The correlation between mechanical factors of running and running economy as measured by metabolic cost is a subject of much interest in the study of locomotion. However, no change in running technique has been shown to result in an immediate improvement in running economy on an intra-individual basis. To evaluate the effect of a modified running technique, it is probably necessary that the individual trains with the new technique for a longer period using a feedback system to control the new kinematics. In this study, we examine the feasibility of using visual and auditory feedback to adapt running technique according to a simplistic model of the mechanical cost of running. The model considers only the mechanical work against gravity, which is the product of the magnitude of the vertical displacement of the runner's centre of mass and the step-frequency. In the experiments reported here, 18 trained runners, running at 16 km · h(-1) on a treadmill, were given feedback on these parameters together with indicated target levels. In almost all cases, the runners were able to adjust their technique accordingly.
A relatively large proportion of clinicians were unfamiliar with the content of evidence-based guidelines and/or with the concept of red flags. The process of implementing research into clinical practice is in need of an overhaul, and the impact of guidelines on clinical practice may be questioned.
This study aims to explore students' argumentation and decision-making relating to an authentic socioscientific issue (SSI)-the problem of environmental toxins in fish from the Baltic Sea. A multi-disciplinary instructional module, designed in order to develop students' skills to argue about complex SSI, was successfully tested. Seven science majors in the final year of their upper secondary studies participated in this study. Their argumentation and decision-making processes were followed closely, and data were collected during multiple stages of the instructional module: group discussions were audio recorded, the participants wrote reports on their decision making, and postexercise interviews were conducted with individual students. The analysis focused on the skill of evaluation demonstrated by the students during the exercise and the relationships between the knowledge, values, and experiences that they used in their argumentation. Even though all of the students had access to the same information and agreed on the factual aspects of the issue, they came to different decisions. All of the students took counter-arguments and the limitations of their claims into account and were able to extend their claims where appropriate. However, their decisions differed depending on their background knowledge, values, and experiences (i.e., their intellectual baggage). The implication to SSI teaching and learning is discussed.
This work studies the immediate effects of altering the vertical displacement of the center of mass (VD) and step frequency (SF) on the metabolic cost of level treadmill running at 16 km · h(-1) on 16 male runners. Alterations of VD, SF, and the product VD × SF was induced using a novel feedback system, which presents target and current values to the runner by visual or auditory display. Target values were set to 5 and 10% reductions from individual baseline values. The results were expressed as relative changes from baseline values. Alterations led to an increase in metabolic cost in most cases, measured as V(O2) uptake per minute and kilogram of body mass. Correlations were weak. Still, linear multiple regression revealed a positive coefficient (0.28) for the relationship between VD × SF and V(O2). Separate rank correlation tests showed negative correlation (τ = -0.19) between SF and V(O2) and positive correlation (τ = 0.16) between VD and V(O2). There is a coupling between VD and SF caused by the mechanics of running; hence, isolated reduction of either factor was hard to achieve. The linear model also showed a negative coefficient for the relationship between the height of the center of mass above the ground (CoMh) and V(O2). The effect size was small (multiple R(2) 0.07 and 0.12). Still the results indicate that reducing VD × SF by reducing the vertical displacement can have a positive effect on running economy, but a concurrent reduction in CoMh may diminish the positive effect. Midterm and long-term effects of altering the technique should also be studied.
We estimated costs associated with injuries to hands from log splitters and circular saws used to cut up firewood and assessed the value of prevention. The study was carried out as a cost of illness study with an incidence approach based on 57 consecutive patients (median age 51; range 8-81) with injuries to the hand or forearm. Twenty-six of the 57 had an amputation which required microsurgery and 31/57 had various injuries. Median Hand Injury Severity Score (HISS) reflecting the severity of all injuries was 67 (range 6-332). Median DASH score after 2-7 years was 12.5 (0-73.3). Total cost (direct costs, costs of lost productivity, and lost quality of life) was estimated to roughly EUR 14 million (EUR 2.8 million/year), where the cost of lost quality of life is 82% of the total cost and loss of productivity and direct costs are 9% each. Injuries sustained from log splitters and circular saws account for considerable costs, but first and foremost human suffering.
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