Children tend to be less well-coordinated than adults and have fairly slow reaction times, especially when they are young. Children also tend to view the risk associated with many activities in a different way to adults, engaging in activities such as tree-climbing which may put them at risk of falling without them realizing. This all contributes to putting children at high risk from injury, especially from accidents such as sports-related injuries or slips and falls. For example a substantial number of children are injured through "play" each year, either while engaging in outdoor games, rough and tumble with bigger children, or while climbing in playgrounds. Children are also vulnerable to abuse from parents and other adults, with a significant amount of injuries to children each year resulting from physical abuse. As children become older they also become vulnerable in other ways, such as in bicycle accidents and motor vehicle accidents, both of which cause significant numbers of injuries to children each year.