Strength Endurance Test: Shoulder Isometric Endurance Tests (10% BW)

The Shoulder Isometric Endurance Tests at 10% body weight assess the time a client can hold a shoulder position against a load equivalent to 10% of body weight. This is a higher-load endurance option that may be suitable for stronger or athletic clients when the position and load are standardised.

Introduction

Shoulder endurance is important in overhead sport, gym training, work tasks and athletic positions requiring sustained shoulder control. While maximal isometric strength tests show peak force capacity, endurance tests provide additional information about how long the shoulder can maintain a position under load.

The 10% BW version is more demanding than the 5% BW version and may be more suitable for stronger or well-trained clients. It should be interpreted carefully because formal norms for this exact protocol are limited.

Quick Summary

Test name: Shoulder Isometric Endurance Tests — 10% BW
Category: Shoulder strength endurance / isometric endurance
Load: 10% of body weight
Test positions: Abduction, external rotation and flexion
Primary score: Time held in seconds
Best suited to: Stronger, trained or athletic clients
Key limitation: Exact published norms for 10% BW endurance holds are limited.

What Is This Assessment?

This assessment requires the client to hold a shoulder position against a load equal to 10% of their body weight. Common positions include shoulder abduction, shoulder external rotation and shoulder flexion.

The test records how long the client can maintain the position without losing form, compensating or stopping due to fatigue or symptoms.

Why It Is Used

The 10% BW shoulder endurance tests may be used to assess:

• Shoulder isometric endurance
• Tolerance to sustained shoulder loading
• Fatigue response in specific shoulder positions
• Side-to-side differences
• Baseline and retest performance
• Progress after shoulder endurance training
• Sport or gym-related shoulder capacity

What It Measures

The primary score is:

Time held in seconds

The result may reflect:

• Shoulder muscle endurance
• Rotator cuff contribution
• Deltoid endurance
• Scapular control
• Trunk control
• Load tolerance
• Pain or symptom response
• Familiarisation and motivation

It does not isolate one muscle or confirm the reason for reduced performance.

Who It Is Useful For

The 10% BW version may be useful for:

• Overhead athletes
• Gym and strength-training clients
• Contact sport athletes
• Throwing athletes
• Racquet sport athletes
• Professionals monitoring shoulder endurance
• Clients who find 5% BW too easy

It may not be suitable for clients with low current shoulder tolerance or those unable to safely hold the required positions.

Equipment Required

• Dumbbell, cuff weight or equivalent external load
• Stopwatch or Measurz stopwatch
• Body mass measurement
• Stable testing surface
• Optional inclinometer to standardise shoulder position
• Optional AR measurement to document setup and arm position
• Optional Measurz metronome if using any rhythm-based related shoulder endurance protocol
• MAT isometric measurement tools, including Anker, Gripper and Muscle Meter, for related shoulder isometric strength testing
• Measurz / MAT platform for recording load, side, time, symptoms and retest comparison

The 10% BW test is primarily a time-to-task-failure endurance test. For a fuller shoulder profile, pair it with MAT isometric tools such as Anker, Gripper or Muscle Meter to record related peak force or strength measures.

Step-by-Step Protocol

1. Load Calculation

Calculate:

10% body weight = body weight × 0.10

For example:

• 70 kg client = 7 kg load
• 80 kg client = 8 kg load
• 90 kg client = 9 kg load

Round load consistently and record the exact load used.

2. Test Positions

Possible positions include:

Shoulder abduction: arm held out to the side at the selected angle.
Shoulder flexion: arm held forward at the selected angle.
External rotation: shoulder and elbow position must be standardised and recorded.

3. Test Procedure

1. Explain the position and stopping criteria.
2. Position the client and apply the load.
3. Start timing once the client reaches the correct position.
4. Stop timing when the client loses position, compensates, drops the arm, reports intolerable symptoms or chooses to stop.
5. Record time in seconds.
6. Repeat on the other side if appropriate.
7. Record pain, symptoms and compensation.

