Secures sluggish individual cycling (5)
I believe the answer is:
nails
'secures' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
(Other definitions for nails that I've seen before include "Horny plates and pointed pins" , "Slain with metal pins" , "measure of hardness?" , "Metal spikes" , "Tacks - arrests" .)