A leading hypothesis for the origin of insect wings is that they evolved from thoracic gills that were serial homologues of the abdominal gills present in fossil pterygotes and in the nymphs of some modern mayflies, damselflies and stoneflies. Co-occurrence of thoracic wings and abdominal gills is the primitive condition for fossil pterygote insects, whereas the winged stage of modern insects a...

Purpose: Considering the role and importance of establishing knowledge management in different organizations, the aim of the current research was presenting the effective factors model on the establishment of knowledge management in the rowing federation. Methodology: This study in terms of purpose was applied and in terms of implementation method was quantitative. The research population was ...

In the sport of rowing, increasing the impulse applied to the oar handle during the stroke can result in greater boat velocities; this may be facilitated by increasing the surface area of the oar blade and/or increasing the length of the oars. The purpose of this study was to compare the effects of different rowing resistances on the physiological response to rowing. 5 male and 7 female club ro...

BACKGROUND Back pain is a frequent health problem in the general population. The epidemiology of back pain in the general population is well researched, but detailed data on the prevalence and risk factors of back pain in athletes are rare. OBJECTIVE The primary objective was to review articles about back pain in athletes to provide an overview of its prevalence in different sports and compar...

We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free l...

Factors that affect boat speed are important determinants of rowing performance and should form the basis of feedback to rowers and their coaches. Biomechanical analysis of rowing has led to variables that are causally linked to boat speed. With modern technology, these variables can be measured and feedback can be presented instantaneously on-water, or be presented simultaneously with video af...

Is the common folklore, that oars are less efficient at propulsion than propellers, correct? Here we examine the propulsive efficiency of the oars used in competitive rowing. We take the propulsive efficiency η of rowing to be the ratio of the energetic benefit, the energy Db dissipated by boat drag, to the energetic cost, the work Wr performed by the rower. Air drag is neglected as is the ener...

With the help of a kinematic analysis we tried to establish whether the competitors with a shorter line of skiing achieve higher velocities among the slalom gates. The first part of research found out that the competitors who had the shortest lines of skiing in the first analysed turn had, as a rule, the longest lines of skiing in the second turn and vice versa. The shortest line of skiing is t...