Why is the world obsessed with warm up?

Across the world, in every school with a playground, the bell goes and children run out and start playing.  Rare is the group that assembles under its own initiative for either static or ballistic stretching, or other activities recommended by the National Curriculum for their capacity to "accustom the body to the demands of exercise". Curiously, equally rare is the playground strewn with paramedics and stretchers struggling to keep pace with the children suffering muscle injuries in limbs surprised by the intensity of exercise into soft tissue damage.

It has long been accepted by scientists that "(before puberty) children tend to have good flexibility and rarely strain muscles". (Alter 1988).  But not by the authors of the National Curriculum, who see a significance for warm up from the Early Years stage.

What is the aim of the start of a session?  To gradually build up the level of physical activity, certainly.  But does this require the adoption of bizarre, unnatural physical activity which detract pupils (and their attention and motivation) from the engaging activity which is, for many, the unique attraction of the subject.  No other curriculum areas choose to start each lesson with prolonged, compulsory performance of some of the least engaging activities available.  Even professional sportsmen cite warm up as the most tedious dimension of their professional lives.

What do pupils want when they arrive at PE and games sessions?  For the great majority, they want to be active.  Immediately.  Not constrained by artificial activity - nor lies about the danger of muscle injury, information which is in sharp contrast with their own recent playground experience.  So why would teachers not harness the power of this motivation and get children immediately active.  In relatively unstructured activity, with a ball or implement  that allows them to raise their body temperature and experiment with a ball without being admonished about the "correct" technique.

This rationale is supported by research evidence - for those who need it.  In a 75 minute games session, a pupil will touch a ball three times more often if the first ten minutes are spent intensive ball activity - rather than in conditioning based activity with the balls confined to the bag they came in.  That is a skill impact, entirely separate from the inevitable engagement impact.

Of course, exercise physiology will inform effective warm up.  However, the relevance of this will be almost exclusively post puberty, and in high performance. This is the preserve of the high performance environment, and obsession with it serves to distract schools from their central purpose of engaging children in sport and leveraging their enthusiasm to be active.  The National Curriculum should know better.