prEN ISO 22675

Prosthetics - Testing of ankle-foot devices and foot units - Requirements and test methods (ISO 22675:2006)

ISO 22675:2006 primarily specifies a cyclic test procedure for ankle-foot devices and foot units of external lower limb prostheses, distinguished by the potential to realistically simulate those loading conditions of the complete stance phase of walking from heel strike to toe-off that are relevant to the verification of performance requirements such as strength, durability and service life.
In addition, ISO 22675:2006 specifies a static test procedure for prosthetic ankle-foot devices and foot units, consisting of a static proof test and a static ultimate strength test, distinguished, besides other features, by the potential to generate heel and forefoot forces at lines of action conforming to those occurring at the instants of maximum heel and forefoot loading during the cyclic test.

Prothetik - Prüfung von Knöchel-Fuß-Passteilen und Fußeinheiten - Anforderungen und Prüfverfahren (ISO 22675:2006)

Prothèses - Essais d'articulations cheville-pied et unités de pied - Exigences et méthodes d'essai (ISO 22675:2006)

L'ISO 22675:2006 spécifie essentiellement un mode opératoire d'essais cycliques portant sur les ensembles cheville-pied et les unités de pied des prothèses externes pour membres inférieurs. Ce mode opératoire se distingue par la possibilité de modéliser de manière réaliste les conditions de mise en contrainte pendant la phase complète d'appui lors de la marche (depuis l'attaque au talon jusqu'au décollement des orteils), qui sont pertinentes pour la vérification des exigences de performances telles que la résistance, la durabilité et la durée de vie de l'appareil.
En outre, l'ISO 22675:2006 spécifie un mode opératoire d'essai statique portant sur les ensembles cheville-pied et unités de pied prothétiques, qui comprend un essai statique de charge et un essai de résistance à la rupture. L'essai se distingue, entre autres, par la possibilité de générer des forces du talon et de l'avant du pied au niveau de lignes d'action comparables à celles développées au moment où s'exercent les contraintes maximales au niveau du talon et de l'avant du pied lors de l'essai cyclique.

Protetika - Preskušanje mehanizmov za gleženj in stopalo ter enot za stopalo - Zahteve in preskusne metode (ISO/DIS 22675:2021)

General Information

• Status: Not Published
• Publication Date: 01-Feb-2024
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: CEN/TC 293 - Technical aids for disabled persons
• Drafting Committee: CEN/TC 293 - Technical aids for disabled persons
• Current Stage: 3098 - Decision to reject - Consensus building
• Start Date: 13-Dec-2010
• Completion Date: 13-Dec-2010
• Directive: 2007/47/EC - Directive 2007/47/EC of the European Parliament and of the council of 5 September 2007 amending Council Directive 90/385/EEC on the approximation of the laws of the Member States relating to active implantable medical devices, Council Directive 93/42/EEC concerning medical devices and Directive 98/8/EC concerning the placing of biocidal products on the market
• Directive: 2017/745 - Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and repealing Council Directives 90/385/EEC and 93/42/EEC
• Directive: 93/42/EEC - Council Directive 93/42/EEC of 14 June 1993 concerning medical devices
• Mandate: M/575 - Medical devices in support of Regulation (EU) 2017/745 and in vitro diagnostic medical devices in support of Regulation (EU) 2017/746
• Ref Project: oSIST prEN ISO 22675:2022 - Prosthetics - Testing of ankle-foot devices and foot units - Requirements and test methods (ISO/DIS 22675:2021)

Relations

• Revises: EN ISO 22675:2006 - Prosthetics - Testing of ankle-foot devices and foot units - Requirements and test methods (ISO 22675:2006)
• Effective Date: 08-Jun-2022

Overview

prEN ISO 22675, titled "Prosthetics - Testing of ankle-foot devices and foot units - Requirements and test methods," is a vital European standard aligned with ISO 22675:2006. Published under the European Committee for Standardization (CEN), this standard specifies rigorous test methods for prosthetic ankle-foot devices and foot units. Its core focus is to establish reproducible cyclic and static test procedures simulating realistic loading conditions throughout the stance phase of human walking-from heel strike to toe-off.

The standard's testing framework enables stakeholders to verify essential performance metrics such as strength, durability, and service life of external lower limb prostheses. This ensures prosthetic devices meet the necessary reliability and safety levels for daily use in medical rehabilitation and mobility assistance.

