A BIOMECHANICAL APPROACH TO RUNNING INJURIES Steven I. Subotnick 19682 Hesperian Boulevard Hayward, California 94541
INTRODUCTION The foot is a marvelous structure designed to adapt to varying surfaces as well as to offer support and rigidity during jogging and running activities. The foot is responsible for accepting all of the rotations occurring from the hip down to the knee, leg, and foot. The foot must convert these rotations into meaningful forward motion. An injury anywhere in the lower extremity may originate at the foot. Long distance running injuries are often caused by a foot fault. An understanding of some basic principles helps the runner avoid these injuries. BIOMECHANICS The term biomechanics is now in vogue. This, simply, means the mechanics of function, in this case, the function of the lower extremity in running. The key term in Biomechanics is neutral position (FIGURES 1 & 2).l-' The neutral position is the situation that exists when the foot is stable. A neutral foot can support body weight, when both feet are on the ground, without the help of muscles or ligaments. In other words, the integrity of the bones and joints of the foot supports the weight of the body. Obviously, when the foot is neutral there is a normal arch, which is not too high or low. The foot is neither pronated (low-arched) or supinated (high-arched) . The heel bone (calcaneus) is about perpendicular to the floor and parallel to the lower one-third of the leg. The metatarsal heads are resting on the ground and the plane of the metatarsal heads is perpendicular to the long axis of the calcaneus. In other words, when the calcaneus is straight up and down the foot is on the ground with a normal arch; the foot is neutral. Research using motion-analyzing films indicates that the foot must be neutral just prior to the time that the heel leaves the ground. When this situation does not exist, the muscles of the lower extremity work overtime, a stable propulsion is impossible, and there is an increased torque upon the leg, which results in overuse injury of the lower extremity.R
THENEUTRALFOOT You can roughly tell what your neutral foot position is by planting your foot on the ground and externally rotating your leg, causing your knee cap to point outwards, until your calcaneus is about perpendicular to the floor and parallel to the lower one-third of your leg (FIGURE 1). This position may feel awkward but, you will notice that your arch appears much more normal.3*6-R
888
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FIGURE1. Diagram of the bones of the normal (neutral) foot and leg. (After Subotnick.")
n
FIGURE2. Diagram showing the neutral foot compared with the pronated foot. (After Subotnick.")
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Annals New York Academy of Sciences RELATIONSHIP BETWEEN
THE
FOOTAND LEG
The normal foot contacts the running surface on the outside of the heel, then quickly rolls inward (everts), to adapt to surface changes (FIGURE 2).R9 This is called contact pronation. Contact pronation is normal for proper foot function. The foot is relatively unstable at heel contact to allow the foot to absorb This is desirable. The foot must then quickly become more rigid (resupinate) to the extent that it is neutral prior to heel-off and rigid prior to toe-off. The foot is, thusly, a rigid lever at toe-off.8 Various structural abnormalities of the leg and foot result in prolonged pronation,sv ? in other words, if the foot never recovers from being relatively unstable at heel contact. The foot then never becomes a rigid lever at toe-off. Running is inefficient and overuse injury is more likely to occur.
OVERUSEINJURY Overuse injuries include runner’s knee, shin splints, stress fractures, Achilles’ tendonitis, runner’s heel bumps, heel spurs, arch fatigue, pain and cramps, neuromas, and boney deformity of the foot such as bunions and hammertoes6,?, These injuries usually start off slowly and gradually increase in severity. They may be related to a sudden increase in mileage, a change in running terrain, improper shoes,15 inflexibility of the body and mind, or faulty biomechanical structure.16 General preventative measures for the overuse syndrome depend upon proper training, proper conditioning, and proper biomechanical structure.’ Training should allow for hard-easy workout sessions on varying surfaces with shoes that provide for adequate shock absorbence. Train don’t strain.3 Conditioning depends upon flexibility exercises before and even more important, after running. The muscles in the back of the thigh and leg (antigravity muscles) must be stretched. Muscles in the front of the thigh, leg and foot (gravity muscles) must be ~trengthened.~, l7 Biomechanical control is obtained through the use of functional foot orthotics made from a neutral cast of the athletes foot.a.
CAREOF SPECIFIC OVERUSEINJURIES The Hip Injuries about the hip, or even low back injuries, may be secondary to a limb length inequality (FIGURE 3).18 The hip is prone to bursitis over the outside protruberance (greater trochanter), and at times the outside supportive tissue (iliotibial band) may snap. Ice and exercise may help this problem as well as limiting runs to level surfaces. Orthotics are sometimes helpful but usually resistant pain is in need of orthopedic consultation.’O
The Thigh Bursitis may be present between tendon bands deep in the thigh. These must be differentiated from tendon strains.20 Pain is present with exercise and
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pressure. Treatment consists of limiting activity, ice massage ten minutes a day following activity, and evaluation by a medical practitioner with an interest in sports medicine. Sciatica
Sciatica is a most disabling problem that results in pain radiating from the low back to the inside of the thigh down the leg. It is more pronounced with straight leg raises done while laying on the back. It appears to be aggravated by pronounced pronation of the foot and may be caused by a short leg syndrome.'* There may be pain present beneath the muscles of the buttocks, which is aggravated by climbing or. running up hills. Orthotics definitely help this problem as well as stretching exercises and back exercises.
