Investigation of treadmill and overground running: implications for the measurement of oxygen cost in children with developmental coordination disorder

Differences in the kinematics and kinetics of overground running have been reported between boys with and without developmental coordination disorder (DCD). This study compared the kinematics of overground and treadmill running in children with and without DCD to determine whether any differences in technique are maintained, as this may influence the outcome of laboratory treadmill studies of running economy in this population. Nine boys with DCD (10.3 ± 1.1 year) and 10 typically developing (TD) controls (9.7 ± 1 year) ran on a treadmill and overground at a matched velocity (8.8 ± 0.9 km/h). Kinematic data of the trunk and lower limb were obtained for both conditions using a 12-camera Vicon MX system. Both groups displayed an increase in stance time (p < 0.001), shorter stride length (p < 0.001), higher cadence (p < 0.001) and reduced ankle plantar flexion immediately after toe-off (p < 0.05) when running on the treadmill compared with overground. The DCD group had longer stance time (p < 0.009) and decreased knee flexion at mid-swing (p = 0.04) while running overground compared to their peers, but these differences were maintained when running on the treadmill. Treadmill running improved ankle joint symmetry in the DCD group compared with running overground (p = 0.019). Overall, these findings suggest that there are limited differences in joint kinematics and lower limb symmetry between overground and treadmill running in this population. Accordingly, laboratory studies of treadmill running in children with DCD are likely representative of the energy demands of running.

A comparison of the oxygen cost and physiological responses to running in children with and without Developmental Coordination Disorder

The aim of this study was to compare the oxygen cost of running in boys with and without Developmental Coordination Disorder (DCD). Fourteen boys with DCD (9.1 ± 1.4 yr) and 16 typically developing (TD) controls (9.4 ± 1.3 yr) were tested on two separate occasions at least a week apart. On the first visit, motor proficiency, body composition and maximal aerobic capacity were established. On the second visit, oxygen consumption was determined via indirect calorimetry while participants ran at three submaximal speeds (7.2 km/h, 8.0 km/h and 8.8 km/h) on a motorised treadmill for 4 min each. Additional physiological responses such as blood lactate, respiratory exchange ratio (RER), heart rate, salivary alpha amylase and pain threshold were monitored at baseline and after each submaximal effort. Although there were no differences in the oxygen cost of running at all three speeds, the boys with DCD had higher blood lactate concentration (7.2 km/h, p=0.05; 8.0 km/h p=0.019), heart rate (p ≤ 0.001), RER (8.0 km/h, p=0.019; 8.8 km/h, p=0.001), salivary alpha amylase (8.0 km/h, p=0.023; 8.8 km/h, p=0.020) and a lower pain threshold (p<0.01). The higher overall metabolic cost of running in boys with DCD as indicated by the higher RER, heart rate and blood lactate concentrations, together with the higher levels of sympathoadrenal medullary activity and sensitivity to pain, may be deterring factors for participation in physical activity in this population.

A comparison of running kinematics and kinetics in children with and without developmental coordination disorder

The aim of this study was to compare running gait in children with and without developmental coordination disorder (DCD). Fourteen boys with DCD (9.5 ± 1 yr) and 14 typically developing (TD) controls (9.6 ± 1 yr) ran at a velocity of 2.44 ± 0.25 m/s along a 15m track, with kinematic and kinetic data of the trunk and lower limb obtained for three cycles of each limb using a 12-camera Vicon MX system and AMTI force plate. Although features of the kinematic and kinetic trajectories were similar between groups, the DCD group displayed decreased peak knee extension compared with the TD group prior to initial foot contact (p = 0.016). Furthermore, the DCD group displayed increased variability in sagittal plane kinematics at the hip and ankle during toe off compared with the TD group. Kinetic analysis revealed that children with DCD displayed significantly reduced knee extensor moments during the stance phase of the running cycle (p = 0.033). Consequently, peak knee power absorption and ankle power generation was significantly lower in the DCD group (p = 0.041; p = 0.017). Furthermore, there was a trend for children with DCD to have shorter strides (p = 0.052, ES = 0.499) and a longer stance period than the TD controls (p=0.06, ES = 0.729). These differences may have implications for the economy of running and subsequently the planning of targeted intervention programs to improve running gait in children with DCD.

Demonstration of the use of the ICF framework in detailing complex functional deficits after major burn

Burns can result in long term impairments, activity limitations and participation restrictions in a patients' life. The focus of current surgeries and therapy is to improve body functions and structures. However, often this does not translate to an improvement in activity and participation for the patient. Improvement in activity and participation is the ultimate goal of all therapy to enhance patient's quality of life. The incorporation of assessment measures at all levels of the International Classification of Functioning, Disability and Health (ICF) can assist in a holistic, patient centred approach to identify the complex impairments that impact on activity and participation, with a view to appropriately targeting future therapeutic interventions. This paper presents an example case of how implementing measures at all levels of the ICF can improve our understanding of a patient's body functions and structures, activity and participation. A number of the outcome measures utilised in this study are novel in the burns population, such that video footage supplements the methodology where relevant.

