What is SSI?

Shoe Stability Index (SSI) is an indicator of shoe stability, as an index. SSI is derived through mathematically combining the quantified measurements of midfoot stability (TCI) and hindfoot stability (VCI), indicating the shoe’s overall ability to control the motion of the foot.

What is TCI?

Torsion Control Index (TCI) is a measurement of midfoot shoe stability, in inch-pound units (in.-lbs.). TCI is measured through actively twisting a shoe around the longitudinal axis of the shoe, from the heel to the area of the toes joints, simulating rotational forces of the foot, and measuring the shoe’s resistance to this motion.

The higher the TCI, the firmer the midfoot and more torsional stability. The lower the TCI, the softer the midfoot and less torsional stability.

What is VCI?

Vertical Compression Index (VCI) is a measurement of hindfoot shoe stability, in millimeters (mm). VCI is measured through compression of the heel portion of the shoe under a fixed amount of pressure, thereby measuring how the structure of the shoe controls rearfoot motion.

The higher the VCI, the softer the midsole and less hindfoot stability. The lower the VCI, the firmer the midsole and more hindfoot stability.

What is Loaded Heel to Toe Drop?

Loaded Heel to Toe Drop is the measurement in millimeters of the height of the heel relative to the fore foot when compressed to a fixed poundage. This can be defined as vertical support.

What is RI?

Rebound Index (RI) is an indicator of energy return of shoe to the foot, in millimeters (mm). RI is measured through compression of the heel portion of the shoe under a fixed amount of pressure, and then determining how much force the shoe exerts on the foot.

What is Fore Flex?

Fore Flex is the measurement in millimeters of the fore foot when compressed to a fixed poundage. The higher the Fore Flex, the softer the sole, allowing more bend at the fore foot. The lower the Fore Flex, the firmer the sole, allowing less bend at the fore foot.

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Ilio-Tibial Band Syndrome

Table List Visual List

The following list of shoes are suitable for your foot type. Those of heavier physical stature may find greater comfort and durability in their footwear if they choose from the next higher level of stability. Those with orthopedic injuries, please consult our Injury Profiler.

Shoe	Weight	TCI	VCI	Vertical Support	Cushion	SSI	Level	RI	Recommendations
New Balance – 1540v3	12.20	67.0 in.-lbs (High)	3.71 mm (Max)	6.29 mm (Max)	Firm	86.6	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet
Salomon – XA Pro 3Dv8	10.90	62.0 in.-lbs (High)	4.08 mm (Max)	7.92 mm (Max)	Firm	80.8	High Stability	High	Supination, Moderate Pronation, Severe Pronation
Brooks – Ariel 20	9.80	57.0 in.-lbs (High)	4.20 mm (Max)	7.8 mm (Max)	Firm	76.7	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet
Brooks – Addiction 15	10.30	61.0 in.-lbs (High)	4.70 mm (Mod)	7.3 mm (Max)	Mod	76.0	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet
Salomon – Speedcross	9.30	53.0 in.-lbs (High)	5.05 mm (Mod)	4.95 mm (Mod)	Mod	68.3	Moderate Stability	High	Supination, Neutral Pronation, Mild Pronation, Moderate Pronation, Severe Pronation
Salomon – SpeedCross 6	10.3	51.0 in.-lbs (High)	5.17 mm (Mod)	4.83 mm (Mod)	Mod	66.2	Moderate Stability	High	Supination, Neutral Pronation, Mild Pronation, Moderate Pronation, Severe Pronation
New Balance – 1540v3	14.3	77.0 in.-lbs (High)	2.60 mm (Max)	7.4 mm (Max)	Firm	100.7	High Stability	Medium	Supination, Moderate Pronation, Severe Pronation, Flat Feet
Salomon – XA Pro 3Dv8	12.1	70.0 in.-lbs (High)	4.39 mm (Max)	7.61 mm (Max)	Firm	84.1	High Stability	High	Supination, Moderate Pronation, Severe Pronation
LaSportiva – Mutant	12.2	61.0 in.-lbs (High)	3.68 mm (Max)	6.32 mm (Max)	Firm	82.8	High Stability	High	Supination, Moderate Pronation, Severe Pronation
Brooks – Addiction 15	11.4	66.0 in.-lbs (High)	4.72 mm (Mod)	7.28 mm (Max)	Mod	79.2	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet
Brooks – Beast 20	11.1	55.0 in.-lbs (High)	4.67 mm (Mod)	7.33 mm (Max)	Mod	72.2	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet
New Balance – 940v4	12.0	64.0 in.-lbs (High)	5.63 mm (Min)	6.37 mm (Max)	Soft	71.8	High Stability	High	Supination, Moderate Pronation, Severe Pronation, Flat Feet

1540v3

New Balance / / 12.20

Overall Stability	SSI: 86.6 (High Stability)
Midfoot Stability	TCI: 67.0 in.-lbs (High)
Hindfoot Stability	VCI: 3.71 mm (Max)
Loaded HTD (Vert Support):	6.29 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	16.56 mm (High)

Injuries View Injury Profiler

Achilles Tendonitis Anterior Shin Splints Hallux Valgus (Bunion) Ilio-Tibial Band Syndrome Lateral Ankle Sprain Medial Shin Splints Neuroma Patello-Femoral (Runner's Knee) Plantar Fasciitis Posterior Tibial Tendonitis