FIGURE 3. Limb length inequality. (After Subotnick.")
The Knee
Runner's knee plagues joggers and long distance runners as well as basketball players and jumpers. This syndrome is responsible for sidelining some of the most promising athletes. Runner's knee may be any one, or a combination of factors: chondromalacia of the knee, patellar (knee cap) compression, patellar subluxation (FIGURE 4) or patellar tendonitis (jumper's knee). The syndrome may also include collateral ligament strain or snapping iliotibial bands. At times, even 21-25 the cartilage of the knee joint itself (the meniscus) may be damaged.'. 1 4 9 Most runner's knee problems are related to improper foot f u n ~ t i o n . ~ ~As the foot abnormally pronates, and becomes excessively mobile with the arch
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Annals New York Academy of Sciences
flattening, the leg internally rotates. The thigh also internally rotates but, the foot is fixed on the ground and cannot turn in. This allows for an unstable patella and results in runner's knee. Characteristically, there is a cracking sensation beneath the patella with excessive bending or flexion of the knee. Pain is present when walking up and down stairs, working the clutch of a car, o r upon rising after sitting for a period of time. Hill running, especially downhill, aggravates the pain. Treatment consists of exercises to build up and strengthen the muscles that stabilize the knee, the quadriceps and hamstrings. Straight leg raises and side leg raises, 20 times per leg, carried out twice a day, utilizing from a 2 to 5 pound weight, are helpful. Isometric exercises holding each contraction of these muscles for 20 seconds each are called quad sets and are of extreme benefit. The runner must avoid hills, and shoes should be in good repair. Foot orthotics are necessary. The main purpose of the foot orthotic is to provide stability at the knee by reducing independant rotation between the leg and foot,
FIGURE4. Lateral patellar subluxations compensating for tibia1 torsion. (After Subotnick:') which occurs with excessive pronation. It appears as though orthotics encourage the runner to run more adducted. Thus, the foot and leg rotate inward and stabilize the knee cap. This provides for a straight line pull between the quadriceps, patella and patellar tendon.', l 9 Stress Fractures
Stress fractures are difficult to detect. They may not show up on initial X rays but will be present from 6 to 8 weeks following an injury. Persistent pain suggests stress fractures and activity must be limited. Medical supervision is suggested. An example of this is pain on the outside ankle bone that does not appear to be shin splints and does not respond to normal shin splint treatment. This may well be a stress fracture of the fibula and responds to rest for approximately 6 weeks. Stress fractures are also common in the metatarsal
Subotnick: Biomechanical Running Injuries
893
bones of the foot. They respond to resting the foot for 3 weeks following which the athlete may begin running again providing the foot is taped for an additional 3 weeks.' The Leg Three problems occur within the leg in regards to running. Shin splints, Achilles tendonitis and strains, and stress fractures. Shin splints is a catch all term which encompasses inflammation of the bone (periostitis), inflammation of the muscle (myositis), or inflammation of the tendons (tendonitis) .i* 2H The muscles in the front of the leg are more commonly involved with running on hard surfaces or hills. Weak muscles contribute to the problem. Overstriding aggravates this problem, which is called anterior shin splints. Anterior shin splints occurs with pain in the front of the leg at the beginning of the track season. Treatment consists of exercising to strengthen the anterior muscles. In addition, the runner must stretch the Achilles' tendon. It is important to utilize ice following a running session on sore muscles for approximately 10 minutes. Workouts on softer surfaces help this problem. Foot orthotics as well as taping may be useful. Persistent or progressive swelling or pain is in need of immediate medical attention and may indicate a stress fracture or a tight muscle com~artment.*~ The muscles located on the inside of the leg are called the flexors and also include the posterior tibia1 tendon and muscles. They are prone to overuse injuries secondary to abnormal pronation of the foot. This is also a form of shin splints. Treatment consists of icing as well as foot orthotics. The results are quite good. The Achilles' tendon may be injured secondary to improper flexibility exercises. Stretching is very important both before and after workouts. Hill running aggravates the problem of Achilles' tendonitis. Toe-dash runners should change their gait to a heel-foot-toe or foot-toe stride. Icing, stretching, and heel lifts are sometimes very effective in treating this problem. Resistant and chronic tendonitis may be aggravated by abnormal heel roll which occurs with abnormal or excessive pronation of the foot. In these cases foot orthotics help. Persistent cases require the attention of a sports minded podiatrist or orthopedist. When excessive swelling of the tendon sheath is present this may represent a tenosynovitis and is in need of medical attention. When excessive swelling of the tendon itself is present, this may represent a tendon strain or partial rupture, in which case, the tendon itself, has been injured and this requires immediate medical attention.
