Our muscles progressively weaken as we age, affecting our ability to perform everyday tasks such as standing up to walking, but the mechanisms behind this have been poorly understood. Now researchers have created the first comprehensive map of ageing human muscles, giving us insight at the cellular and molecular level that could ultimately help us develop new interventions and therapies. The muscle atlas, made by researchers at the Wellcome Sanger Institute and their collaborators at Sun Yat-sen University in China, forms part of the enormous Human Cell Atlas project, mapping every cell type i…