Quirks & Quarks·New

Chimps are stronger than you and here's why

Pound for pound, chimps are stronger than humans. It turns out this is because of the fibres that make up their muscles.
A chimpanzee drinks a beverage to cool off the summer heat. (REUTERS)

It has always been assumed that chimps are much stronger than humans, despite the fact that on average they are smaller than us. A new study by Dr. Matthew O'Neill from The University of Arizona College of Medicine set out to find out exactly what gives chimps such super-strength. 

Skeletal muscle fibres were sampled from three young male chimps and compared to those of humans. The big difference was found to be in the way those muscle fibres are distributed. 

Having more fast twitch muscle fibre than humans give chimps the strength to climb. (Eric Kilby/Wikimedia Commons)
 In chimps, one third of their muscles are slow twitch fibres and the other two thirds are made up of two types of fast twitch muscle fibres. Fast twitch muscle contracts more quickly and provides more force in quick bursts, but fatigues faster. This accounts for a chimp's ability to climb and jump rapidly over short distances.

On average, humans have 70 per cent slow twitch and 30 per cent fast twitch muscle fibre. This gives us greater endurance, but less strength in bursts. 

Chimp muscle fibre was found to be 1.35 times more powerful that that of humans. It may be that humans traded strength for endurance when the lineages separated millions of years ago, giving us the ability to travel farther to find food.     

Paper in the journal PNAS: Chimpanzee super strength and human skeletal muscle evolution