Scoring and Interpretation

The primary score is:

Time held in seconds

Interpretation should consider:

• Load used
• Body mass
• Side tested
• Dominance
• Shoulder angle
• External rotation position
• Pain or symptoms
• Scapular compensation
• Trunk lean
• Fatigue behaviour

Normative Data, Benchmarks or Reference Values

Published normative data for the exact 10% BW shoulder isometric endurance protocol are limited. Therefore, interpretation should prioritise:

• Baseline comparison
• Side-to-side comparison
• Internal Measurz benchmarks
• Sport and activity demands
• Symptom response
• Comparison with the 5% BW version

Practical 10% BW Endurance Guide

Use these as broad practical field bands only:

• Strong endurance at 10% BW: 45 seconds or more
• Moderate endurance: 25–45 seconds
• Developing endurance: 15–25 seconds
• Low current tolerance: under 15 seconds

These are not formal norms and should not be used as pass/fail criteria.

Reliability and Validity

Direct reliability evidence for the exact 10% BW shoulder endurance holds is limited. However, shoulder isometric strength research supports the importance of standardised position, movement direction, device and protocol.

A 2023 study published normative isometric shoulder strength values in healthy adults and highlighted that age, sex, body size, activity level and dominance can influence shoulder strength.  

Research on test-retest reliability of isometric shoulder strength during abduction and rotation tasks also supports the importance of standardising shoulder position and measurement method.  

Common Errors and Limitations

Common errors include:

• Incorrect load calculation
• Rounding load inconsistently
• Changing shoulder angle between tests
• Allowing trunk lean
• Allowing scapular elevation
• Not recording symptoms
• Comparing 5% BW and 10% BW results directly
• Testing without familiarisation
• Using different equipment between sessions

Practical Applications

These tests can help professionals:

• Monitor shoulder endurance under higher load
• Compare sides
• Track endurance changes over time
• Identify positions that fatigue earlier
• Combine endurance data with shoulder strength and range results
• Build internal Measurz benchmarks for sport or training groups

How to Record This in Measurz / MAT

Record:

• Test name
• Load percentage: 10% BW
• Exact load used
• Body mass
• Side tested
• Dominance
• Test position: abduction, external rotation or flexion
• Shoulder angle
• Time held
• Units: seconds
• Pain score
• Symptoms
• Compensations
• Reason for stopping
• Retest date
• Related shoulder strength and endurance tests

Measurz can record endurance hold times, while MAT isometric tools such as Anker, Gripper and Muscle Meter can support related strength testing. The inclinometer can help standardise shoulder angle, the stopwatch can record hold time, and Measurz can store this alongside ROM, orthopaedic tests, outcome measures and other shoulder assessments.

Related Tests or Internal Links

• Shoulder Isometric Endurance Tests — 5% BW
• Posterior Shoulder Endurance Test
• Isometric Shoulder Abduction
• Isometric Shoulder External Rotation
• Athletic Shoulder Test
• Push-Up Test
• Closed Kinetic Chain Upper Extremity Stability Test

FAQs

What does the 10% BW shoulder endurance test measure?

It measures how long the client can maintain a shoulder position against a load equal to 10% of body weight.

Who should use the 10% BW version?

It is generally more suitable for stronger, trained or athletic clients who can safely tolerate higher shoulder loading.

Is 10% BW better than 5% BW?

Not necessarily. It is simply more demanding. The best version depends on the client’s capacity, goals and test purpose.

Are there published norms?

Published norms for this exact endurance protocol are limited, so baseline, side-to-side comparison and internal benchmarks are recommended.

Can MAT tools be used with this test?

Yes. The endurance test itself records hold time, while MAT tools such as Anker, Gripper and Muscle Meter can be used for related isometric shoulder strength testing.

Key Takeaways

• The 10% BW shoulder endurance test is a higher-load shoulder endurance assessment.
• The primary score is time held in seconds.
• Exact protocol and load must be recorded.
• Published norms are limited, so baseline and internal comparison are important.
• Measurz can track side, load, time, symptoms and progress.

References

Bradley, H., & Pierpoint, L. (2023). Normative values of isometric shoulder strength among healthy adults. International Journal of Sports Physical Therapy. https://doi.org/10.26603/001c.83938   

Westrick, R. B., Duffey, M. L., Cameron, K. L., Gerber, J. P., & Owens, B. D. (2013). Isometric shoulder strength reference values for physically active collegiate males and females. International Journal of Sports Physical Therapy.