Shell flexibility

 

It’s hard to know how flexible your orthotics will come out. Judging your arch aight with shell modifications is no easy deal. Hopefully, this guide will help you out. All examples here are with a men’s size US 9 with an arch height of 18mm (average -20% fill). Note that the minimum shell thickness is 2mm. Custom thickness can be asked for when prescribing.

Standard model

These have no shell modifications:

2.5mm – Ultra-flex

3mm – flex

3.5mm – medium flex

4mm – firm flex

4.5 – semi Ridgid

5mm – Ridgid

 

Sport model/dress model

These models would be approximately 1.5mm thinner than the standard shell to have the same flexibility as the standard shell. These have no shell modifications:

2mm – flex

2.5mm – medium flex

3mm – Ridgid

 

Modifications

Arch 28+mm reduce by 1.5mm

Arch 24-28mm reduce by 1mm

Arch 21mm – 24mm- reduce by 0.5mm

Arch 16mm – add 0.5mm

Fascial groove or cavity in the arch – add 0.5mm

Medial flange – reduce by 0.5mm

Extrinsic posts – reduce by 0.5mm

 

Children’s flex

These are based on a size 6 youth These have no shell modifications:

2mm –  flex

2.5mm – medium flex

3mm – semi Ridgid

3.5mm – Ridgid