WPI offers several muscle tester platforms, including the:

• SI-CTS200 –Cell Tester for experiments on single cells and small muscle tissues
• SI-MT –Basic Muscle Tester for most muscle experiments
• SI-MKB –Comprehensive Muscle Plaftorm

These systems include a Signal Conditioning Amplifier System which is the electronic component of the system. It is configured for a researchers individual needs and comes with the modules a researcher chooses. The amplifier system can accommodate up to eight channels.
Current available SI-H modules include:

• SI-BAM21-LCB –Optical Transducer Amplifier
• SI-AOSUB –Anti-Oscillation Unit
• SI-MOTTEST –Linear Motor Controller
• SI-TCM2 –2-Channel Temperature Controller
• SI-SARCAM –Sarcomere Spacing Module
• SI-COLU –Constant Load Unit (In the future this could be a module, but for now, it is a standalone unit.)

SI-BAM21-LCB

The SI-BAM21-LCB powers the force transducer and converts the output of the transducer to an amplified analog voltage that is proportional to the force applied to the transducer. The output signal can be multiplied by a factor of 1, 2, 5 or 10 to provide better resolution for a minimal change in applied force.

SI-AOSUB

Each force transducer has a resonance frequency at which it vibrates. The SI-AOSUB, when properly tuned to that resonance frequency, removes the resonance noise from the output signal of SI-BAM21-LCB transducer amplifier. An SI-AOSUB is necessary when a linear motor is used.

SI-MOTTEST

When a linear motor is required, this module powers the motor and provides an output indicating the actual motor position. It connects to an analog to digital converter output of the data acquisition system (like LabTrax 8/16) to control the waveform and timing for the motor control. The output connects with an analog input of the data acquisition system to monitor the sensor feedback from the motor.

SI-TCM2

When temperature control is required, the SI-TCM2 is used. It can control two cuvettes simultaneously, using digital control to maintain a constant temperature. It has both high and low alarm warnings which can be user defined.

SI-SARCAM

Sarcomere spacing measurement requires a system with an optical cuvette (cuvette with a window). A laser passes through the muscle, and the diffracted light is captured with a CCD camera. By monitoring the diffraction pattern, the length of the sarcomeres can be calculated.

When a laser light is shined through the muscle fibers, the light is diffracted in a pattern, which is determined by the spacing between the muscle fibers (sarcomeres). Because of the sarcomere structure, the refraction pattern looks similar to placing a grating in front of the light source. In other words, the monochromatic light (from the laser) passing through a muscle preparation is diffracted corresponding to the distance of the grating, also called the grating constant.

As the light shines through the muscle fiber, the sarcromeres diffract the light in a pattern.

Constant Load Module

It is often important to maintain a constant sarcomere length rather than keep the total length of the preparation constant during an isometric contraction.  Even though the distance between the ends of the muscle is kept constant, the muscle contraction causes an internal shortening of the sarcomeres of the muscle. In order to get a true isometric muscle contraction, the sarcomere length must be kept constant during the contraction. For this purpose the output signal of the camera (SI-SARCAM) can be fed into the feedback controlling the linear motor position using the SI-COLU. The feedback system controls the linear motor so that the sarcomere length is held constant.

System Images

Click the thumbnail to see a larger image of the Muscle Tester (left), MKB System (center) or the Cell Tester (right).

For basic muscle physiology information, see Muscle Physiology Basics.
For more information on the Sarcomere Spacing Module, see Sarcomere Spacing.

If you have any questions regarding the SI-H Muscle Physiology line or other WPI products, give us a call toll-free at 866.606.1974 or email us at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it . Visit the online store to purchase WPI products.