The Ankle The ankle is involved with recurrent sprains as well as boney arthritis secondary to overuse. Recurrent sprains suggest a need for stabilizing foot orthotics as well as taping before athletic events that occur on uneven surfaces or which involve
894
Annals New York Academy of Sciences
excessive motion from side to side, such as football.l3, 28-30 Rehabilitative exercises to build up ankle flexibility and strength are very helpful. Limitations of ankle flexion secondary to boney spurs can be disabling and may require surgical intervention. Pain is usually present in the front of the ankle when this problem is i n v ~ l v e d . ~
The Foot A myriad of overuse injuries occur in the foot. The initial treatments of all foot injuries begin with establishing proper foot function with foot orthotics. Of course, a proper diagnosis must be arrived at. As with all injuries proper training and conditioning is outlined. Let us review the more common foot injuries.
FIGURE 5. Heel spurs. (After Subotnick?')
Heel Spurs Heel spurs (FIGURE 5 ) cause pain on the bottom of the foot where the arch meets the heel. An actual boney spur is present and this is noticed on X rays. This is often surrounded by soft tissue damage and bursitis. Orthotics as well as cortisone injections are helpful and usually resolve this problem. Low-dye taping and felt padding are helpful.7 I n resistant cases surgery may be indicated.
Heel Neuromas Heel pain located in the center of the heel may be due to a heel bruise with secondary formation of a benign nerve enlargement. Treatment consists of injections of the traumatic neuroma as well as foot orthotics. A felt pad with an aperature may help. Surgery may be required, but usually no bone resection is necessary and recovery is rapid.'
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FIGURE 6. Retrocalcaneal exostosis (runner's bump). (After Subotnick.")
Runner's Bumps Runner's bumps (retrocalcaneal exostosis) (FIGURES 6-8) occur beneath the Achilles' tendon on the outer back surface of the calcaneus.:tl This problem is aggravated by excessive heel roll at foot contact. Runners who are bowlegged or land excessively on the outside of their heel, are more prone to this problem. Foot orthotics with a rearfoot control help greatly with this problem. If bursitis is present, an injection of cortisone may handle the problem readily. Excessive boney projections may require surgical excision.
FIGURE 7. Retrocalcaneal exostosis, rear view. (After Subotnick.")
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Annals New York Academy of Sciences
Arch Pain Arch pain is often secondary to a fascia (FIGURE 9) o r muscle strain, or a nerve entrapment. Pain more prevalent at toe-off suggests plantar fascia1 strain. Pain with pressure beneath the inner ankle bone, which radiates and is sharp, indicates nerve compression. This is called a tarsal tunnel syndrome (FIGURE 10). This may be accompanied by a tight muscle at the inner aspect of the arch. Taping, orthotics, and level-surface running at slow speeds appear to help. At times an injection of cortisone is necessary along with these other modalities.'
FIGURE 9. The plantar fascia. (After Subotnick.")
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Bunions, Hammertoes, and Plantar Callouses Boney deformity of the foot is either congenital o r secondary to improper foot function. Foot function must be normal in order to help control these problems. These are problems that you should consult your podiatrist a b o ~ t . ~ ~ - ~ ~
Shoes Shoes are merely a covering for the foot. They protect the foot from the running surface, absorb shock, and grip the running surface. They do not, however, control abnormal pronation or offer any significant foot support. This has been amply demonstrated by motion analyzing films of runners. A good training shoe should have two to three layers of various thicknesses and firmness of rubber, which provides resistance to wear, shock absorbance,
FIGURE 10. Tarsal tunnel syndrome. (After Subotnick.m)
and stability. There must be ample room for the toes and a rounded toe box. The heel counter should be high enough to well grip the heel and prevent heel slippage. This also facilitates placing an orthotic within the shoe. The running shoe must have an elevated heel of moderate degree. Attempts at running with a negative heel shoe have been disasterous. The role of the shoe should be thick, yet flexible at the junction of the ball of the foot to the toes. Nylon uppers are lighter and may be washed. Leather uppers can be stretched and water-proofed. Soles should be periodically repaired and a glue gun greatly helps in guarding against excessive shoe wear.15 SUMMARY I have introduced the concept of controlling overuse syndromes by controlling the etiology. The etiology of most overuse syndromes is biomechanical deformity of the lower extremity as well as nonadherence to sound principles
