Sports and fitness injuries are costing British employers a staggering £9 billion every year, according to new research.

Thousands of Brits phone in sick on a Monday morning after prancing around the living room to home workouts during the weekend. The poll of 2,500 people, conducted by the joint supplement Lubramine, revealed that fans of celebrity fitness videos are the biggest culprits of the Monday morning injury sickie.

The turn of the millennium has seen a wealth of celebrities – such as Jade Goody, Davina McCall, Coleen McLoughlin and Nell McAndrew – bring out fitness videos, encouraging couch potatoes to exercise in the comfort of their own home.

But home workouts are leaving the average adult unable to go to work at least twice days a year.

Based on the average annual salary of £24,908 this costs British businesses £191.60 per employee – or £9,005,200,000 across the 47,000,000 adults living in the UK.

And Mondays are the worst day for sickies – as 60 per cent of folk admit they over-do it on a weekend.

Leading rheumatologist and joint health expert Dr Taher Mahmud said: “Exercise has many health benefits, but people need to remember if they are not used to exercising, over exertion can put additional strain on their ligaments and joints resulting in injury and time off work.”

But incorrect exercise clothing is to blame for many sports injuries – often leaving people hobbling around or clutching pulled muscles the following day.

A staggering 65 per cent don’t even wear shoes to exercise, while a worrying 41 per cent of people work out to home videos in just their underwear.

Unsurprisingly, 55 per cent of bosses are completely unsympathetic when employees complain of suffering with sports injuries.

And one in 10 colleagues have been known to tease others about their pulled muscles or achy limbs.

A third of exercise enthusiasts say they find it difficult to concentrate when at work with an injury.

Working out at home is the preferred option for a third of people, closely followed by going to the gym.

But team sports such as hockey, cricket, and rugby are no longer as popular with the average adult – less than five per cent of people do any of these activities.