Simplified ACL-rupture thresholds on skis (middle graph), 50th percentile ...

Описание: Please follow longitudinal time-series data that shows Simplified ACL-rupture thresholds on skis (middle graph), 50th percentile ... wait for it! All Credit to Rick Howell ... Howell Ski 🎿 Bindings!

These graphs crack the code on the main load-thresholds that cause ACL-rupture on skis.

The first graph shows the mixture of peak ‘abduction-moments’ (green threshold) and peak ‘torsional-tibia-torques’ (red threshold) at ACL-rupture — as a function of where applied-abduction-forces enter the back-half of the ski. For comparison, ‘torsional-tibia-torque’ at tibia-fracture is also shown (black threshold) as a function of where applied-abduction-forces enter the ski.

On the left-side of the first graph, the green and red thresholds are depicted in soft hues — to add countervailing emphasis to the black threshold positioned immediately below the soft-green and soft-red lines. This softening of the green and red and highlighting of the black represents the fact that when applied-abduction-force enters a ski more than 55cm behind the tibia-axis — and the binding does not release — the tibia fractures at a lower threshold than the ACL-rupture threshold. Today’s bindings address this scenario: proper release occurs at threshold that is less than the torsional-tibia-fracture threshold (11.3 daNm for an average male; black) is reached.

On the other side of the first graph where the green and red lines are depicted as strong hues and where the black line softens to become gray — where applied-abduction-force enters the back-half of the ski just-behind the tibia — the ACL-ruptures at a lower threshold than the tibia-fracture threshold. ‘But the 2 (combined) ACL-rupture thresholds involve 2 simultaneous-variables — making it too difficult for an ordinary binding to effectively process.

The 2nd graph shows a simple single-variable threshold of applied-abduction-force that produces tibia-fracture — or ACL-rupture — as a function of where the applied-abduction-force enters the ski (black: tibia-fracture; orange: ACL-rupture). The orange threshold is softened on the left where tibia-fracture (black) occurs at a lower threshold than ACL-rupture. The black threshold softens to gray on the right where ACL-rupture (strong orange) occurs at a lower threshold than tibia-fracture.

The simplified, single-variable, applied-abduction-force threshold represents a major discovery for ‘friendly-skiing’ — because a binding with ordinary lateral toe release can be tuned to release below tibia-fracture (black threshold on left) and a binding with additional, non-pre-releasing, lateral-heel release can be tuned to release below ACL-rupture (orange threshold on right). ✅🔆❄️

The 3rd graph repeats the 1st graph — for added emphasis on the resultant-loads that are too complex for ordinary ski-bindings.

To be clear about the relationship between the 2 CADD-graphs — the 2nd (middle) graph depicts the peak-applied-abduction-forces that produce the peak-tibial-torques AND peak-abduction-moments shown 1st and 3rd graphs. The middle-graph provides a single-variable to which the special ski-binding, described above, can react — only when needed, without pre-release — below the key biomechanical thresholds shown.