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Annals New York Academy of Sciences
of training and conditioning. It is important to realize these factors to provide for many years of injury-free athletic involvement. REFERENCES
1. ROOT, M. L., W.ORIEN,J. H. WEED & R. J. HUGHS. 1971. Biomechanical examination of the foot. I n Clinical Biomechanics Corp. Vol. 1. Los Angeles, Calif. 2. SGARLATO, T. E. 1971. A Compendium of Podiatric Biomechanics. California College of Podiatric Medicine. San Francisco, Calif. 3. SUBOTNICK, S. I., Ed. 1975. Athlete’s Feet. Runner’s World Publications. Mountain View, Calif. 4. SUBOTNICK, S. I. 1971. The equinus deformity as it effects the forefoot. J. Amer. Pod. Assoc. 61: 423-427. 5. SUBOTNICK, S. I. 1973. The flexible flatfoot. I n Arch. Pod. Med. Foot Surg. l(1): 7-33. S. I. 1975. Orthotic foot control in the overuse syndrome. Phys. 6. SUBOTNICK, Sportsmed. 3(1): 75-79. 7. SUBOTNICK,S. I. 1975. The abuses of orthotics in sports medicine. Phys. Sportsmed. 3(7). 8. SUBOTNICK,S. I. 1974. The overuse syndrome of the foot and leg. Part 11. Symposium, California College of Podiatric Medicine. San Francisco, Calif. 9. JAMES, S. L. & C. E. BRUBAKER. 1973. Biomechanics of running. Orthoped. Amer. 4(3): 605-616. 10. SYMPOSIUM ON SPORTSMEDICINE. 1969. American Academy of Orthopedic Surgeons. C. V. Mosby Co. St. Louis, Mo. 11. BRUBAKER, T. E. & S. L. JAMES. 1974. Injuries to runners. I n Laboratory for Human Performance, University of Oregon. 12. CORRIGAN, A. B. & K. E. FITCH.1972. Complications of jogging. _ _ _ Med. J. Austral. :363. 13. ODONOGHUE, D. H. 1975. Treatment of Injuries to Athletes. 2nd edit. W. B. Saunders Co. PhiladelDhia. Pa. 14. SHEEHAN, G. M. 1972. Chondromalacia in runners. Amer. College Sports Med. Newslett. 7(4). 15. SUBOTNICK, S. I. 1973. Shoes and injuries in shoes for runners. In Runner’s World Booklet of the Month. Vol. 25: 70-71. 16. SUBOTNICK, S. I. 1974. Morton’s foot. Runner’s World 94. 17. DUVRIES,H. L. 1966. Physiology of Exercises for Physical Education and Athletics. William Brown & Co. St. Louis, Mo. 18. SUBOTNICK, S.I. 1974. Long legs, short legs. Runner’s World 9:21-22. 19. JAMES, S.L. 1975. Personal communications. 20. CRAIG, T. T. 1973. Comments in sports medicine. J. Amer. Med. Assoc. 231: 333. M.E., R. K. KERLAN,F.W. JOBE,V. S. CARTER& G.CARLSON.1973. 21. BLAZINA, Jumper’s knee. In Orthopedic Clinics of Northern America. Vol. 4 (3): 665-678. 22. KLINE, C. & F. L. ALMAN,JR. 1969. The Knee in Sports. Jenkins Publishing Co. The Premerton Press. Austin, Texas. 23. NICHOLAS,J. A. 1975. Injuries to the menisci of the knee. Orthoped. Clinic N. Amer. 4(3): 647-664. 24. ODONOGHUE,D. H. 1975. Treatment of acute ligamentous injuries of the knee. In Orthoped. Clinic N. Amer. 4(3): 617-645. 25. SLOCUM,D. B., R. L. LARSON& S. L. JAMES. 1975. Late reconstruction procedures used to stabilize the knee. Orthoped. Clinic N. Amer. 4(3): 679-689. D. W. & D. BAILEY. 1975. Shin splints in the young white: A non26. JACKSON, specific diagnosis. Phys. Sportsmed. 3(3): 45-51.
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27. SUBOTNICK, S. I. 1975. Compartment syndromes in the lower extremities. J. Amer. Pod. Assoc. 65(4): 342-347. 28. CERNEY,J. P. A Complete Book of Athletic Taping Techniques. Parker Publishing Inc. West Nyack, N.Y. 29. JOHNSON& JOHNSON.1958. Therapeutic Uses of Adhesive Tape. 2nd edit. New Brunswick, N.J. 30. NELLEN,J. W. 1968. Medicine and the Green Bay Packers. Upjohn Co. 31. SUBOTNICK, S. I. 1973. Why bumps grow. Runner’s World : 24-30. 32. DUVRIES,H. L. 1964. Surgery of the Foot. C. V. Mosby Co. St. Louis, Mo. 33. GERBERT,J., et nl. 1974. The Surgical Treatment of the Intractable Plantar Keratoma. : 247. Futura Publishing Co. Mt. Kisco, N.Y. 34. GERBERT, J., 0. A. MERCADO & T. H. SOKOLOFF.1975. The Surgical Treatment of the Hallux-Abducto-Valgus and Allied Deformities. : 140. Futura Publishing Co. Mt. Kisco, N.Y.. 35. GERBERT, J., T. E. SOARLATO & S. I. SUBOTNICK.1972. Preliminary study of a closing wedge osteotomy of the fifth metatarsal for correction of tailor’s bunion deformity. J. Amer. Pod. Assoc. 62: 212-218. S. I. Observations of plantar callouses. Arch. Pod. Med. Foot Surg. 36. SUBOTNICK, l ( 4 ) : 329-337. 37. SUBOTNICK, S. I. 1975. Podiatric Sports Medicine. Futura Publishing Co. Mt. Kisco, N.Y.
