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Howell ACL-Friendly Test Fixture


Optional for Howell SkiBindings — but suggested.

Available now.

        Howell ACL-friendly Test Fixture demonstrates and calibrates the unique ACL / MCL / meniscus friendly function of Howell SkiBindings.  

       Photo 1, bolted to ski-tuning bench and metal saw horses.  Photo 2, holding an alpine ski-boot and ski.    

       Made of 303 stainless-steel — one piece, welded.  Two stainless-steel micro fiddle blocks and high-strength sailing line included.  Mounting bolts, metal saw horses and ski tuning bench are not included.

       ‘Relies on a combination of industry-standardized torsional release torque-settings, given boot-sole lengths, and the test-fixture’s holding of any ski boot upside-down on just about any sturdy bench — to provide user-applied unmeasured lateral-force to the ski — to test the special lateral-heel release-function of Howell SkiBindings for ACL, MCL and meniscus friendly skiing according to Howell SkiBindings specifications.  See BETA chart in photo gallery.  

Recommended lateral-heel release-setting specifications apply ONLY to Howell SkiBindings.

     The recommended test-values that are supplied together with the Howell ACL-Friendly Test Fixture are uniquely gender-specific.

     Works by applying position-dependent lateral-force to the ski according to the data supplied in the special lateral-heel release-settings chart. 

     Testing can be completed in minutes.

     ‘Metallic-foot is fully-integrated.

     ‘Howell ACL Friendly Test Fixture is intended for ski shops — but can be purchased by any skier — to test or demonstrate the special ACL, MCL, and/or meniscus friendly function of Howell SkiBindings.  ‘Also useful for demonstrating how ordinary 2-mode alpine bindings have no possibility of providing ACL or MCL friendly skiing at any setting.


(1)  All three visual release indicators on each left and right Howell SkiBinding should be ‘pre-set’ according to the ‘Howell SkiBindings Recommended Release Setting Chart’ — which pre-settings conform to DIN/ISO 9462 and ISO 8061 for ordinary lateral-toe and forward-heel settings.  See BETA chart in photo gallery (BETA — and not for use with any ski-bindings other than Howell SkiBindings.  This beta chart will be updated and printed prior to October, 2023).  No standards apply to Howell SkiBindings lateral-heel release settings because this is an additional mode of release not provided (yet) by other alpine ski binding companies.  Boots must conform to ISO 5355 — the main international alpine ski boot standard.  Boots must not have metal inserts for ‘pin-bindings’ (‘pin-bindings’ are hardly “tech”).

(2)  Affix the Howell ACL-Friendly Test Fixture to a sturdy bench.

(3)  Firmly affix the ski-boot to the Howell ACL-Friendly Test Fixture.

(4)  Select the recommended ‘Transition-Point’ from the Howell ACL-Friendly Lateral-Heel Release Settings Chart.  ‘See photo gallery.  (BETA — and not for use with any ski-bindings other than Howell SkiBindings.  This beta chart will be updated and printed prior to October, 2023).  Mark the Transition Point on the ski.

(5)  Attach the ski to the upside-down ski-boot that is held by the Howell ACL-Friendly Test Fixture.  Secure the ski through the use of your own ‘limiter-lines’ to block the range of motion of the released ski to prevent injury to the person conducting the tests.

(6)  Apply abduction (lateral) force to the ski as follows:

     (5.a)  Apply lateral force with a gloved-hand to the ski at a point located 5 cm greater-than the chart-recommended Transition-Point — to cause lateral-toe release;

     (5.b)  Apply lateral-force with a gloved hand to the ski at a point located 5 cm less-than the chart-recommended Transition-Point — to cause lateral-heel release.

(6)  If lateral-toe release AND lateral-heel release do not take place as described in points #5.a AND #5.b (both) do NOT change the lateral-toe release-settings / do not change the forward-heel release-settings.  Do not change the forward-pressure adjustment.  Change ONLY the special additional lateral-heel release settings — provided, however, that no change in the lateral-heel release-indicator setting is greater than 2 lateral-heel release-indicator numbers.

(7)  If a change of more than 2 lateral-heel release-indicator numbers is required to cause the function that is specified in points #5.a AND #5.b — a list of ‘Troubleshooting Actions’ is provided by Howell SkiBindings to correct the function of the ski-boot-binding system.  (The few problems that arise are typically with the boot-interface ... and can be easily resolved ... for example, by removing mold-flashings on the boot sole.)

(8)  If after applying the Troubleshooting Actions the functions in points #5.a AND #5.b are still not occurring — the binding, the boot, or both — are defective and/or incompatible and should be returned for warranty replacement.  

WARNING !   In the unlikely adverse scenario of #8 — Howell SkiBindings may still comply with ordinary 2-mode alpine binding function according to ISO, DIN, AfNOR and ASTM standards however ACL, MCL, meniscus, tibial-plateau friendly skiing may be adversely compromised, just as it always is compromised with all ordinary 2-mode alpine bindings. 

     Using the Howell ACL-Friendly Test Fixture is simple and fast. 

      Use of the Howell ACL-Friendly Test Fixture is optional with Howell SkiBindings but suggested.


