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Defective Running Shoes as a Contributing Factor in Plantar Fasciitis in a Triathlete

Bruce R. Wilk, PT, OCS1

Karen L. Fisher, MS, PT2

William Gutierrez, MS, PT, OCS, ATC3

FIGURE 3. A, In this posterior view, a clear arrow points to the left racing (R) shoe heel counter. B, A black arrow points to the visible inward defor­mity of the right racing (R) shoe heel counter. The outside borders of the heel counters show that the shoe in A has heel counter that is glued in at a perpendicular angle, whereas the shoe in B has a heel counter that is glued in at a slightly medial angle.

Treatment to decrease inflammation included soft tissue mobilization and deep friction massage of the plantar fascia in a stretched position (ie, ankle dorsi­flexion). The patient rolled his foot with a firm pres­sure on a 3/4-in-diameter wooden dowel rod for 5 minutes daily. The patient also received 8 ultrasound treatments to the right plantar fascia at an intensity of 1.0 W/cm2, continuous wave frequency of 1.0 MHz, for 5 minutes. A cold pack was applied daily to the bottom of the right foot for 20 minutes.

The patient performed 20 minutes of stretching exercises daily for the right lower extremity as part of his home exercise program. Physical therapy sessions included passive and active assistive stretches that em­phasized increasing the flexibility of the plantar fas­cia and the posterior lower extremity musculature (ie, piriformis, hamstring, iliotibial band, gastrocne­mius and soleus, and both the intrinsic and extrinsic toe flexor musculature). The patient performed calf stretches leaning toward a wall in a weight-bearing position by moving the tibia anteriorly over the foot, with the knee flexed and with the knee extended. The patient also stretched off the edge of a step by keeping the toes pointing slightly inward with the forefoot weight-bearing on the step. The patient then dropped the heel downward slowly, while pre­venting the foot from pronating.

A progressive rehabilitation protocol was imple­mented (Table 2). Strengthening exercises were per­formed on alternate days in series of 3 sets to tempo­rary muscle fatigue (ie, loss of form or ability to push the resistance through the full range of motion or substitution of a stronger muscle group for a weaker muscle group). The patient continued a swimming program and biking outside his treatment sessions. As soon as the patient was pain-free during activity in the morning, he began the walking pro­gram described in week 1 of the rehabilitation proto­col (Table 2). Balance, conditioning, and agility skills were also addressed in a home program that was consistent with the progression of the treatment plan.

The patient was educated about the components of sound athletic shoe construction. The following guidelines were developed to teach the patient how to look for sound shoe construction:

 

• The shoe should be glued together securely. Test this by holding the shoe and trying to pull the upper part of the shoe away from the midsole and the mid-sole from the outsole (Figure 4).

• The upper part of the shoe should be glued straight into the sole. Test this by using a goniometer to measure a 90° angle. Place the vertical arm (of the goniometer) along the center of the posterior heel counter and the horizontal arm parallel to the surface on which the shoe is resting (Figure 5A). As you view the shoe from the back on a level surface, the whole upper part of the shoe should appear even. Figure SB shows the upper shoe leaning to the right.

• The sole of the shoe should be level to the sur­face on which the shoe is resting. Test this by mea­suring the medial and lateral vertical distance of the posterior sole on the heel of each shoe. With a tape measure or a ruler, measure the distance from the top edge of the posterior sole to the surface on which the shoe is resting (Figure 6A and B). Com­pare these measurements within each shoe.

• The shoes should not roll excessively inward or outward when resting on a level surface. Test this by applying a downward medial and then a downward lateral force to both the right and left shoe to see if they rock inward or outward (Figure 7A and B).

• Air pockets and gel pockets must be inflated evenly. Test this by pushing a thumb into the air and gel pockets to check for firmness of inflation (Figure 8). Also, push with a medially directed downward force from the top of the shoe upper over the heel counter. Repeat this test with a laterally directed downward force (Figure 9A and B). Look for a loss of height in the pocket.

The patient was seen for treatment 2 times a week for 4 weeks. Heel pain during standing and walking and morning foot pain were monitored to determine progression of activity and treatment.