Key Topics

• Cyclic Test Procedure

  • Simulates continuous loading during the full stance phase of walking
  • Focuses on repetitive loading to assess durability and fatigue performance
  • Replicates heel and forefoot loading corresponding to natural gait dynamics

• Static Test Procedure

  • Includes static proof and ultimate strength tests
  • Generates specific heel and forefoot forces reflecting peak loads encountered in use
  • Verifies structural integrity under both typical and extreme conditions

• Test Loading Conditions and Levels

  • Defined to represent varying activity intensities and patient weights
  • Detailed force vectors applied in relevant coordinate systems
  • Includes worst-case alignment scenarios to ensure comprehensive testing

• Test Sample Preparation and Compliance

  • Requirements for sample selection including size and completeness
  • Conditions for repeatability and reuse of test samples
  • Documentation protocols to support traceability and standard conformance

• Equipment and Accuracy

  • Specifications for test apparatus, end attachments, and jigs
  • Calibration and procedural accuracy to maintain test validity

Applications

prEN ISO 22675 is primarily applied in:

• Prosthetic Device Manufacturing
  Assists manufacturers in designing and validating ankle-foot prostheses to meet prescribed safety and performance benchmarks.

• Quality Assurance and Certification
  Enables independent testing laboratories and certification bodies to conduct standardized evaluations prior to market release.

• Clinical and Rehabilitation Settings
  Provides clinicians with assurance regarding prosthesis durability in supporting patient mobility throughout treatment and long-term use.

• Research and Development
  Supports engineering innovations by setting clear, reproducible criteria for functional testing under realistic biomechanical conditions.

Related Standards

• ISO 10328 – Structural testing of lower-limb prostheses
• ISO 22523 – Requirements for lower limb prostheses alignment
• ISO 14155 – Clinical investigation of medical devices for human subjects
• CEN EN 1621 – Protective devices for motorcyclists, relevant for prosthetic impact resistance

By aligning test protocols with prEN ISO 22675, manufacturers and users of ankle-foot prosthetic devices can ensure enhanced performance, improved patient safety, and compliance with internationally recognized best practices in prosthetic testing.

Keywords: prosthetics testing, ankle-foot prosthesis, prosthetic foot units, cyclic testing, static proof test, lower limb prostheses, prosthetics durability, ISO 22675, prosthetic device standards, prosthetic performance verification

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2022
Protetika - Preskušanje mehanizmov za gleženj in stopalo ter enot za stopalo -
Zahteve in preskusne metode (ISO/DIS 22675:2021)
Prosthetics - Testing of ankle-foot devices and foot units - Requirements and test
methods (ISO/DIS 22675:2021)
Prothetik - Prüfung von Knöchel-Fuß-Passteilen und Fußeinheiten - Anforderungen und
Prüfverfahren (ISO/DIS 22675:2021)
Prothèses - Essais d'articulations cheville-pied et unités de pied - Exigences et
méthodes d'essai (ISO/DIS 22675:2021)
Ta slovenski standard je istoveten z: prEN ISO 22675
ICS:
11.040.40 Implantanti za kirurgijo, Implants for surgery,
protetiko in ortetiko prosthetics and orthotics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT INTERNATIONAL STANDARD
ISO/DIS 22675
ISO/TC 168 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-12-23 2022-03-17
Prosthetics — Testing of ankle-foot devices and foot units
— Requirements and test methods
Prothèses — Essais d'articulations cheville-pied et unités de pied — Exigences et méthodes d'essai
ICS: 11.040.40
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22675:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2021