INTRODUCTION The foot is a marvelous structure designed to adapt to varying surfaces as well as to offer support and rigidity during jogging and running activities. The foot is responsible for accepting all of the rotations occurring from the hip down to the knee, leg, and foot. The foot must convert these rotations into meaningful forward motion. An injury anywhere in the lower extremity may originate at the foot. Long distance running injuries are often caused by a foot fault. An understanding of some basic principles helps the runner avoid these injuries. BIOMECHANICS The term biomechanics is now in vogue. This, simply, means the mechanics of function, in this case, the function of the lower extremity in running. The key term in Biomechanics is neutral position (FIGURES 1 & 2).l-' The neutral position is the situation that exists when the foot is stable. A neutral foot can support body weight, when both feet are on the ground, without the help of muscles or ligaments. In other words, the integrity of the bones and joints of the foot supports the weight of the body. Obviously, when the foot is neutral there is a normal arch, which is not too high or low. The foot is neither pronated (low-arched) or supinated (high-arched) . The heel bone (calcaneus) is about perpendicular to the floor and parallel to the lower one-third of the leg. The metatarsal heads are resting on the ground and the plane of the metatarsal heads is perpendicular to the long axis of the calcaneus. In other words, when the calcaneus is straight up and down the foot is on the ground with a normal arch; the foot is neutral. Research using motion-analyzing films indicates that the foot must be neutral just prior to the time that the heel leaves the ground. When this situation does not exist, the muscles of the lower extremity work overtime, a stable propulsion is impossible, and there is an increased torque upon the leg, which results in overuse injury of the lower extremity.R
THENEUTRALFOOT You can roughly tell what your neutral foot position is by planting your foot on the ground and externally rotating your leg, causing your knee cap to point outwards, until your calcaneus is about perpendicular to the floor and parallel to the lower one-third of your leg (FIGURE 1). This position may feel awkward but, you will notice that your arch appears much more normal.3*6-R
888
Subotnick: Biomechanical Running Injuries
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FIGURE1. Diagram of the bones of the normal (neutral) foot and leg. (After Subotnick.")
n
FIGURE2. Diagram showing the neutral foot compared with the pronated foot. (After Subotnick.")
890
Annals New York Academy of Sciences RELATIONSHIP BETWEEN
THE
FOOTAND LEG
The normal foot contacts the running surface on the outside of the heel, then quickly rolls inward (everts), to adapt to surface changes (FIGURE 2).R9 This is called contact pronation. Contact pronation is normal for proper foot function. The foot is relatively unstable at heel contact to allow the foot to absorb This is desirable. The foot must then quickly become more rigid (resupinate) to the extent that it is neutral prior to heel-off and rigid prior to toe-off. The foot is, thusly, a rigid lever at toe-off.8 Various structural abnormalities of the leg and foot result in prolonged pronation,sv ? in other words, if the foot never recovers from being relatively unstable at heel contact. The foot then never becomes a rigid lever at toe-off. Running is inefficient and overuse injury is more likely to occur.
OVERUSEINJURY Overuse injuries include runner’s knee, shin splints, stress fractures, Achilles’ tendonitis, runner’s heel bumps, heel spurs, arch fatigue, pain and cramps, neuromas, and boney deformity of the foot such as bunions and hammertoes6,?, These injuries usually start off slowly and gradually increase in severity. They may be related to a sudden increase in mileage, a change in running terrain, improper shoes,15 inflexibility of the body and mind, or faulty biomechanical structure.16 General preventative measures for the overuse syndrome depend upon proper training, proper conditioning, and proper biomechanical structure.’ Training should allow for hard-easy workout sessions on varying surfaces with shoes that provide for adequate shock absorbence. Train don’t strain.3 Conditioning depends upon flexibility exercises before and even more important, after running. The muscles in the back of the thigh and leg (antigravity muscles) must be stretched. Muscles in the front of the thigh, leg and foot (gravity muscles) must be ~trengthened.~, l7 Biomechanical control is obtained through the use of functional foot orthotics made from a neutral cast of the athletes foot.a.
CAREOF SPECIFIC OVERUSEINJURIES The Hip Injuries about the hip, or even low back injuries, may be secondary to a limb length inequality (FIGURE 3).18 The hip is prone to bursitis over the outside protruberance (greater trochanter), and at times the outside supportive tissue (iliotibial band) may snap. Ice and exercise may help this problem as well as limiting runs to level surfaces. Orthotics are sometimes helpful but usually resistant pain is in need of orthopedic consultation.’O
The Thigh Bursitis may be present between tendon bands deep in the thigh. These must be differentiated from tendon strains.20 Pain is present with exercise and
Subotnick: Biomechanical Running Injuries
891
pressure. Treatment consists of limiting activity, ice massage ten minutes a day following activity, and evaluation by a medical practitioner with an interest in sports medicine. Sciatica
Sciatica is a most disabling problem that results in pain radiating from the low back to the inside of the thigh down the leg. It is more pronounced with straight leg raises done while laying on the back. It appears to be aggravated by pronounced pronation of the foot and may be caused by a short leg syndrome.'* There may be pain present beneath the muscles of the buttocks, which is aggravated by climbing or. running up hills. Orthotics definitely help this problem as well as stretching exercises and back exercises.
