Robert J. Johnson

Hip muscle weakness and overuse injuries in recreational runners

Objective: To test for differences in strength of 6 muscle groups of the hip on the involved leg in recreational runners with injuries compared with the uninvolved leg and a control group of noninjured runners. Design: Descriptive analysis. Setting: Three outpatient physical therapy clinics in the Minneapolis/St. Paul metropolitan area. Participants: Thirty recreational runners (17 female, 13 male) experiencing a single leg overuse injury that presented for treatment between June and September 2002. Thirty noninjured runners (16 female, 14 male) randomly selected from a pool of 46 volunteers from a distance running club served as controls. Main Outcome Measures: Self-report demographic information on running habits, leg dominance demonstrated by preferred kicking leg, and injury information. Muscle strength of the 6 major muscle groups of the hip was recorded using a hand-held dynamometer. The highest value of 2 trials was used, and strength values were normalized to body mass2/3. Results: Results comparing the injured and noninjured groups showed that leg dominance did not influence the leg of injury (χ2(1) = 0.134; P = 0.71). Correlations for internal reliability of muscle measurements between trials 1 and 2 with the hand-held dynamometer ranged from 0.80 to 0.90 for the 6 muscle groups measured, and all P values were less than 0.0001. No significant side-to-side differences in hip group muscle strength were found in the noninjured runners (P = 0.62-0.93). Among the injured runners, the injured side hip abductor (P = 0.0003) and flexor muscle groups (P = 0.026) were significantly weaker than the noninjured side. In addition, the injured side hip adductor muscle group was significantly stronger (P = 0.010) than the noninjured side. Duration of symptoms was not a contributing factor to the extent of injury as measured by muscle strength imbalance between injured and uninjured sides. Conclusions: Although no cause-and-effect relationship has been established, this is the first study to show an association between hip abductor, adductor, and flexor muscle group strength imbalance and lower extremity overuse injuries in runners. Because most running injuries are multifaceted in nature, areas secondary to the site of pain, such as hip muscle groups exhibiting strength imbalances, must also be considered to gain favorable outcomes for injured runners. The addition of strengthening exercises to specifically identified weak hip muscles may offer better treatment results in patients with running injuries.

Effects of brief, heavy exertion on circulating lymphocyte subpopulations and proliferative response

Ten healthy males (mean age 22.3 +/- 0.8 yr) pedaled with maximal effort for 30 s against a workload adjusted prior to the start of the test to 0.98 N.kg body mass-1. Blood samples were collected before, and 3 min and 1 h following exercise. Peak and average power mean values were 1020 +/- 51 and 738 +/- 34 W, respectively. Total leukocytes increased 40% in response to the exercise bout, but were 16% below pretest levels after 1 h of recovery (F = 123, P < 0.001). Neutrophils and lymphocytes represented approximately 60% and 30% of the leukocytosis, respectively. Lymphocytes increased 30% following exercise, but were 36% below pretest levels after 1 h recovery (F = 56.4, P < 0.001). The post-test lymphocytosis can be explained primarily from the 176% increase in natural killer cells (NK) and 28% increase in cytotoxic/suppressor T cells, while the 1-h recovery lymphopenia occurred because of a sharp decrease in total T cells and a moderate decrease in NK cells. No significant changes in lymphocyte proliferative response or serum immunoglobulin levels were found when appropriate adjustments for changes in plasma volume or lymphocyte subset changes were made. Plasma epinephrine increased 300% in response to the exercise bout, and best explains the measured changes in circulating levels of lymphocyte subsets. These results demonstrate that changes in circulating levels of leukocyte and lymphocyte subsets, especially NK cells, occur rapidly in response to 30 s of brief, heavy exertion.

NSAIDs and musculoskeletal treatment: What is the clinical evidence?

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed for musculoskeletal injuries because the conditions are believed to be inflammatory in nature. However, because inflammation is a necessary component in the healing process, decreasing inflammation may prove counterproductive. Also, many tendon injuries called tendinitis are, in fact, degenerative and not inflammatory conditions. An analysis of the pathophysiology and healing of musculoskeletal injuries questions the use of NSAIDs in many treatment protocols. Because NSAIDs have profound side effects, they should not automatically be the first choice for treating musculoskeletal injuries.

