a shoe has an activity level meter that displays , in a highly noticeable fashion , such as by lighting bright leds , the highest level of activity reached by a wearer of the shoe . in one embodiment , the display is a three - element led display in which zero to three leds flash briefly , but brightly each time the weight of the wearer is fully pressed against the inner sole of the shoe during a period of activity . a period of time after the activity ends , the leds light again for a longer period of time to indicate the highest level of activity reached during the activity period .