HTML document for the World Wide Web Runner Maintenance Fast runners are part science and part art so keep in mind that what is given here are just opinions.
Sharp runners are more important on hard ice.
Because the sheet pressure must be kept less to avoid breaking loose the rear end, acceleration and to a lesser extent top end are reduced by dull runners. A dull front runner is more noticeable in the turns. You can preserve the runner edge longer by avoiding sharp turns where the runners will slide. The reach on the lake that day was only 0.15 miles so somewhere around 296 turns were involved. The runners were sharp at the beginning of the day and dull near the end.