Measuring a school day

A class of grade eight students decided to measure how much they actually moved during a normal school day. The result changed the way their teachers thought about breaks.

The method was deliberately cheap. Twenty students carried a simple step counter for five days. Two students recorded the timetable, and one recorded the weather, because rain changes everything. No special equipment was borrowed, and no expert was involved.

The headline figure was 3,100 steps between arriving and leaving, about a third of what health guidance suggests for a whole day. More interesting was the distribution. Almost half the steps happened in two short periods: the walk between buildings after period three, and the first four minutes of the lunch break. Physical education lessons, which everyone expected to dominate, contributed less than a fifth, partly because much of the lesson was spent listening and waiting for a turn.

The students were careful about what the numbers could not show. A step counter does not measure intensity, so a slow walk and a fast run look similar. It does not see squats, push-ups or climbing stairs correctly. And twenty students in one class is not a sample from which anyone should generalise to a city.

What the data did support was a modest change. The school moved one break five minutes earlier so that the corridor was less crowded, and allowed the hall to be used during rain. Three weeks later the same twenty students averaged 3,900 steps. The class wrote both numbers on the noticeboard, together with the sentence: this is one class, for five days, with a cheap device.