Metric: Torque

Torque measures the rotational effect of force around a joint or axis. In strength testing, it helps describe how much turning force a client can produce around a joint, such as the knee, hip, ankle, shoulder or elbow.

Torque is commonly used in isometric testing, isokinetic dynamometry, handheld dynamometry, fixed dynamometry and strength profiling. It is especially useful when professionals want a more mechanically meaningful measure than raw force, because torque accounts for the distance between the joint axis and where force is applied.

A high torque result generally suggests greater joint-specific force capacity in the tested position or movement. A low torque result may suggest reduced force capacity around that joint, but it may also reflect pain, fatigue, poor confidence, testing setup, lever-arm error, poor stabilisation or unfamiliarity with the task.

Torque should not be interpreted in isolation. It is most useful when combined with symptoms, movement quality, side-to-side comparison, body weight, joint angle, test position, rate of torque development, function and the client’s goals.

Isokinetic dynamometry is commonly described as a gold-standard approach for muscle strength and power measurement, and isometric strength can be measured as torque in newton-metres. However, reliability and usefulness depend strongly on population, device, joint, protocol and measurement quality.

Introduction

Many health and fitness professionals measure strength using force. For example, a client may push into a handheld dynamometer and produce 35 kg or 77 lb of force. That number is useful, but it does not always tell the full mechanical story.

Torque adds another layer by asking:

“How much rotational force is being produced around the joint?”

This matters because the body moves around joints. When the quadriceps extend the knee, the hamstrings flex the knee, the calf produces plantar flexion, or the rotator cuff rotates the shoulder, the result is not just straight-line force — it is rotational force around a joint.

In Measurz, torque can help professionals track joint-specific strength, compare sides, monitor progress, communicate objective changes and better understand how force relates to movement. Like all metrics, torque should support assessment reasoning and progress tracking. It should not be used by itself to diagnose a condition, explain symptoms, clear participation or prescribe an intervention.

Quick Summary

• Metric name: Torque

• What it means: Rotational force around a joint or axis

• Simple formula: Torque = force × moment arm

• Common units: Newton-metres, or N·m

• Other practical units: lb·ft, kgf·m, kgf·cm or device-specific units

• Common testing methods: Isokinetic dynamometry, handheld dynamometry, fixed dynamometry, load cells, cable-based systems and joint-specific strength testing

• Best use: Joint-specific strength assessment, side-to-side comparison, progress tracking, body-weight-normalised strength profiling and client education

• High torque: Usually indicates greater joint-specific rotational force capacity in the tested position or movement

• Low torque: Usually indicates lower joint-specific rotational force output in that test, but the reason must be interpreted with context

• Major limitation: Torque depends heavily on joint angle, lever arm, position, device setup and protocol

What Is Torque?

Torque is the rotational effect of force.

A simple way to understand it:

Force tells you how hard something is pushed or pulled.
Torque tells you how much turning effect that force creates around a joint.

For example, if a client performs an isometric knee extension test, the force may be measured at the lower leg. To calculate torque, that force is multiplied by the distance from the knee joint axis to the point where force is applied. That distance is called the moment arm or lever arm.

Simple formula

Torque = force × moment arm

For example:

• Force = 300 N

• Moment arm = 0.40 m

• Torque = 300 × 0.40

• Torque = 120 N·m

This means the client produced 120 newton-metres of knee extension torque in that test position.

How Is Torque Measured?

Torque can be measured directly by some devices or calculated from force and lever arm.

Common tools include:

• Isokinetic dynamometers

• Handheld dynamometers

• Fixed dynamometry systems

• Load cells

• Cable-based strength devices

• Muscle Meter-style systems

• Custom strength testing setups

• Some force-measuring systems with lever-arm input

Torque is commonly recorded in:

• N·m: newton-metres

• N·m/kg: newton-metres per kilogram of body mass

• Nm/BW or body-weight-normalised torque

• lb·ft: pound-feet

• kgf·m or kgf·cm, depending on the device or calculation method

If the device displays force in kilograms or pounds, torque may need to be calculated if the lever arm is known. The key is to record the device, unit, lever arm and protocol clearly so the result can be repeated and compared accurately.

Why Torque Is Used

Torque is used because many human movements occur around joints, not in straight lines.

