Our knees are arguably one of our most important joints, but also one of the most poorly looked after. Science tells us putting in some work now pays dividends later.

You might start to notice it as early as your thirties: the dull knee aches when the weather changes, the morning stiffness when you get out of bed. You might think twice about crouching down. They're all unwelcome signs that your knees are not quite the well-oiled joints they once were.

This will be especially true if you have a physical job or play a lot of sport. But it can be exacerbated by other things too. Weight gain, underlying autoimmune conditions and genetics can all accelerate the onset of knee problems.

But it's also not surprising that our knees take a battering. Research indicates that just by walking, the force on your knees is already equivalent to one and a half times your body weight.

Five minutes to stay young

From reading a page of a book every day to knee-strengthening exercises, this series looks at simple lifestyle changes you can make now that will have a big impact on how you age. The best part? They all take around five minutes.

After back pain, throbbing aches in the knees are the most commonly cited musculoskeletal ailment in older adults, impacting everything from mobility to quality of life.

"The knee is one of the most complex joints in the entire body," says Anikar Chhabra, an orthopaedic surgeon and chair of sports medicine at Mayo Clinic in Phoenix, US. "It bears the full load of our body weight with every step we take."

There are assorted reasons for focusing on your knee health that can bring benefits both now and later in life, and a number of simple steps which we can all take to stay as mobile as possible for longer.

Our knees rely heavily on four surrounding muscle groups – the hamstrings, the gluteal muscles, the quadriceps muscles and the calf muscles. These support the knee and provide it with the stability and shock absorption capability that enables it to function.

"When these muscles aren't interacting and working together, that's when you put more stress on the joint," says Chhabra. "That's what leads to pain."

Research has shown that strengthening these muscle groups through exercise can avoid degeneration of the cartilage in the knee which leads to osteoarthritis. This can either delay or prevent the need for knee replacement surgery. Some studies also indicate that keeping these muscles strong can decrease the load on the joint and reduce pain in people in the early stages of osteoarthritis.

Alexis Colvin, a professor of orthopaedic surgery at the Icahn School of Medicine at Mount Sinai in New York, US, explains that exercise can also improve the health of the cartilage cells themselves.

"There's like a motor oil on the inside of our knees called synovial fluid," she says. "Exercise helps stimulate production of it, which decreases stiffness and inflammation, and helps with lubricating the cartilage surface."

Some exercises can also strengthen the knee bones themselves, reducing the risk of osteoporosis or bone thinning around the knee joint in later life. Knee strengthening can be particularly important for older adults, says Chhabra, as improving the stability of the surrounding muscles can reduce the risk of falls.

But knee exercises can have other surprising and often overlooked benefits such as

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