ISO/DIS 22675:2021(E)
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/DIS 22675:2021(E)
Contents Page
Foreword . vi
Introduction .viii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Designations and symbols of test forces . 2
5 Strength and related performance requirements and conditions of use .3
6 Coordinate system and test configurations . 4
6.1 General . 4
6.2 Origin and axes of the coordinate system . 4
6.3 Reference points. 5
6.4 Test force F . 6
6.5 Line of application of test force F . 6
6.6 Lines of action of resultant reference forces F and F . 6
R1 R2
6.7 Longitudinal axis of the foot and effective ankle joint centre . 6
6.7.1 General . 6
6.7.2 Longitudinal axis of the foot . 7
6.7.3 Effective ankle-joint centre, C . 7
A
7 Test loading conditions and test loading levels . 8
7.1 Test loading conditions . 8
7.2 Test loading levels and Test Ranges . 9
8 Values of test forces, dimensions and cycles .10
9 Compliance .18
9.1 General . 18
9.2 Particular arrangements and requirements concerning the part required to
connect an ankle-foot device or foot unit to the remainder of a prosthetic structure . 19
9.2.1 Arrangements for testing . 19
9.2.2 Requirements for claiming compliance . 19
9.3 Number of tests and test samples required to claim compliance with this document . 19
9.4 Multiple use of test samples . . 19
9.4.1 General . 19
9.4.2 Restriction .20
9.5 Testing at particular test loading levels not specified in this document .20
10 Test samples .21
10.1 Selection of test samples . 21
10.1.1 General . 21
10.1.2 Selection of ankle-foot devices and foot units of appropriate size of foot . 21
10.2 Types of test sample . .22
10.2.1 Complete structure . 22
10.2.2 Partial structure .22
10.3 Preparation of test samples . 22
10.4 Identification of test samples . 22
10.5 Alignment of test samples .22
10.6 Worst-case alignment position of test samples . 23
11 Responsibility for test preparation .25
12 Test submission document . .26
12.1 General requirements .26
12.2 Information required for test samples . 26
12.3 Information required for tests . 27
iii
ISO/DIS 22675:2021(E)
12.3.1 General . 27
12.3.2 For all tests . 27
12.3.3 For the static proof test and the static ultimate strength test . 27
12.3.4 For the static ultimate strength test . 27
12.3.5 For the cyclic test . 27
13 Equipment .28
13.1 General .28
13.2 End attachments .28
13.2.1 General .28
13.2.2 Proof test of end attachments.28
13.3 Jig (optional) . 31
13.4 Test equipment . 31
13.4.1 Test equipment to perform static heel and forefoot loading . 31
13.4.2 Test equipment to perform cyclic loading . 32
14 Accuracy .38
14.1 General .38
14.2 Accuracy of equipment .39
14.3 Accuracy of procedure . 39
15 Test principles .39
15.1 General .39
15.2 Static test procedure .40
15.3 Cyclic test procedure .44
16 Test procedures . 44
16.1 Test loading requirements .44
16.1.1 Preparation for test loading .44
16.1.2 Test loading conditions . 47
16.2 Static proof test .48
16.2.1 Test method .48
16.2.2 Performance requirement .50
16.2.3 Compliance conditions .50
16.3 Static ultimate strength test . 52
16.3.1 Test method . 52
16.3.2 Performance requirements .54
16.3.3 Compliance conditions .54
16.4 Cyclic test . 55
16.4.1 Test method . 55
16.4.2 Performance requirements .58
16.4.3 Compliance conditions .58
16.5 Separate static test in torsion . 61
16.5.1 General . 61
16.5.2 Purpose of test . 61
16.5.3 Test method . 61
16.5.4 Performance requirements . 62
16.5.5 Compliance conditions .63
17 Test laboratory/facility log .63
17.1 General requirements .63
17.2 Specific requirements .63
18 Test report .63
18.1 General requirements .63
18.2 Specific requirements .64
18.3 Options.64
19 Classification and designation .64
19.1 General .64
19.2 Example of classification and designation .64
iv
ISO/DIS 22675:2021(E)
20 Compliance to Standard .65
20.1 General .65
20.2 Example of identifier layout .65
20.3 Identifier placement .65
Annex A (informative) Reference data for the specification of the test loading conditions
and test loading levels of this document .66
Annex B (informative) Guidance on the application of an alternative static ultimate
strength test .75
Annex C (informative) Application of an additional test loading level P6, P7, and P8 .76
Annex D (informative) Summary of the records to be entered in the test laboratory/facility
log .77
[1]
Annex E (informative) Information on Technical Report ISO/TR 22676 .83
Annex F (informative) Reference to the essential principles of safety and performance
of medical devices according to ISO/TR 16142 .95
Annex G (informative) Background Data (reduced) of the six minute walk test for Adults
(see [3]) .96
Annex ZA (informative) Relationship between this European standard and the General
Safety and Performance Requirements of Regulation (EU) 2017/745 aimed to be
covered .97
Bibliography .99
v
ISO/DIS 22675:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 168, Prosthetics and orthotics.
This third edition cancels and replaces the second edition (ISO 22675:2016), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Test loading levels P7 and P8 have been introduced in Table 11, Table A.1, Table C.1, Table C.2 and the