FIGURE 3. Limb length inequality. (After Subotnick.")
The Knee
Runner's knee plagues joggers and long distance runners as well as basketball players and jumpers. This syndrome is responsible for sidelining some of the most promising athletes. Runner's knee may be any one, or a combination of factors: chondromalacia of the knee, patellar (knee cap) compression, patellar subluxation (FIGURE 4) or patellar tendonitis (jumper's knee). The syndrome may also include collateral ligament strain or snapping iliotibial bands. At times, even 21-25 the cartilage of the knee joint itself (the meniscus) may be damaged.'. 1 4 9 Most runner's knee problems are related to improper foot f u n ~ t i o n . ~ ~As the foot abnormally pronates, and becomes excessively mobile with the arch
892
Annals New York Academy of Sciences
flattening, the leg internally rotates. The thigh also internally rotates but, the foot is fixed on the ground and cannot turn in. This allows for an unstable patella and results in runner's knee. Characteristically, there is a cracking sensation beneath the patella with excessive bending or flexion of the knee. Pain is present when walking up and down stairs, working the clutch of a car, o r upon rising after sitting for a period of time. Hill running, especially downhill, aggravates the pain. Treatment consists of exercises to build up and strengthen the muscles that stabilize the knee, the quadriceps and hamstrings. Straight leg raises and side leg raises, 20 times per leg, carried out twice a day, utilizing from a 2 to 5 pound weight, are helpful. Isometric exercises holding each contraction of these muscles for 20 seconds each are called quad sets and are of extreme benefit. The runner must avoid hills, and shoes should be in good repair. Foot orthotics are necessary. The main purpose of the foot orthotic is to provide stability at the knee by reducing independant rotation between the leg and foot,
FIGURE4. Lateral patellar subluxations compensating for tibia1 torsion. (After Subotnick:') which occurs with excessive pronation. It appears as though orthotics encourage the runner to run more adducted. Thus, the foot and leg rotate inward and stabilize the knee cap. This provides for a straight line pull between the quadriceps, patella and patellar tendon.', l 9 Stress Fractures
Stress fractures are difficult to detect. They may not show up on initial X rays but will be present from 6 to 8 weeks following an injury. Persistent pain suggests stress fractures and activity must be limited. Medical supervision is suggested. An example of this is pain on the outside ankle bone that does not appear to be shin splints and does not respond to normal shin splint treatment. This may well be a stress fracture of the fibula and responds to rest for approximately 6 weeks. Stress fractures are also common in the metatarsal
Subotnick: Biomechanical Running Injuries
893
bones of the foot. They respond to resting the foot for 3 weeks following which the athlete may begin running again providing the foot is taped for an additional 3 weeks.' The Leg Three problems occur within the leg in regards to running. Shin splints, Achilles tendonitis and strains, and stress fractures. Shin splints is a catch all term which encompasses inflammation of the bone (periostitis), inflammation of the muscle (myositis), or inflammation of the tendons (tendonitis) .i* 2H The muscles in the front of the leg are more commonly involved with running on hard surfaces or hills. Weak muscles contribute to the problem. Overstriding aggravates this problem, which is called anterior shin splints. Anterior shin splints occurs with pain in the front of the leg at the beginning of the track season. Treatment consists of exercising to strengthen the anterior muscles. In addition, the runner must stretch the Achilles' tendon. It is important to utilize ice following a running session on sore muscles for approximately 10 minutes. Workouts on softer surfaces help this problem. Foot orthotics as well as taping may be useful. Persistent or progressive swelling or pain is in need of immediate medical attention and may indicate a stress fracture or a tight muscle com~artment.*~ The muscles located on the inside of the leg are called the flexors and also include the posterior tibia1 tendon and muscles. They are prone to overuse injuries secondary to abnormal pronation of the foot. This is also a form of shin splints. Treatment consists of icing as well as foot orthotics. The results are quite good. The Achilles' tendon may be injured secondary to improper flexibility exercises. Stretching is very important both before and after workouts. Hill running aggravates the problem of Achilles' tendonitis. Toe-dash runners should change their gait to a heel-foot-toe or foot-toe stride. Icing, stretching, and heel lifts are sometimes very effective in treating this problem. Resistant and chronic tendonitis may be aggravated by abnormal heel roll which occurs with abnormal or excessive pronation of the foot. In these cases foot orthotics help. Persistent cases require the attention of a sports minded podiatrist or orthopedist. When excessive swelling of the tendon sheath is present this may represent a tenosynovitis and is in need of medical attention. When excessive swelling of the tendon itself is present, this may represent a tendon strain or partial rupture, in which case, the tendon itself, has been injured and this requires immediate medical attention.
