Strength Isometric Test: Shoulder Horizontal Adduction

The Shoulder Horizontal Adduction [Muscle Meter] test measures how much force a client can produce when moving the arm across the body against resistance. It is commonly used to assess isometric horizontal adduction force in a controlled setup. This can provide useful context for pushing, pressing, grappling, tackling, throwing preparation, contact sport demands, upper-limb strength profiling and progress tracking.

The Muscle Meter is used to measure force output during the test. When used on its own, the Muscle Meter primarily measures peak force, which is the highest force value produced during the effort. When used with Measurz, Muscle Meter data can be recorded and analysed with broader strength and force-time metrics, including peak force, impulse, torque, rate of force development, time to peak and fatigue index.

For routine shoulder horizontal adduction testing, peak force is usually the main metric. Force as a percentage of body weight may be useful if directly calculated from the client’s test force and body weight, especially for baseline comparison, side-to-side comparison and retesting. Torque may be useful if the lever arm is measured and a more biomechanical interpretation is required. Rate of force development and time to peak may be useful when rapid pushing, tackling, bracing, striking or sport contact tasks are relevant. Impulse may be useful if sustained force over a defined time window is intentionally tested. Fatigue index is only relevant if repeated or sustained horizontal adduction contractions are part of the protocol.

The result can support assessment reasoning and progress tracking, but it does not diagnose shoulder pain, pectoral injury, instability, nerve injury, injury risk, sport readiness or work capacity on its own.

What Is the Shoulder Horizontal Adduction [Muscle Meter] Test?

The Shoulder Horizontal Adduction [Muscle Meter] test is an isometric force assessment where the client pushes the arm across the body into the Muscle Meter without visible shoulder movement.

The movement direction is shoulder horizontal adduction. The test may be performed supine, seated, standing or in another standardised position depending on the goal and available setup.

The Muscle Meter is positioned so the client produces force across the body. Depending on the protocol, the device may be placed against the distal humerus, forearm or hand. Device placement should be comfortable and repeatable.

Consistent setup matters because shoulder elevation angle, elbow position, forearm position, trunk position, scapular position, device placement, strap angle, stabilisation and client effort can all affect the result. This test measures force output in a specific setup. It does not fully measure pressing ability, push-up capacity, throwing performance, contact sport capacity, shoulder control or movement quality on its own.

Step-by-Step Protocol / Practice

1. Prepare the client

Explain that the test measures how strongly they can push the arm across the body into the Muscle Meter.

Record baseline symptoms, shoulder discomfort, chest or pectoral symptoms, elbow symptoms, wrist symptoms, neck symptoms, fatigue, recent training and confidence with the test.

Use at least one submaximal practice trial so the client understands the movement direction and effort required.

2. Set the client position

Choose a repeatable test position.

Common options include supine, seated or standing. Supine or strap-stabilised setups may reduce trunk compensation and improve repeatability.

Record:

• body position
• side tested
• shoulder elevation angle
• shoulder start position
• elbow angle
• forearm position
• wrist or hand position
• trunk position
• scapular position
• whether straps or handheld resistance are used

3. Set up the Muscle Meter

Place the Muscle Meter or strap so the client can produce horizontal adduction force in the intended direction.

For improved repeatability, use a strap-stabilised or fixed setup where possible. If handheld, record this because handheld scores may be influenced by professional strength and stabilisation.

4. Place the device or strap

Position the device at the agreed contact point, such as the distal humerus, forearm or hand depending on the protocol.

Avoid uncomfortable pressure on bony areas, the elbow, wrist or sensitive tissue.

5. Stabilise the position

Stabilise the trunk and shoulder girdle so the client does not compensate with trunk rotation, shoulder elevation, elbow movement, wrist movement, scapular protraction or breath holding beyond the intended setup.

6. Give clear instructions

Use consistent instructions such as:

“Push your arm across your body into the device as hard as you can and hold.”

“Build up smoothly, then push hard.”

“Keep your trunk and shoulder position still.”

“Keep breathing.”

“Tell me if you feel pain, cramping, tingling or anything unusual.”

7. Record trials

Use 1–2 practice trials, then record 2–3 maximal trials.

A common contraction duration is 3–5 seconds.

Rest for 30–60 seconds between trials, or longer if symptoms, cramping or fatigue occur.

