Possible Clues:

• Move by dragging body on the ground
• Rush-hour pace
• Slow progress in Sussex town — being upset, you'll leave
• What a swimmer might do to move slowly?
• Move like a toddler
• With which Allen Tate's eponymous sportsmen move fast. Or slowly?
• The first stroke children learn in the water?
• Way of swimming naked through chlorine
• After this crescendo, what a bore not to be on one's feet!
• Be a creep, wet behind the ears in class