The Ankle The ankle is involved with recurrent sprains as well as boney arthritis secondary to overuse. Recurrent sprains suggest a need for stabilizing foot orthotics as well as taping before athletic events that occur on uneven surfaces or which involve
894
Annals New York Academy of Sciences
excessive motion from side to side, such as football.l3, 28-30 Rehabilitative exercises to build up ankle flexibility and strength are very helpful. Limitations of ankle flexion secondary to boney spurs can be disabling and may require surgical intervention. Pain is usually present in the front of the ankle when this problem is i n v ~ l v e d . ~
The Foot A myriad of overuse injuries occur in the foot. The initial treatments of all foot injuries begin with establishing proper foot function with foot orthotics. Of course, a proper diagnosis must be arrived at. As with all injuries proper training and conditioning is outlined. Let us review the more common foot injuries.
FIGURE 5. Heel spurs. (After Subotnick?')
Heel Spurs Heel spurs (FIGURE 5 ) cause pain on the bottom of the foot where the arch meets the heel. An actual boney spur is present and this is noticed on X rays. This is often surrounded by soft tissue damage and bursitis. Orthotics as well as cortisone injections are helpful and usually resolve this problem. Low-dye taping and felt padding are helpful.7 I n resistant cases surgery may be indicated.
Heel Neuromas Heel pain located in the center of the heel may be due to a heel bruise with secondary formation of a benign nerve enlargement. Treatment consists of injections of the traumatic neuroma as well as foot orthotics. A felt pad with an aperature may help. Surgery may be required, but usually no bone resection is necessary and recovery is rapid.'
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FIGURE 6. Retrocalcaneal exostosis (runner's bump). (After Subotnick.")
Runner's Bumps Runner's bumps (retrocalcaneal exostosis) (FIGURES 6-8) occur beneath the Achilles' tendon on the outer back surface of the calcaneus.:tl This problem is aggravated by excessive heel roll at foot contact. Runners who are bowlegged or land excessively on the outside of their heel, are more prone to this problem. Foot orthotics with a rearfoot control help greatly with this problem. If bursitis is present, an injection of cortisone may handle the problem readily. Excessive boney projections may require surgical excision.
FIGURE 7. Retrocalcaneal exostosis, rear view. (After Subotnick.")
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Arch Pain Arch pain is often secondary to a fascia (FIGURE 9) o r muscle strain, or a nerve entrapment. Pain more prevalent at toe-off suggests plantar fascia1 strain. Pain with pressure beneath the inner ankle bone, which radiates and is sharp, indicates nerve compression. This is called a tarsal tunnel syndrome (FIGURE 10). This may be accompanied by a tight muscle at the inner aspect of the arch. Taping, orthotics, and level-surface running at slow speeds appear to help. At times an injection of cortisone is necessary along with these other modalities.'
FIGURE 9. The plantar fascia. (After Subotnick.")
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Bunions, Hammertoes, and Plantar Callouses Boney deformity of the foot is either congenital o r secondary to improper foot function. Foot function must be normal in order to help control these problems. These are problems that you should consult your podiatrist a b o ~ t . ~ ~ - ~ ~
Shoes Shoes are merely a covering for the foot. They protect the foot from the running surface, absorb shock, and grip the running surface. They do not, however, control abnormal pronation or offer any significant foot support. This has been amply demonstrated by motion analyzing films of runners. A good training shoe should have two to three layers of various thicknesses and firmness of rubber, which provides resistance to wear, shock absorbance,
FIGURE 10. Tarsal tunnel syndrome. (After Subotnick.m)
and stability. There must be ample room for the toes and a rounded toe box. The heel counter should be high enough to well grip the heel and prevent heel slippage. This also facilitates placing an orthotic within the shoe. The running shoe must have an elevated heel of moderate degree. Attempts at running with a negative heel shoe have been disasterous. The role of the shoe should be thick, yet flexible at the junction of the ball of the foot to the toes. Nylon uppers are lighter and may be washed. Leather uppers can be stretched and water-proofed. Soles should be periodically repaired and a glue gun greatly helps in guarding against excessive shoe wear.15 SUMMARY I have introduced the concept of controlling overuse syndromes by controlling the etiology. The etiology of most overuse syndromes is biomechanical deformity of the lower extremity as well as nonadherence to sound principles