Short pulse laser train for laser plasma interaction experiments

A multiframe, high-time resolution pump-probe diagnostic consisting of a consecutive train of ultrashort laser pulses (approximately ps) has been developed for use with a chirped pulse amplification (CPA) system. A system of high quality windows is used to create a series of 1054 nm picosecond-laser pulses which are injected into the CPA system before the pulse stretcher and amplifiers. By adding or removing windows in the pulse train forming optics, the number of pulses can be varied. By varying the distance and thickness of the respective optical elements, the time in between the pulses, i.e., the time in between frames, can be set. In our example application, the CPA pulse train is converted to 527 nm using a KDP crystal and focused into a preformed plasma and the reflected laser light due to stimulated Raman scattering is measured. Each pulse samples different plasma conditions as the plasma evolves in time, producing more data on each laser shot than with a single short pulse probe. This novel technique could potentially be implemented to obtain multiple high-time resolution measurements of the dynamics of physical processes over hundreds of picoseconds or even nanoseconds with picosecond resolution on a single shot.

The effect of distinctive parts on recognition of depth-rotated objects by pigeons (Columba livia) and humans

To explore whether effects observed in human object recognition represent fundamental properties of visual perception that are general across species, the authors trained pigeons (Columba livia) and humans to discriminate between pictures of 3-dimensional objects that differed in shape. Novel pictures of the depth-rotated objects were then tested for recognition. Across conditions, the object pairs contained either 0, 1, 3, or 5 distinctive parts. Pigeons showed viewpoint dependence in all object-part conditions, and their performance declined systematically with degree of rotation from the nearest training view. Humans showed viewpoint invariance for novel rotations between the training views but viewpoint dependence for novel rotations outside the training views. For humans, but not pigeons, viewpoint dependence was weakest in the 1-part condition. The authors discuss the results in terms of structural and multiple-view models of object recognition.

Binding and recognition of GATATC target sequences by the EcoRV restriction endonuclease: a study using fluorescent oligonucleotides and fluorescence polarization

Oligonucleotides labeled with hexachlorofluorescein (hex) have enabled the interaction of the restriction endonuclease EcoRV with DNA to be evaluated using fluorescence anisotropy. The sensitivity of hex allowed measurements at oligonucleotide concentrations as low as 1 nM, enabling K(D) values in the low nanomolar range to be measured. Both direct titration, i.e., addition of increasing amounts of the endonuclease to hex-labeled oligonucleotides, and displacement titration, i.e., addition of unlabeled oligonucleotide to preformed hex-oligonucleotide/EcoRV endonuclease complexes, have been used for K(D) determination. Displacement titration is the method of choice; artifacts due to any direct interaction of the enzyme with the dye are eliminated, and higher fluorescent-labeled oligonucleotide concentrations may be used, improving signal-to-noise ratio. Using this approach (with three different oligonucleotides) we found that the EcoRV restriction endonuclease showed a preference of between 1.5 and 6.5 for its GATATC target sequence at pH 7.5 and 100 mM NaCl, when the divalent cation Ca2+ is absent. As expected, both the presence of Ca2+ and a decrease in pH value stimulated the binding of specific sequences but had much less effect on nonspecific ones.

Perception of coherent motion in random dot displays by pigeons and humans

Pigeons and humans were required to discriminate coherent from random motion in dynamic random dot displays. Coherence and velocity thresholds were determined for both species, and both thresholds were found to be substantially higher for pigeons than for humans. The results are discussed with reference to differences in motion processing in mammals and birds. It is suggested that the inferior motion sensitivity of pigeons can be attributed to poorer spatiotemporal motion integration.

An exploratory study of social support: a cross-cultural comparison of Chinese-, Japanese-, and Anglo-American breast cancer patients

This paper investigated the nature of social support for Asian- and Anglo-American women post breast cancer treatment. Forty-six Anglo- and Asian-American (13 Anglo-American, 18 Chinese-American and 15 Japanese-American women) women were assessed 6 months to 3 years post-treatment. Assessments consisted of a semi-structured interview plus standardized psychological tests. Three major hypotheses were developed and tested in the study. Results showed: (1) Anglo-American women indicated a greater need for social support than either of the two Asian-American groups in 66% of the categories; (2) no differences were found between the three ethnic groups in receipt of emotional or tangible social support; and (3) the network size and composition differed significantly in 83% of the categories between the Anglo group and at least one of the Asian groups. These differences were in size, mode, and perceived adequacy of social support. Implications for culturally-based clinical practice which emerge from these findings are discussed.

"Home or away?" The effect of mode of locomotion on consumption of sugar by bumble bees (Hymenoptera: Apidae)

The results of two experiments confirmed predictions from the hypothesis that bumble bees use mode of locomotion rather than distance from the hive in discriminating between food in the hive and in the field ("home" and "away"). When the distance between the hive and a feeder containing sugar solution was manipulated, for bees walking from the hive, the time spent ingesting the sugar solution did not vary with distance. When the mode of locomotion was manipulated, bees spent almost 4 times as much time extracting sugar solution from the feeder when they were required to fly to the food as when they were required to walk.