Available now.

Biomechanical Proof

     Howell ACL-Friendly Test Fixture is based on 19-years of intensive biomechanical research conducted by Rick Howell — peer-reviewed and approved by bona fide scientific research committees at major international orthopedic / engineering / skiing safety conferences ...

     International Society for Skiing Safety (ISSS) Pontresina, Switzerland, 2003 (presented by University of Montréal biomechanical engineering researchers based on a 2001 grant-application promulgated by Rick Howell.  All other venues listed below involve scientific presentations investigated and presented by Rick Howell ) ...

... ISSS-Niigata, Japan, 2005;  ISSS-Aviemore, Scotland, 2007;  ISSS-Bariloche, Argentina, 2013;  ISSS-Cortina, Italy, 2015;  ISSS-Innsbruck, Austria, 2017;  ISSS-Squaw Valley, USA, 2019;  

     SITEMSH (International Medical Society for Skiing Safety [Société Internationale de Traumatologie et Médecine des Sports d’Hiver]) SITEMSH-Flachau, Austria, 2014;  SITEMSH-Inawashiro, Japan, 2016;  SITEMSH-Barcelona, Spain, 2018;

     International Olympic Committee (IOC) World Conference on Prevention of Injury and Illness in Sport, Monte Carlo, Monaco, 2017 and 2021;

     European Society for Knee Surgery, Arthroscopy and Sports Traumatology (ESSKA), Barcelona, Spain, 2016 — peer-reviewed, approved, and published in British Journal of Sports Medicine ( Br J Sports Med 2017;51:283-412 );  and ESSKA-Virtual, May, 2021.

     International Society for Science in Skiing (ICSS), Voukatti, Finland, 2019;

     ... as well as forthcoming international orthopedic-engineering skiing-safety research-conferences postponed to 2022 due to the pandemic.

Biomechanical Engineering-Technology

        The biomechanical engineering-technology behind ACL-Friendly Howell SkiBindings and the Howell ACL-Friendly Test Fixture is simple.

        During ‘Slip-Catch’ and/or ‘Phantom Foot’ (large abduction-moment) events that are the primary cause of skiing ACL and MCL ruptures — the center of the injury-producing forces enters a shaped-ski, laterally, close-behind the projected-axis of the tibia.  This point where the center of Slip-Catch forces enter the ski is not sensed by ordinary 2-mode alpine ski bindings because there is no effective lever-arm within an ordinary 2-mode boot-binding to cause release:  there’s no possibility of release, irrespectively of the release-settings.  But this same centrally-located Slip-Catch abduction-force acts over the length of the lower-leg to produce a large abduction-moment about the ACL, MCL, meniscus, and tibial-plateau.

        However, a binding with ADDITIONAL, non-pre-releasing, lateral-heel release can respond to abduction loads by releasing the ski from the boot IF the additional lateral-heel release setting is ‘properly’ tuned according to Howell SkiBindings specifications.

        HOWEVER — AN  IMPORTANT  HOWEVER — specially-tuned lateral-heel release that provides ACL, MCL, meniscus and/or tibial-plateau friendly skiing MUST also NOT pre-release.  Howell SkiBindings uniquely provide key know-how to block pre-release without high settings in all 3-modes of release (2).  Anti-pre-release is uniquely and decisively provided through functional decoupling of each of the 3-modes of release (decoupling them from each other) and through functional decoupling of each mode of release from the skiing-control-modes that do not involve release.  See ‘Retention’ sub-link in the Menu.  Each mode of release is a separate system;  and each of the 3 modes of release uniquely articulate-to-release without being adversely effected by ski-flex or by edging.  Other bindings do not provide these combined features because Howell know-how has refined these features during the course of decades of R&D and tacit-knowledge application.

        The Howell ACL-Friendly Test Fixture holds the boot to uniquely transfer lateral loads through an unconstrained ski to a binding’s toe — or laterally to the heel — depending on the position of where the force is applied to the ski;  depending on the length of the boot-sole;  and depending on the ratio of lateral-toe release-force to the lateral-heel release-force.  

       This custom fixture provides a means to tune lateral-heel release with Howell SkiBindings for ACL, MCL, meniscus and tibial-plateau friendly skiing.

        Mitigation of skiing ACL, MCL, meniscus and tibial-plateau injury through the use of Howell SkiBindings and through the optional-use of the Howell ACL-Friendly Test Fixture does not imply that all ACL, MCL, meniscus or tibial-plateau injuries can be ‘prevented’.  Further, other less-common ACL and MCL injury-mechanisms (e.g., pure-BIAD) are NOT addressed by all Howell SkiBindings models and NOT addressed by the Howell ACL-Friendly Test Fixture.

        100% 303 stainless steel:  7.75-pounds.  
        Shipping weight:  11-pounds.

        Lifetime Limited Warranty.

Available now.


‘Howell ACL Friendly Release Test Fixture’ (sm) is a Service Mark of Howell SkiBindings (sm).

Copyright © by Howell SkiBindings, Inc.; Howell Product Development Holding, Inc.; and Rick Howell, 2022.  All rights reserved.