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of training and conditioning. It is important to realize these factors to provide for many years of injury-free athletic involvement. REFERENCES
1. ROOT, M. L., W.ORIEN,J. H. WEED & R. J. HUGHS. 1971. Biomechanical examination of the foot. I n Clinical Biomechanics Corp. Vol. 1. Los Angeles, Calif. 2. SGARLATO, T. E. 1971. A Compendium of Podiatric Biomechanics. California College of Podiatric Medicine. San Francisco, Calif. 3. SUBOTNICK, S. I., Ed. 1975. Athlete’s Feet. Runner’s World Publications. Mountain View, Calif. 4. SUBOTNICK, S. I. 1971. The equinus deformity as it effects the forefoot. J. Amer. Pod. Assoc. 61: 423-427. 5. SUBOTNICK, S. I. 1973. The flexible flatfoot. I n Arch. Pod. Med. Foot Surg. l(1): 7-33. S. I. 1975. Orthotic foot control in the overuse syndrome. Phys. 6. SUBOTNICK, Sportsmed. 3(1): 75-79. 7. SUBOTNICK,S. I. 1975. The abuses of orthotics in sports medicine. Phys. Sportsmed. 3(7). 8. SUBOTNICK,S. I. 1974. The overuse syndrome of the foot and leg. Part 11. Symposium, California College of Podiatric Medicine. San Francisco, Calif. 9. JAMES, S. L. & C. E. BRUBAKER. 1973. Biomechanics of running. Orthoped. Amer. 4(3): 605-616. 10. SYMPOSIUM ON SPORTSMEDICINE. 1969. American Academy of Orthopedic Surgeons. C. V. Mosby Co. St. Louis, Mo. 11. BRUBAKER, T. E. & S. L. JAMES. 1974. Injuries to runners. I n Laboratory for Human Performance, University of Oregon. 12. CORRIGAN, A. B. & K. E. FITCH.1972. Complications of jogging. _ _ _ Med. J. Austral. :363. 13. ODONOGHUE, D. H. 1975. Treatment of Injuries to Athletes. 2nd edit. W. B. Saunders Co. PhiladelDhia. Pa. 14. SHEEHAN, G. M. 1972. Chondromalacia in runners. Amer. College Sports Med. Newslett. 7(4). 15. SUBOTNICK, S. I. 1973. Shoes and injuries in shoes for runners. In Runner’s World Booklet of the Month. Vol. 25: 70-71. 16. SUBOTNICK, S. I. 1974. Morton’s foot. Runner’s World 94. 17. DUVRIES,H. L. 1966. Physiology of Exercises for Physical Education and Athletics. William Brown & Co. St. Louis, Mo. 18. SUBOTNICK, S.I. 1974. Long legs, short legs. Runner’s World 9:21-22. 19. JAMES, S.L. 1975. Personal communications. 20. CRAIG, T. T. 1973. Comments in sports medicine. J. Amer. Med. Assoc. 231: 333. M.E., R. K. KERLAN,F.W. JOBE,V. S. CARTER& G.CARLSON.1973. 21. BLAZINA, Jumper’s knee. In Orthopedic Clinics of Northern America. Vol. 4 (3): 665-678. 22. KLINE, C. & F. L. ALMAN,JR. 1969. The Knee in Sports. Jenkins Publishing Co. The Premerton Press. Austin, Texas. 23. NICHOLAS,J. A. 1975. Injuries to the menisci of the knee. Orthoped. Clinic N. Amer. 4(3): 647-664. 24. ODONOGHUE,D. H. 1975. Treatment of acute ligamentous injuries of the knee. In Orthoped. Clinic N. Amer. 4(3): 617-645. 25. SLOCUM,D. B., R. L. LARSON& S. L. JAMES. 1975. Late reconstruction procedures used to stabilize the knee. Orthoped. Clinic N. Amer. 4(3): 679-689. D. W. & D. BAILEY. 1975. Shin splints in the young white: A non26. JACKSON, specific diagnosis. Phys. Sportsmed. 3(3): 45-51.
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27. SUBOTNICK, S. I. 1975. Compartment syndromes in the lower extremities. J. Amer. Pod. Assoc. 65(4): 342-347. 28. CERNEY,J. P. A Complete Book of Athletic Taping Techniques. Parker Publishing Inc. West Nyack, N.Y. 29. JOHNSON& JOHNSON.1958. Therapeutic Uses of Adhesive Tape. 2nd edit. New Brunswick, N.J. 30. NELLEN,J. W. 1968. Medicine and the Green Bay Packers. Upjohn Co. 31. SUBOTNICK, S. I. 1973. Why bumps grow. Runner’s World : 24-30. 32. DUVRIES,H. L. 1964. Surgery of the Foot. C. V. Mosby Co. St. Louis, Mo. 33. GERBERT,J., et nl. 1974. The Surgical Treatment of the Intractable Plantar Keratoma. : 247. Futura Publishing Co. Mt. Kisco, N.Y. 34. GERBERT, J., 0. A. MERCADO & T. H. SOKOLOFF.1975. The Surgical Treatment of the Hallux-Abducto-Valgus and Allied Deformities. : 140. Futura Publishing Co. Mt. Kisco, N.Y.. 35. GERBERT, J., T. E. SOARLATO & S. I. SUBOTNICK.1972. Preliminary study of a closing wedge osteotomy of the fifth metatarsal for correction of tailor’s bunion deformity. J. Amer. Pod. Assoc. 62: 212-218. S. I. Observations of plantar callouses. Arch. Pod. Med. Foot Surg. 36. SUBOTNICK, l ( 4 ) : 329-337. 37. SUBOTNICK, S. I. 1975. Podiatric Sports Medicine. Futura Publishing Co. Mt. Kisco, N.Y.
