Commuters will be given free access to shower and gym facilities across Fitness First's 47 London outlets when they show their Oyster card during the strike.
Fitness First, which is owned by British sports retailer DW Sports, said this year’s campaign will ensure Londoners have no excuses not to get their workouts done.
If the strike goes ahead, it will severely disrupt the majority of the London Underground, Transport for London (TfL) said.
Up to 4,000 staff, including members of the RMT and TSSA unions, are expected to walk out in a dispute over job losses and ticket office closures.
According to a note on the TfL website, staff from the two unions will strike for 24 hours from 6pm on Sunday, leading to services being "severely disrupted" with the majority of Zone 1 stations closed.
- Are you running any stunts or promotions on behalf of your clients to coincide with the strikes? Let me know.