Nicholas, unfortunately there isn't a way in the current app, and I'm not likely to get to modifications in the near future — the app is more or less on auto-pilot for the time being.
If you're comfortable using the Javascript console and jQuery syntax, it's pretty trivial to batch-modify all the select elements on a page, though; by my quick experimentation just now, the following will set all the pull-down select elements on the activities page to a given ID (you have to view source to see the correct ID for your specific pair of shoes):
$('select').val(14677);
You'd do that, then save those activities, and then move on to the next page, etc.
Jason