Test 1: The Subtalar Motion Test assesses biomechanics and joint function.
Manual Therapy Techniques are used to assess joint motion and mobilize any restrictions. Range of motion, quality of motion, end feel and restriction of motion are examined and restrictions are mobilized. The alignment of the leg, rearfoot and forefoot is assessed as per the Root method. Angles can be measured but may not predict the functional effect of the orthoses. The range of Pronation and Supination and the Neutral Subtalar Position are identified. Deviations from the mechanically ideal alignment are noted. The foot is examined in stance to determine the difference between its relaxed posture and the Neutral Calcaneal Stance alignment.
Test 2: The Alignment Test assesses Closed Kinetic Chain Mechanics.
Biomechanical principles are used to assess skeletal alignment. The patient is examined in stance, from both the front and the back, and “misalignments” from the Theoretically Ideal are noted. The examination is from head to toe. There are numerous reasons for asymmetry or “misalignment” of musculoskeletal structures. They are frequently related to dysfunction of the foot and leg. However, apparent mechanical “deformity” in the foot may be a compensation for joint and/or soft tissue restrictions in structures of the spine, pelvis, hips or knees. The assessment is done in Resting and Neutral Calcaneal Stance.
Test 3: The Supination Resistance Test relates to the Subtalar Joint Axis.
The examiner manually supinates the foot and grades the force required from 1 to 5. The force required to supinate the foot is related to the axis of the subtalar joint and varies significantly from person to person. In gait this force is generated by muscles in the foot and leg. The higher the supination resistance, the greater will be the loading on these muscles and associated structures and the more likely that overuse symptoms will occur. Orthoses that reduce supination resistance decrease this loading and therefore can relieve or prevent symptoms. The therapist should be familiar with the anatomy, enervation and function of all muscles of the foot and leg.
Test 4: Jack’s Test relates to the Windlass Mechanism.
This clinical test assesses the tension in the plantar fascia associated with heel lift and propulsion. The way in which the terminal slips of the plantar fascia wind around the metatarsal heads has been called the Windlass Mechanism (Hicks, 1954). The Subtalar joint must supinate in order for the toes to dorsiflex.
People vary greatly in the force required to dorsiflex the great toe to “activate the windlass mechanism”. The examiner manually dorsiflexes the great toe until the foot supinates and grades the force required from 1 to 5. Orthoses that decrease this force reduce strain in the Plantar Fascia and improve the efficiency of gait.
Test 5: The Balance Test relates to Proprioception and Postural Stability.
The patient stands on one leg, establishes balance and then closes the eyes. The arch rises and the foot seeks a “Functional Neutral Position”. It then oscillates about this position. Balance is eventually lost either medially or laterally. The examiner observes the stability of balance, the duration of balance, the “Functional Neutral Position” and the loss of balance (medial or lateral). The Orthoses should improve the stability and duration of balance but should not induce lateral instability.
Test 6: The Forefoot Stability Test relates to Propulsion.
Efficient Propulsion requires a stable base. The patient is instructed to stand on one foot and then rise up onto the toes. The examiner observes the ease of rising onto the toes, the stability and the tendency to inversion instability. The Orthoses should improve stability and prevent inversion instability.