For health and fitness professionals, torque can help answer:

• How much joint-specific strength can the client produce?

• Is one side producing less torque than the other?

• Has joint-specific force capacity improved after training?

• Is the client stronger at one joint angle than another?

• Does the client produce enough torque relative to their body size or sport demands?

• Is strength improving while symptoms, function or movement quality are also changing?

• Does the client have high peak torque but slow rate of torque development?

Torque is widely used in isokinetic dynamometry because it captures joint rotational output. A systematic review of isokinetic dynamometry reliability found peak torque was the most frequently used outcome measure and was reliable in included neuromuscular disease populations, although the overall evidence quality varied across conditions and measurement error data were limited.

What Torque Measures

Torque measures joint rotational force output in a specific test.

It may provide context about:

• Joint-specific strength

• Muscle group force capacity

• Side-to-side difference

• Agonist-to-antagonist comparison

• Training adaptation

• Exercise progression

• Recovery or readiness trends

• Force capacity relative to body mass

• Joint-angle-specific strength

• Strength across different contraction modes

Torque does not directly measure:

• Pain cause

• Tissue status

• Movement skill

• Power

• Balance

• Coordination

• Endurance

• Whole-body performance

• Return-to-sport readiness

• Whether a client needs a specific intervention

A torque result is only meaningful when the joint, movement, position, joint angle, lever arm, device and protocol are known.

Torque vs Force

Torque and force are related, but they are not the same.

Force asks:
“How hard did the client push or pull?”

Torque asks:
“How much rotational effect did that force create around the joint?”

This matters because two clients can produce the same force but different torque if their lever arms are different.

Example

• Client A produces 300 N with a 0.35 m lever arm

• Torque = 105 N·m

• Client B produces 300 N with a 0.45 m lever arm

• Torque = 135 N·m

Both clients produced the same force, but Client B produced more torque because the force was applied farther from the joint axis.

This is why torque can be more mechanically meaningful than raw force for joint-specific testing.

Torque vs Peak Force

Peak force is the highest force recorded during a test. Peak torque is the highest torque recorded during a test.

Peak force may be enough when you are interested in raw force output. Peak torque is often more useful when you want to understand the turning effect around a joint.

For example:

• Hip abduction force tells you how much force was applied.

• Hip abduction torque tells you how much rotational force was produced around the hip, accounting for lever arm.

In practice, torque is especially useful when comparing clients with different limb lengths, or when you need a joint-specific strength value.

Torque vs Rate of Torque Development

Torque tells you how much rotational force was produced.

Rate of Torque Development, or RTD, tells you how quickly torque was produced.

A client may have:

• High peak torque but slow RTD

• Low peak torque but fast initial RTD

• Good torque on one side but delayed torque development

• Similar torque between sides but different time-to-peak values

This matters because some clients can produce high joint torque eventually, but not quickly enough for fast tasks such as sprinting, cutting, landing, stepping or balance recovery.

What Does High Torque Mean?

A high torque result usually means the client produced greater rotational force around the tested joint.

This may suggest:

• Greater joint-specific strength capacity

• Better force production in the tested position

• Improved adaptation to strength training

• Stronger agonist muscle group output

• Better ability to create joint movement or resist external load

• Improved strength relative to baseline

• Greater strength relative to body mass if normalised values also improve

High torque may be a positive finding when:

• It improves under the same protocol

• Symptoms remain stable or improve

• Movement quality is acceptable

• The result aligns with better function or performance

• The client’s goal requires higher joint-specific strength

However, high torque is not automatically better in every context.

A high torque result still needs to be interpreted with:

• Joint angle

• Speed of contraction

• Pain or symptoms

• Movement quality

• Body mass

• Sport or task demand

• Opposite side

• Agonist-to-antagonist balance

• Related performance tests

Safer interpretation

“Torque was higher in this test, suggesting greater joint-specific rotational force output under this protocol. This should be interpreted with symptoms, movement quality, body size, joint angle and related performance measures.”

What Does Low Torque Mean?

A low torque result usually means the client produced less rotational force around the tested joint in that test.

