IF your 2012 health drive involves introducing regular power-walks to your exercise schedule, you might want to consider going jogging instead.
A new study has found that a gentle run is actually less tiring — and is better for your muscles — than a brisk walk.
This is because running at around two metres per second helps a ‘car clutch’ calf muscle to work more efficiently than it does when we’re walking briskly.
This more efficient movement helps the muscle release more momentum-boosting energy, which increases stamina levels.
US researchers used ultrasound technology to scan the muscles of people on a treadmill to see how they behaved differently while walking or running.
This revealed how the medial gastrocnemius muscle attached to the Achilles tendon adjusted as volunteers walked and ran at various speeds.
Results, published in journal proceedings of the National Academy of Sciences, showed that this part of the calf muscle acts the same way as a car clutch — which allows you to shift into a different gear.
This muscle engages as we start to move, holding one end of the tendon while the body’s energy is transferred to stretch it. And the authors found that later the Achilles – a long, elastic tendon running down the back of the lower leg — ‘springs into action’ releasing this stored energy to help keep us moving.
The team, from North Carolina State University noted that walking fast makes the muscle work harder but provide less energy, with this inefficiency ultimately decreasing our stamina.
However, jogging at a speed of just two metres per second prompted the muscle to change its length more slowly, providing more power even though it isn’t working as hard.
Study author Dr Gregory Sawicki says the findings also show why the niche sport of ‘speed-walking’ does not have that many followers, saying: “Muscles work too inefficiently to speed walk, so the body turns to running in order to increase efficiency and comfort, and to conserve energy.”
He added: “Other than Olympic race walkers, people generally find it more comfortable to run than walk when they start moving at around two metres per second – about 4.5 miles per hour.
“The muscle can’t catch up to the speed of the gait as you walk faster and faster.
‘But when you shift the gait and transition from a walk to a run, that same muscle becomes almost static and doesn’t seem to change its behavior very much as you run faster and faster.”
The study did not stretch so far as to see if this also applied when you were sprinting.