She said: "Online shopping may be very convenient but it does mean that we are losing some of the methods that used to exist for strengthening our muscles.
"We're carrying fewer bags home from the supermarket because it arrives at our door.
"We're also waiting at home for other goods to be delivered when in the past we would have gone out to buy them. This isn't an argument against progress, the Daily Mail reports.
"It's just to show that maintaining strength and being active doesn't have to mean going to the gym, and we should look for ways to build it into our everyday lives."
The rise of online shopping
The proportion of people who do all their grocery shopping online has doubled in two years with the rise of same day delivery.
The figure rose from 7per cent in 2014 to 14per cent - one in seven - in Britain last year, The Mail reported earlier this year. Around a quarter of American households currently buy some groceries online.
As we grow older, our skeletal muscles tend to wither and weaken, a phenomenon known as sarcopenia.
Recommended exercise
NHS guidelines suggest people do two strengthening sessions a week, such as exercising with weights, or lifting and carrying heavy loads such as groceries.
For people aged 65 and over, the sessions can also include activities that involve stepping and jumping, such as dancing.
Professor Middleton said people should not think that becoming weaker and frailer was an inevitable part of getting older.
She added: "As the guidelines set out, it doesn't mean immediately hitting the gym to lift weights.
"To start, it can be digging in the garden or simple body-weight exercises like standing up out of a chair 10 times.
"There are easy ways to do it but the essential thing is to get started and these poll results show a lot of work needs to be done to get that message out."
The dangers of weak muscles
Scientists have previously found that failing muscle power could be linked to Alzheimer's disease in older adults.
While links between a lack of muscle and arthritis are more established and have been touched upon by scientists for decades.
Professor Middelton's comments come on the back of a survey of 2,000 people to highlight how many pensioners are at risk of falls.
They discovered that 24 per cent of adults over the age of 65 do no strengthening activities all week.
