Table 1.

Responses to rapid impulsive perturbations during running

All trials (N=11)Perturbation occurs during stance phase of tripod LF,RM,LR (N=6)Perturbation occurs during stance phase of tripod RF,LM,RR (N=5)
Phase of perturbation in stride (%)37±2835±2640±32
Maximum lateral velocity (cm s-1)21.0±6.920.5±7.321.5±7.1
Time to lateral velocity decrease (ms)*13±512±613±4
Minimum yaw velocity (degrees s-1)-451±283-438±293-465±315
Time to yaw velocity decrease (ms)14±912±616±12
Minimum pitch velocity (degrees s-1)-498±364-530±338-467±435
Time to pitch velocity decrease (ms)10±126±114±16
Minimum roll velocity (degrees s-1)-596±837-806±911-336±746
Time to roll velocity decrease (ms)14±2621±356±1
  • Values are means ± S.D.

    Reported velocities are increases or decreases in velocity relative to scaled mean reference velocities from unperturbed trials.

    LF, left front leg; RM, right middle leg; LR, left hind leg; RF, right front leg; LM, left middle leg; RR, right hind leg.

  • * Indicates the time from the beginning of the perturbation until the magnitude of relative velocity begins to decrease from its maximal value.