MyoDynamics Muscle Strip System – 840MD

Four-channel muscle physiology for isometric, eccentric and concentric studies

Name: Muscle Strip Myograph – 840MD
Brand: DMT

The DMT 840MD is a four-channel MyoDynamics system for functional studies of intact muscle and muscle strips up to 30 mm in length. It combines precise force measurement, programmable motorized length control, stimulation timing and independently controlled bath conditions in one integrated platform.

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Four independent baths Run separate muscle preparations and protocols in parallel.

2–30 mm preparations Supports intact muscle and muscle-strip preparations.

0.5–12 mm/sec User-defined motor speed for controlled length changes.

DMT MyoDynamics Muscle Strip System 840MD

4 independently controlled baths for advanced muscle studies

Why choose 840MD

Control force, muscle length and contraction mode in one platform

The 840MD is designed for muscle physiologists who need independent, parallel experiments rather than a single force measurement. Each channel combines a sensitive force transducer, manual preload adjustment and programmable motor movement.

Four independent baths

Program, start and stop up to four muscle-strip experiments separately while maintaining individual chamber control.

Three contraction modes

Perform isometric, eccentric and concentric studies using force measurement together with controlled motor movement.

Motorized length control

Stretch or retract the preparation from 10 µm up to 11 mm at user-defined speeds from 0.5 to 12 mm/sec.

Stimulation-ready chambers

Optional chamber-cover electrodes support direct or field stimulation using compatible DMT stimulators.

Controlled bath conditions

Individually regulated heating, gassing, suction and drainage help maintain stable experimental conditions.

Parallel screening workflow

Four separated preparations support drug testing, intervention comparisons, fatigue studies and multi-condition protocols.

DMT 840MD muscle chamber unit — Individual chamber unit with tissue supports, force transducer, manual preload adjustment and motorized micropositioner.

System overview

Independent bath control for advanced muscle contraction studies

Each aluminium bath unit contains a stainless-steel chamber with tissue supports on either side. One support is connected to a sensitive force transducer, while the other is connected to a combined manual preload mechanism and motorized micropositioner.

The manual positioner establishes the initial preload. The motor then stretches or retracts the preparation according to user-defined protocol commands, enabling controlled eccentric and concentric experiments.

Four separate protocols Run each chamber independently or coordinate multiple channels.

Manual preload Establish the initial muscle length and preload before the experimental protocol begins.

Motorized movement Apply controlled length changes during contraction or relaxation.

Integrated chamber functions Control temperature, gassing and drainage through the system interface.

Measurement modes

Select the contraction mode that matches the research question

The 840MD combines force measurement with active control of muscle length. This allows the same system to support static-force studies and protocols involving programmed lengthening or shortening.

Isometric contraction Maintain muscle length while measuring force development, relaxation, twitch responses or tetanic contraction.

Eccentric contraction Lengthen an activated muscle at a controlled speed and distance for fatigue, damage or force-response studies.

Concentric contraction Shorten or retract the preparation using programmable motor movement during or following activation.

Fatigue protocols Combine repeated stimulation, timing commands and motor movement to investigate declining force performance.

Force-frequency studies Evaluate muscle-force responses to defined stimulation frequencies and protocol sequences.

Applications

Muscle reactivity, fatigue and disease-model studies

The 840MD is suited for contractile and electrophysiological studies where force, length and stimulation timing must be controlled together.

Its four-channel layout supports parallel comparisons between healthy, diseased, treated and untreated preparations.

Neuromuscular dystrophy Duchenne muscular dystrophy Myofibrillar myopathy Metabolic myopathy Ion-channel disorders Sports and exercise physiology Muscle fatigue

Neuromuscular disease models

Study dystrophic muscle, ataxia-related models, mechanome-affected muscle and myofibrillar myopathies.

Metabolic muscle studies

Investigate force effects associated with glycolysis, glycogen metabolism and fatty-acid conversion.

Ion-channel research

Evaluate muscle-force changes associated with altered excitation, stimulation and ion-channel function.

Fatigue and contractile damage

Apply repeated stimulation and motor-controlled length changes in fatigue or eccentric-damage protocols.

Intervention and screening studies

Compare drugs, treatment groups and experimental conditions across four independent preparations.

Protocol control and stimulation

Coordinate motor movement, force response and external triggers

The 840MD controller supports user-defined commands for motor movement, force conditions, timing and digital trigger behaviour.

Optional chamber-cover electrodes support field stimulation. Stimulation requirements should be confirmed during configuration.

Motor speed and distance Define movement from 10 µm up to 11 mm at speeds between 0.5 and 12 mm/sec.

Protocol timing Build user-defined sequences for movement, waiting periods, triggers and repeated experimental events.

Force-dependent commands Use force changes as part of the protocol logic where relevant to the experiment.

Digital inputs and outputs Two digital input and two digital output ports per chamber support external synchronization.

Electrical stimulation Optional chamber-cover electrodes support direct or field stimulation with compatible DMT CS4+ or CS8 systems.

System components

Integrated hardware for force, movement and bath control

The 840MD combines four muscle chambers, force transducers, motorized micropositioners and an integrated controller for protocol programming, environmental control and data output.

