Force plates are sensitive test instruments. Building and ground vibrations can result in unwanted signal noise; therefore, we strongly suggest that all strain gage platforms are mounted in a manner that minimizes vibration of the entire device.
Mounting is best accomplished by securing a force plate to a flat surface that is bonded to a solid structural foundation, such as a ground-level concrete slab or heavy concrete construction. AMTI’s standard mounting system uses precision-machined aluminum rails adhesively bonded to a concrete floor.
If ground-level installation is not possible, it is best to locate force plates over support beams, near support columns, or near supporting walls in order to minimize vibration as much as possible. Locations near equipment which can cause vibrations, such as heating and ventilating systems, should be avoided. In the event that a force plate must be installed at a vibration-prone location, we recommend the use of high frequency platforms, such as the OPT400600HF, OPT464508HF, OR6-6 and BP400600HF.
At AMTI we understand that every laboratory has a unique set of requirements and challenges. For more than 30 years, we have been working directly with our clients to help create force plate installations that are specifically suited to their needs. As a result of that experience, we have recently created a set of pre-drilled mounting rails which afford the majority of our customers the mounting flexibility needed at a reasonable cost. Yet, if after considering this offering, your requirements fall outside of it and that of most of our customers, please do not hesitate to contact us if we can be of any assistance.
Freestanding installationA platform may be left freestanding for certain activities, such as balance, that have relatively low-frequency dynamic content, low impulse loading, and low side loads. Freestanding installation may provide satisfactory results in these instances but is typically not recommended by AMTI unless using a portable force plate specifically designed for these applications. AMTI does not recommend using unmounted or unsecured force plates for dynamic activities that could result in movement of the platform, potentially injuring a subject.
If using a free standing installation, care must be used to ensure the platform is on a flat surface. If the platform rocks or shakes when a load is applied, noise artifacts may be introduced into the data. Low pile carpeted floors generally work reasonably well under freestanding platforms as they distribute the applied load evenly. On hard floors, it is best to shim the platform until no rocking is evident with paper or metal shims.
Raised installationThis is the simplest method of mounted installation and is often used when a pit installation is not possible, such as on a second-floor laboratory. The force plate is mounted on top of the existing floor and raised floor is built up around the platform. In labs with more than one force plate, a raised access flooring system combined with an array of alternative mounting rails can provide the ability to configure the force plates into multiple layouts.
Researchers and clinicians conducting balance studies may elect to just provide a short ramp for patients to safely and easily get on and off the force plate. Some may even choose to simply leave the top surface of the platform sitting several inches above the floor. This arrangement may be satisfactory for balance activities since the entire range of motion occurs within a platform's top surface.
Gait and athletic performance studies require lead-in and walk-out areas that are level with the top surface of the force plate. Many gait labs have achieved this using computer room raised access flooring or self-made solutions.
Recessed pit installationPit installation is the typical method of mounting a force platform, placing the working surface of the force plate level with the floor of the lab. This method does not inherently provide the same degree of flexibility offered by some of the other mounting methods; however, our engineers have helped design many client-specific mounting layouts that allow users to arrange their force plates into multiple configurations based on the research being conducted.
Pit mounting begins by creating a recessed pit in the concrete of the ground floor. This is easiest and most often accomplished in new construction. In existing buildings, this method requires the removal of concrete and the preparation of the area prior to installation of force plates. This typically necessitates the involvement of an organization’s facilities department and may require the assistance of an architect and contractor. As pit construction is an involved undertaking, it is recommended that the potential for future expansion is taken into account. In general, creating a larger pit, such as one large enough for four plates when only two are being installed, can be done with minimal additional effort and expense. Please contact AMTI if you require assistance with any portion of this process.