The latest activity tracker for the vagina is this device by Elvie, designed to help women strengthen their pelvic floor muscles and monitor their progress.

Elvie was designed by London studio Goodwin Hartshorn and follows the launch of similar devices including the kGoal earlier this year.

"People don't often talk about issues with this part of the body let alone design for them," Goodwin Hartshorn co-founder Richard Hartshorn told Dezeen. "But the truth is that at some point in their lives one in three women will have an issue related to the strength of their pelvic floor muscle."

The Elvie device is inserted like a tampon, with the "tail" that curves back over the form resting outside the body.

"Through over 30 forms and countless prototypes, we've developed a device that is comfortable, simple to use and easy to clean," said Edward Goodwin, the studio's other co-founder.

The user completes a series of exercises that involve squeezing the rounded silicone pod with their pelvic floor muscles, which run from the front to the back of the body below the pelvis.

"The pod is formed from two internal skeleton components that are then covered in a soft flexible silicone," said Hartshorn. "When the pelvic floor muscle is flexed the two components are pushed together and this force is then measured by the internal electronics."

The device uses a bluetooth antenna located in the tail to send the collected data to a complementary smartphone app. This gives the user direct real-time feedback on their muscle contractions and tracks improvements over time.

The exercises are designed to improve the strength of the muscles, which help to control continence but can become weakened over time or after childbirth.

Sexual health expert Tania Boler set up Elvie to find solutions to the problems faced by women with this issue.

With funding from backers including Alexander Asseily, founder of consumer technology company Jawbone, and support from an advisory group made up of international scientists, Boler worked with Goodwin Hartshorn to create Elvie – the brand's first product.

"Women have guided the design process throughout," Edward Goodwin said. "Over 100 women have tested and influenced the design decisions we've made for both the pod and the dock. Their needs have been central to the evolution of this intimate product."

The device, which comes with a discrete case that doubles as a portable charger, has been in development for a year and launched for pre-sale yesterday.