Abdominal wall injuries: rectus abdominis strains, oblique strains, rectus sheath hematoma.

Abdominal wall injuries are reported to be less common than actually perceived by sports medicine practitioners. National Collegiate Athletic Association injury statistics for 2004–2005 cite a high of 0.71 abdominal muscle injuries per 1000 player-hours in wrestling competition to a low of 0.01 injuries per 1000 player-hours in autumn football practices. British professional soccer clubs reported an incidence of torso injuries of up to 7% of all injuries over the course of several seasons. Injury definition is most likely the explanation for this discrepancy. The abdominal wall muscles (rectus abdominis, external and internal obliques, and transverse abdominis) are injured by direct blows to the abdomen or by sudden or repetitive trunk movement, either rotation or flexion/ extension. With the exception of the rare rectus sheath hematoma that does not self-tamponade, the treatment for these problems is nonoperative with symptoms guiding rehabilitation and return to play decisions.

Skiing and snowboarding injuries: When schussing is a pain

Downhill and cross-country skiing and snowboarding are growing rapidly in popularity. With the ever-increasing number of participants, physicians must be prepared to deal with the injuries specific to these sports. More important, physicians need to use epidemiologic data to advise patients of methods to minimize the risk of injury as they participate in these healthy and vigorous winter sports.

SCHEMA THEORY: A TEST OF THE HYPOTHESIS, VARIATION IN PRACTICE

Schema theory predictions concerning variation in practice and the production of novel movement received only partial support. Subjects error was documented as a powerful source of variation in practice which should be given consideration in further tests of the theory and also in the structure of training.

Current review of sports medicine

Spine and chest wall Shoulder and upper arm Elbow and forearm Athletic injuries to the hand and wrist Hip and thigh Knee ligament problems Knee Ankle and foot Stress fractures and overuse injuries Sports epidemiology and prevention of injury Biomechanical principles of sports medicine Cardiovascular aspects of sports medicine Sports neurology Drugs and sports Nutrition Environmental issues Biopsychosocial effects on the athlete Conditioning and training Women in sports The young athlete The mature athlete Medicolegal issues Immunology and sports.

HIV INFECTION IN ATHLETES : WHAT ARE THE RISKS ? WHO CAN COMPETE ?

The activities of athletes and personnel who provide their medical care may place them at slightly greater risk for infection with human immunodeficiency virus (HIV) than their nonathletic peers. At this point, there is no reason to disallow participation of athletes who are HIV-infected. Thus, sports physicians need to assume that they are at risk for accidental exposure to HIV and use appropriate precautions. Most important, physicians can educate athletes, coaches, and trainers to practice safe athletics and medical care to minimize the risks of exposure to and transmission of HIV. Testing for HIV can be encouraged for athletes who may be at risk and should be done for any athlete who specifically requests it. Physicians should encourage further study to clarify the specific issues and risks of HIV infection created by athletic competition and prepare to deal with the changing knowledge about HIV and AIDS.

Mechanisms of the Most Common Ski Injuries

Knee sprains and tibial fractures are two of the most common injuries in skiing. The authors explore their possible causes and discuss ways to prevent them.

Sudden death during exercise: A cruel turn of events

The causes of sudden death in exercisers age 35 and younger are generally not preventable because they are typically structural and difficult to detect. The best a physician can do is be alert to important information in the family and patient history and to the occasional sign or symptom that may warrant further evaluation. For the over-35 exerciser, screening tests may be appropriate, especially if the person is just beginning an exercise program, although this remains an area of controversy. The screening tests available are far from perfect. If exercise testing is performed, the asymptomatic patient must be apprised of the possibility of a false-positive result and the consequences and attendant risks of overdiagnosis or additional testing (coronary angiography). Physicians should be alert to suspicious symptoms in physically active patients, but they should avoid the tendency to have these patients stop their exercise program. Instead, after appropriate diagnostic testing, they should advise a modified exercise program that is safely within the limits of the disease process involved. It is important to realize that physical activity can be a preventer of cardiac disease but also a provoker of sudden death. Even so, the benefits of regular exercise clearly outweigh the risk.