Roymech engineering encyclopedia

Human Strength and Endurance Data for Engineering Design




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This page provides human strength and endurance data for engineering design, including static, dynamic and explosive strength characteristics relevant to ergonomics and mechanical design.

For control forces and operator interaction, see machine interfaces and control design. Human strength data should also be considered alongside anthropometric data and human body dimensions when designing equipment and workspaces.

The information supports engineers in designing equipment, assessing manual handling tasks and understanding human performance limits. Human capability varies considerably, however, and the values on this page should be treated as indicative engineering data rather than universal design limits.

Human Strength and Endurance Overview

Human strength varies considerably between individuals and depends on factors including body size, age, physical condition, posture, joint position, grip, direction of force and the duration and frequency of the task.

The values on this page are provided as general engineering guidance and should not be treated as fixed human capability limits. Where manual handling, operator safety or regulatory compliance is involved, the relevant legislation, standards and validated human-factors data should be used for the intended user population and application.

Strength Categories and Characteristics

Human strength can broadly be considered in three categories:

  • Static (isometric) strength — force exerted while the body or limb remains substantially stationary.
  • Dynamic strength — force exerted while the body or limbs are moving, such as when lifting, pushing or pulling.
  • Explosive or impulsive strength — high force or power produced for a short period of time.

Factors Affecting Human Strength

The force that a person can exert is not a single fixed value. Capability can change significantly with the position of the body, the direction in which force is applied and the way the load or control is gripped.

Important factors include:

  • Body size and physical condition
  • Age and individual capability
  • Posture and joint position
  • Grip size, shape and surface condition
  • Direction of applied force
  • Whether one or both hands are used
  • Duration of the exertion
  • Frequency and repetition of the task
  • Fatigue and available recovery time
  • Clothing and personal protective equipment
  • Working temperature and environmental conditions

Strength, Endurance and Repetitive Tasks

Maximum strength and endurance should not be treated as the same design quantity. A person may be capable of producing a relatively high force for a short period but may be unable to sustain that force or repeat it frequently without fatigue.

Task frequency and duration are therefore important engineering considerations. A force or movement required only occasionally may present a different ergonomic demand from the same action repeated many times during a working shift.

Frequency should not be considered in isolation. The required force, posture, reach, duration, load, working environment and consequences of an error or loss of control should also be considered.

Selected Human Strength Values

The following values provide indicative examples of the forces and torques that may be associated with particular human actions. They are useful for developing an appreciation of the approximate magnitude of human forces but should not be treated as universal design values.

Human capability varies considerably with the population, test method, posture, equipment geometry and operating conditions. For safety-critical design, manual handling assessment or specification of operator forces, appropriate current standards and validated data for the intended user population should be used.

Data source: Selected human strength data on this page are derived from Peebles, L. and Norris, B. J. (1998), Adultdata: The Handbook of Adult Anthropometric and Strength Measurements – Data for Design Safety, Department of Trade and Industry, UK, URN 98/736.


Gripping Strength

Persons aged 31–50 years; gripping a test handle approximately 50 mm wide × 100 mm long.

Sex Mean (N) S.D. (N) Range (N)
Male 54.03 7.04 43.10 – 64.40
Female 31.42 4.99 21.50 – 37.30

Turning a Circular Knob

Persons aged 31–50 years; smooth circular knob approximately 40 mm diameter × 20 mm deep with a horizontal axis.

Sex Mean (Nm) S.D. (Nm) Range (Nm)
Male 4.48 1.69 2.56 – 6.08
Female 3.89 1.32 1.45 – 6.13

Twisting a Lid

Persons aged 31–50 years; knurled lid approximately 65 mm diameter.

Sex Mean (Nm) S.D. (Nm) Range (Nm)
Male 7.94 1.67 5.29 – [verify original upper value]
Female 4.75 1.72 1.22 – 6.93

Note: The upper value in the original male range should be checked against the source data before publication because the legacy entry contains an apparent transcription error.


Pulling a Horizontal Bar

Persons aged 31–50 years; horizontal cylindrical bar 20 mm diameter × 300 mm long, using one hand.

Sex Mean (N) S.D. (N) Range (N)
Male 477.3 213.75 408.48 – 647.03
Female 294.87 96.29 189.75 – 460.09

Pushing a Horizontal Bar

Persons aged 31–50 years; horizontal cylindrical bar 20 mm diameter × 300 mm long, using one hand.

Sex Mean (N) S.D. (N) Range (N)
Male 457.22 99.37 290.65 – 543.61
Female 314.47 136.42 215.91 – 500.26

Pressing a Pedal

Persons aged 31–50 years; pedal 400 mm long and 30 mm wide, positioned within a 55 mm wide space to restrict the amount of the foot that could be placed on the pedal.

