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Howell ACL-Friendly Shop Test Device


Optional for Howell SkiBindings — but suggested.

Available now.

        Howell ACL Friendly Shop Test Device (sm) validates, demonstrates, calibrates the ACL / MCL / meniscus-friendly function of Howell SkiBindings. ‘Relies on a combination of the standardized pre-set torsional release torque-setting, the given boot-sole length and the test-device’s ‘automatic’ transfer of potential injury-producing abduction-moments — to test the release-function any ski-boot-binding system for ACL, MCL and meniscus friendliness.  

     Recommended test-values are gender-specific.

     Works by applying lateral force, by hand, to the numbered-section of the test-arm according to the data supplied in the special chart.  See chart in photo gallery.


     Testing can be completed in minutes.

     ‘Metallic-foot is fully-integrated.

     ‘Howell ACL Friendly Release Test Device is intended for ski shops — but can be purchased by shops or skiers — to test, calibrate or demonstrate the special ACL, MCL 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 release 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 recommended lateral-toe and forward-heel pre-settings conform to ISO 9462 and ISO 8061.  See chart in photo gallery.  Boots must conform to ISO 5355 — the international alpine ski boot standard.

(2 — optional)  Fine-tune the torsional release torque toe-settings using a torque measuring device such as the Vermont Release Calibrator by Vermont Safety Research (Vermont Safety Research is NOT affiliated with Howell SkiBindings).

(3)  Set-up the Howell ACL Friendly Release Test Device with the numbered-section of the arm positioned over the top-rear section of the ski.

(4)  Select the recommended ‘Transition-Point’ from the Howell ACL/MCL-Friendly Release Chart.  ‘See photo gallery.  

(5)  Apply force by hand to the numbered-section of the arm as follows:

     (5.a)  Apply lateral force at a point that’s 4cm greater-than the chart-recommended Transition-Point — to cause lateral-toe release;

     (5.b)  Apply lateral-force at a point that’s 4cm less-than the chart-recommended Transition-Point — to cause lateral-heel release.

(6)  If lateral-toe release or lateral-heel release does 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.  Change ONLY the lateral-heel release settings — provided, however, that no change in the lateral-heel release setting is greater than 2 lateral-heel release-indicator numbers.

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

WARNING in the unlikely adverse-scenario #8 — Howell SkiBindings will still comply with ordinary 2-mode alpine binding function for tibia-integrity (according to ISO, DIN, AfNOR and ASTM standards) but ACL/MCL-integrity may be adversely compromised. 

     Using the Howell ACL Friendly Release Test Device is simple and fast. 

      Use of the Howell ACL Friendly Release Test Device is optional with Howell SkiBindings, but suggested.


Available now !!

Biomechanical Proof

     Howell ACL Friendly Release Test Device 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 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;

     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 );  ESSKA-Virtual, May, 2021.

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

     ... as well as at 2 forthcoming international orthopedic-engineering research-conferences postponed to 2022 due to the pandemic.

Biomechanical Engineering

        The biomechanical engineering behind ACL / MCL-Friendly Howell SkiBindings and the Howell ACL Friendly Release Test Device is actually simple.

        During ‘Slip-Catch’ (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 enters the ski is not sensed by ordinary 2-mode alpine ski bindings because there is no lever-arm within an ordinary 2-mode boot-binding system to cause release:  there’s no possibility of release, irrespectively of the release-settings.  But this same centrally-located Slip-Catch abduction-force produces a large abduction-moment centered within the ACL and MCL.  

        Pop. 💥

        However, a binding with ADDITIONAL, non-pre-releasing, lateral-heel release can respond to unique Slip-Catch forces IF properly tuned.  

        HOWEVER — AN  IMPORTANT  HOWEVER — specially-tuned lateral-heel release that provides ACL and MCL friendly skiing MUST also NOT pre-release.  Howell SkiBindings uniquely provide key know-how and key intellectual property 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.  Each mode of release is a separate system;  and each of the 3 modes of release uniquely articulate without being effected by ski-flex.    Other bindings do not provide these combined features because Howell know-how has refined these features during the course of decades of R&D.

        The Howell ACL Friendly Release Test Device uniquely transfers force to a binding’s toe — or heel — depending on the position where the force is applied on indexed-arm;  depending on the length of the boot-sole;  and depending on the ratio of the lateral-toe release setting to the lateral-heel release setting.  

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

        Mitigation of skiing ACL, MCL and/or meniscus injury through the use of Howell SkiBindings and through the optional-use of the Howell ACL Friendly Release Test Device does not imply that all ACL, MCL or meniscus injuries can be prevented.  Other, less-common ACL and MCL injury-mechanisms (BIAD, backward-twisting) are NOT addressed by all Howell SkiBindings models and NOT by the Howell ACL Friendly Release Test Device.

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

        Lifetime Limited Warranty.

Available now !!


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

Copyright © by Howell SkiBindings, Howell Product Development Holding, Inc., and Rick Howell, 2021.  All rights reserved.