Foot & Ankle Biomechanics

Foot Biomechanics During Walking and Running

Distal Foot Anatomy

• Distal hallux
• Proximal phalanx
• Proximal hallux
• Medial (tibial) sesamoid
• Lateral (fibular) sesamoid
• Metatarsals
• Cuneiforms

Plantar Aponeurosis

The plantar aponeurosis originates from the calcaneal tuberosity and courses distally to blend with skin, flexor tendon sheaths, and transverse metatarsal ligaments. By virtue of its distal insertions, the plantar aponeurosis becomes tight with flexion of the metatarsophalangeal joints; it lends support to the longitudinal arches because of a “windlass” effect and stabilizes the metatarsophalangeal joints.

Basic Biomechanics of the Foot

Cardinal Planes

• Sagittal Plane: Dorsiflexion (upward) and plantar flexion (downward)
• Frontal Plane: Inversion (adduction) and eversion (abduction)
• Transverse Plane: Adduction (internal rotation) and abduction (external rotation)

Pronation and Supination

• Supination: Inversion, adduction, and plantar flexion
• Pronation: Eversion, abduction, and dorsiflexion

Special Qualities of the Foot

The foot adapts to various terrains by unlocking at the initial ground contact, allowing more freedom of motion. Later, as the foot is about to leave the ground, it locks to become a rigid lever that propels the leg forward with body weight.

Ankle Joint

The ankle joint is a synovial articulation between the inferior aspects of the tibia and fibula and the superior surface of the talus. No muscles attach directly to the talus, so there are no pure dorsiflexors or plantar flexors.

Foot Biomechanics During Walking and Running

Subtalar Joint Mechanics

The axis of the subtalar joint runs downward, posteriorly, and laterally, at a mean angle of 41° from the horizontal plane and is 23° rotated from the long axis of the foot. This orientation allows for more equally triplanar motion compared to the ankle joint. However, there is a pronounced variation in this orientation, with interindividual ranges of motion of 21 to 69° from the horizontal and 4 to 47° from the long axis of the foot.

• Axis Orientation:
  • Mean angle from horizontal: 41°
  • Rotation from long axis of the foot: 23°

As the axis becomes more horizontal, the joint contributes more to eversion and inversion than to abduction and adduction. Similarly, the closer the axis is to the sagittal plane, the less the joint contributes to plantar flexion or dorsiflexion.

Motion and Rotation

When rotation is imparted to the superior aspect of the talus, it causes rotation of the calcaneus in the opposite direction. External rotation of the leg produces inversion, and internal rotation causes eversion of the calcaneus. Inversion occurs in the subtalar joint when the calcaneus is brought toward the midline, and eversion of the hindfoot occurs throughout the first 15% of the stance phase, at which time inversion begins. This motion at the subtalar joint is passed through the talus and calcaneus to the navicular and cuboid bones.

Transverse Tarsal Joint

The transverse tarsal joint is a combination of the calcaneocuboid and talonavicular synovial gliding joints. The motion in this joint can be described by a pair of functional axes:

• Longitudinal Axis: Parallels the subtalar joint axis and provides eversion-abduction and inversion-adduction.
• Oblique Axis: Close to the ankle joint axis and provides primarily plantar flexion and dorsiflexion.

The subtalar and transverse tarsal joints are closely related; as one joint supinates, the other follows. With eversion of the calcaneus (pronation of the subtalar joint), the axes of the calcaneocuboid and talonavicular joints become parallel, allowing increased motion in the transverse tarsal joint and thus leading to a flexible foot. With supination, the axes are no longer parallel, making the foot rigid.

Kinematic Chains

When the foot is fixed (in a closed kinematic chain), such as during walking or running in the stance phase, the motion of the foot and ankle is translated proximally to the tibia, fibula, and femur. The periods of external and internal rotation of the lower limb are correlated with the positions of the hindfoot, influencing the overall limb motion.

This understanding of foot and ankle mechanics is crucial for runners to optimize their biomechanics and reduce injury risk.

Foot Biomechanics During Walking and Running

Schema of Mechanism by Which Rotation of Tibia is Transmitted Through Subtalar Joint Into Foot

• Outward rotation of tibia: Causes inward rotation of calcaneus and subsequent elevation of the medial border of the foot and depression of the lateral border of the foot.
• Inward rotation of tibia: Causes outward rotation of calcaneus and depression of the medial side of the border of the foot and elevation of the lateral border of the foot.

