Researchers from the University of Tennessee and the University of Pittsburgh investigated whether the Hawthorne effect, which causes human behavior to change when under observation, affects the gait pattern of people who use lower-limb prostheses. The results of the study suggest that users of lower-limb prostheses walk differently when their gait is being assessed-such as in the prosthetist’s office-than in situations without observers. The study’s authors noted that this may explain, in part, clinical experience that modifications of prosthetic fit or alignment provide only short-term improvement.
Primary outcome measures were gait parameters of initial double support time and upper-body lateral tilt angle, which were collected with a mobile sensor attached to the subjects’ backs. To make subjects feel unwatched, two different conditions were created and statistically compared against each other: one in which the subjects were initially unaware of the observers’ attention and another one in which the same subjects were aware of a group of observers.
Data from the two participants, who used transfemoral prostheses, demonstrated a change in step initial double support percentage by up to 14.2 percent. Considerable changes were also noted in secondary outcome measures including speed, stride length, and stride symmetry, according to the study, which was published online September 29 in Prosthetics and Orthotics International.
