RUNNING INJURIES

Gait parameters Walking Stance phase

Swing phase

Double support Energy cost

Long Short

Present Low

Low

Running Short

Long

Absent High

Ground reaction force 70% of body weight Two to three times body weight Injury risk

Stride length Stride rate

Short Low

2. The orthoses ensure that the midtarsal joint is fully pronated during the mid- stance locking and thus stabilising the forefoot on the rearfoot

3. It also ensures that the first ray is allowed to normally plantarflex during the propulsion phase

Foot orthoses are meant to resist the severe deforming forces produced by abnormal biomechanical compensation. Therefore they are usually made of rigid material. Most are also made to fit unique- ly to the individual foot structure and are fabricated from a non-weight bearing neu- tral plaster of paris cast of the foot.

The

rigid orthoses provide the maximum ‘bio- mechanical’ control but may be incompati- ble with some sports, especially football, hockey and track events.

In such sports

and in patients who are not able to toler- ate rigid orthoses, semi-rigid or soft orthoses are indicated.

There have been few reported studies to evaluate the efficacy of orthoses in spite of becoming a popular adjunct in the treat- ment of stress related injuries. Most stud- ies show around 75% improvement in symptoms following orthotic therapy. However in these studies orthoses were an adjunct to a combination of other treat- ments which included physiotherapy and steriod injections. In the author’s experi- ence orthoses alone are less effective.

Conclusion There is growing evidence that exercise related musculoskeletal injuries occur as result of abnormal biomechanics of the lower limb.

The biomechanics of the foot has been the focus of research as the foot 26 SportEX

High Long High

Table 3: Differences in gait between the walking and running cycle

forms the interface between body move- ment and the unforgiving ground.

Foot

orthoses have been used successfully in the management of the musculo-skeletal disorders associated with structural varia- tions in foot position and foot motion.

References 1. Lysholm J and Wiklander J. Injuries in run- ners. Am J Sports Med 1997;15:168-171 2. Neely FG. Intrinsic risk factors for exercise- related lower limb injuries. Sports Medicine 1998;26(4):253-263 3. Hick JH. The mechanics of the foot: The joints. J Anatomy 1953;87:35 4. Isman RE and Inman VT. Anthropometric stud- ies of the human foot and ankle. Bull Prosth Res 1969;97-127 5. Root ML, Orien WP and Weed JH. Normal and abnormal function of the foot. Clinical Biomechanics Corporation, Los Angeles. Vol II, 1997 6. Root ML, Weed JH, Sgarlato TE and Bluth D.

Axis of motion of subtalar joint. J Am Pod Assoc 1996;56:149-155 7. Black KP and Taylor DE. Current concepts in the treatment of common compartment syn- dromes in athletes. Sports Medicine 1993;15(6):406-418 8. Padhiar N and King JB. Foot orthoses can change compartmental pressures in the leg. Br J Sports Med 1998;32(1):89 9. Padhiar N, Bader DL, King JP R. A pilort study to identify pathomechanical factors in exercise induced leg pain. J Br Pod Med 1997;52(1):3-5

Further reading For more information on biomechanical assessment refer to: ● Root ML, Orien WP, Weed JH and Hughes RJ. Biomechanical examination of the foot. Clinical Biomechanics Corporation, LA. Vol.I 1997 ● McRae R. Clinical orthopaedic examina- tion. Churchill Livingstone, 2nd edition, 1983

Online running clinic From 18-28 April only This is the first in a trial series of online clinics to be held in the discussion area at www.sportex-medicine.com To tie in with the London Marathon the authors of the biomechanics/lower limb/ Achilles tendonosis articles will be online to answer your questions. Got any tricky cases, want an opinion on rehab tech- niques, suspect a biomechanical element but are not sure how to progress? Post your questions in the discussion forum and Nat and Dylan will endeavour to answer them.