clauses pointing at these tables have been updated or removed.
— Table 10 "Test forces for all tests and prescribed number of cycles for the cyclic test, for all test
loading levels and for all Test Ranges" has been revised.
— The content of Annex C has changed from informative to normative by moving it from Annex into
the standard.
— This edition specifies three Test Ranges by specifying locomotion profiles in combination with the
number of test cycles for the cyclic test in relation to the intended use. Furthermore it clarifies the
position of the Ankle joint related to the connecting device of ankle foot devices and it emphasizes
the fact, that the top load application point Pt shall not bear moments exceeding the accuracy defined
in this standard.
— This edition describes, how to consider testing ankle-foot-devices and foot units used in less
severe loading conditions than the average most active users do. Therefore this standard not only
distinguishes the test level (p-level) by the applied force (profile), but also the Test Range (R) by
different tilting or static plate angles.
— This edition takes into consideration, that technical development for example in the area of robotics
increase the availability for sensors, signal processors and control units, which can be used for the
defined test of this standard too. Therefore the coordinate systems for geometries and forces of this
Standard are adapted to the ISO definitions for robotics.
vi
ISO/DIS 22675:2021(E)
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
vii
ISO/DIS 22675:2021(E)
Introduction
This document offers alternatives to the structural tests on ankle-foot devices and foot units specified
in 17.2 of ISO 10328:2016, which still suffer from several “weaknesses”, such as:
a) the inconsistency of the lines of application of the heel and forefoot test forces with those of the test
forces of test loading conditions I and II for the principal structural tests specified in 16.2 (static
tests) and 16.3 (cyclic test) of ISO 10328:2016;
b) the unrealistic course and magnitude of loading in the phase between the instants of maximum
heel and forefoot loading during the cyclic test;
c) the effect of periodical “stepping in a hollow” during the cyclic test, resulting from simultaneous
heel and forefoot loading at different angles.
In this relation it is important to note that the complexity of the test equipment required for the testing
of ankle-foot devices and foot units specified in this document is low, comparable to that of the test
equipment required for the corresponding separate structural tests specified in ISO 10328:2016.
Apparently, basic components of both types of test equipment are similar and can be re-used in a
modified design.
Finally, it has to be noted that the potential of the general concept applied to the test procedures
specified in this document allows other applications directed to the assessment of specific performance
characteristics of ankle-foot devices and foot units that may be of relevance in the future.
NOTE Further guidance on the specification of the test loading conditions and test loading levels and on
the design of appropriate test equipment is given in a separate document, published as a Technical Report (see
Bibliography).
viii
DRAFT INTERNATIONAL STANDARD ISO/DIS 22675:2021(E)
Prosthetics — Testing of ankle-foot devices and foot units
— Requirements and test methods
1 Scope
IMPORTANT — This document is suitable for the assessment of the conformity of prosthetic
ankle-foot devices and foot units with the strength requirements specified in 4.4 of
ISO 22523:2006 (see NOTE 1). Prosthetic ankle-foot devices and foot units on the market,
which have demonstrated their compliance with the strength requirements specified in 4.4 of
ISO 22523:2006 through submission to the relevant tests of ISO 10328:2016, need not be retested
to this document.
WARNING — This document is not suitable to serve as a guide for the selection of a specific ankle-
foot device or foot unit in the prescription of an individual lower limb prosthesis! Any disregard
of this warning can result in a safety risk for amputees.
This document primarily specifies a cyclic test procedure for ankle-foot devices and foot units of
external lower limb prostheses, distinguished by the potential to realistically simulate those loading
conditions of the complete stance phase of walking from heel strike to toe-off that are relevant to the
verification of performance requirements such as strength, durability and service life.
This potential is of particular importance for the assessment of the performance of a variety of recent
designs of ankle-foot devices and foot units with specific characteristics that will only develop under
realistic conditions of loading. In addition, this document specifies a static test procedure for prosthetic
ankle-foot devices and foot units, consisting of a static proof test and a static ultimate strength test,
distinguished, besides other features, (see NOTE 2) by the potential to generate heel and forefoot forces
at lines of action conforming to those occurring at the instants of maximum heel and forefoot loading
during the cyclic test.