This may suggest:

• Reduced joint-specific force capacity

• Reduced muscle strength in that movement

• Pain inhibition or symptom limitation

• Poor confidence or apprehension

• Fatigue

• Poor familiarisation

• Submaximal effort

• Poor stabilisation

• Inconsistent joint angle

• Incorrect lever-arm measurement

• Different device placement

• Poor test setup

Low torque does not automatically mean a muscle is “not activating” or that a specific tissue is injured. It simply means that the measured rotational output was lower in that test.

Low torque may be meaningful when:

• It is lower than the client’s baseline

• It is clearly lower than the opposite side

• It is lower than matched reference data

• It aligns with reduced function or performance

• It appears consistently across repeated trials

• It occurs with symptoms or reduced confidence

Low torque may be less meaningful when:

• The client was unfamiliar with the task

• The test setup changed

• The lever arm was measured differently

• The result was affected by pain or fear

• The effort was submaximal

• Only one trial was recorded

Safer interpretation

“Torque was lower in this test today, which may indicate reduced joint-specific rotational force output. This should be interpreted with baseline, symptoms, effort, setup quality and related findings.”

How Health and Fitness Professionals Can Use Torque With Clients

1. Measure joint-specific strength

Torque is useful when the goal is to understand strength around a joint.

Examples:

• Knee extension torque for quadriceps strength

• Knee flexion torque for hamstring strength

• Hip abduction torque for lateral hip strength

• Ankle plantar flexion torque for calf capacity

• Shoulder external rotation torque for shoulder rotation strength

• Elbow flexion torque for upper-limb pulling capacity

This can help professionals move from general statements like “weak glutes” or “weak quads” to objective, trackable strength measures.

2. Track progress over time

Torque can show whether a client is producing more joint-specific force after a training block.

Example:

A client improves knee extension torque from 110 N·m to 135 N·m using the same device, position and joint angle. This suggests improved knee extension force capacity under that protocol.

3. Compare left and right sides

Torque is useful for side-to-side comparison, especially in unilateral tests.

Example:

• Right knee extension torque: 160 N·m

• Left knee extension torque: 128 N·m

The left side is producing 80% of the right side.

This may help identify an asymmetry worth monitoring. However, symmetry alone can be misleading. In ACL reconstruction contexts, limb symmetry index is commonly used, but research shows it may fail to capture wider neuromuscular control or performance deficits, especially if the comparison limb is also affected.

4. Compare torque relative to body mass

Relative torque helps professionals understand how much joint-specific force a client produces compared with their body size.

This is important when the client needs to move their own body weight, such as during running, stairs, jumping, squatting or changing direction.

5. Support exercise progression

Torque can help guide progression by showing whether force capacity is improving in a controlled test.

Examples:

• Low torque and high symptoms may suggest staying with lower-load options.

• Improving torque and stable symptoms may support gradual loading progression.

• High torque but poor control may suggest the client needs coordination, balance or movement strategy work.

Torque does not prescribe the exercise, but it can support reasoning.

6. Educate clients objectively

Torque gives clients a clear number that can help explain progress.

Examples:

• “Your knee extension torque has improved since baseline.”

• “Your left side is producing less torque than your right in this test.”

• “Your torque is improving, but we still need to see how it transfers to movement.”

• “Your peak torque is good, but your ability to develop torque quickly may still need work.”

What Torque Means in Different Client Populations

General fitness clients

For general fitness clients, torque can be used to monitor strength progress and side-to-side differences.

It is useful when:

• A client is following a structured strength program

• A professional wants objective progress data

• One side feels weaker or less confident

• The client wants measurable feedback

Interpretation should focus on baseline and retesting rather than elite athlete comparison.

Athletes and sport clients

For athletes, torque can help profile joint-specific strength and monitor changes across training.

Relevant applications include:

• Quadriceps and hamstring torque in running and field sport clients

• Hip torque in cutting, sprinting and change-of-direction sports

• Ankle torque in jumping and running sports

• Shoulder rotation torque in throwing and overhead sports

However, sport performance is not determined by torque alone. Performance also depends on rate of torque development, power, impulse, movement skill, speed, coordination, fatigue resistance and sport-specific decision-making.

Older adults

For older adults, torque may provide useful information about lower-limb strength and physical function. Research in older women notes that muscle strength is an important component of sarcopenia identification, and that isometric torque methods can be used when grip strength testing is not feasible. In that study, isometric knee extension strength was correlated with several sarcopenia-related criteria and showed moderate diagnostic accuracy for sarcopenia screening in community-dwelling older women.

