Gymnastics studies examine new injuries and interventions

Gymnasts bend, but they also break. A recent flurry of research suggests hand and wrist injuries in young gymnasts may be even more prevalent than previously thought, but also offers hope for preventing the low back pain that affects a majority of athletes in this high-impact sport.

Of 125 pediatric MRI scans of the hand and wrist reviewed during a two year period, a team of San Diego researchers found that 12 involved gymnasts and revealed injuries not previously associated with the sport in the medical literature. Those previously undocumented abnormalities included metacarpal head necrosis, focal lunate necrosis at the scapholunate attachment, and triangulofibrocartilage tears.

“We'd never seen these injuries before in gymnasts,” said Jerry Dwek, MD, an assistant clinical professor of radiology at the University of California San Diego.

In the 12 gymnasts, all of whom were female and between the ages of 12 and 16, the San Diego researchers also found four cases of chronic physeal stress injury at the distal radial physis, which had been previously reported in the literature as associated with gymnastics. The findings were presented in December at the annual meeting of the Radiological Society of North America.

“When you tumble and jump onto your hands, there is significant force that is generated. It's possible that there may be some specific exercises that are causing these injuries,” Dwek said, although he added that information about the injured gymnasts' skill levels and practice patterns was not available.

Those same repetitive forces, however, are often credited for the elevated bone mineral density levels typically seen in gymnasts, suggesting that when it comes to loading there may be a fine line between stimulation and aggravation.

This is underscored by a December Journal of Women's Health study from the University of Illinois at Chicago, which found that 15 female collegiate gymnasts averaged 24% higher BMD and 34% greater bone mineral content at the ultradistal radius than 15 controls matched for age, height and body mass.

Gymnasts who had suffered wrist fractures in the previous five years—potentially including injuries like those seen in San Diego—were excluded from the Chicago study. Still, the Chicago researchers have reason to believe that the bone remodeling process may involve periods of vulnerability, according to Mary Lou Bareither, PhD, a clinical associate professor of kinesiology and nutrition at UIC.

The Chicago researchers' long-term objective is to develop user-friendly interventions to help improve BMD and prevent wrist fractures in postmenopausal women, and a subsequent study took another step toward that goal by measuring bone mineral content in healthy young women before and after an intervention in which they repeatedly pushed down on a load cell attached to an oscilloscope. In that study, which was presented in March 2008 at the annual meeting of the Orthopaedic Research Society, BMC increased from baseline at 15 weeks but actually had decreased slightly at seven weeks before reversing course. Although those study subjects were not gymnasts, there may be injury-risk implications for athletes as well.

“If these young women are changing their style of activity and experiencing more loading, and if that bone starts to remodel, it may be slightly weaker for a while before it mineralizes again,” Bareither said.

The outlook is sunnier for gymnasts suffering from low back pain, in light of a University of Wisconsin-LaCrosse study in which training the trunk musculature was positively associated with reduced episodes of low back pain.

Fifteen members of the UW-LaCrosse women's gymnastics team performed a 10-minute exercise regimen, emphasizing endurance of the extensors and lateral flexors, at the beginning of every practice for 10 weeks leading up to the competitive season. At the end of the intervention, the gymnasts demonstrated significant improvements on four trunk endurance tests relative to baseline.

What's more, whereas training staff had previously reported seeing three to four cases of LBP per season, no new episodes of low back pain were reported during the season following the intervention, The results were published online December 3 by the Journal of Strength & Conditioning Research.

Although a direct causal relationship cannot be assumed since the study did not include a control group of athletes, the findings are encouraging given that low back pain has been reported to affect up to 86% of gymnasts. At issue may be the sport's tendency to overemphasize the trunk flexors at the expense of the extensors, said Chris J. Durall, DPT, ATC, director of physical therapy at the UW-LaCrosse Student Health Center and lead author of the study. Trunk extensor endurance in particular increased by 32% during the 10-week intervention.

“Preseason training is really loaded toward the flexors,” Durall said. “These girls have amazing strength and endurance in the anterior abdominal muscles, but we've been surprised to see extensors really aren't where they should be, given the demands of the sport.”

None of the subjects said the training adversely affected their gymnastics performance. Some, however, said they felt their stamina was improved.

“We chose to focus on endurance of trunk muscles rather than strength,” Durall said. “Research has shown that endurance may actually be more important for spine health, because those muscles are really designed for endurance. So it makes sense to train them in a fashion that's consistent with their design and intent.”