Sex Mean (N) S.D. (N) Range (N)
Male 329.183 129.99 173.00 – 579.70
Female 237.99 106.80 121.50 – 435.60

Arm Strength Values

The following values are based on US data and represent adjusted values derived from tests on young men. They are retained as indicative engineering reference data only. The force that can be exerted by the arm depends strongly on posture, arm position, direction of force and individual capability.

Arm strength positions for seated operator


Angle B C D E F G
  L (N)R (N) L (N)R (N) L (N)R (N) L (N)R (N) L (N)R (N) L (N)R (N)
180° 177.6184.8 149.6177.6 3249.6 46.660.8 46.671.2 28.849.6
150° 149.6199.2 106.4149.6 53.664 6471.2 53.671.2 28.853.6
120° 120.8149.6 92.8128 60.885.6 74.492.8 71.278.4 3653.6
90° 113.6132 78.4128 60.871.2 74.492.8 56.864 3656.8
60° 92.885.6 78.4120.8 53.671.2 60.871.2 42.460.8 LR

Lifting Height

The following legacy data provide indicative lifting capabilities for young, fit men with adequate working space:

  • 180 N to a lifting height of approximately 1.5 m
  • 280 N to a lifting height of approximately 0.9 m
  • 590 N to a lifting height of approximately 0.6 m
  • 680 N to a lifting height of approximately 0.3 m

These values should not be interpreted as recommended manual handling limits. The acceptability of a lifting task depends on factors including load, frequency, duration, starting and finishing height, horizontal reach, twisting, grip, posture and the characteristics of the intended user population.


Leg Strength

The legs are used in standing, walking, lifting, cycling and the operation of foot controls and can generally exert considerably greater forces than the arms. However, published leg-strength values vary substantially according to posture, joint angle, test method and the population being measured.

For this reason, simple leg-strength values should be used cautiously. Validated data and appropriate standards should be used where leg force forms an important part of an equipment or workplace design.

Illustrative Bicycle Pedal Torque

As a simple mechanics example, the approximate static torque produced when the full body weight is applied to one horizontal bicycle pedal may be estimated from:

Torque = Force × Pedal Radius

For a person of mass 82 kg and a pedal radius of 160 mm, using body weight as the applied force gives an approximate torque of 129 Nm.

This is an illustrative mechanics calculation and should not be interpreted as a general human leg-strength design value.


Standing Strength

Standing push, pull and operating forces depend strongly on body posture, foot position, available support, direction of force and the friction between the footwear and floor. Values should therefore be interpreted in relation to the test arrangement and intended application.

Standing human strength and force positions

Engineering Design Considerations

Human strength data should be applied in the context of the actual engineering task. A value measured under controlled test conditions does not automatically represent a suitable operating force or manual handling limit.

Engineers should consider the intended user population together with the posture, reach, grip, task frequency, duration, working environment and consequences of an error or loss of control.

For frequently repeated operations, reducing the required force can be particularly important because fatigue and cumulative physical loading may become significant. An occasional inspection or adjustment may justify different ergonomic criteria from a control operated hundreds of times during a working shift, subject to the applicable safety and regulatory requirements.

Ergonomic guidance should also be considered alongside other engineering requirements including safety, security, maintainability and operational needs. Where requirements conflict, the applicable legislation, standards and industry-specific procedures should be established and the engineering decision appropriately assessed.

References

Peebles, L. and Norris, B. J. (1998), Adultdata: The Handbook of Adult Anthropometric and Strength Measurements – Data for Design Safety, Department of Trade and Industry, UK, URN 98/736.

Peebles, L. and Norris, B. J. (2003), "Filling 'gaps' in strength data for design", Applied Ergonomics, Vol. 34, No. 1, pp. 73–88.

Frequently Asked Questions

What is human strength data used for in engineering?

Human strength data is used to design equipment, controls and workspaces that can be safely operated by the intended user population without excessive force or risk of injury.

What are the types of human strength?

Human strength is generally categorised as static or isometric strength, dynamic strength and explosive or impulsive strength, depending on how force is applied over time.

How accurate is human strength data?

Human strength varies considerably between individuals and with posture, task and test conditions. The values presented on this page are indicative and should not be used for detailed or safety-critical design without reference to validated data sources and relevant standards.

How does human strength affect mechanical design?

Human strength influences the forces required to operate controls, handle components and interact with equipment. The required capability should be considered together with the intended user population, task frequency, posture and duration when designing equipment and workplaces.

See Also

For access and clearance considerations, see human access space requirements.