The loading conditions addressed in the third paragraph are characterized by a loading profile
determined by the resultant vector of the vertical and horizontal (A-P) ground reaction forces and by a
locomotion profile determined by the tibia angle.
The test loading conditions specified in this document are characterized by standardized formats of
these loading and locomotion profiles, to be applied by the cyclic and static test procedures to each
sample of ankle-foot device or foot unit submitted for test.
This document specifies Test Ranges by specifying locomotion profiles for the cyclic test in relation
to the intended use. According to the concept of the tests of this International Standard, each sample
of ankle-foot device or foot unit submitted for test is, nevertheless, free to develop its individual
performance under load.
NOTE 1 The lines of action of the heel and forefoot forces generated by the static test procedure for Test
Range 4 (R4) specified in this International Standard approach those determining the sagittal plane loading of the
test loading conditions I and II for the principal structural tests referring to ISO 10328:2016, without changing
the values of the angles of the heel and forefoot platform(s) for the structural tests on ankle-foot devices and foot
units specified in ISO 10328:2016.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO/DIS 22675:2021(E)
ISO 8549-1:1989, Prosthetics and orthotics — Vocabulary — Part 1: General terms for external limb
prostheses and external orthoses
ISO 10328:2016, Prosthetics — Structural testing of lower-limb prostheses — Requirements and test
methods
ISO 22523:2006, External limb prostheses and external orthoses — Requirements and test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8549-1:1989 and the following
apply.
3.1
proof strength
static load representing an occasional severe event, which can be sustained by the ankle-foot device or
foot unit and still allow it to function as intended
3.2
ultimate strength
static load representing a gross single event, which can be sustained by the ankle-foot device or foot
unit but which could render it thereafter unusable
3.3
fatigue strength
cyclic load that can be sustained by the ankle-foot device or foot unit for a given number of cycles
3.4
batch
set of test samples of an ankle-foot device or foot unit submitted together to a test laboratory/facility to
undertake tests to demonstrate compliance with one or more requirements of this document
3.5
shock absorption capacity
capacity of a specimen to absorb energy by deflection without a proportional increase of force
3.6
force
force applied to a sample under test. Following technical development, this version uses forces in the
direction of ISO definitions in other fields of applications (like robotics). Test equipment, build to test
to previous versions of this standard (using compression force with a positive sign) do not need to be
reprogrammed.
4 Designations and symbols of test forces
The designations and symbols of all relevant test forces are listed in Table 1.
Table 1 — Designations and symbols of test forces
Designation Symbol
Test forces F, F , F
1 2
Settling test force F
set
Stabilizing test force F
stab
Proof test force of end attachments F
pa
Static proof test force on heel/forefoot F , F
1sp 2sp
NOTE  Further details of the test forces listed are given in Table 4.
ISO/DIS 22675:2021(E)
Table 1 (continued)
Designation Symbol
Static ultimate test force on heel/forefoot F , F
1su 2su
Pulsating test force F (t); F (β)
c c
1st and 2nd maximum value of pulsating test force F , F
1cmax 2cmax
Intermediate minimum value of pulsating test force F
cmin
Final static test force on heel/forefoot F , F
1fin 2fin
NOTE  Further details of the test forces listed are given in Table 4.
5 Strength and related performance requirements and conditions of use
5.1 According to 4.4.1 of ISO 22523:2006, a prosthetic ankle-foot device or foot unit “… shall have
the strength to sustain the loads occurring during use by amputees […] in the manner intended by the
manufacturer for that device according to his written instructions on its intended use”. Based on the
written instructions, the manufacturer assigns a Test Range (Rx) which is appropriate to test the
strength for the intended use. The manufacturer / supplier is responsible for the instructions for use
and the related assignment. National or international classification schemes are independent to the
instructions and the related assignment. For the assessment of the conformity of ankle-foot devices and
foot units with the above requirement (see also Scope), this document provides means of determining
different categories of strength. These are defined in 3.1 to 3.3 and listed in Table 2, together with the
related performance requirements and the test methods for their verification.
5.2 In order to satisfy the general requirement in 5.1 for a specific ankle-foot device or foot unit, the
following safety concept shall apply:
The device shall
a) comply with the requirements of this document (see 9.1 and 9.2) for a specific test loading level
(see 7.2)
and
b) be used in accordance with the body mass limit specified by the manufacturer in consideration of
