Motion Analysis

Motion Analysis

A typical gait lab evaluation takes about 2 to 2 1/2 hours. When a patient arrives in the gait lab for testing, the following events usually occur:

A typical gait lab evaluation takes about 2 to 2 1/2 hours. When a patient arrives in the gait lab for testing, the following events usually occur: Boy with light makers on his limbs
  • The patient is asked to change into tight-fitting shorts (i.e. bicycle shorts) and remove their shoes and socks.
  • Video is taken of the patient walking along the walkway. This is done both from the front and from the side.
  • Passive range of motion is assessed on an examination table in the lab.
  • Anthropometric data - including height, weight, leg length, ankle and knee width, inter-ASIS distance, and ASIS-trochanter distance are recorded.
  • Lower extremity strength measurements are taken while seated and lying down using a hand-held dynamometer.
  • Surface EMG electrodes are placed over the left and right rectus femoris, hamstring, tibialis anterior, and gastrocnemius muscles. If a fine-wire EMG is to be used, it is done by itself, after all other testing has been completed.
  • Fifteen reflective markers are placed at specific anatomic locations using double-sided tape. These include the sacrum, as well as the left and right ASIS, thigh, knee, shank, ankle, heel, and toe.
  • A static trial data capture is conducted with a knee alignment device placed along each knee flexion axis.
  • With the knee alignment devices removed, the patient walks along the walkway while kinematic, kinetic and EMG data is collected.
  • After each pass, the data is saved and the patient returns to their starting point. Walking continues until at least four "clean" force plate strikes are recorded for each foot. A "clean" strike means that a given foot is in contact with the ground while completely within the boundary of the force plate. In addition, only that foot may strike the plate. The other foot (in whole or in part), as well as any assistive devices (such as a walker or crutches) may not contact the force plate during the walk.
  • If conditions other than barefoot walking are to be studied, such as walking in orthoses, these are put on, and the process repeats, beginning with the static trial.
  • Often, a Gross Motor Function test (GMFM) is administered after the gait study to assess functionality in five general domains.

Results Reporting

The basic results of a gait study are usually obtained within 48 hours (less if necessary). This consists of graphs showing kinematic, kinetic, and EMG data compared to an age-matched normal subject. This information, along with the GMFM scores, range of motion and video data is reviewed and analyzed. Recommendations (surgery, bracing, follow-up, etc.) are made at this time based on the gait analysis results and on other available information (clinical evaluation, x-rays, etc.).

The full gait analysis report, including data, physical therapist review, and physician recommendations is usually available within eight-to-ten weeks after the visit date.