Four-channel MyoDynamics platform

Integrated controller and four independently operated bath units for parallel muscle contraction and intervention studies.

Individual muscle chamber

Stainless-steel chamber with tissue supports, force transducer, manual preload control and motorized length adjustment.

Technical data

Key 840MD specifications

Chamber, movement, force, temperature and data-output specifications for planning a complete 840MD installation.

Select the force range, stimulation method and mounting supports according to the preparation, expected force output and intended contraction protocol.

Chambers

Number of chambers: 4 independent
Chamber material: Stainless steel
Standard chamber volume: 8 ml
Maximum chamber volume: 15 ml
Minimum segment length: 2 mm
Maximum segment length: 30 mm
Chamber cover: Manual or automatic
Gassing: Individually controlled

Movement

Manual micrometer reach: 12 mm
Motor reach: 11 mm
Motor speed: 0.5–12 mm/sec
Minimum motor resolution: 10 µm
Distance tolerance: ±15 µm

Force

Selectable force range: ±200 / ±400 / ±800 / ±1600 mN
Force resolution: 0.1 mN
Frequency range: 0–20 Hz
Force calibration: Integrated

Temperature

Temperature range: Ambient to 40 °C
Temperature resolution: 0.1 °C
Temperature stability: ±0.2 °C
Active cooling flow: 50–300 ml/min
Maximum cooling pressure: 0.5 bar

Data and triggers

Analogue outputs: 4 BNC connectors
Analogue output range: ±2.5 V
Output impedance: <200 Ohm
Digital inputs: 2 per chamber
Digital outputs: 2 per chamber
Digital input range: 5–24 VDC
Maximum digital output: 24 VDC / 30 mA

Physical

Power input: 100–240 VAC to 24 VDC
Dimensions: 49 × 30 × 17 cm
System weight: 9 kg
Operating environment: 15–30 °C
Maximum air pressure: 10 bar

Configuration guidance

Plan the complete 840MD muscle physiology workflow

The correct configuration depends on preparation type, muscle length, expected force output, contraction mode, stimulation needs, acquisition setup and required chamber volume.

Preparation and protocol

Define the muscle type, preparation length, minimum segment size and whether the primary workflow is isometric, eccentric, concentric, fatigue, intervention or screening.

Force and stimulation

Select the appropriate force range from ±200 to ±1600 mN and confirm whether direct or field stimulation and compatible DMT stimulator integration are required.

Acquisition and laboratory equipment

A complete workflow may require PowerLab acquisition, a computer, dissection microscope, light source, dissection tools, heating circulator, vacuum package, gas manifold and pH equipment.

Stimulator – CS4+ Stimulator – CS8 Muscle strip systems Training and installation Technical support

Frequently asked questions

Common questions about the 840MD

What is the MyoDynamics 840MD used for?

The MyoDynamics 840MD is used to measure the function and mechanics of isolated muscle tissue. It enables researchers to evaluate muscle force, contraction, fatigue, and length changes under controlled laboratory conditions, making it ideal for skeletal, cardiac, and smooth muscle research.

What types of muscle can be studied with the 840MD?

The 840MD is designed for skeletal muscle, cardiac muscle, and other isolated muscle strips up to 30 mm in length. It is ideal for researchers studying muscle physiology, disease models, and functional responses under controlled laboratory conditions.

What measurements can the MyoDynamics 840MD perform?

The system measures isometric force, eccentric and concentric contractions, fatigue, muscle reactivity, and length-tension relationships. It also supports programmable stretch and motor-controlled movement for advanced muscle mechanics experiments.

Can the 840MD be used for muscle fatigue studies?

Yes. The 840MD is specifically designed for fatigue and repeated contraction protocols, making it well suited for neuromuscular disease research, exercise physiology, and studies of muscle performance and recovery.

Can the 840MD perform electrically stimulated muscle contractions?

Yes. The system supports optional direct or field stimulation when paired with DMT's CS4+ or CS8 Stimulator, allowing researchers to perform twitch, tetanic, and other stimulation-based muscle experiments.

What research applications is the 840MD best suited for?

The 840MD is widely used in skeletal muscle physiology, cardiac muscle research, neuromuscular disorders, muscular dystrophy, metabolic disease, pharmacology, and drug development where precise muscle function measurements are required.

What's the difference between the 840MD and the Tissue Puller 560TP?

The 840MD measures active muscle function, including contraction, relaxation, fatigue, and stimulation responses. The 560TP is designed for passive tissue mechanics, such as stiffness, elasticity, tensile strength, and stress-strain analysis. The right system depends on whether your research focuses on active muscle physiology or passive biomechanical properties.

Is the 840MD the right system for my research?

Choose the 840MD if your research focuses on muscle contraction, force generation, fatigue, electrical stimulation, or length-tension relationships. If your primary goal is measuring passive tissue mechanics like stiffness or compliance, the Tissue Puller 560TP is likely the better fit.

Resources

840MD documentation and related guidance

Use the official product documentation and protocol material when evaluating, configuring or operating the 840MD system.

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