Record whether the final score uses the best trial or average of recorded trials.

8. Identify invalid trials

Repeat or mark a trial as invalid if:

• the trunk rotates
• the shoulder position changes
• the elbow angle changes
• the device slips
• the strap or anchor moves
• the client pushes in a different direction
• pain limits effort
• the client starts before the device is ready
• the professional cannot hold the device steady
• the effort becomes more of a trunk or whole-body push than shoulder horizontal adduction

9. Record symptoms

Record shoulder pain, chest or pectoral discomfort, elbow pain, wrist pain, neck symptoms, paraesthesia, cramping, confidence and apprehension.

For retesting, match the same position, device placement, shoulder angle, instructions, contraction duration, rest period, scoring method and symptom recording.

Why It Is Used

The Shoulder Horizontal Adduction [Muscle Meter] test is used to quantify horizontal adduction force output in a repeatable setup.

It may be useful for:

• baseline shoulder strength assessment
• side-to-side comparison
• monitoring change over time
• tracking upper-limb strength after reduced loading
• supporting pushing and pressing strength profiling
• assessing contact, grappling, tackling or bracing strength context
• reviewing force output during cross-body pushing tasks
• comparing strength with shoulder ROM, push tests, push-up testing and horizontal abduction testing
• client education

The test should support assessment reasoning. It should not be used as a stand-alone diagnostic or clearance measure.

What It Measures

The test primarily measures isometric shoulder horizontal adduction force in the chosen setup.

It may provide useful information about:

• horizontal adduction force capacity
• pectoralis and anterior shoulder force context
• side-to-side force difference
• confidence producing cross-body pushing force
• pain response during resisted horizontal adduction
• change in force over time
• relationship between strength and related pushing or contact tasks

It does not directly measure:

• isolated pectoralis strength
• tissue integrity
• shoulder diagnosis
• pressing technique
• push-up capacity
• contact sport performance
• shoulder endurance
• work capacity
• sport readiness

Understanding the Result, Reference Values and What to Look For

What a higher or lower result may suggest

A higher score may suggest greater horizontal adduction force output in that specific setup. A lower score may suggest reduced force output, but the reason should be interpreted carefully.

Lower force may be influenced by pain, apprehension, poor familiarisation, fatigue, guarding, shoulder symptoms, chest discomfort, inconsistent device placement, poor stabilisation, altered shoulder angle or reduced confidence.

One result should not be interpreted in isolation. Interpretation is strongest when the same setup is repeated over time and reviewed alongside symptoms, confidence, movement quality, related tests and functional goals.

What can influence the result

Important influences include:

• shoulder elevation angle
• shoulder start position
• elbow angle
• device placement
• strap angle
• trunk position
• scapular position
• stabilisation
• pain
• apprehension
• fatigue
• guarding
• breath holding
• client confidence
• professional strength if handheld

Normative, reference and comparative values

Published Muscle Meter-specific universal norms for Shoulder Horizontal Adduction are limited.

Direct hand-held dynamometry research has investigated shoulder horizontal adduction strength measurement and has shown that fixation method and professional stabilisation can influence reliability and interpretation. Belt-fixed or fixed setups may improve repeatability, especially when force exceeds what the professional can stabilise manually.

For most Measurz use, the most useful comparisons are:

• the client’s own baseline
• right versus left comparison
• change across retests
• pain or symptom response
• confidence during testing
• relationship to related shoulder and upper-limb assessments
• bodyweight-normalised force if directly calculated

A side-to-side difference of around 10% or more is often worth reviewing more closely in strength testing, especially if it matches symptoms, previous injury, confidence changes or functional differences. This should not be used as a strict pass/fail rule.

Reference values provide context, not diagnostic or clearance cut-offs.

Practical interpretation priorities

Use this order:

• compare with the client’s own baseline
• compare right and left sides when relevant
• consider symptoms during and after testing
• consider confidence and effort quality
• review whether compensations were present
• compare with related strength, mobility or performance tests
• relate the result to sport, gym, work or daily-life demands
• retest under the same conditions to monitor change
• do not use reference values as pass/fail criteria

What to Look at for Each Relevant Muscle Meter Metric

Peak force

Use for maximum horizontal adduction force output, baseline strength, side-to-side comparison, progress tracking and comparing force across retests.

