The stabilizing effect of TSM ankle supports
The most severe loads occur in sporting activities. In this case, supports/orthoses are intended to provide the greatest possible protection while inhibiting normal movement patterns as little as possible.
In order to be able to determine the stabilizing effect experimentally, a goniometer (see figure) was developed which allows the measurements to be made while the product is being worn by a test subject. Thanks to its gimbal mounting, the goniometer is capable of analyzing the stabilizing effect in the supination/pronation or plantar flexion/dorsal extension directions separately or in combination.
During the measurements, which are performed with a standard sports shoe attached to the goniometer platform, the angles of deflection together with the input moments (Nm) for supination, pronation, dorsal extension or plantar flexion are recorded. The values thus relate to the angular movement of the surface of the shoe sole. The foot has a certain degree of residual mobility in the shoe and is thus not forced completely to comply with the movement of the shoe.
Two test subjects were investigated, one with a healthy ankle (P), the other with an unstable joint (F), i.e. with stretched external ligaments (sports accident some 4 months previously).
Results:
1. Supination
TSM support no. 3181 is the most effective at stabilizing both the healthy joint (P) with a value of 70% (= reduction of mobility relative to the unprotected joint to 70%) and the unstable joint (F) with a value of 45%.
TSM support no. 3381 has a lower stabilizing effect on the healthy joint (P) with a value of 84%, as does comparison orthosis A with a value of 81%.
However, on the unstable joint (F), no. 3381 exhibits stabilization at 49% which is almost as good as no. 3181. Comparison orthosis A (comp. orth. A), in contrast, is markedly inferior at 62%.
2. Plantar flexion
The injuries which occur in this case are primarily the result of overstretching the joint. All the tested supports had a similar limiting effect on plantar flexion in the healthy joint (approx. 70%).
On the unstable joint (F), however, thanks to the stabilizing straps which pass over the ankle bone, no. 3181 limits plantar flexion and forward displacement of the talus substantially better with a value of 41% than do the other supports with a value of approx. 50%.
| Supination | Supination | Pronation | Pronation | ||||
Moment - Angle index | Moment - Angle index | |||||||
Probant P | Probant F | Probant P | Probant F | |||||
Support Designation | Degree/NM | % | Degree/NM | % | Degree/NM | % | Degree/NM | % |
without support | 7,65 | 100 | 11,95 | 100 | 4,75 | 100 | 5,76 | 100 |
No. 3181 | 5,35 | 70 | 5,38 | 45 | 3,96 | 83 | 3,72 | 65 |
No. 3381 | 6,42 | 84 | 5,87 | 49 | 4,33 | 91 | 4,48 | 78 |
Orth. A | 6,19 | 81 | 7,40 | 62 | 4,43 | 93 | 5,30 | 92 |
| Plantarflexion | Plantarflexion | Dorsalextension | Dorsalextension | ||||
Moment - Angle index | Moment - Angle index | |||||||
Probant P | Probant F | Probant P | Probant F | |||||
Support Designation | Degree/NM | % | Degree/NM | % | Degree/NM | % | Degree/NM | % |
without support | 3,77 | 100 | 5,15 | 100 | 1,51 | 100 | 1,87 | 100 |
No. 3181 | 2,61 | 69 | 2,13 | 41 | 1,48 | 98 | 1,52 | 81 |
No. 3381 | 2,69 | 71 | 2,52 | 49 | 1,50 | 99 | 1,69 | 90 |
Orth. A | 2,55 | 67 | 2,68 | 52 | 1,63 | 108* | 1,56 | 83 |
* due to the relative movement between orthosis and shoe
Supination / Pronation:
the lower the force absorbed (degree/Nm) or the % value, the greater the stabilizing effect
Planta flexion / Dorsal extension:
the smaller the deviations from the unsupported joint, the smaller the restriction of movement
Graphical representation of measurements on ankle orthoses
Comparison of platform deflection in supination direction
- TSM ankle support
- Comparison orthosis A
- Without support