Motion and Rotation in the Foot

• First ray: Primarily contributes to plantar flexion-eversion, with minimal contributions to abduction-adduction.
• Second through fourth rays: Allow essentially pure plantar flexion and dorsiflexion.
• Fifth ray: Results in pronation-supination between the fifth metatarsal and the cuboid.
• Metatarsophalangeal joints: Biaxial joints allowing plantar flexion-dorsiflexion and abduction-adduction.
• Interphalangeal joints: Hinge joints resulting in simple flexion-extension.

Influence of Leg Rotation on Foot Mechanics

• External rotation of the leg: Causes inversion of the heel and consequent elevation on the medial side of the foot and depression on the lateral aspect.
• Internal rotation of the leg: Produces the opposite effect on the foot.

Axes of Rotation in the Midfoot

• Axes of rotation: Difficult to determine due to small excursion between any two bones.
• Total motion: Ranges from just a few degrees of dorsiflexion to about 15° of plantar flexion.
• Motion of all tarsal and tarsometatarsal joints: Affects the shape of the arch.

Stability and Motion in the Midfoot

• First ray movement: Upward or downward movement affects the second through the fifth rays successively less.
• Fourth and fifth ray movement: Upward or downward movement imparts more stability to the medial rays.

Keylike Configuration in the Second Tarsometatarsal Joint

• Second tarsometatarsal joint: Recessed into the midfoot and forms a “keylike” configuration with the second cuneiform.
• Stability: This situation restricts motion at the second ray, making it more stable than the first ray and the lateral three rays.

Foot Biomechanics During Walking and Running

Version Inversion

Fig. 5. Axes of rotation in talonavicular (77V) and calcaneocuboid (CC) joints. When the hindfoot is everted, these axes are parallel, allowing relatively free motion in the transverse tarsal joint. When the hindfoot is inverted, axes are divergent, restricting motion in the transverse tarsal joint and increasing stability.

In summary, the rotations that occur in the lower segment act on the talus. The translation of this rotation through the oblique hinge at the subtalar joint transmits the rotation to the foot. The changes of the axes of the transverse tarsal joint and those that occur distal to this joint convert the flexible foot into a rigid arch system. Any abnormal rotation in one of these segments can alter the entire gait pattern.

Gait Biomechanics

The hypothetical normal foot position during the stance phase occurs when:

1. The heel bone is in line with the leg and perpendicular to the ground.
2. The plane of the forefoot (metatarsal heads) is perpendicular to the rearfoot and parallel to the ground.
3. The ankle joint can dorsiflex 10°.
4. No forces are on the foot from the leg in any of the three body planes (sagittal, frontal, or transverse) causing it to invert or evert, abduct or adduct, dorsiflex or plantar flex.

The major joints of the lower extremity are the hip, knee, ankle, and those of the foot (subtalar, midtarsal, first and fifth metatarsals, and toes). The hip joint is a ball-and-socket design and has free rotational movement in all directions (flexion, extension, abduction, adduction, internal rotation, external rotation, and circumduction). For normal foot motion, sagittal and frontal planes of motion must be smooth, but smoothness is not as important as rotation, which controls the angle of gait and supination and pronation of the foot.

The knee joint is a hinge type, primarily allowing flexion and extension, with small amounts of rotation and gliding motions possible. The ankle joint, also a hinge type, allows gliding and angulation.

Fig. 6. Motion in subtalar joint during normal walking cycle. At initial floor contact, rapid eversion is followed by progressive inversion until lift-off, after which eversion recurs.

Foot and Ankle Mechanics During Walking and Running

Tarsometatarsal Axes of Rotation

• First Tarsometatarsal Joint Axis
• Fifth Tarsometatarsal Joint Axis

Figure 7. Tarsometatarsal axes of rotation. (From Sammarco GJ. Biomechanics of the foot. In: Frankel VH, Nordin M, editors. Basic Biomechanics of the Skeletal System. Philadelphia: Lea & Febiger, 1980: 193-220. By permission.)

