The authors declared that they have no conflicts of interest.
Mouse Shoulder Morphology Responds to Locomotor Activity and the Kinematic Differences of Climbing and Running†
Article first published online: 20 AUG 2012
Copyright © 2012 Wiley Periodicals, Inc.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
Volume 318, Issue 8, pages 621–638, December 2012
How to Cite
2012. Mouse shoulder morphology responds to locomotor activity and the kinematic differences of climbing and running. J. Exp. Zool. (Mol. Dev. Evol.) 318B:621–638., , .
- Issue published online: 30 NOV 2012
- Article first published online: 20 AUG 2012
- Manuscript Accepted: 1 JUL 2012
- Manuscript Revised: 22 JUN 2012
- Manuscript Received: 30 APR 2012
- Wenner-Gren Foundation
- National Science Foundation IGERT. Grant Number: 9987590
- NSF Doctoral Dissertation Improvement. Grant Number: BCS-0824552
Mechanical loads play a significant role in determining long bone shape and strength, but less work has explored how these loads influence flat bones like the scapula, which has been shown to vary with locomotor preference among primate taxa. Here, we tested the effects of voluntary running and climbing exercise in mice to examine how the mechanical loads borne from different locomotor patterns influence shoulder morphological development. Ninety-nine female wild-type mice were distributed equally among sedentary control, activity-wheel running, and vertical climbing experimental conditions. Running mice had the lowest body masses, larger intrinsic shoulder muscles, and the most pronounced differences in scapular size and shape relative to the other groups. Climbing mouse scapular morphology also differed significantly from the control individuals, but these differences were not as marked as those between the running and control mice. This might be attributable in part to greater levels of activity in the wheel-runners relative to the climbers. Additionally, climbing mice held their bodies closer to the substrate and maintained more flexed limbs and posterior hand positions compared with the kinematics of running. As a result, climbers differed significantly from both the running and control mice in developing a relatively broader infraspinous region, which is likely related to preferential recruitment of the infraspinatus and teres minor muscles to maintain flexed shoulder postures. The results of this study demonstrate that variation in activity level and type of locomotor regime over a significant portion of the life history influences muscle and bone development in the shoulder. J. Exp. Zool. (Mol. Dev. Evol.) 9999B:621–638, 2012. © 2012 Wiley Periodicals, Inc.