Look for best score or average score, consistent setup, side-to-side difference, change from baseline, pain response and compensation during maximal effort.

Force as percentage of body weight

Use only when calculated directly from test force and body weight.

Look for changes over time and side-to-side differences. Do not treat it as a universal target unless the comparison data use the same method.

Torque

Use only when lever arm is measured and a more biomechanical interpretation is needed.

Torque may help when arm length or device contact point changes the raw force reading. It should not be used as normative data unless the reference data match the setup closely.

Rate of force development

Use when rapid horizontal adduction force production matters, such as tackling, grappling, striking, bracing or explosive pushing tasks.

Look for early force production and whether RFD changes while peak force stays similar.

Time to peak

Use to understand whether force is produced quickly or gradually.

Look for delayed peak force, faster time to peak across retests, and whether a slower time reflects caution, pain, poor cueing or actual performance difference.

Impulse

Use only if a sustained force window is intentionally tested.

Look for whether the client can produce and sustain force briefly and whether impulse improves while peak force stays similar.

Fatigue index

Use only if repeated or sustained horizontal adduction contractions are part of the protocol.

Look for drop-off across repeated trials, symptom-related fatigue and whether fatigue improves across a training block.

Assessing and Providing Context for Different Client Populations

Youth clients

Consider growth, maturation, coordination, attention, training age and familiarisation. Practice trials are important so the client learns to push across the body without excessive trunk or shoulder compensation.

Adults and general fitness clients

Use the test for baseline strength, progress tracking and confidence with pushing and cross-body force. Compare results with shoulder ROM, push-up capacity and general training goals.

Older adults

Consider shoulder comfort, chest wall symptoms, fatigue, daily pushing tasks and confidence. A lower score may provide useful context, but it should not be interpreted without functional assessment.

Athletes and sport clients

Consider contact sport, grappling, tackling, throwing, bracing, pressing and gym demands. Peak force alone does not equal sport performance, but it can support a broader upper-limb strength profile.

Workplace and manual task clients

Consider pushing, pulling, carrying, bracing, reaching and manual handling demands. Do not use one strength score to clear work duties.

Clients returning after injury

Use the test to monitor force output, confidence and symptom response over time. Strength alone should not confirm readiness.

Clients with pain or persistent symptoms

Pain, fear, guarding, fatigue, apprehension and confidence may influence force. Record symptoms carefully and compare with related findings.

Higher body mass clients

Absolute force and force relative to body mass may both be useful. Avoid assumptions and interpret the result in relation to goals, symptoms and function.

Reliability, Validity and Measurement Considerations

Repeatability improves when the same setup is used each time.

Record and standardise:

• same body position
• same side tested
• same shoulder elevation angle
• same shoulder start position
• same elbow position
• same trunk position
• same scapular position
• same device placement
• same strap setup, if used
• same anchor height and distance, if straps are used
• same stabilisation
• same instructions
• same contraction duration
• same rest period
• same scoring method
• same symptom and compensation recording

Research on shoulder horizontal adduction dynamometry supports the importance of reliable fixation and consistent method. Handheld testing can be useful, but may be affected by professional strength. Strap-stabilised or belt-fixed setups can improve consistency where available.

Common Errors and Limitations

Common errors include:

• inconsistent device placement
• changing shoulder elevation angle
• changing elbow position
• allowing trunk rotation
• allowing shoulder elevation or shrugging
• allowing scapular movement beyond the intended setup
• poor stabilisation
• device slipping
• strap or anchor movement
• breath holding
• testing through high pain
• comparing different protocols directly
• treating the score as a diagnosis

Limitations include:

• testing is setup-dependent
• manual resistance may be limited by professional strength
• strap setup requires careful anchor control
• Muscle Meter-specific universal norms may be limited
• pain, fear or guarding can reduce force output
• peak force does not measure endurance or movement quality
• side-to-side symmetry does not automatically mean function is ready for sport or work
• the test does not determine sport or work readiness on its own

Practical Applications

The Shoulder Horizontal Adduction [Muscle Meter] test may be useful for:

• establishing a baseline
• tracking horizontal adduction strength over time
• comparing right and left sides
• reviewing force relative to body weight if directly calculated
• monitoring response to exercise or intervention
• supporting pushing, pressing and contact strength profiling
• comparing with shoulder ROM, push tests, push-up force and horizontal abduction strength
• educating the client about measurable progress
• reviewing sport, gym, work or daily-life demands

Ideas to Make the Result Better

If force is low on both sides, consider assessing shoulder ROM, chest wall comfort, pushing strength, push-up capacity, grip strength, fatigue and confidence with loading.