For older adults, torque should be interpreted with:

• Gait

• Balance

• Sit-to-stand performance

• Fatigue

• Confidence

• Symptoms

• Daily function

• Fall risk context

Torque may be useful, but it should not replace functional assessment.

Clients with pain or persistent symptoms

For clients with pain, torque can help monitor how much joint-specific force they are willing and able to produce in a controlled test.

A low torque value may reflect:

• Pain

• Guarding

• Reduced confidence

• Reduced strength

• Fear of loading

• Fatigue

• Poor test tolerance

• Strategy changes

Record symptoms, pain score and confidence with every test. Avoid claiming that low torque proves a muscle is inhibited or that a specific tissue is the cause of pain.

Post-injury or return-to-performance clients

Torque can be useful in post-injury monitoring because it allows side-to-side and baseline comparison.

For example:

• Knee extension torque may be tracked after knee injury.

• Ankle plantar flexion torque may be tracked after calf or Achilles-related issues.

• Shoulder rotation torque may be tracked in overhead athletes.

However, return-to-performance decisions should never be made from torque alone. Torque should be interpreted with symptoms, movement quality, sport-specific tasks, fatigue response, confidence and other performance measures.

Youth clients

In youth clients, torque changes may reflect growth, maturation, coordination, body size, training history and test familiarity.

A larger youth client may produce higher absolute torque due to size. Relative torque can help, but it does not remove all growth and maturation effects.

Use youth-specific reference data only when the population and protocol match closely.

Higher body mass clients

Higher body mass clients may produce higher absolute torque, but relative torque can provide more useful context for bodyweight tasks.

For example:

• A client with high absolute knee extension torque may still have low torque relative to body mass.

• This may matter for stairs, squatting, running or jumping, where the body must be moved against gravity.

Use both absolute and relative torque where appropriate.

What If Torque Is Reported Relative to Body Weight?

Torque is often reported relative to body mass or body weight.

Common formats include:

• N·m/kg

• N·m/body mass

• % body weight, depending on the system

• Torque normalised to body mass

This helps answer:

“How much torque is the client producing relative to the body they need to move?”

Simple explanation

If two clients produce the same torque but one weighs more, the lighter client has higher torque relative to body mass.

This can be important for bodyweight tasks such as:

• Standing from a chair

• Squatting

• Running

• Jumping

• Climbing stairs

• Changing direction

Important limitation

Normalisation helps, but it does not solve every comparison issue. Research on strength normalisation shows that the choice of scaling method can meaningfully affect interpretation, and different anthropometric scaling methods may lead to different conclusions.

For Measurz, relative torque is useful when:

• Comparing clients of different body sizes

• Tracking bodyweight task readiness

• Comparing against matched reference data

• Monitoring change over time

But it still needs to be interpreted with the exact test, device, joint angle, client population and goal.

Normative Data, Reference Data and Benchmarks

Are there universal torque norms?

No. There are no true universal torque norms that apply across all clients, joints, devices and protocols.

Torque values depend on:

• Joint tested

• Movement tested

• Contraction type

• Joint angle

• Test speed

• Device

• Lever arm

• Body position

• Stabilisation

• Sex

• Age

• Body mass

• Training history

• Symptoms

• Activity level

• Test instructions

A 2025 systematic review of Biodex isokinetic dynamometer peak torque reference values found large heterogeneity between protocols and populations, and reported that meta-analysis was not feasible because of differences in study methods. The authors created decision trees to help clinicians choose appropriate reference values, which supports using matched reference data rather than universal norms.

What does peer-reviewed research support?

The best evidence-based approach is to use:

• Client baseline

• Side-to-side comparison

• Body-mass-normalised torque

• Age-, sex-, sport- and protocol-matched reference data when available

• Internal team or business benchmarks

• Repeated testing under the same protocol

• Related movement and performance tests

Handheld dynamometry research has also developed standardised protocols and reported reliability, SEM and MDC values for maximal isometric muscle strength torque across multiple muscle groups in healthy adults, supporting the use of torque values when procedures are standardised.

