ASTM F2333-04

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An American National Standard
Designation:F2333–04
Standard Test Method for
Traction Characteristics of the Athletic Shoe–Sports Surface
Interface
This standard is issued under the fixed designation F2333; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope shoe and surface varies with the level of performance and from
individual to individual. The extent to which particular levels
1.1 This test method covers specifications for the perfor-
of traction contribute to individual athletic performance and
mance of sports shoe-surface traction measuring devices, but
risk of injury is not known.
does not require a specific device or mechanism to be used.
1.11 The values stated in SI units are to be regarded as the
Figs. 1 and 2 show schematic diagrams of generic apparatus.
standard.
1.2 This test method is appropriate for measuring the effects
1.12 This standard may involve hazardous materials, opera-
of athletic shoe outsole design and materials on traction at the
tions and equipment. This standard does not purport to address
shoe-surface interface.
all of the safety concerns, if any, associated with its use. It is
1.3 This test method is appropriate for measuring the effects
the responsibility of the user of this standard to establish
of sport surface design and materials on traction at the
appropriate safety and health practices and determine the
shoe-surface interface.
applicability of regulatory limitations prior to use.
1.4 This test method specifies test procedures that are
appropriate for both field and laboratory testing.
2. Referenced Documents
1.5 Traction characteristics measured by this test method
2.1 SAE Standard:
encompass friction forces developed between shoe outsoles
SAE J211 Recommended Practice for Instrumentation for
and playing surfaces.
Impact Tests
1.6 Traction characteristics measured by this test method
encompass traction achieved by penetration of cleats or studs
3. Terminology
into playing surfaces.
3.1 Definitions:
1.7 This test method specifies test procedures for the mea-
3.1.1 footform—a rigid form approximating the shape of a
surement of traction during linear translational motion and
foot or shoe last to which the shoe under test may be tightly
rotational motion, but not simultaneous combinations of linear
fitted and through which the loads required by this test method
and translational motion.
may be transmitted.
1.8 Theloadsandloadratesspecifiedinthistestmethodare
3.1.2 traction—resistancetorelativemotionbetweenashoe
specific to sports activities. The test method is not intended for
outsole and a sports surface that does not necessarily obey
measurement of slip resistance or traction of pedestrian foot-
classical laws of friction.
wear.
3.1.2.1 dynamic traction—tractionmeasuredduringrelative
1.9 Testresultsobtainedbythismethodshallbequalifiedby
sliding motion between the shoe and the surface.
the characteristics of the specimen.
3.1.2.2 linear traction—traction related to rectilinear mo-
1.9.1 Comparative tests of surfaces shall be qualified by the
tion parallel to the surface.
characteristics of the shoes used to test the surfaces, including
3.1.2.3 rotational traction—traction related to rotational
the cushioning, outsole material, and sole design.
motion about an axis normal to the surface.
1.9.2 Comparative tests of shoes shall be qualified by the
3.1.2.4 static traction—traction measured at the start of
pertinent characteristics of the surfaces on which shoes are
relative sliding motion between the shoe and the surface.
tested, including the surface type, material, condition, and
3.1.3 tractionratio—ratioofthetractionforceortorqueand
temperature.
the normal force acting at the shoe-surface interface.
1.10 This test method does not establish performance or
3.1.3.1 dymamic traction ratio (T,R )—linear or rotational
k k
safety criteria. The level of traction required between a sport
traction ratio measured during constant velocity relative mo-
tion between the shoes and the surface.
This test method is under the jurisdiction of ASTM Committee F08 on Sports
EquipmentandFacilitiesandisthedirectresponsibilityofSubcommitteeF08.54on
Athletic Footwear.
Current edition approved Dec. 1, 2004. Published December 2004. DOI: Available from Society of Automotive Engineers (SAE), 400 Commonwealth
10.1520/F2333-04. Dr., Warrendale, PA 15096-0001.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2333–04
A. Shoe under test, mounted on a footform.
B. Surface under test.
C. Guide rails with linear bearings or other means of maintaining rectilinear motion.
D, E. Vertical shaft and bearing mounted carriage or other means of maintaining motion parallel to the plane of the shoe-surface interface.
