Temporary Gym Membership - San Pedro del Pinatar

Hi,

Could anyone tell me if there is a hotel - gym in San Pedro close to the Hotel Thalasia and the Nature reserve? . I only need a temporary membership for a non resident  - day membership , whilst visiting the area on a few occasions in 2018. I'm hardly a bodybuilder so just the basic gym would be fine.

I have seen a few gyms online above the town itself .... football stadium etc but they are a bit of a trek from where we are ( Just around the corner from Amigos Bar) and  we don't intend to hire a car.

Any help much appreciated. Richard