When published reference values are useful

Published torque reference values may be useful when they match:

• The same joint

• The same movement

• The same contraction type

• The same device

• The same test speed

• The same joint angle

• The same population

• The same units

• The same normalisation method

If those details do not match, the values should be treated as broad context only.

Misconceptions About Torque

Misconception 1: Torque and force are the same

They are related, but not the same. Force is a push or pull. Torque is the rotational effect of that force around a joint.

Misconception 2: Higher torque always means better function

Not always. Higher torque may help, but function also depends on movement quality, confidence, endurance, balance, speed, coordination and task skill.

Misconception 3: Low torque proves a muscle is inhibited

No. Low torque may reflect pain, fatigue, poor confidence, poor setup, submaximal effort or reduced strength. It does not prove one mechanism.

Misconception 4: Limb symmetry means the client is ready

Symmetry is useful, but it can be misleading. A client may have similar torque on both sides while both sides remain below expected values for their sport, age or activity level.

Misconception 5: Torque values can be compared across devices

Not always. Different devices, stabilisation methods, lever arms and software calculations can produce different results.

Misconception 6: Reference values are universal

No. Torque reference values are highly protocol-specific. Use matched data or baseline comparison.

Limitations of Torque Testing

Torque testing can be affected by:

• Joint angle

• Lever arm measurement

• Device placement

• Stabilisation

• Body position

• Warm-up

• Familiarisation

• Pain

• Fatigue

• Motivation

• Effort

• Contraction type

• Test speed

• Device reliability

• Assessor skill

• Body size

• Dominance

• Testing instructions

Handheld dynamometry is practical and accessible, but its reliability can be limited in stronger muscle groups or when the assessor cannot stabilise the device well. Isokinetic dynamometry offers strong control and sensitivity, but it is less portable, more expensive and may not reflect all real-world tasks.

How to Improve Torque Testing Quality

To improve torque data quality:

• Use the same device each time.

• Use the same joint angle.

• Use the same body position.

• Measure the lever arm consistently.

• Record the exact landmark.

• Stabilise the client well.

• Use the same contraction type.

• Use the same test speed if isokinetic.

• Use the same warm-up.

• Provide clear instructions.

• Allow familiarisation trials.

• Record multiple trials.

• Use the same scoring method.

• Record symptoms and pain.

• Record body mass if calculating relative torque.

• Avoid comparing different protocols.

• Interpret torque with related metrics and client goals.

How to Record Torque in Measurz

Record:

• Metric: Torque

• Score/result: torque value

• Units: N·m, N·m/kg, lb·ft, kgf·m, kgf·cm or device-specific unit

• Torque type: peak torque, average torque, isometric torque, isokinetic torque or phase-specific torque

• Joint tested: knee, hip, ankle, shoulder, elbow, trunk or other

• Movement tested: extension, flexion, abduction, adduction, internal rotation, external rotation, plantar flexion or dorsiflexion

• Side: left, right or bilateral

• Dominance: dominant or non-dominant side

• Position: seated, standing, supine, prone, side-lying or sport-specific position

• Joint angle: if relevant

• Lever arm: distance from joint axis to force application point

• Device used: handheld dynamometer, fixed dynamometer, isokinetic dynamometer, Muscle Meter, load cell or other device

• Contraction type: isometric, concentric, eccentric or isokinetic

• Test speed: if isokinetic

• Trial number: trial 1, trial 2, trial 3

• Final score method: best score, average score or selected trial

• Body mass: if normalising torque

• Pain score: before, during or after testing

• Symptoms: pain, apprehension, fatigue, cramping or none

• Effort quality: maximal, submaximal, hesitant or unclear

• Related metrics: peak force, rate of torque development, time to peak, fatigue index or functional test

• Baseline comparison: previous result

• Retest date: planned follow-up

• Progress note: contextual factors that may explain the result

Measurz should be used to support measurement, comparison, monitoring, education and progress tracking. Torque should not be positioned as diagnosing a condition or confirming readiness on its own.

Practical Examples

Example 1: General fitness client

A client completes a hip abduction torque test. Their right side produces 72 N·m and their left side produces 61 N·m. This may suggest a side-to-side difference worth monitoring, especially if it aligns with their goals or symptoms.

