The average running shoe used by millions of jogging enthusiasts does more damage to the joints than tottering along in a pair of high heels, researchers have found.
Although running shoes protect the foot by cushioning the impact, they impose greater stress on the joints in the ankle, knee and hip than running barefoot, they say.
The finding will dismay the tens of thousands of runners in training for the London marathon next April, many of whom will have spent large sums on state-of-the-art running shoes.
The researchers tested 68 adults of both sexes who were observed running on a treadmill, wearing a typical running shoe "selected for its neutral classification and design characteristics typical of most running footwear" and barefoot.
They measured the forces ("torque") exerted and found they were 54 per cent greater at the hip, 36 per cent higher at the knee and 38 per cent higher at the ankle than when running barefoot.
Writing in the journal of the American Academy of Physical Medicine and Rehabilitation, they say the construction of modern running shoes provides good support and protection of the foot itself but neglects the effects on the joints.
The authors from JKM Technologies, manufacturers of footwear, and the department of physical medicine at the University of Virginia, say: "Remarkably, the effect of running shoes on knee joint torques during running (36 - 38 per cent increase) that the authors observed here is even greater than the effect that was reported earlier of high-heeled shoes during walking (20 -26 per cent increase)."
"Considering that lower extremity joint loading is of a significantly greater magnitude during running than is experienced during walking, the current findings indeed represent substantial biomechanical changes."
What is needed, they say, is a footwear design that reduces forces on the joints to that of barefoot running, while still cushioning the feet as traditional shoes do.
- THE INDEPENDENT