RESULTS

By the end of the first week of treatment, the pa­tient’s subjective pain level was 6 of 10 to deep pal­pation of the calcaneal attachment and medial bor­der of the plantar fascia. The patient no longer had

TABLE 2. Rehabilitation protocol for patient with plantar

WEEK 1

•      Ankle and foot strengthening exercises in non-weight-bearing positions with light elastic bands

•      Marble pick ups and towel pushing and pulling for intrinsic foot muscle strengthening

•      Double-limb heel raises on ankle board

•      Single-limb balance exercises on 3-in foam

•      Lower-body ergometer 30 minutes at 70—80% maximum heart rate at a pedaling cadence of 80—100 revolutions per minute

•      Functional agility activities of forward and backward and lateral walking drills

•      Home exercise program of walking for 1 hour 4 times per week

WEEK 2

•      Single-limb heel raises from a flat surface

•      Heel raises from the edge of a step beginning with both limbs and progressing to single limb

•      Continue single-limb balance exercises on 3-in foam

•      Lower-body ergometer 30 minutes as in previous week

•      Functional agility activities as in week 1 with resistive tubing

•      Home exercise program of walking for 20 minutes, jogging 2 minutes, and walking 3 minutes for a 20-minute period, ending with walking for 20 minutes, for a total time of 1 hour 4 times per week

WEEK 3

•      Right lower extremity weight-bearing exercises using elastic tubing resistance around the left ankle to resist hip flexion, extension, abduction, and adduction patterns to stress the muscles of the right foot and calf

•      Single-limb balance exercises emphasizing posture assumed during running

•      Lower-body ergometer 30 minutes as in week 1

•      Functional agility activities of forward and backward and lateral jogging drills

•      Home exercise program of 20 minutes walking and 20 minutes jogging, ending with 20 minutes walking, for a total time of 1 hour 4 times per week

WEEK 4

•      Lower-body weight-bearing exercises on pulley system with an adjustable weight stack

•      Lower-body ergometer 30 minutes as in week 1

•      Running drills (drills performed at a slow jogging pace for 46 m)

a. High kicks—exaggerate kicking behind by kicking the heel of each foot back and upward tapping the buttock with each step taken to work on increasing stride length and enhancing the follow through of each leg

b. High knee turnovers—exaggerate lifting each knee upward in a marching fashion without extending the knee or throwing the foot forward to work on keeping knees high during running to prevent a shuffling pattern

c. Hands on head emphasizing a neutral posture—run with hands placed on the top of the head to exaggerate an upright posture to work on preventing a forward lean and forward posture, emphasizing forward progression from the pelvis

d. Exaggerated trunk twisting and correction—begin with exaggerated (contralateral) trunk rotation with the forward progression of each leg and slowly correct to smooth, efficient control of trunk motion to work on conserving energy by not allowing unnecessary trunk motion to occur

e. Exaggerated arm swings and correction—begin with exaggerated (contralateral) arm swinging with each step taken and slowly correct to smooth, efficient arm swing being sure not to allow arms to cross midline to work on efficiency of arm use for enhancing forward progression

f.  Bounding—leap with large strides exaggerating the push-off of each foot to work on the power of pushing off with each lower extremity

•      Home exercise program of 10 minutes walking and 40 minutes jogging, ending with 10 minutes walking, for a total time of 1 hour 4 times per week

FIGURE 4. The upper shoe is separating from the midsole when testing is performed to pull these 2 parts of the shoe apart. The outsole stays intact with the midsole.

After learning how to evaluate shoe construction, the patient purchased a new pair of the same model of running shoes he had worn for the half-ironman race. He brought the shoes to a treatment session, and there appeared to be no visible manufacturing defects. He started to use the new running shoes and was able to walk for 1 hour with a normal gait pat­tern. He could perform 10 single-limb heel raises be­fore showing signs of fatigue. After week 2 of rehabil­itation, the patient’s pain level dropped to a 4 dur­ing deep palpation and was 1—2 at the end of a busy day. His muscle strength was in the good manual muscle testing range. He was tolerating 20 minutes of combined jogging and walking, with 40 minutes of walking.  By week 3 of rehabilitation, the patient had a 1—2 pain level to palpation and no pain with active or passive dorsiflexion or at rest. The flexibility of the right gastrocnemius muscle was equal to the left, and he could perform 16 heel raises before showing signs of fatigue. He was able to tolerate 20 minutes of jogging in his 60-minute walking program. At the end of the fourth week, the patient was ready for dis­charge from physical therapy. He reported a 0—1 pain level to deep palpation of the plantar fascia and no pain at rest. He was able to run 40 minutes with­out pain or gait deviation. The plantar flexor strength of the right lower extremity was 4+/S (ie, good plus), and the flexibility was within normal limits. At a 1-month follow-up visit, the patient was asymptomatic and progressing his running program in intensity and time. The patient displayed equal flexibility of the right lower extremity to the left low­er extremity of 15° ankle dorsiflexion, with 0° knee joint extension. He had no complaint of heel pain with active or passive dorsiflexion and was able to complete 20 heel raises through full range of motion against gravity, representing gastrocnemius strength within normal limits. The patient was able to walk and run with a pain-free, normal gait pattern.