F. Weights, actuator or other means of applying a downward vertical force.
G. Actuator or other means of applying a horizontal force.
H. Force plate or other means of measuring vertical and horizontal forces.
J. Velocity transducer.
FIG. 1 Schematic Diagram of a Generic Device for Measuring Linear Traction
3.1.3.2 linear traction ratio (T)—ratio of the force resisting upon the sport, will typically be higher than an athlete’s body
relative rectilinear motion of the shoe parallel to the surface weight. Normal loads, and the shoe axes along which traction
and the normal force at the shoe-surface interface. needs are greatest, have been determined by research. Some of
3.1.3.3 rotational traction ratio (R)—ratio of the torque the loading conditions that have relevance for traction testing
resisting relative rotational motion about an axis normal to the of outsoles designed for particular sports are itemized by sport
surface and the normal force acting at the shoe-surface category in Table 1. Tests should be conducted at these normal
interface. loads or at a normal load of 1000 6 75 N unless otherwise
3.1.3.4 static traction ratio (T,R )—linear or rotational specified. The normal loads can be applied by means of
s s
traction ratio measured at the start of relative sliding motion weights or hydraulic cylinders, springs in compression or other
between the shoe and the surface. appropriate means and transmitted through a shaft to which the
footform is securely attached.
4. Summary of Test Method
4.4 Thenormalloadisdistributedentirelybeneaththedistal
4.1 A test shoe outsole or specimen is tested for traction half or the forefoot region of the outsole unless otherwise
characteristics on the type of playing surface for which the specified. The proximal half or the rearfoot should not contact
shoe is intended. the playing surface except as noted in Table 1.Alternatively, if
4.2 Ashoe containing the outsole to be tested is pulled over deemed appropriate for the sports movement for which the
a foot form, creating a tight fit capable of properly transmitting shoe outsole design is intended, normal loads are distributed
forces through the shoe material to the outsole-playing surface uniformly beneath the proximal half or the rearfoot portion of
interface. Alternatively, an outsole material specimen can be the outsole. If the shoe construction typically includes a
fastened to a mounting plate and tested in the same manner as midsole that provides cushioning, an appropriate midsole
an outsole on an intact shoe. should be included in the test shoe. If the test involves a
4.3 The shoe on the footform is loaded against the test specimen of outsole material fastened to a mounting plate, an
surface under a normal load specific to the sport category for equivalent midsole material of appropriate thickness is to be
which the shoe is intended. These normal loads, depending included between the mounting plate and the outsole material.
F2333–04
A. Shoe under test, mounted on a footform.
B. Surface under test.
D, E. Vertical shaft and bearings or other means of constraining rotation about the vertical axis parallel to the plane of the shoe-surface interface.
F. Weights, actuator or other means of applying a downward vertical force.
G. Actuator or other means of applying a torque.
H. Force plate or other means of measuring vertical force and torque about the vertical axis.
J. Angular velocity transducer.
FIG. 2 Schematic Diagram of a Generic Device for Measuring Rotational Traction
TABLE 1 Distribution of Normal Loads and Application of Pulling not reproduce the distribution of loads transmitted through the shoe
Forces
bottom to the outsole by the loaded human foot, but does increase test
repeatability.
Normal Load Direction
Sport Movement
Load (N) Distribution of Motion
4.5 For linear traction measurements, a linear actuator is
A
Running Push-off 800 Forefoot Distal-proximal
used to overcome the static traction and produce relative
Sprinting Push-off 1500 Forefoot Distal-proximal
rectilinear motion of the shoe and surface, parallel to the shoe
Tennis, Cutting 2200 Forefoot Medial-lateral
B
basketball, outsole-playing surface interface. The actuator may be pneu-
C
soccer,
matically, hydraulically, or electrically driven. The distance of
football
relative sliding motion between the shoe and the surface shall
Stopping 3000 Forefoot Proximal-distal
D
Shuffling 1300 Forefoot Medial-lateral
be a minimum of 20 cm, unless the interacting surfaces deform
Starting 1500 Forefoot Distal-proximal
or fail at a smaller distance.
Football Pushing 900 Forefoot Distal-proximal
4.6 Sliding velocity shall be recorded and reported. The
Aerobic dance 500 Forefoot Medial-lateral
-1
Golf Downswing 600 Lateral outsole Medial-lateral recommended minimum sliding velocity is 0.3 m s .
A
Valiant, G. A., “Friction–Slipping–Traction,” Sportverletzung Sportschaden,7,
NOTE 2—Under some conditions, for example, cleated shoes on artifi-
1993, pp. 171-178.
