive phase of bipedal gait. Non-human primates, in contrast, have a more mobile midfoot that is adaptive for tree climbing. Here, we report plantar pressure and video evidence that a small percentage of modern humans (n = 32/398) possess both elevated lateral midfoot pressures and even exhibit midfoot dorsiflexion characteristic of a midtarsal break. Those humans with a midtarsal break had on average a significantly flatter foot than those without. Midtarsal breakers also had significantly more medial weight transfer (pronation) during the stance phase of gait than those without this midfoot mobility. These data are in accordance with Elftman (Clin Orthop 16 (1960) 41-45) who suggested that pronation aligns the axes of the transverse tarsal joint, permitting elevated midfoot mobility.

Midtarsal break variation in modern humans: Functional causes, skeletal correlates, and paleontological implications

The midtarsal break was once treated as a dichotomous, non-overlapping trait present in the foot of non-human primates and absent in humans. Recent work indicates that there is considerable variation in human midfoot dorsiflexion, with some overlap with the ape foot. These findings have called into question the uniqueness of the human lateral midfoot, and the use of osteological features in fossil hominins to characterize the midfoot of our extinct ancestors. Here, we present data on plantar pressure and pedal mechanics in a large sample of adults and children (n = 671) to test functional hypotheses concerning variation in midfoot flexibility. Lateral midfoot peak plantar pressure correlates with both sagittal plane flexion at the lateral tarsometatarsal joint, and dorsiflexion at the hallucal metatarsophalangeal joint. The latter finding suggests that midfoot laxity may compromise hallucal propulsion. Multiple regression statistics indicate that a low arch and pronation of the foot explain 40% of variation in midfoot peak plantar pressure, independent of age and BMI. MRI scans on a small subset of study participants (n = 19) reveals that curvature of the base of the 4th metatarsal correlates with lateral midfoot plantar pressure and that specific anatomies of foot bones do indeed reflect relative midfoot flexibility. However, while the shape of the base of the 4th metatarsal may reliably reflect midfoot mobility in individual hominins, given the wide range of overlapping variation in midfoot flexibility in both apes and humans, we caution against generalizing foot function in extinct hominin species until larger fossils samples are available.

Influence of dual-task constraints on whole-body organization during walking in children who are overweight and obese.

ObjectiveThe aim of this study was to examine the influence of dual-task constraints on movement and force control in children who are overweight and obese. DesignTwelve children who are overweight and obese (4–12 yrs old) and 12 age-matched children with normal weight participated. The children walked along a path at a self-selected pace under two conditions: walking carrying nothing (baseline condition) and walking while carrying a box (dual-task condition). ResultsThe overweight/obese group showed less normalized hand vertical motion and shoulder range of motion compared with the control group (all P’s < 0.05). However, in comparison with the baseline condition, the overweight/obese group decreased gait velocity and stride length and increased step width, lateral hand movement, lateral spine movement, and medial/lateral ground reaction force during the dual-task condition (all P’s < 0.05). ConclusionsThese findings indicate that children who are overweight and obese modify lateral movements and force organization when faced with dual-task constraints, which may influence their ability to maintain safety when dual tasking is required.

Optimising motor adaptation in childhood obesity

Childhood obesity is a major public health concern. According to the World Health Organization, more than 22 million children worldwide are classified as overweight (WHO, 2009). In Australia, the most recent data available show that 4.5% of boys and 5.5% of girls ages 2–18 years old are obese (Magarey & Daniels, 2001). Cutoffs for body mass index, weight in kilograms divided by height in metres squared, ‡ 30 kg/m2 for obesity are universally accepted for adults. International cutoffs for obesity designed for children (Cole, Bellizzi, Flegal & Dietz, 2000) use age, gender and body mass index to define obesity (e.g. the cutoff for a 2-year-old boy is 20.09 kg/m2, whereas the cutoff for a 171⁄2-year-old girl is 29.84 kg/m2). Current research on the role of occupational therapy in addressing childhood obesity has focussed on weight loss, weight gain prevention, or increases in physical activity by restructuring environments and routines (Ziviani, Desha, Poulsen & Whiteford, 2010). However, weight loss is not immediate. Examining how to maintain children’s safety during weight loss is important. Obesity affects children’s ability to maintain safety (Bazelmans et al., 2004) while performing their occupations. Impairments in motor adaptation, altering actions to cope with continuously changing environments, result in increased safety risks for children who are obese. They also influence occupational performance, ‘the ability to perceive, desire, recall, plan and carry out roles, routines, tasks, and subtasks for the purpose of self-maintenance, productivity, leisure and rest in response to demands of

Influence of weight classification on children stepping over obstacles.

