Thursday night's 200-meter track final at Olympic stadium was supposed to be a showdown between Michael Johnson and Maurice Greene of the U.S. team. Instead, it will be a poignant chapter in the ongoing story of how a rather ordinary injury can bring down extraordinary athletes.Johnson, who won a gold medal in the 200 meters in Atlanta and holds the world record for the event, and Greene, the most probable heir apparent, both suffered hamstring injuries during final qualifying heat of the event at the Olympic trials in Sacramento.
Both men are here in Sydney and seemed to be in fine form, as Johnson picked up the gold medal in the 400 meters and Greene won the gold in the 100 meters. But the 200 meters will be somebody else's Cinderella story, particularly after Frankie Fredericks of Namibia, who took silver in both the 100 and 200 meters in Atlanta, pulled out of both events with an Achilles tendon injury.
For some reason, hamstring injuries have hit the U.S. 200-meter stars especially hard. Inger Miller had pulled out of the women's 100-meter event last week but said she hoped to still challenge teammate Marion Jones and Australian icon Cathy Freeman in the 200. In the end, though, the hamstring had its way, and Miller will leave Sydney without competing.
The most basic hamstring injury diagnosis does not require much in the way of sophisticated technology-most athletes can tell right away if that's what has occurred. It would be invaluable, however, if imaging technology could be used to assess the severity of the injury and predict healing time.
MRI seems to be the preferred imaging modality for diagnosing hamstring injuries. Researchers from the University of Iowa College of Medicine reviewed findings seen on radiography, CT, and MRI for 22 patients with hamstring injuries and found that only MRI was helpful, regardless of how long after injury the exam took place. Plain x-rays obtained less than one week after injury were normal or showed avulsion of an ischial apophysis. Callus and osteolysis formation limited the usefulness of x-rays obtained more than one week but less than three months after injury. The findings appeared in the October 1995 issue of Radiology.
In a study published in February of this year, researchers from the University of Wisconsin in Madison used MRI to examine hamstring injuries in more detail. In a series of 15 collegiate athletes, they found that the biceps femoris was the hamstring muscle most commonly injured, followed by the semitendinosus muscle. Multiple muscles were involved in one third of the athletes. All intramuscular injuries in the study occurred at the musculotendinous junction, either within the belly of the muscle or at the ends. The findings were published in the American Journal of Roentgenology.
The medical literature reveals little about the prognostic value of hamstring images, but a 1993 study from Christ Hospital in Cincinnati did suggest that MRI could be used to predict the "convalescence interval" following injury. The researchers obtained T1- and T2-weighted spin-echo images of 15 professional athletes with hamstring injuries and identified the following factors associated with convalescent intervals longer than six weeks:
* complete transection
* greater than 50% cross-sectional muscle involvement
* ganglionlike fluid collections (on long T1 and T2 sequences)
* hemorrhagelike signal intensity (on short T1 and T2 sequences)
* distal myotendinous junction tears
* deep muscular tears
The findings were published in Radiology.