Gliding Motion and Weight Bearing

• The gliding motion of the foot compensates for forward and backward displacements of the body’s center of gravity during dorsiflexion and plantar flexion.

Foot and Leg Interaction

• During stance, as the foot pronates, the leg internally rotates on the foot.
• As the foot supinates, the leg externally rotates, and concurrent stress extends up the limb.

Joint Motion Descriptions

• Many descriptions of joint motion are based on original reports, primarily observations rather than complete investigations.
• The application of these studies to gait analysis is hypothetical.

Speed and Gait Cycle

• The speed of normal walking is between 3.6 and 4.5 km/h.
• A person averages approximately 60 cycles/min and spends 60% of each cycle in the stance phase and 40% in the swing phase.
• The cycle from heel strike on one leg to the next heel strike on the same leg equals 100% of the total gait cycle.
• The period from 0 to 15% is the heel strike phase, from 15 to 30% is midstance, from 30 to 45% is push-off, and from 45 to 60% is acceleration of the swinging leg.
• The swing phase is subdivided into swing-through and deceleration of the swinging leg.
• At the end of the stance phase of one leg and the beginning of the stance phase of the other, a time of double-limb support continues for approximately 11% of the gait cycle.

Rotational Movements During Gait

• Each lower segment of the skeleton rotates in the transverse plane.
• The degree of rotation progressively increases from the more proximal segments to the more distal segments.
• During walking on level ground, the pelvis rotates a mean of 6°; the femur, 13°; and the tibia, 18°.
• The lower limb rotates internally from the beginning of toe-off through the swing phase and the first 15% of the stance phase.
• During the middle of the stance phase and at push-off, the direction is reversed, and external rotation culminates just after toe-off, when internal rotation recurs.
• This transverse rotation is passed to the talus through its articulation with the tibia and fibula.
• As external rotation occurs, a degree of increased stability is attained along the medial aspect of the hip, knee, ankle, and foot.
• Muscle contraction and ligaments also aid in stabilizing the foot until it is lifted off the ground.

Plantar Flexion and Dorsiflexion

• Plantar flexion at heel strike continues until the onset of midstance.
• Progressive dorsiflexion occurs from heel-off until the 40% point of the cycle, when plantar flexion begins again.
• During the swing phase, dorsiflexion continues.

Foot Biomechanics During Walking and Running

Transverse Rotation of Pelvis, Femur, and Tibia

During the normal walking cycle, there is inward rotation until the foot is flat at 20% of the cycle. After this point, progressive outward rotation is noted until toe-off, when inward rotation recurs.

[Figure 9: Transverse rotation of pelvis, femur, and tibia during normal walking cycle] Rotation is inward until foot is flat at 20% of cycle, after which progressive outward rotation is noted until toe-off, when inward rotation recurs. (From Mann RA. Biomechanics of the foot. In: American Academy of Orthopaedic Surgeons, editor. Atlas of Orthotics: Biomechanical Principles and Application. St. Louis: Mosby, 1975: 257-266. By permission.)

Schema of Complete Walking Cycle

The schema below shows rotations in various segments and joints, as well as activity in foot and leg musculature throughout the walking cycle.

Segment/Joint	Initial Floor Contact (15%)	30%	45%	60%	Mid-Stance	Terminal Stance	Pre-Swing	Initial Swing	Terminal Swing
Tibia	-	-	-	-	-	-	-	-	-
Ankle Joint	-	-	-	-	-	-	-	-	-
Subtalar Joint	-	-	-	-	-	-	-	-	-
Transverse Tarsal Joint	-	-	-	-	-	-	-	-	-
Talo-Navicular Joint	-	-	-	-	-	-	-	-	-
Intrinsic Muscles	-	-	-	-	-	-	-	-	-
Pretibial Muscles	-	-	-	-	-	-	-	-	-
Calf Muscles	-	-	-	-	-	-	-	-	-
Plantar Flexion	-	-	-	-	-	-	-	-	-

Activity in foot and leg musculature:

• External Rotation - Dorsiflexion - Eversion - Unstable - Inactive
• Plantar Flexion - Increasing Stability - Increasing Activity
• Dorsiflexion - Eversion - Unstable - Inactive
• Inactive

[Figure 10: Schema of complete walking cycle, showing rotations in various segments and joints and activity in foot and leg musculature] (From Mann RA. Biomechanics of the foot. In: American Academy of Orthopaedic Surgeons, editor. Atlas of Orthotics: Biomechanical Principles and Application. St. Louis: Mosby, 1975: 257-266. By permission.)

