Humans are getting weaker and today's generation, especially women, simply don't have the same muscle power as their parents, experts warn.
"In Western countries such as the UK, US and Canada, muscular strength has hit a plateau and muscular endurance -the ability to repeatedly exert force, such as doing sit-ups -has declined by 8 to 10% since the Eighties," said Dr Grant Tomkinson, senior lecturer in health sciences at the University of South Australia, a leading researcher on trends in fitness over time.
It seems our average muscle power peaked in 1985 - since then we've increased in weight, but our muscles have got weaker and weaker, especially among women, the 'Daily Mail' reported.
"I'm seeing a massive epidemic of weak women who have no muscle strength," said London-based physiotherapist Sammy Margo.
"There are skinny women who have no muscles supporting their spine, and overweight ladies who don't have any muscles under the fat," Margo said.
Experts say poor muscle strength is to blame for a host of health problems such as osteoporosis and fractures, arthritis and back pain.
"The majority of young females want to look thin. They don't eat much, they don't exercise much, and because of that they have weak musculatures - it's really not a healthy way to be," said Ken Fox, professor of exercise and health sciences at the University of Bristol.
Girls and women often avoid muscle-building exercise such as weightlifting or press-ups because they're afraid of becoming too muscular and bulky.
But many experts say it's actually difficult for women to 'bulk up' because of their hormones.
This resistance exercise, as it is known, triggers muscle growth by causing small amounts of trauma to the muscles - the body repairs the damage by adding protein strands to the muscle to increase its strength and size.
Testosterone is the hormone that triggers this process and men naturally have higher levels of it than women, meaning it's much harder for women to develop big muscles, explained Fox.
Our sedentary lifestyle has been blamed for expanding waistlines, but it is also causing our muscles to waste away, experts said.