Neandertal knees and ankles: a comment on Miller and Gross

Abstract

I was pleased to see the application of current biomechanical analytical techniques [SIMM (Delp et al., 1990)] to the interpretation of past human locomotor eƒciency by Miller and Gross (1998). The appropriate application of such methodologies will greatly assist those of us who study human paleobiology to comprehend the adaptive significance of both past changes in human biology and the nature of modern human variability. However, I have diƒculty accepting some aspects of their interpretation of Neandertal locomotor eƒciency. They used mean percentage di⁄erences in the ratios of knee and ankle moment arms to tibial length to adjust a modern male based model for muscle moment calculations. At the knee, patellar thickness and tibial tuberosity projection (anterior tuberosity to mid-condyles) were used as measures of the quadriceps femoris moment arm, and at the ankle the posterior pedal moment arm (mid talar trochlea to calcaneal tuberosity) was employed to approximate the triceps surae moment arm. Although the patellar, proximal tibial and posterior pedal skeletal measures are reasonable approximations (on dry skeletal remains) of the actual moment arms (or a portion thereof in the case of the patellar thickness), scaling them to tibial length has consequences. Tibial length, except in unusual athletic activities, does not represent the actual load arms for these muscles. The normal locomotor load arm for quadriceps femoris is the perpendicular from the knee axis of rotation to the line between the hip and ankle joints. Since Neandertals had hyperarctic body proportions with relatively short tibiae (Holliday, 1997), tibial length is a poor