1. The metabolic and mechanical costs of step time asymmetry in walking by Richard G. Ellis, Kevin C. Howard, and Rodger Kram Proceedings B Volume 280(1756):20122784 April 7, 2013 ©2013 by The Royal Society

2. Step diagram of conditions. Richard G. Ellis et al. Proc. R. Soc. B 2013;280:20122784 ©2013 by The Royal Society

3. (a) Net metabolic power and (b) external mechanical power plotted versus stride time. Richard G. Ellis et al. Proc. R. Soc. B 2013;280:20122784 ©2013 by The Royal Society

4. (a) Ensemble average vertical and (b) horizontal GRF and horizontal CoM velocity (c) profiles for the 0% (symmetric), +12.5/−12.5% (moderately asymmetric) and +25/−25% (highly asymmetric) conditions. Richard G. Ellis et al. Proc. R. Soc. B 2013;280:20122784 ©2013 by The Royal Society

5. Ensemble average mechanical power across a stride for (a) the 0% (symmetric), (b) +12.5/−12.5% (moderately asymmetric) and (c) +25/−25% (highly asymmetric) conditions. Richard G. Ellis et al. Proc. R. Soc. B 2013;280:20122784 ©2013 by The Royal Society

6. Individual limb work for the (a) right and (b) left leg as the leading leg, during single support and as the trailing leg. Richard G. Ellis et al. Proc. R. Soc. B 2013;280:20122784 ©2013 by The Royal Society