B
cialturf,spikedshoesonrunningtracks,itmaynotbepossibletogenerate
Valiant, G. A. and Eden, K. B., “Evaluating Basketball Shoe Design with
sliding at the recommended velocity. Under these circumstances, the force
Ground Reaction Forces,” Proceedings of the Second North American Congress
on Biomechanics, Chicago, August 24-28, 1992, pp. 271-272.
and velocity developed should be recorded and dynamic traction coeffi-
C
Valiant, G. A., “Ground Reaction Forces Developed on Artificial Turf,” Science
cients should not be reported.
and Football, T. Reilly, A. Lees, and W. J. Murphy, Eds., E. & F.N. Spon, London,
1988, pp. 406-415. 4.7 For rotational traction measurements, the loaded shoe
D
McClay, I. S., Robinson, J. R., et al., “A Profile of Ground Reaction Forces in
outsole is rotated about the vertical shaft transmitting the
Professional Basketball,” Journal of Applied Biomechanics, 10(3), 1994, pp.
normal loads. The rotary motion may be applied manually, or
222-236.
by means of a rotary actuator. The minimum rotation applied
shall be 90° unless the interacting surfaces deform or fail at a
lesser rotation. The minimum rate of rotation shall be 45°/s.
NOTE 1—Thecushioningmaterialhelpstodistributenormalloadsmore
uniformly between the outsole and the playing surface. The cushion does
Angular velocity shall be recorded and reported.
F2333–04
4.8 For linear traction tests, the measured variables are 6.6 A means of maintaining the outsole or sample perpen-
normal forces, horizontal or traction forces, and sliding veloc- dicular to the playing surface during rotation (for example, low
ity. For rotational traction tests, measured variables are normal friction rotary bearings) is required for measurement of rota-
forces, the moment (torque) resisting rotation about a vertical tional traction ratios.
axis, and angular velocity during rotation. Traction ratios are
6.7 Transducers, signal conditioners and other instrumenta-
calculated from these measurements.
tion are required to measure normal force, horizontal force,
4.9 All variables are recorded as functions of time, from
torque, velocity, and angular velocity. The performance of the
before the application of horizontal or rotational motion until
measurement systems shall, as a minimum, conform to the
after the cessation of motion.
requirements of a CFC Class 100 Data Channel, as defined by
SAE J211. Anti-aliasing filters shall be used to filter data
5. Significance and Use
channels at a -3dB cutoff frequency of 250 6 20 Hz before
5.1 This test method will be used by athletic footwear
they are digitized.
manufacturers to characterize the traction of the athletic
shoe-sports surface interface, and as a tool for development of NOTE 4—For laboratory-based measurements, an appropriate means of
measuring forces and torques is a multi-axis force plate to which the
athletic shoe outsoles.
surface being tested is securely attached (Figs. 1 and 2).
5.2 This test method will be used by researchers to deter-
mine the effect of sport surface conditions (for example,
6.8 The apparatus should have the capability of differenti-
moisture, grass species, turf density, soil texture, soil compo-
ating static traction forces from dynamic traction forces.
sition, and so forth) on traction characteristics of the athletic
Typically, the velocity or angular velocity measuring trans-
shoe-sports surface interface.
ducer will be used for this purpose.
5.3 This test method will be used by sports surface manu-
6.9 The data acquisition system should sample and store
facturers to characterize the traction of the athletic shoe-sports
force, torque, velocity, and angular velocity signals at a
surface interface, and as a tool for development of sports
minimum sampling rate of 500 samples/s.
surfaces.
6.10 The complete apparatus used to make the traction
5.4 Careful adherence to the requirements and recommen-
measurements shall be anchored or have a large enough inertia
dations of this test method will provide results that compare
to prevent it from being moved by the application of linear or
with results from different laboratory sources.
rotary motion to the shoe-surface system under test.
5.5 The method will be used to research relationships
between traction at athletic shoe-sports surface interfaces and
7. Procedure
athletic performance or injury. This research may lead to
recommendations for appropriate levels of traction. 7.1 Select a sample of the playing surface appropriate for
the outsole to be tested and prepare it in accordance with the
6. Apparatus
required conditions of the traction test.
6.1 A footform.
7.2 If the test is conducted in the field, locate the trac
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