Overview

• Liverpool John Moores University researchers found that Alexander’s 1976 trackway formula overstates theropod speeds by up to 4.7 times on soft mud substrates.
• High-speed video of helmeted guineafowl moving across varying mud consistencies revealed that footprints are distorted and stride lengths appear artificially long.
• The original equation was derived from mammalian data under hard-ground assumptions and failed to account for the pull effect of compliant substrates.
• Revised estimates suggest dinosaurs such as Velociraptor and T. rex may have walked or jogged rather than sprinted in many recorded trackways.
• The team recommends reporting speed calculations from fossil tracks in broad terms and calls for further studies across diverse animal sizes and sediment types.