Foot and Ankle Mechanics During Walking and Running

Overview of Muscle Activity

The extrinsic muscles of the lower extremity posterior to the ankle axis are the plantar flexors, and those anterior to the ankle axis are the dorsiflexors. Those medial to the subtalar axis are invertors, and those lateral to the subtalar axis are evertors.

• Dorsiflexors (anterior compartment): Active during the swing phase and early stance phase. They help clear the foot during swing and decelerate the foot as it strikes the ground, preventing foot slapping at heel strike.
• Plantar Flexors: Generally function during midstance and terminal stance phases until toe-off. The intrinsic muscles of the foot are also active during the midstance until toe-off.

Role of the Plantar Fascia

The plantar fascia arises from the inferior tubercle of the calcaneus and passes forward, dividing into bands that circle the flexor tendons and insert into the base of each proximal phalanx. This forms a cable between the heel and the toes, creating a combined truss and Spanish windlass mechanism at the metatarsophalangeal attachment of the fascia.

• Mechanism: As the metatarsophalangeal joints extend passively when standing on the ball of the foot, the plantar fascia is pulled distally, shortening the distance from the calcaneus to the metatarsal heads. This shortening increases the height of the arch and locks the tarsal bones into a forced flexion position, creating a solid structure of support.

Summary of Gait Cycle

During the gait cycle at heel strike:

• The lower segment of the skeleton internally rotates until foot flatness is achieved at 15% of the cycle.
• The heel is everted, and the forefoot is flexible and adapting to the ground.
• The pretibial muscle is active during the first 15% of the stance phase.

When midstance begins:

• The lower segment reverses into external rotation and the heel inverts, with progressive stabilization of the longitudinal arch until toe-off.
• Active contraction of the posterior calf muscles and the intrinsic muscles of the foot is present.

As the foot is “loaded”:

• The convex head of the talus is firmly seated in the concave navicular.
• The plantar fascia exerts its forces on the arch as weight passes over the foot and the toes are extended.
• The lower segment achieves maximal external rotation, the heel is maximally inverted, intrinsic muscle and plantar flexor activity is at its maximum, and the axes of the transverse tarsal joint are divergent just before toe-off.
• Stabilization of the longitudinal arch is achieved.

Foot Biomechanics During Walking and Running

Overview of Biomechanical Models

Fig. 12. A, Truss. Wooden structure is analogous to bony structures of the foot. The plantar fascia is represented by a tether between the ends of the bone. The shorter the tether, the higher the truss is raised. B, Spanish windlass. Upper drawing, the metatarsal is represented by a fixed wooden structure, and the proximal phalanx is represented by a moving one. The rope attached to the moving structure represents the attachment of the plantar fascia to the proximal phalanx. Lower drawing, as the moving structure turns, the rope advances. C, Combined truss and Spanish windlass. As the plantar fascia raises the arch of the foot (upper drawing), it concurrently locks joints and makes a single unit from multiple individual bones and joints (lower drawing). (From Sammarco GJ. Biomechanics of the foot. In: Frankel VH, Nordin M, editors. Basic Biomechanics of the Skeletal System. Philadelphia: Lea & Febiger, 1980: 193-220. By permission.)