FIGURE 5. A, Dotted lines show a 90° angle, measured with a goniometer formed by the vertical center of the posterior left shoe heel counter and a horizontal line that is parallel to the resting surface. B, Vertical and horizontal dotted lines show the outward lean of the heel counter of the right shoe because it is glued into the midsole with a lateral angle.

FIGURE 6. A, The lateral (a) and medial (b) vertical heights of the posterior sole are equal on the left shoe, demonstrating that the left shoe sole is level. B, The medial (c) vertical height of the posterior sole of the right shoe is larger than the lateral (d) vertical height, demonstrating that the right shoe sole is not level.

FIGURE 7. A, A downward, medially directed force does not rock the left shoe inward. B, A downward, medially directed force does rock the right shoe inward

DISCUSSION

Pronation occurs at the subtalar joint during the stance phase of the gait cycle. Midtarsal joint (ie, tal­onavicular and calcaneal cuboid) motion results and the medial arch flattens. The talus adducts, plantar flexes, and moves anteriorly with respect to the calca­neus. The calcaneus everts, and forefoot valgus oc­curs. In the lower leg, the tibia internally rotates and migrates anteriorly to maintain ankle joint congruen­cy. Pronation provides for shock absorption and ad­aptation to the terrain under the foot. When this motion is excessive, a torsional force is created and stretches the plantar fascia, leading to inflammation and pain.

FIGURE 8. A force is directed into the inside air and gel pockets, with the thumb, to check for firmness and symmetry of inflation.

FIGURE 9. A, A downward force on the lateral aspect of the left shoe (depicted by black arrows) demonstrates compression but no loss of height in the outside air pocket. B, A downward force on the medial aspect of the right shoe (depicted by black arrows) causes the inside air pocket to lose height and collapse. 

 

Plantar fasciitis is characterized by inflammation or degeneration of the plantar fascia, particularly at the calcaneal attachment.22 Excessive pronation of the

subtalar joint beyond the normal range of approxi­mately 9.4° is the primary cause of plantar fasciitis.”

Anatomic causes of abnormal pronation include ab­normalities secondary to neuromuscular disease, con­genital pes planus, and acquired deformities. Exces­sive pronation can be acquired from limited flexibili­ty of the gastrocnemius and soleus muscle groups, re­sulting in a shortened Achilles tendon.5”5

We feel that this case study reveals that a defective­ly manufactured running shoe may have promoted

the development of plantar fasciitis in the presence of other contributing factors. There are ample stud­ies that record potential sources that might cause

plantar fasciitis.2’4’6’8”2”3’16’17 In this case, the patient had a predisposition to pronate, which he compen­sated for by wearing a running shoe designed to en­hance foot stability. The running mileage on the rac­ing shoes was low and fell within the 480—800 km of wear guideline used for replacing worn-out shoes.9

Although the patient’s training program seemed well rounded, the demands of a hilly race course and the accumulation of long distance workouts must be con­sidered as potential causes of this overuse injury.

Also, the influence of demands on the gastrocnemius and soleus muscles are complicated in a sporting

event that involves 3 different activities (ie, swim­ming, biking, and running). There is the potential for the calf muscles to tighten during the swim and bike ride to produce increased pronation during the run.2 The defective running shoe may have facilitat­ed the patient’s pronation because the heel counter was canted inward. If the rainy weather conditions

caused the shoe to stretch and become more unsta­ble, the pronation deviation may have worsened. Therefore, the defective shoe may have added to the combination of factors that could cause plantar fasci­itis because it might not have properly stabilized the right foot.

Because today’s running shoes tend to be some­what customized, it is beneficial for patients to know their foot type and running style to purchase shoes designed to support their needs. Various sources have documented the appropriate running shoe de­sign and selection related to lower extremity anatomy and biomechanics.”°”3’17”8’21’23

We felt it was important for patients to know how to avoid buying defective athletic shoes. The guide­lines developed to teach the patient in this case study how to look for sound shoe construction were made available to our patients and local athletic community.

CONCLUSION

This case study describes a patient with heel pain and plantar fasciitis after completing a triathion. We feel this case identifies faulty running shoe construc­tion as a factor that contributed to the development of plantar fasciitis. Lower extremity overuse running injuries usually arise from multiple sources. The type of running shoe worn by an athlete can be an im­portant factor in the prevention and treatment of overuse injuries.”11”8’23 Shoes that are appropriate and compensate for a biomechanical deviation may not prevent injury if they are manufactured with a defect. An increased awareness of the need to assess athletic shoe construction may potentially prevent an athlete from using a defective shoe that might con­tribute to ankle injury.

ACKNOWLEDGMENTS

We thank Willesley Chin for his assistance with our literature search and Ann Carre for the original drawings she created.

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