You probably need a high sugar snack before your sporting exercise - even when you remove your pump there is still insulin swimming around your system, and that combined with hard exercise of any kind is likely to bring you crashing down. Or try reducing your basal for before you exercise AND have a high carb snack before the exercise. Part way through the excersise, stop and check again. And keep checking every half an hour or so. Even if this level seems normal at the end of exercise have another snack and keep checking because there might be a delayed reaction.
