Whole Organism Performance

Increased limb length has evolved many times in mammals in the context of locomotor specializations such as running and jumping. In Longshanks, we used artificial selection to "forward engineer" the same ecomorphology. Here, we use a biomechanics framework to understand if, and how, increased limb length improves locomotor performance in Longshanks.

Gait: limb length influences features of gait such as stance duration and stride length. We have shown that the increased limb length in Longshanks has increased its stance duration and decreased its stride frequency, i.e., it takes fewer, longer steps to cover the same distance as controls. See Sparrow et al (2017)

Jumping performance:  We are studying if/how the longer limbs of Longshanks improve its performance in jumping. Leaping species tend to have relatively longer hindlimbs. It is thought that this may enable them to jump farther and/or more efficiently, though the exact mechanisms that make this possible are not well understood. Longshanks provides a unique opportunity to test biomechanical hypotheses on jumping behavior.

Running economy: Longer limbs have also been proposed to reduce the cost of transport, e.g., by increasing stance duration and stride length. We are currently testing this hypothesis in Longshanks using a combination of metabolic treadmills and gait analyses.