Editing Gait analysis (section)

=== Kinematics ===
# [[Chronophotography]] is the most basic method for recording of movement. [[Strobe lighting]] at known frequency has been used in the past to aid in the analysis of gait on single photographic images.<ref>[[Étienne-Jules Marey]]</ref><ref>[[Muybridge|Eadweard Muybridge]]</ref>
# [[Cine film]] or video recordings using footage from single or multiple cameras can be used to measure joint angles and velocities. This method has been aided by the development of analysis software that greatly simplifies the analysis process and allows for analysis in three dimensions rather than two dimensions only.
# Passive marker systems, using reflective markers (typically reflective balls), allows for accurate measurement of movements using multiple cameras (typically five to twelve cameras), simultaneously. The cameras utilize high-powered strobes (typically red, near infrared or infrared) with matching filters to record the reflection from the markers placed on the body. Markers are located at palpable anatomical landmarks. Based on the angle and time delay between the original and reflected signal, triangulation of the marker in space is possible. Software is used to create three dimensional trajectories from these markers that are subsequently given identification labels. A computer model is then used to compute joint angles from the relative marker positions of the labeled trajectories.<ref>{{cite journal |vauthors=Davis RB, Õunpuu S, Tyburski D, Gage JR| year = 1991 | title = A gait analysis data collection and reduction technique | journal = Human Movement Science | volume = 10 | issue = 5| pages = 575–587 | doi=10.1016/0167-9457(91)90046-z}}</ref> These are also used for [[motion capture]] in the motion picture industry.<ref>Robertson DGE, et al. (2004). ''Research Methods in Biomechanics''. Champaign IL:Human Kinetics Pubs.</ref>
# Active marker systems are similar to the passive marker system but use "active" markers. These markers are triggered by the incoming infra red signal and respond by sending out a corresponding signal of their own. This signal is then used to triangulate the location of the marker. The advantage of this system over the passive one is that individual markers work at predefined frequencies and therefore, have their own "identity". This means that no post-processing of marker locations is required, however, the systems tend to be less forgiving for out-of-view markers than the passive systems.<ref>{{Cite book|last1=Best|first1=Russell|last2=Begg|first2=Rezaul |year=2006|publication-date=30 March 2006|chapter=Overview of Movement Analysis and Gait Features| chapter-url=https://books.google.com/books?id=0yis6idPgy8C&pg=PA11|editor-last=Begg|editor-first=Rezaul|editor2-last=Palaniswami|editor2-first=Marimuthu|title=Computational Intelligence for Movement Sciences: Neural Networks and Other Emerging Techniques|publisher=Idea Group|pages =11–18|isbn=978-1-59140-836-9}}</ref>
# Inertial (cameraless) systems based on [[MEMS]] inertial sensors, biomechanical models, and sensor fusion algorithms. These full-body or partial body systems can be used indoors and outdoors regardless of lighting conditions.