8 research outputs found
Dynamic Bayesian belief network to model the development of walking and cycling schemes
This paper aims to describe a model which represents the formulation of decision-making processes (over a number of years) affecting the step-changes of walking and cycling (WaC) schemes. These processes can be seen as being driven by a number of causal factors, many of which are associated with the attitudes of a variety of factors, in terms of both determining whether any scheme will be implemented and, if it is implemented, the extent to which it is used. The outputs of the model are pathways as to how the future might unfold (in terms of a number of future time steps) with respect to specific pedestrian and cyclist schemes. The transitions of the decision making processes are formulated using a qualitative simulation method, which describes the step-changes of the WaC scheme development. In this article a Bayesian belief network (BBN) theory is extended to model the influence between and within factors in the dynamic decision making process
Are there differences in performance, metabolism, and quadriceps muscle activity in black African and Caucasian athletes during brief intermittent and intense exercise?
The purpose of the present study was to determine
whether there are any differences in power output (PO) and/or
quadriceps muscle (Quad) activity between black African and
Caucasian football players during a force-velocity (fv) exercise
test, which consisted of performing maximal 6-s sprints against
an increasing load. Each subject started the test with a load of 2
kg and then recovered for 5 min before repeating the same test
with a load increased by 2 kg. When the pedal frequency did not
exceed 130 rev·min–1, the load was increased by only 1 kg.
Each subject attained the load corresponding to his maximal
power if an additional increase in load (+1 kg) induced a power
decrease. Nine black Africans (mean age 24.2 ± 3.3 years) and
nine Caucasians (24.7 ± 4.2 years) (matched for stature and
aerobic fitness) participated in the fv exercise test. During the
test, PO, blood lactate, and the quadriceps electromyography
(EMG) root mean square (Quad RMS) were assessed. Higher
blood lactate was observed in Caucasians than in black Africans
for POs over the load range from 4 kg up to the maximal power.
However, PO and Quad RMS values were similar in Caucasians
and black Africans. They also had similar lean leg volume (LLV)
and consequently produced similar PO/LLV and Quad RMS/LLV
values. Overall, our results suggest that Caucasians and black
Africans matched for stature, max, and training background
have similar PO and Quad RMS values, but different blood lactate
concentrations during brief, intermittent, intense exercise
performed on a cycloergometer