Cellulite is present in 90% of post-pubertal females regards of their weight or shape. Thus it can be considered a very normal condition. That doesn't mean us women like it or are any more accepting of it. Sadly, there is no good treatment for cellulite. Lasers, radiofrequency devices (such as thermage), massaging devices (endermology), light devices (tri-active, velashape), creams, creams with special shorts, supplements have all been tried for cellulite.
Some lead to improvement but ususally this is small improvement and only temporary improvement meaning the treatments must be maintained.
If you have loose skin on the inner thighs, the radiofrequency treatment, Thermage, can be helpful -- especially since you are fit and only dealing with loose skin, not loose skin and fat. It is likely that for greatest benefit more than one treatment will be needed.
New protocols make the Thermage treatment much more effective and more comfortable.