Speed Classification and Gait Phases

Muscle activity, and joint reaction forces all vary primarily on the basis of speed and often from one step to the next. The speed of gait can generally be classified into jogging (3.31 m/s or 8 min/mile), running (4.77 m/s or 6 min/mile), and sprinting (10.8 m/s or 9.21 s/100 m). In contrast, walking is defined as 1.32 m/s (20 min/mile). Gait can be categorized into a stance phase (60%), which consists of two periods of double-limb support (each 12%) and one period of single-limb support (35%), and a swing phase (40%). As the speed of gait increases, a third phase—the nonsupportive float phase—develops. This phase distinguishes running from walking by increasing speed, from a slow jog, to a run, to a sprint. (The stance phase decreases, and the swing and especially the float phases increase.) From walking to sprinting, the period of the stance phase decreases from 0.62 to 0.14 second. As during walking, the center of gravity of the body resembles a sinusoidal curve in space, with the peak during the float phase and the bottom during the stance phase before the onset of knee extension and ankle plantar flexion. This vertical oscillation of the center of gravity decreases with increased running speed. During running, each foot lands in the midline; thus, the leg is in a functional varus of 8 to 14°. The feet are generally neutral or slightly internally rotated and land under the knee below the center of gravity. At a running pace of 6 min/mile, initial ground contact is usually made along the posterior 60% of the lateral border of the foot. Usually, contact occurs in the posterior third of the foot (rearfoot or heel strikers). During the stance phase, range of motion of the lower extremity joints and periods of muscle activity increase with higher speeds. Rotation of the pelvis, femur, and tibia has been well quantified during walking but less so during running.

Foot Biomechanics During Walking and Running

Muscle Activity

Pretibial muscle, Triceps (calf), and Foot (intrinsic muscle) activity during the stance and swing phases of gait are illustrated in Figure 13. The schematic shows phasic activity of leg and foot muscles during normal gait.

Pronation and Shock Absorption

Pronation is a mechanism for absorbing shocks. Runners with cavus (high-arched) feet generally absorb forces more poorly than those with lower arches. Rearfoot motion does not vary consistently with speed but is influenced by shoe wear. Running barefoot typically results in increased pronation, possibly due to changes in biomechanics where the musculoskeletal system must absorb some of the force that would otherwise be dissipated by the shoe. Some runners with excessive pronation in their shoes have neutral motion when running barefoot, which may be attributed to the cushioning properties of the shoe, other biomechanical changes, or inaccuracies in measuring foot motion through shoe movement.

Supination and Stability

After maximal pronation, the foot begins to supinate. Once the foot is fully loaded and the center of gravity has passed the base of support, external rotation of the lower extremity causes inversion of the calcaneus, creating a rigid foot on which muscles can act. The obliquity of the metatarsal break also helps to supinate the foot by enhancing external rotation of the tibia as the toes are dorsiflexed. Stability of the foot is enhanced by the plantar aponeurosis and intrinsic foot muscles. External rotation that produces supination is initiated by the forward swing of the opposite leg, which brings the pelvis forward. The femur of the stance leg rotates externally due to its fixation to the pelvis by the adductors. This rotation is passed through the knee joint to the tibia and then to the ankle and foot.

Ankle Actions

Typically, long-distance runners initially contact the ground heel-first or with the foot flat, whereas sprinters commonly land on the midfoot. In a study of 753 distance runners, 80% were rearfoot strikers and the others midfoot strikers. Faster runners were often midfoot strikers. At the time of heel strike, rapid dorsiflexion at the ankle joint, along with hip and knee flexion, helps absorb the force of impact. In contrast, during walking, plantar flexion occurs at heel strike.

Clinical Overview of Foot and Ankle Mechanics Relevant to Runners

Walking vs. Running Gait Cycles

Running gait cycle differs from walking because of an increase in double-limb unsupported time, or float phase, a decrease in stance phase, and an increase in swing phase. (From Adelaar RS. The practical biomechanics of running. Am J Sports Med 1986;14:497-500. By permission of American Orthopaedic Society for Sports Medicine.)

Forces During Running

During running, pronounced forces—the vertical force, fore and aft shear, medial and lateral shear, and torque—develop between the foot and the ground. The vertical force rarely exceeds 120% of body weight during walking, whereas during running, it approaches 275%. These impact forces are even higher in children, approximately 3.4 times body weight for 6-year-olds and 4 times for 4-year-olds. Localized forces may be as high as 13 times body weight at the ankle and 10 times at the Achilles tendon. Vertical force plate analysis generally shows a brief impact spike followed by two peaks during walking but only a single peak after the impact spike during running. The probable explanation is that two periods of double-limb support occur during walking. The impact peak is actually smaller than the second peak, which is associated with propulsion, because more force is generated with propulsion than with impact. With midfoot or forefoot strikers, the initial impact peak generally flattens out and dissipates.

