Request Appointment
(904) JOI-2000 JOI Bill Pay

FootMaxx™

Have pain when walking or running? Let the trained staff at JOI Rehabilitation assess your gait pattern and design custom orthotics to fit your individual needs! Watch the video below to see how the Footmaxx Metascan system works.

Click here to schedule an appointment with a JOI foot and ankle specialist near you

Click here to schedule an appointment with a JOI Physical Therapist near you

Click here to read about JOI’s new Sports Center!

Basic Biomechanics

Biomechanics is the study of the body in motion. Foot biomechanics studies the relationship of the foot to the lower leg. During walking and running the musculoskeletal system generates forces to propel the body forward. The foot serves two main functions. It acts as a mobile adaptor to adjust to varying terrain, and as a rigid lever for forward propulsion in locomotion. The two functions are time specific in that when the foot spends too much time being a mobile adaptor it is not spending enough time being a rigid lever and vice versa. Biomechanics of the foot analyzes how the various structures of the foot, work together to perform specific functions (timing being of utmost importance.) Excessive or prolonged motion or lack of motion will cause various deformities and pathologies discussed in the next section. Proper biomechanics allow human beings to walk, run, jump, and move freely without pain or dysfunction.

The following are important terms used frequently in the study of the biomechanics of the foot:

1. Gait Cycle (see Figure 2.5)- a complete gait cycle when the foot is in contact with the ground (weight bearing)

2. Stance Phase (see Figure 2.6)- A portion of the gait cycle when the foot is in contact with the ground (weight bearing)

3. Swing phase- the portion of the gait cycle when the foot is in the air (non-weight bearing)

4. Subtalar joint- neutral position- the position of the subtalar joint in which the foot is neither pronated nor supinated. When the hindfoot is neutral, the bisector of the calcaneus is the 90 to the supporting surface.

biomechanics of the foot

5. Subtalar joint pronation- is a coordinated triplane motion of the foot which involves three planes of motion: abduction, dorsiflexion and eversion.

biomechanics pronation

6. Subtalar joint supination- a coordinated triplane motion of the foot which involves three planes of motion: adduction, plantarflexion and inversion 

foot biomechanics supination

7. Pronated and supinated- adjectives which describe the position of the foot (they do not describe the action of pronation or supination). Thus a “pronated foot” is one which is in a pronated position as compared to a neutral position.

8. Degrees of pronation and/or supination- this is measured by the degrees of inversion (in the case of supination) or eversion (in the case of pronation) away from the neutral position.

9. Normal centre of pressure line (gait line)- is the average vector of all forces that act on the bottom of the normal foot as it goes through the stance phase of gait. Figure 2.5 shows the progression of the forces in the “Normal centre of pressure line” as the foot goes from contact phase to propulsion.

Foot biomechanics

Interpreting the Center of Pressure Line

Footmaxx orthotics shortShort (heel through mid-foot)
Metatarsalgia • Dropped metatarsal head(s) • Sesamoiditis • Hyper-lordosis

Accommodations: 1st ray cut-out, met bar, met pad
Suggested Orthotics: Sulcus-length Dress, Pro-Baseball, Allsport

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics straightStraight (medial deviation)
Forefoot hypermobility • Calcaneal eversion • Plantar fascia strain • Knee, hip, low back pain

Suggested Orthotics: Dress, Pro-Baseball, Pro-Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics lateLate (midfoot through metatarsals)
Achilles tendonitis • Tight calf muscles • Heel spur/plantar fasciitis • Kyphosis

Accommodations: Heelmaxx™, heel lift, soft arch strips 
Suggested Orthotics: Dress, Pro-Marathoner, Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics heelHeel Instability
Ankle instability • Pelvic rotation • Rearfoot varus

Accommodations: Heel lift
Suggested Orthotics: Dress, Pro-Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics midfootMid-foot Instability
Arch elongation • Fascial strain • Flexible plantarflexed 1st ray

Accommodations: Soft arch strips
Suggested Orthotics: Dress, Pro-Crosstrainer, Pro-Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics forefootForefoot Instability
Knee strain (patellofemoral, ilio tibial strain) • Metatarsal instability
Hallux limitus • Anterior/posterior tibial strain

Accommodations: Soft arch strip/fill, heel lift, met pad
Suggested Orthotics: Dress, Pro-Marathoner, Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.


Footmaxx orthotics forefoot instabilityForefoot Instability with Torque
Knee instability • Trauma to the knee • Hallux limitus

Accommodations: Soft arch strip/fill, heel lift
Suggested Orthotics: Dress, Pro-Crosstrainer, Pro-Marathoner

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.



Footmaxx orthotics instabilityComplete Instability
Instability in gait (geriatric population, MS patients)
Knee instability • Hypermobile midtarsal joint

Accommodations: Soft arch strips/fills
Suggested Orthotics: Dress, Pro-Crosstrainer, Arthritic 2

Normal center of pressure (COP) line shown in red.
Deviated COP line shown in black.