Retension spokes?

cj504
cj504 Posts: 110
edited August 2007 in Workshop
hi guys,
i have a pair of aksiums on my winter/work bike and recently whenever i've got out of the seat or climbed in a high gear the back rim has been hitting the brake pad really badly. They must have done three thousand odd miles and I was wondering if they need, or if you can retension a wheel? they used to be really stiff and its the only cure I can really think of?
Cheers
Thresholds, 60-80%, HRM's...I'll just go for a ride