the intended use of that device (see NOTE).
and
c) be used solely for the intended use as described in the IFU.
The conditions in a), b) and c) are regarded in both the classification and designation of ankle-foot
devices and foot units according to Clause 19 and their indicators according to Clause 20.
NOTE The statement of the body mass limit not to be exceeded by amputees is part of the conditions of use to
be specified, with justification, by the manufacturer in his written instructions on the intended use of a specific
ankle-foot device or foot unit, taking account of all other factors affecting the loads expected to be exerted on
that ankle-foot device or foot unit by amputees (see Clause A.1).
ISO/DIS 22675:2021(E)
Table 2 — Categories of strength addressed in this document, together with the related
performance requirements and test methods for their verification
a
Category of strength Related performance requirement Test method for verification
Structure shall sustain static loading by the
Proof strength proof test forces F and F at the pre- Static proof test (16.2.1), successively
1sp 2sp
(see 3.1) scribed values for the prescribed time (see applying heel and forefoot loading.
16.2.2).
Structure shall sustain static loading by the Static ultimate strength test (16.3.1),
Ultimate strength
ultimate test forces F and F at the pre- separately applying heel and forefoot
1su 2su
(see 3.2)
scribed values (see 16.3.2). loading.
Structure shall sustain successively (see
16.4.2)
Cyclic test procedure (16.4.1),
1) cyclic loading by the pulsating test force
repeatedly applying a loading profile
Fatigue strength
F (t) or F (β) at the prescribed profile for
c c
simulating the stance phase of walk-
(see 3.3)
the prescribed number of cycles and
ing, followed by final static heel and
forefoot loading.
2) final static loading by the final test
forces F and F at the prescribed
1fin 2fin
values for the prescribed time.
a
The performance requirements related to a specific category of strength are specified in full in an individual subclause
following the subclause in which the test method for their verification is specified.
6 Coordinate system and test configurations
6.1 General
The test configurations of this document are defined in a manner similar to that applied in
ISO 10328:2016.
Each test configuration shall be defined in a two-dimensional, rectangular coordinate system (see
Figure 1).
Each test configuration specifies reference parameters both for the position of the line of application of
the test force and for the alignment of test samples within the coordinate system.
6.2 Origin and axes of the coordinate system
The origin and the axes of the coordinate system are specified in a) to d) in relation to a prosthesis
which is standing on the ground in an upright position. In Figure 1 the ground is represented by the
bottom plane B.
NOTE ISO 9787 defines coordinate systems for robots. ISO 8855 defines the same coordinate system for
vehicles in a right hand system:  Upward (u), thumb: z; Forward (f), pointer finger: x; Outward (o) (to the left),
middle finger: y.
If a test sample is not in the vertical position, the axes of the coordinate system shall be rotated to
correspond.
a) The origin 0 of the coordinate system is located in the bottom plane B.
b) The u-axis extends from the origin 0 perpendicular to the bottom plane B and passes through the
effective ankle-joint centre C , specified in 6.7.3 (see Figure 1). Its positive direction is upwards (in
A
the proximal direction).
NOTE 1 The location of the effective ankle-joint centre C (see Figure 1) is defined in 6.7.3.4. Connectors
A
or ankle-joint units, connecting the ankle-foot unit to proximal elements, can be located in positions different
to C .
A
ISO/DIS 22675:2021(E)
NOTE 2 The u-axis also passes through the effective knee-joint centre C (see Figure 1). This may be
K
relevant to the setting-up of test samples of specific designs of ankle-foot devices or foot units which extend
towards the knee unit of a lower limb prosthesis and which, therefore, may also require the knowledge of
the position of the effective knee joint centre.
c) The f-axis extends from the origin 0 perpendicular to the u-axis (see Figure 1). Its positive direction
is forward towards the toe (in the anterior direction).
d) The o-axis extends from the origin 0 perpendicular to both, the u-axis and to the f-axis (see
Figure 1). Its positive direction points medial for right sided foot.
Key
B bottom plane (see 6.2)
0 origin of coordinate system [see 6.2 a)]
U (upward) axis of coordinate system [see 6.2 b)]
F (forward) axis of coordinate system [see 6.2 c)]
O (outward) axis of coordinate system [see 6.2 d)]
C effective ankle-joint centre [see 6.2 b) and 6.7.3]
A
C effective knee-joint centre [see NOTE of 6.2 b)]
K
P top load application point (see 6.3)
T
P , P knee load reference points (see 6.3)
K1 K2
P , P ankle load reference points (see 6.3)
A1 A2
P , P bottom load application points (see 6.3)
B1 B2
1 line of application of test force F (see 6.5)
2 line of action of resultant reference force F (heel loading) (see 6.6)
R1
3 line of action of resultant reference force F (forefoot loading)
...