Biomechanics
data can include measures of force and motion of body position, posture, and
joint movement over a wide range of static and dynamic conditions. Biomechanics
measurements are meaningful for a wide variety of research applications, such as
biomedical engineering, exercise physiology, sports training or rehab, and
ergonomics (for characteristics of a specific work activity or environment).
Biomechanics transducers include goniometers, torsiometers, and
accelerometers. Transducers are unobtrusive and lightweight, and can be worn
comfortably and undetected under clothing or attached to external
equipment—leaving the subject to move freely in the normal
environment.
Biomechanics transducers connect directly to the BIOPAC Acquisition Unit as part of an MP or BSL System. For a more complete physiological analysis, additional signals can be recorded (e.g., EMG, respiration, heart rate) and video data can be tightly-synchronized for a clear and detailed view of the biomechanics of a movement with the subject’s physiological data.
Goniometers incorporate gauge elements that measure bending strain along or around a particular axis and transform angular position into a proportional electrical signal. The gauge mechanism allows for accurate measurement of polycentric joints. As the joint moves through a determined angle, the relative linear distance between the two mounting positions will change. A telescopic endblock prevents the measuring element from becoming over-stretched or buckled as the limb moves. The bending strain is proportional to the sum total angular shift along the axis. Because the bending force is extremely small, the output signal is uniquely a proportional function of the angular shift.
Twin-axis goniometers measure rotation about two orthogonal planes
simultaneously to record limb angular movement, such as adequate bending in the
elbows or knees, unsafe rounding in the lower spine, wrist or ankle
flexion/extension, abduction/adduction, radial/ulnar deviations, etc.
Single-axis goniometers measure the angle in one plane only and are used to
record digit joint movement of fingers, thumb or
toes.
Torsiometers measure rotation about a single axis (e.g., forearm pronation/supination) to record angular twisting (as opposed to bending) of the torso, spine or neck.
Tri-Axial Accelerometers are high level output transducers that provide three outputs to measure acceleration along the X-, Y- and Z-axes simultaneously. To reliably record head tilt, place an accelerometer on the head. To measure accelerations when performing slow movements, such as walking and hand tremor, ±5 G accelerometers are optimal; ±50 G are more suitable for quick movements, such as swinging a tennis racket.
For applications where quick or rapid movements are involved, fit a “sock” bandage over the whole sensor and interconnect lead. For accurate results from long recordings, use double-sided adhesive between the endblocks and skin, and place single-sided adhesive tape over the top of the endblocks. No tape should come into contact with the spring. The connection lead should also be taped down near the sensor element.
Biomechanics transducers connect directly to the BIOPAC Acquisition Unit as part of an MP or BSL System. For a more complete physiological analysis, additional signals can be recorded (e.g., EMG, respiration, heart rate) and video data can be tightly-synchronized for a clear and detailed view of the biomechanics of a movement with the subject’s physiological data.
Goniometers incorporate gauge elements that measure bending strain along or around a particular axis and transform angular position into a proportional electrical signal. The gauge mechanism allows for accurate measurement of polycentric joints. As the joint moves through a determined angle, the relative linear distance between the two mounting positions will change. A telescopic endblock prevents the measuring element from becoming over-stretched or buckled as the limb moves. The bending strain is proportional to the sum total angular shift along the axis. Because the bending force is extremely small, the output signal is uniquely a proportional function of the angular shift.
Torsiometers measure rotation about a single axis (e.g., forearm pronation/supination) to record angular twisting (as opposed to bending) of the torso, spine or neck.
Tri-Axial Accelerometers are high level output transducers that provide three outputs to measure acceleration along the X-, Y- and Z-axes simultaneously. To reliably record head tilt, place an accelerometer on the head. To measure accelerations when performing slow movements, such as walking and hand tremor, ±5 G accelerometers are optimal; ±50 G are more suitable for quick movements, such as swinging a tennis racket.
For applications where quick or rapid movements are involved, fit a “sock” bandage over the whole sensor and interconnect lead. For accurate results from long recordings, use double-sided adhesive between the endblocks and skin, and place single-sided adhesive tape over the top of the endblocks. No tape should come into contact with the spring. The connection lead should also be taped down near the sensor element.
