Jan 29, 2015
Bulletin Board

Knee Geometry and ACL Risk

When it comes to risk factors for sustaining a noncontact ACL injury, size matters. So says a study that appeared in the August issue of the American Journal of Sports Medicine, which cites knee geometry as a significant predictor of noncontact ACL tears.

Researchers at the University of Vermont used MRI to measure the thickness of the bony ridge at the anteromedial outlet of the femoral notch, femoral notch volume, ACL volume, and ACL cross-sectional area in the injured knees of 88 college and high school athletes. All subjects had suffered grade III, first-time noncontact ACL tears. Their results were then compared to MRI exams from 88 non-injured athletes who were members of the same teams as the injured players.

The analysis showed that as the volumes of the femoral notch and ACL decreased, injury risk increased. It was also found that as the bony ridge thickness increased, so did the athlete’s corresponding risk for injury.

As the researchers move forward with identifying noncontact ACL injury factors, they will continue to seek out the variables that may lead to better injury prediction. “The first step is to establish the athletes most at risk; targeting injuries comes second,” Bruce Beynnon, PhD, lead researcher and McClure Professor of Musculoskeletal Research at Vermont, said in an article on the university’s website.

The abstract of the study, “Relationship Between the Risk of Suffering a First-Time Noncontact ACL Injury and Geometry of the Femoral Notch and ACL: A Prospective Cohort Study with a Nested Case-Control Analysis,” can be found by searching its title at: ajs.sagepub.com.

Fish Oil Aids Exercise In looking for a nutritional boost, many athletes find fish oil to be a helpful supplement. Now, new research shows additional benefits: enhanced exercise economy.

In a double-blind study that was published online in Bioscience, Biotechnology, and Biochemistry in August, 20 college-aged males who were regularly active in recreational activities were equally divided into either a fish oil group or a control group. Those in the fish oil group ingested 3.6 grams of the supplement daily for eight weeks.

To test the subjects’ VO2 levels and VO2 max before and after the eight-week period, researchers had them pedal on stationary bicycles until volitional exhaustion was reached. While the study showed no significant differences in VO2 max between pre- and post-supplementation for the two groups, there were varying VO2 levels during the submaximal exercise test.

After five minutes of cycling, the fish oil subjects showed significantly decreased VO2 levels compared to the control group. In addition, the fish oil group’s VO2 remained lower for the duration of the test.

The results also showed a 148 percent increase of eicosapentaenoic acid (EPA), a polyunsaturated fatty acid, and a 13 percent rise in docosahexaenoic acid (DHA), an omega-3 fatty acid, in the red blood cells of the fish oil subjects after eight weeks. Researchers concluded that these heightened levels contributed to the decreased VO2 in the fish oil group.

“There was a negative linear correlation between EPA and [VO2] during submaximal exercise,” wrote the research team in the study. “We showed that EPA-rich fish oil supplementation improves exercise economy and reduces perceived exertion in normal healthy subjects.”

To view the full text of the study, search its title, “Supplementation with Eicosapentaenoic Acid-rich Fish Oil Improves Exercise Economy and Reduces Perceived Exertion During Submaximal Steady-state Exercise in Normal Healthy Untrained Men,” at: www.ncbi.nlm.nih.gov.

Measuring Weightroom Gains

Small variations in weightlifting results are typical for most athletes who take part in a strength training program, making it difficult to know when those changes reflect substantial gains as opposed to chance increases in performance. So researchers at the University of Missouri set out to determine what constituted the “smallest worthwhile difference” in reps using NFL-225 bench press test results. They found the magic number was three.

“If the stars and moon aligned right on a day, [an athlete] might get one or two extra reps. The next day, [they] might be back down to where [they] normally are,” Bryan Mann, PhD, CSCS, SCCC, Assistant Director of Strength and Conditioning and Assistant Teaching Professor at Missouri, said in a press release. “But when somebody moves up three reps, that’s showing that the training did in fact work, and those changes were a physiological change.”

The study, which was published in the May issue of the Journal of Strength and Conditioning Research, examined NFL-225 results, which measure the number of bench press reps an athlete can complete with a load of 225 pounds. Mann and his colleagues analyzed weekly results of 72 Missouri football players during the team’s winter strength training program. When the data was broken down by position and reps completed, the smallest worthwhile difference was three across all groups.

Mann believes this research could help strength coaches better evaluate the effectiveness of their current training systems. “The goal is for athletic programs to have scientific evidence backing their training regimens rather than operating a certain way because that’s how everyone before them had done things,” he said.

To view an abstract for the study, “Reliability and Smallest Worthwhile Difference of the NFL-225 Test in NCAA Division I Football Players,” search for its title at: journals.lww.com/nsca-jscr/.

Core Tied to Pitching Injuries

The route to avoiding baseball pitching injuries may travel through the core rather than the arms. New research from Ohio State University points to a correlation between pitchers’ lumbopelvic control and their likelihood to miss significant playing time due to injury.

In the study, which appeared online in August ahead of publication in the American Journal of Sports Medicine, researchers assessed 347 professional pitchers’ lumbopelvic control during spring training. The athletes lifted one of their feet about four inches off the ground, and the degree of tilt in their pelvis was measured using a tilt sensor attached to their sacrum.

Researchers found that pitchers who exceeded eight degrees of tilt in their pelvis were up to three times more likely to miss at least 30 days during the subsequent season than those who had less than four degrees and twice as likely than those with four to seven degrees of tilt. In addition, of pitchers who missed time due to injury, subjects with readings above eight degrees sat out more than twice as long as those with lower values.

“A stabilized core lets energy pass through it… leading to less torque on the shoulder and elbow and better efficiency,” lead study author Ajit Chaudhari, PhD, FACSM, Associate Professor in Ohio State’s School of Health and Rehabilitation Sciences, said in a press release. “I’d compare the stability difference to jumping from solid ground versus jumping out of a canoe.”

Although the study did not establish causation between core stability and injury risk, the findings suggest that core strength may help reduce time lost to injury. “We’ll eventually explore whether improving lumbopelvic control makes a difference by reducing injury,” Chaudhari said. “That’s what everybody would like to know.”

To view an abstract for the study, “Lumbopelvic Control and Days Missed Because of Injury in Professional Baseball Pitchers,” search for its title at: ajs.sagepub.com.


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