Introduction In reduced gravity <0.5g, running requires less energy than walking • In space, the pressure inside space suits is high enough that it helps support the total weight http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal. pone.0006614#pone.0006614.s003
Introduction Space suits affect the walk-run transition by mobility restriction, changes in stability, and increased joint mechanical work
Introduction Froude Number By modeling walking as an inverted pendulum, we find that walking occurs only when Fr≤1.
Introduction Apollo Number The Apollo number is defined as the Froude number multiplied by the inverse of the mass ratio M. When no space suit is present, M=1 and Ap=Fr
Variables v=velocity L=hip height or center of mass height M=ratio of human carried mass to total transported mass g=gravitational acceleration α&β=shape and location of the state transition
Physiological The physiological variables include the length of the leg, L, and the mass ratio, M. When attempting to manipulate the Apollo number, the variable M can be changed. This can give either a higher or lower chance to be in a “run” state.
Important models Change in M to keep the Apollo number constant. Probability that gait=1
RecreationMATLAB was used to recreateWalk or Run state Apollo Number http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal. pone.0006614#pone.0006614.s003
Alteration Lower space suitTo allow a shorter weight/Shorter hip heightastronaut to run at thesame speed as a taller Apollo Numberastronaut, the weight of Higher space suit weight/the space suit must be Longer hip heightaltered. Mass Ratio
Possibilities Emergency situation occurs
Benefits Optimizing space suits for travel to the Moon and Mars
Conclusion In a suit with a higher mass, M, the walk-run transition will occur at lower speeds As loads reduce the self-support, M, walking becomes possible at higher velocities