Shear Forces During Running

Shear forces are similar during walking and running, although again the magnitude is greater during running. Mediolateral shear forces vary substantially, most likely because of wide variations in anatomic alignments and foot placements among runners. During running, a second period of medial shear seems to occur that has questionable importance. The anteroposterior shear forces peak at approximately half the body weight during the first part of stance and contribute to a braking force; a second, similar force, associated with forward propulsion, then develops in the opposite direction. At impact, the foot (or shoe) has a horizontal velocity component of approximately 17% of the runner’s forward velocity. The resulting shear force (rather than high vertical forces) contributes to shoe wear; thus, increased areas of shoe wear reflect initial ground contact rather than peak force. Minimizing the horizontal component of the ground reaction force (that is, the braking force) is apparently important in optimizing performance. Although the magnitude of this force seems to be related to foot speed

Foot Biomechanics During Walking and Running

Vertical Ground Reaction Forces and Shear Forces

Figure 15 illustrates the distribution of forces acting on the sole during running, including vertical ground reaction forces, fore and aft shear forces, and medial and lateral shear forces.

Center of Pressure Measurement

The distribution of forces acting on the sole can be averaged to obtain a measurement known as the center of pressure. This measurement reflects the gait pattern of the runner. For a typical heel striker, the center of pressure begins outside the outline of the shoe due to lateral displacement caused by shear forces. The center of pressure varies among individuals, with speed, and even between right and left feet.

Maximal Pressure Areas

Maximal pressures have been measured at the heel, the metatarsal heads, and the great toe. The center of pressure measurement reflects the gait pattern of the runner. A typical heel striker generates the pressure shown in Figure 16.

Stride Length and Rate

Stride length is defined as the distance from the point of initial contact of one leg to the point of initial contact of the other. Stride rate and length both increase at higher velocities. At higher speeds, stride rate increases to a greater extent than does length (Fig. 17). A study of a world-class sprinter at speeds up to 9.5 m/s showed that stride length increased to a larger extent at higher speeds and that stride rate decreased concurrently. No consistent relationship seems to exist between stride characteristics and runner size.

Foot Biomechanics During Walking and Running

Center of Pressure Patterns

Fig. 16. Center of pressure patterns of three subjects all running at the same speed. Note great differences among subjects despite matched running speeds.
A. Rearfoot striker.
B. Midfoot striker.
C. Forefoot striker.
(From Cavanagh. By permission of Mosby.)

Stride Length and Leg Length

Stride length apparently increases in parallel with leg length; however, individual variations are substantial. In general, trained runners seem to have a longer stride at a specific speed, although some studies have shown the opposite.

Efficiency and Running Styles

Efficiency contributes to running styles. No definitive studies have been done, however, to determine whether runners naturally adopt efficient styles or what constitutes an efficient style. Training has been reported to increase running economy, and, in fact, biomechanics may be more closely related to the economy of running, which is defined as the metabolic cost of performing a particular task and is not necessarily related to efficiency. Runners tend to have a stride length that is within 4.2 cm of the most economic length; the importance of this finding is questionable because fairly large differences in stride length result in small changes in energy consumption. Furthermore, the specific criteria that dictate optimal stride length have not been definitively ascertained. In fact, the length may be related to the efficiency and velocity of the muscle contractions themselves (this hypothesis is strengthened by the observation that when runners are fatigued, they tend to adopt a longer stride).

Variability of Stride Length and Stride Rate

Fig. 17. Variability of stride length (step length) and stride rate (step frequency) with velocity.
(From Hoshikawa T, Matsui H, Miyashita M. Analysis of running pattern in relation to speed. Med Sports 1973;8:342-348. By permission of S. Karger.)

Characteristics of Economic Runners

Economic runners have less vertical motion of the center of gravity, generally small anteroposterior and vertical ground reaction forces, a low impact peak in the vertical force, and a rearfoot striking pattern.

Conclusion

We have described the anatomy and biomechanics of the foot and have explained how movement and gait are integrated in the foot during walking and running. With an understanding of these factors, the clinician should be better able to evaluate foot problems.

References

1. Anderson JE. Grant’s Atlas of Anatomy. 8th ed. Baltimore: Williams & Wilkins, 1983
2. Hollinshead WH, Jenkins DB. Functional Anatomy of the Limbs and Back. 5th ed. Philadelphia

Clinical Overview of Foot and Ankle Mechanics Relevant to Runners

Introduction

The biomechanics of the foot and ankle during walking and running are crucial for understanding the mechanics involved in endurance activities. This overview draws from various clinical studies and texts to provide a comprehensive understanding of the anatomical and functional aspects of the foot and ankle in runners.

