The size of the capture volume is a key consideration, since it affects the resolution of the system and, therefore, the precision with which position data can be recorded. The chosen capture volume is a compromise between the need to accommodate the movement being studied and maximising the resolution of the system by using the smallest volume possible. The volume must be sufficiently large to accommodate the movement in question fully for all expected sizes of participant. It is important to remember that this may need to include, for example, the hand of an outstretched arm in throwing sports, not just the torso.
However, the volume only needs to cover the portion of the movement that is being studied. For example, a complete running stride, from foot strike of one foot to the next foot strike of the same foot may be two metres long. However, if the research question relates only to the stance phase of running, the length of the capture volume in the direction of running could be reduced from around 2.5 m, which would be needed to ensure that a complete stride occurs within the volume, to around 1 m.
These require considerably less floor space than tripods, but must be attached to the floor to remain upright and stable, reducing the flexibility of the set-up. In the typical motion analysis laboratory, which is used for multiple concurrent projects, the flexibility gained by the use of tripods is often preferable, as it enables cameras to be positioned around the most appropriately sized capture volume for each study.