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

XA Pro 3Dv8

Salomon / / 10.90

Overall Stability	SSI: 80.8 (High Stability)
Midfoot Stability	TCI: 62.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.08 mm (Max)
Loaded HTD (Vert Support):	7.92 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	16.80 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Ariel 20

Brooks / / 9.80

Overall Stability	SSI: 76.7 (High Stability)
Midfoot Stability	TCI: 57.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.20 mm (Max)
Loaded HTD (Vert Support):	7.8 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	16.36 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Addiction 15

Brooks / / 10.30

Overall Stability	SSI: 76.0 (High Stability)
Midfoot Stability	TCI: 61.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.70 mm (Mod)
Loaded HTD (Vert Support):	7.3 mm (Max)
Cushioning:	Mod
RI Index (Energy Return):	18.21 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Speedcross

Salomon / / 9.30

Overall Stability	SSI: 68.3 (Moderate Stability)
Midfoot Stability	TCI: 53.0 in.-lbs (High)
Hindfoot Stability	VCI: 5.05 mm (Mod)
Loaded HTD (Vert Support):	4.95 mm (Mod)
Cushioning:	Mod
RI Index (Energy Return):	20.32 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

SpeedCross 6

Salomon / / 10.3

Overall Stability	SSI: 66.2 (Moderate Stability)
Midfoot Stability	TCI: 51.0 in.-lbs (High)
Hindfoot Stability	VCI: 5.17 mm (Mod)
Loaded HTD (Vert Support):	4.83 mm (Mod)
Cushioning:	Mod
RI Index (Energy Return):	26.02 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

1540v3

New Balance / / 14.3

Overall Stability	SSI: 100.7 (High Stability)
Midfoot Stability	TCI: 77.0 in.-lbs (High)
Hindfoot Stability	VCI: 2.60 mm (Max)
Loaded HTD (Vert Support):	7.4 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	12.61 mm (Medium)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

XA Pro 3Dv8

Salomon / / 12.1

Overall Stability	SSI: 84.1 (High Stability)
Midfoot Stability	TCI: 70.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.39 mm (Max)
Loaded HTD (Vert Support):	7.61 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	17.26 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Mutant

LaSportiva / / 12.2

Overall Stability	SSI: 82.8 (High Stability)
Midfoot Stability	TCI: 61.0 in.-lbs (High)
Hindfoot Stability	VCI: 3.68 mm (Max)
Loaded HTD (Vert Support):	6.32 mm (Max)
Cushioning:	Firm
RI Index (Energy Return):	15.99 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Addiction 15

Brooks / / 11.4

Overall Stability	SSI: 79.2 (High Stability)
Midfoot Stability	TCI: 66.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.72 mm (Mod)
Loaded HTD (Vert Support):	7.28 mm (Max)
Cushioning:	Mod
RI Index (Energy Return):	17.84 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Beast 20

Brooks / / 11.1

Overall Stability	SSI: 72.2 (High Stability)
Midfoot Stability	TCI: 55.0 in.-lbs (High)
Hindfoot Stability	VCI: 4.67 mm (Mod)
Loaded HTD (Vert Support):	7.33 mm (Max)
Cushioning:	Mod
RI Index (Energy Return):	17.68 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

940v4

New Balance / / 12.0

Overall Stability	SSI: 71.8 (High Stability)
Midfoot Stability	TCI: 64.0 in.-lbs (High)
Hindfoot Stability	VCI: 5.63 mm (Min)
Loaded HTD (Vert Support):	6.37 mm (Max)
Cushioning:	Soft
RI Index (Energy Return):	24.54 mm (High)

Injuries View Injury Profiler

Foot Pattern

Supination Neutral Pronation Mild Pronation Moderate Pronation Severe Pronation Flat Feet

Shoe Definitions

What is SSI?

What is TCI?

The higher the TCI, the firmer the midfoot and more torsional stability. The lower the TCI, the softer the midfoot and less torsional stability.

What is VCI?

The higher the VCI, the softer the midsole and less hindfoot stability. The lower the VCI, the firmer the midsole and more hindfoot stability.

What is Loaded Heel to Toe Drop?

Loaded Heel to Toe Drop is the measurement in millimeters of the height of the heel relative to the fore foot when compressed to a fixed poundage. This can be defined as vertical support.

What is RI?

What is Fore Flex?


Supination	Neutral	Mild/Moderate Pronation	Severe Pronation / Flat Foot

Characterized by a high arch that remains rigid through the gait cycle	Characterized by a moderate arch height with a minimal degree of motion through the gait cycle	Indicated by a mild to moderate amount of inward rotation of the midfoot (or "collapsing" of the medial arch) when weight-bearing	Indicated by a high degree of inward rotation of the midfoot (or "collapsing" of the medial arch) when weight-bearing, to where the foot appears flat.

Determining Foot Pattern

Compare your feet and water footprints to the images seen above. All pictures were taken in a weight bearing position (standing). Once again, these images should only be used as a casual guide until you can be evaluated properly.

The most accurate way to determine your foot pattern is to have a professional observe you walking barefoot. A doctor, physical therapist or a specialty running store should be able to do this for you. Although not perfect, the “water” test can also give you some idea of your foot type. This entails getting your feet wet, walking on dry cement, and observing the prints left behind (see images above).

Please remember that foot patterns are defined by the motion of the foot (or lack thereof) through the gait cycle, and not solely the height of the arch. Although the type of heel strike can often be determined by the wear of a shoe, shoe wear does not always indicate the actual foot pattern (which occurs in the mid-stance of the gait cycle, after heel strike).

December 2022 test data is now live!