Key References

1. Frankel VH, Nordin M. Basic Biomechanics of the Skeletal System. Philadelphia: Lea & Febiger, 1980.
2. Riegger CL. Anatomy of the ankle and foot. Phys Ther 1988;68:1802-1814.
3. American Academy of Orthopaedic Surgeons, editor. Atlas of Orthotics: Biomechanical Principles and Application. St. Louis: Mosby, 1975.
4. Mann RA, Baxter DE, Lutter LD. Running symposium. Foot Ankle 1981;1:190-224.
5. Czerniecki JM. Foot and ankle biomechanics in walking and running: a review. Am J Phys Med Rehabil 1988;67:246-252.
6. Inman VT. The Joints of the Ankle. Baltimore: Williams & Wilkins, 1976.
7. Manter JT. Movements of the subtalar and transverse tarsal joints. AnatRec 1941;80:397-410.
8. Mann RA, Hagy J. Biomechanics of walking, running, and sprinting. Am J Sports Med 1980;8:345-350.
9. Oatis CA. Biomechanics of the foot and ankle under static conditions. Phys Ther 1988;68:1815-1821.
10. Mann RA. Biomechanics of running. In: Mack RP, editor. American Academy of Orthopaedic Surgeons Symposium on the Foot and Leg in Running Sports. St. Louis: Mosby, 1982: 1-29.
11. Hicks JH. The mechanics of the foot. II. The plantar aponeurosis and the arch. J Anat 1954;88:25-30.
12. Kottke FJ, Lehmann JF. Krusen’s Handbook of Physical Medicine and Rehabilitation. 4th ed. Philadelphia: Saunders, 1990.
13. BasmajianJV. Muscles Alive: Their Functions Revealed by Electromyography. 3rd ed. Baltimore: Williams & Wilkins, 1974.
14. Mann RA, Moran GT, Dougherty SE. Comparative electromyography of the lower extremity in jogging, running, and sprinting. Am J Sports Med 1986;14:501-510.
15. Williams KR. Biomechanics of running. Exerc Sport Sci Rev 1985;13:389-441.
16. SubotnickSI. The biomechanics of running: implications for the prevention of foot injuries. Sports Med 1985;2:144-153.
17. Cavanagh PR, Hennig EM, Bunch RP, Macmillian NH. A new device for the measurements of pressure distribution inside the shoe. In: Matsui H, Kobayoshi K, editors. Biomechanics VIII-B. Champaign (IL): Human Kinetics Publishers, 1983: 1089-1096.
18. Cavanagh PR. The shoe-ground interface in running. In: Mack RP, editor. American Academy of Orthopaedic Surgeons Symposium on the Foot and Leg in Running Sports. St. Louis: Mosby, 1982: 30-44.
19. Burdett RG. Forces predicted at the ankle during running. Med Sci Sports Exerc 1982;14:308-316.
20. Putnam CA, Kozey JW. Substantive issues in running. In: Vaughan CL, editor. Biomechanics of Sport. Boca Raton (FL): CRC Press, 1989: 1-33.
21. Chapman AE, Caldwell GE. Kinetic limitations of maximal sprinting speed. J Biomech 1983;16:79-83.
22. Cavanagh PR, Lafortune MA. Ground reaction forces in distance running. J Biomech 1980;13:397-406.
23. Luhtanen P, Komi PV. Mechanical factors influencing running speed. In: Assmussen F, Jorgenson K, editors. Biomechanics VI-B. Baltimore: University Park Press, 1978: 23-29.

Key Coaching Points

• Understanding the mechanics of the foot and ankle is essential for optimizing running performance and preventing injuries.
• The subtalar and transverse tarsal joints play a critical role in foot movement during running.
• Electromyography studies reveal the activation patterns of lower extremity muscles during different running intensities.
• Ground reaction forces and pressure distribution inside the shoe are crucial factors in running biomechanics.

Conclusion

This overview highlights the importance of foot and ankle mechanics in running and provides a foundation for further exploration into the biomechanics of endurance activities.