ACSM Basics Exercise-Induced Leg Pain www.acsm.org

Introduction forms of exercise-induced leg pain are (excessive flattening of the arch of the Anatomically speaking, the leg is the region described below. during locomotion) and tibialis posterior between the and the . Repetitive . weight bearing exercise commonly causes Muscle • Region most affected: Tibialis posterior. painful injuries in this region. The sources • What is it? Muscle fiber damage However, tibialis anterior, achilles and of leg pain are varied, but the cause is often • How does it occur? Over-stretching a peroneal tendinopathy can also occur the same. In the modern day, the pursuit muscle following micro-tears. of athletic excellence has reached such • Region most affected: Tibialis anterior • : Pain, swelling and phenomenal extremes, the human body is muscle (front of the leg, beside the shin palpable crepitance (crunchy feeling) along often subjected to degrees of physical work it bone) often following chronic downhill the during muscle contraction and is not able to tolerate. While most body tissues . stretch. For tibialis posterior tendinopathy, have the capacity to adapt and strengthen in • Signs and symptoms: Acute, focal (site this can be mainly felt behind the medial response to increased loading, overuse injuries of the tear) pain within the muscle during malleolus (inside ankle bone.) Pain is result when loading increases occur too quickly contraction and stretch. May be swollen and likely to occur primarily at the start of and for adequate adaptation to take place. warm. following exercise. • Prevention: Attain good muscle flexibility, • Prevention: Gradual increases in training. Types of Leg Pain warm up, introduce training modifications Leg (tibialis posterior and tibialis anterior) “Shin splints” is a lay term that has gradually, vary training. and foot muscle strengthening to support the been associated with a large number of • Treatment: After the swelling has subsided, arch of the foot when not injured. Orthotic fundamentally different exercise-induced leg stretch and strengthen the affected muscle inserts in the shoes to reduce chronic per injuries. Initially, shin splints was thought within the limits of pain. planus (flat foot) or hyperpronation during to be caused by tibialis posterior tendon exercise, if necessary. injury. Later, other conditions associated with Tendinopathy • Treatment: Initially, take anti-inflammatory chronic exercise, including compartment • What is it? Micro-tears in tendon that medication and minimize painful activities. syndrome, tibialis anterior strain, tibial may cause inflammation in the surrounding Complete rest is not advised as tendon heals and tibial were tissue. Often incorrectly referred to as better when given mild, normal loading. indiscriminately referred to as shin splints. tendinitis. Once inflammation and pain has subsided, Given the very different pathologies of those • How does it occur? Over-training stretch and strengthen the muscle associated conditions, use of the term “shin splints” in repetitive movements, particularly with the tendon. is clearly inappropriate for the purposes of over-stretching and eccentric loading diagnosing and managing exercise-induced (muscle contracting while being forced to leg pain. Instead, specific conditions must be lengthen). There may be a relationship identified and addressed. The most common between repetitive hyperpronation MEDIAL TIBIAL STRESS SYNDROME -MTSS (APERIOSTITIS) • What is it? Over-stimulation or inflammation of the medial tibial periosteum (membrane surrounding bone) - the most common leg injury. • How does it occur? Bone bending is a natural consequence of weight bearing. Wider bones resist bending better than narrower ones and are, therefore, less prone to injury. Chronic repetitive bending stimulates a long bone to widen its cross section by activating bone cells in its periosteum to lay down new bone. If increases in training intensity continue to occur during this process of adaptation, the bone cells cannot keep up, micro-damage occurs and the region becomes inflamed and painful. The injury may be compounded by simultaneous, repetitive muscle or fascial pull positive within 48 hours of injury. Edema is • Signs and symptoms: Deep, diffuse, aching, on the periosteum. visible on MRI. cramping leg pain, swelling and tightness, • Region most affected: Inside border of the • Prevention: Gradual increases in training leg muscle weakness, numbness in the leg distal half to third of the (shin bone), in intensity. Same as for MTSS. and/or foot, reduced pulse at the front of the the region of the narrowest cross section. • Treatment: A period of complete rest (15 ankle, occasional muscle herniations through • Signs and symptoms: Pain during weight days minimum) from painful weight-bearing fascial defects. Initially, pain develops around bearing (particularly running and jumping). activity is vital. Although uncommon, 30 minutes into a moderate exercise bout Tenderness on palpation. Sometimes spontaneous complete fractures may occur at but, with time, pain occurs earlier. If the swelling, redness and warmth. the site of the stress fracture with continued activity is promptly ceased, pain resolves • Prevention: Gradual training increases (<10 loading. Typical tibial stress fractures within 10 to 15 minutes. The diagnosis percent per week). Attaining good dorsi will heal within four to eight weeks with may be confirmed by compartment pressure flexion flexibility (moving the top of the foot modified rest. An important exception is testing during or immediately following toward the shin) and leg muscle strength stress fractures on the anterior (foremost) exercise. Unlike muscle strain, tendinopathy, preseason, wearing appropriate footwear, border of the tibia that can take many MTSS or stress fracture, symptoms are varying the training surface and consuming months to heal and may require extrinsic absent between exercise bouts. 1000 mg/day dietary calcium. stimulation (pulsed electromagnetic field or • Prevention: Nothing known to be effective. • Treatment: Rest (7 to 10 days minimum) low-intensity pulsed ultrasound) or surgery. • Treatment: Acutely, immediate rest and leg from painful activities. Pool, run and cycle to It is not uncommon for tibial stress fractures elevation. Fasciotomy (a minimally invasive maintain aerobic fitness. Return to training to recur. If so, further rest is necessary and surgical procedure involving the cutting of very gradually. Do not stretch or strengthen the return to training must be at a much in the leg to release the compartments) muscles while symptomatic. While there is slower rate than previously. A diet, hormone is the only effective long-term solution if little scientific evidence that lower extremity and evaluation is recommended a patient is to remain active. Rest, anti- alignment anomalies (e.g. or to rule out underlying factors that may be inflammatories and stretching are ineffective hyperpronation) cause MTSS, for a small predisposing the individual to stress fracture. treatments. Exercises that increase muscle proportion of people, prevent bulk will compound the problem. injury and/or reduce symptoms. CHRONIC CONCLUSION TIBIAL STRESS FRACTURE • What is it? A condition of leg muscle For most exercise-induced painful leg • What is it? An incomplete crack or cracks in ischemia (lack of blood) induced by exercise. conditions, prevention is the most effective the tibia following repetitive impact loading. It is relatively rare. form of management. The recurring • How does it occur? May follow MTSS if • How does it occur? Normally, during preventive theme is gradual increases in training is continued at, or higher than, exercise, an elevated demand for oxygen training intensity. Such gradation is necessary the intensity at which periostitis occurred. induces increased flow of blood to the in order to avoid overloading the body’s Stress fractures, however, are likely preceded muscles, causing them to swell about adaptive mechanisms. by a greater degree of bone remodelling 20 percent. If the sheaths of connective (bone resorption followed in due course tissue (fascia) surrounding the muscles are About the Author by formation) than MTSS, with resultant unusually inelastic, this expansion is limited, Written for the American College of Sports Medicine by Belinda R. Beck, Ph.D., FACSM. temporary bone porosity and weakness. and the increase in blood flow is prevented. • Region most affected: As for MTSS. Less Suggested Citation: Beck BR. Exercise-Induced Leg Pain. Muscles starved of oxygen produce cramping Indianapolis, IN: American College of Sports Medicine; 2016. commonly, below the knee, medially. pain. Nerves and arteries passing through ACSM Sports Medicine Basics are official statements by the • Signs and symptoms: Profound, localized the compartment will be impinged. American College of Sports Medicine concerning topics of interest pain during running and jumping. In to the public at large. ACSM grants permission to reproduce this fact • Region most affected: The anterior sheet if it is reproduced in its entirety without alteration. The text severe cases, pain may occur when walking compartment. However, the deep posterior may be reproduced in another publication if it is used in its entirety and nonweight bearing at night. Focal without alteration and the following statement is added: Reprinted and peroneal compartments may also be with permission of the American College of Sports Medicine. tenderness and swelling on palpation. A affected. The condition occurs in both legs Copyright ©2016 American College of Sports Medicine. Visit ACSM online at www.acsm.org. triple-phase 99mTc bone scan may be in 90 percent of cases.