ABSTRACTThe objective of this study was to evaluate how weight classification relates to meeting task constraints. Using a cross-sectional design, three-dimensional motion data were collected while children crossed obstacles of various heights. Twelve normal-weight (≥5th and <85th percentile on growth charts) and 12 overweight or obese (≥85th percentile on growth charts) 4- to 13-yr-olds participated. During obstacle crossing, children who were overweight or obese took longer to reach maximum knee height and to achieve foot contact (all P = 0.04). Normal-weight children landed flat-footed after obstacle crossing whereas overweight and obese children landed heel first (P = 0.04). Children had higher coefficients of variation for ankle position at heel contact after crossing medium obstacles (P = 0.02). Slower rates of obstacle crossing and landing heel first after crossing obstacles could be behind higher risks of falls for children who are overweight or obese.

Quantifying the Effects of Body Mass Index on Safety: Reliability of a Video Coding Procedure and Utility of a Rhythmic Walking Task

OBJECTIVES To evaluate the association between body mass index (BMI) and motor actions related to safety risks (primary aim), and to examine the reliability of a video coding procedure and the utility of a rhythmic walking task in identifying safety risks (secondary aims). DESIGN Using a cross-sectional design, participants were filmed during a rhythmic walking task at slow, normal, and fast audio metronome paces. A video coding procedure was used to quantify signs of safety risks from the videotaped sessions. SETTING Motor development laboratory in a university. PARTICIPANTS Adults (N=32) with normal (n=15) and overweight (n=17) BMI scores participated. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Chi-squared analyses were conducted to compare the occurrence of coded motor actions (forward and lateral tripping) between participants with normal and overweight BMI scores. A kappa coefficient was computed as a measure of interrater reliability on the video codes. RESULTS Participants who were overweight exhibited more safety risks compared with participants with normal BMI scores at the slow (χ(2)(1,N=32)=3.94, P<.05, d=.75) and fast (χ(2)(1,N=32)=3.85, P<.05, d=.74) metronome paces. Interrater reliability was high (κ=.90, P<.01). CONCLUSIONS In support of the primary aim, the findings show a relationship between overweight BMI scores and safety risks. Toward the secondary aims, the results demonstrate that a video coding procedure can be reliably used to assess safety risks and that creating tasks appropriate for assessing safety risks in overweight adults is needed.

Influence of dual task constraints during walking for children

The effects of dual-task constraints on bimanual coordination and walking in three age groups: young (4-6 years old), middle (7-9 years old), and older groups (10-13 years old) were examined. Children were asked to first walk along a path (baseline condition) and then to walk along the same path while carrying a box steady and level (dual-task condition). The young group showed less bimanual coordination with less level and more variable normalized vertical box positioning (mean hand differences, young: 3.68%, middle: 2.42%, older: 1.61%), less correlated hand movements (mean correlation, young: r(8)=0.58, middle: r(8)=0.77, older: r(8)=0.79), and more elbow and shoulder joint excursion on the dominant side (all Ps<0.05). In addition, the young group had shorter stride lengths and less normalized anterior/posterior ground reaction forces under the dual-task condition than the baseline condition (all Ps<0.05). These findings indicate that 4- to 6-year-old children might still be developing their ability to perform activities requiring dual-task constraints that involve simultaneous use of the upper and lower extremities.

Motor and language abilities from early to late toddlerhood: using formalized assessments to capture continuity and discontinuity in development.

Developmental tests reflect the premise that decreases in skills over time should be a sign of atypical development. In contrast, from a psychological perspective, discontinuity may be viewed as a normal part of typical development. This study sought to describe the variability in patterns of continuity and discontinuity in developmental scores over time. Seventy-six toddlers (55% boys) from a larger screening study were evaluated at 13 and 30 months using the Mullen Scales of Early Development (MSEL) in five areas: gross motor, fine motor, visual perception, receptive language, and expressive language. Parents completed the First Year Inventory (FYI) at 12 months as well. At 30 months, 23.68% of the sample received a clinical diagnosis (e.g., developmental delay, autism spectrum disorder [ASD]). Toddlers were classified as stable, increasing, or decreasing by at least 1.5 standard deviations (SD) on their scores in each of the five MSEL areas from 13 to 30 months. Between 3.9% and 51.3% of the sample was classified as increasing and 0-23.7% as decreasing across areas. Decreases in motor areas were associated with increases in language areas. None of the toddlers showed decreases greater than 1.5 SD on their MSEL composite scores. There was no single pattern that characterized a certain diagnosis. Higher FYI sensory-regulatory risk was associated with decreases in gross motor. Lower FYI risk was linked with increases in receptive language. Developmental discontinuity in specific developmental areas was the rule rather than the exception. Interpretations of decreases in developmental levels must consider concurrent increases in skill during this emerging period.