Example 2: Strength progress

A client increases knee extension torque from 105 N·m to 128 N·m after an eight-week strength block. If the protocol was consistent, this may suggest improved quadriceps force capacity in that test.

Example 3: Athlete

A field sport athlete has strong peak knee extension torque but slow rate of torque development. This suggests they may have good maximal strength but may still need to improve how quickly torque is produced for faster sport tasks.

Example 4: Older adult

An older adult improves knee extension torque and sit-to-stand performance. The combination provides stronger evidence of functional progress than either measure alone.

Example 5: Post-injury client

A client reaches 90% limb symmetry in knee flexion torque but still reports apprehension and shows poor landing control. Torque symmetry is useful, but it should not be used alone for participation decisions.

Example 6: Higher body mass client

A client has high absolute torque but lower torque relative to body mass. This may be relevant if their goal involves bodyweight tasks such as stairs, running or jumping.

FAQs

What is torque?

Torque is rotational force around a joint or axis. In strength testing, it shows how much turning force a client can produce around a joint.

How is torque different from force?

Force is a push or pull. Torque is the turning effect of that force around a joint. Torque accounts for the lever arm.

What units is torque measured in?

Torque is commonly measured in N·m. It may also be reported as N·m/kg, lb·ft, kgf·m, kgf·cm or another device-specific unit.

What does high torque mean?

High torque usually means greater joint-specific rotational force output in the tested position or movement. It should be interpreted with symptoms, technique, body mass and task demands.

What does low torque mean?

Low torque usually means lower joint-specific rotational force output in the tested position or movement. It may reflect reduced strength, pain, fatigue, poor confidence, poor setup or submaximal effort.

Are there universal torque norms?

No. Torque norms are highly dependent on joint, device, test speed, joint angle, population and protocol. Use matched reference data, baseline comparison and repeated testing.

What does torque relative to body weight mean?

It means torque has been adjusted for body size. This may be useful when the task involves moving body weight, such as stairs, squatting, jumping or running.

Can torque be used with general fitness clients?

Yes. Torque can help track joint-specific strength progress, compare sides and educate clients using objective data.

Can torque diagnose an injury?

No. Torque can support assessment and monitoring, but it does not diagnose an injury or explain symptoms by itself.

Should torque be used alone?

No. Torque should be interpreted with symptoms, movement quality, function, client goals and related metrics.

Key Takeaways

• Torque measures rotational force around a joint.

• It is useful for joint-specific strength assessment.

• High torque generally suggests greater joint-specific force capacity.

• Low torque generally suggests reduced rotational force output, but the reason must be interpreted with context.

• Torque is more mechanically specific than raw force because it accounts for lever arm.

• There are no universal torque norms.

• Reference values should only be used when the test, device, joint, population and protocol match.

• Measurz should record torque with joint angle, lever arm, device, position, symptoms and related findings.

References

Ansanello, N. B., Brenninkmeijer, R., Mattiello-Sverzut, A. C., & Bartels, B. (2025). Decision trees of peak torque reference values and methodological quality considerations for assessment of muscle strength in isokinetic dynamometry: A systematic review. Physical Therapy in Sport. https://doi.org/10.1016/j.ptsp.2025.07.011

Morin, M., Hébert, L. J., Perron, M., Petitclerc, É., Lake, S.-R., & Duchesne, E. (2023). Psychometric properties of a standardized protocol of muscle strength assessment by hand-held dynamometry in healthy adults: A reliability study. BMC Musculoskeletal Disorders, 24, Article 405. https://doi.org/10.1186/s12891-023-06400-2

Pérez-Ros, P., Barrachina-Igual, J., Pablos, A., Fonfria-Vivas, R., & Cauli, O. (2024). Diagnostic accuracy of isometric knee extension strength as a sarcopenia criteria in older women. BMC Geriatrics, 24, Article 923. https://doi.org/10.1186/s12877-024-05569-y

Vandenberghe, A., De Schutter, E., Roebroeck, M. E., Stam, H. J., & Bussmann, J. B. J. (2022). Reliability of muscle strength and muscle power assessments using isokinetic dynamometry in neuromuscular diseases: A systematic review. Physical Therapy, 102(10), pzac099. https://doi.org/10.1093/ptj/pzac099