The charity, Sport and Arts in the Community, was established in 2016 to save the centre and the gym refurbishment for the fitness suite cost £90,000.
The investment was made possible because of support from the local community which has so far raised £267,000 to support the centre.
Charity trustees, along with local supporters, volunteers and local councillors were joined by the leader of Shropshire Council Lezley Picton, Deputy Lieutenant Fiona Rogers-Coltman and James Roberts at the opening ceremony.
Councillor Picton said: "The community’s encouragement and support have been of huge importance to the centre and its staff, and much valued by Shropshire Council."
She said that she hoped that the new gym would provide a local attraction for both young and older people.
Guests were able to see the gym equipment in use and test out the new technology before talks with the trustees about the next steps to be taken by the charity.
A variety of fundraising ideas were discussed, including the possibility of a refurbishment of the pool as the next priority.
Chairman of trustees Jean Shirley said: "Refurbishing the fitness suite with top-of-the-range equipment supplied by technology is the culmination of six years of community action across South West Shropshire.
"We see it as a critical milestone in our efforts to ensure the future sustainability of the centre in what looks to be a rocky financial future, and encourage everyone with the slightest interest to book a gym induction session.
"The equipment has been deliberately selected with a whole range of skills and needs in mind."
SpArC trustee Councillor Ruth Houghton said: "Once again the charity would like to say a big thank you to the local community, including the many volunteers who support the theatre, work in the surrounding garden and organise fundraising events.
"This ongoing commitment and support is vital to the SpArc Centre."