If one side is much lower, compare with symptoms, injury history, shoulder mobility, pectoral discomfort, neck symptoms, upper-limb strength and functional tasks.

If pain limits the result, record the pain response and review whether the test position, pressure point or effort level needs modification.

If force is good but function is limited, compare with push-up capacity, pressing tolerance, contact tasks, throwing, scapular control and sport or work demands.

If the client is improving, keep the same protocol and monitor whether strength, symptoms, confidence and function improve together.

Recommended Standard Protocol Summary

Position: Supine, seated or standing, standardised
Start position: Shoulder and elbow position recorded
Joint or trunk angle: Record shoulder elevation angle, elbow angle, trunk position and scapular position
Trials: 1–2 practice trials, then 2–3 recorded trials
Contraction duration: 3–5 seconds
Rest: 30–60 seconds between efforts
Metric: Peak force, plus percentage of body weight only if directly calculated
Attachment or device setup: Muscle Meter positioned for shoulder horizontal adduction force; strap-stabilised or fixed setup if used
Final score: Best trial or average of trials
Key retesting requirement: Same position, device placement, shoulder angle, instructions, contraction duration, rest and scoring method

FAQs

What does the Shoulder Horizontal Adduction test measure?

It measures isometric force output as the client pushes the arm across the body.

Is it an isolated pectoralis test?

No. It may bias the pectoral and anterior shoulder region, but other shoulder, scapular and trunk muscles may contribute.

Should the result be recorded as percentage of body weight?

It can be if calculated directly from test force and body weight. Use it for baseline and side-to-side comparison rather than as a universal target.

Are there universal Muscle Meter norms for this test?

Published universal Muscle Meter norms for this exact protocol are limited. Baseline comparison, side-to-side comparison and retesting under the same setup are usually more useful.

Can this test diagnose shoulder or pectoral injury?

No. It can measure force output, but it does not diagnose the cause of symptoms on its own.

Why does shoulder angle matter?

Changing the shoulder angle changes the force direction and muscle contribution. Record the angle and repeat it at retest.

What can make the result unreliable?

Different device placement, shoulder position, trunk compensation, stabilisation, fatigue, pain and inconsistent instructions can affect results.

What should be recorded in Measurz?

Record side, position, shoulder angle, device placement, peak force, percentage of body weight if directly calculated, symptoms, compensations, confidence, scoring method and related findings.

Key Takeaways

• Shoulder Horizontal Adduction [Muscle Meter] measures isometric cross-body pushing force.
• Peak force is usually the main routine Muscle Meter metric.
• Percentage of body weight should only be used when calculated directly from force and body weight.
• Setup consistency is essential because shoulder angle, device placement and stabilisation strongly affect the result.
• Baseline comparison, side-to-side comparison and retesting consistency are usually more useful than broad norms.
• Measurz should capture setup, symptoms, bodyweight-normalised values where directly calculated, compensations and retesting conditions.

References

Katoh, M., & Isozaki, K. (2015). Absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer. Journal of Physical Therapy Science, 27(7), 2125–2128. https://doi.org/10.1589/jpts.27.2125

Katoh, M. (2015). Test-retest reliability of isometric shoulder muscle strength measurement with a handheld dynamometer and belt. Journal of Physical Therapy Science, 27(6), 1719–1722. https://doi.org/10.1589/jpts.27.1719

Manchado, M. C., et al. (2023). Isometric shoulder testing using a forcemeter is a reliable method for muscle function evaluation. Sensors, 23(22), 9106. https://doi.org/10.3390/s23229106

Moraux, A., Canal, A., Ollivier, G., Ledoux, I., Doppler, V., Payan, C., & Hogrel, J.-Y. (2023). Psychometric properties of a standardized protocol of muscle strength assessment by hand-held dynamometry in healthy adults. BMC Musculoskeletal Disorders, 24, 311. https://doi.org/10.1186/s12891-023-06400-2