Professional baseball pitchers with poor core stability are more likely to miss 30 or more days in a single season because of injury compared with pitchers who have good control of muscles in their pelvis and lower back, according to a study published August 26 online ahead of print in the American Journal of Sports Medicine.
The study shows association, not causation, but does suggest that pitchers might benefit from training to improve their lumbopelvic control. “The nice thing about lumbopelvic control is that there’s not any downside we can think of to trying to improve it,” said Ajit Chaudhari, PhD, Associate Professor of Health and Rehabilitation Sciences and of Orthopedics at The Ohio State University and lead author of the study.
Ajit Chaudhari, PhD
A total of 347 pitchers were assessed for lumbopelvic control during spring training, then followed for the ensuing season. Most participants were between the ages of 18 and 22 years and played on teams at the developmental, minor league, or major league level.
Investigators tested their lumbopelvic control by assessing how much the pelvis tilted forward or backward as pitchers lifted a single foot about 10 cm in a movement similar to stepping up onto a curb or beginning a pitch. Study authors then placed an iPod-based tilt sensor on each participant’s sacrum and a score was assigned to each player based on the magnitude of the tilt.
Medical staff from each baseball organization recorded how many missed days players had throughout the season that followed spring training (a missed day was defined as any day a study participant could not complete his scheduled work because of an injury suffered during baseball-related activity). The majority of injuries recorded were elbow strains, shoulder strains, tears, and fractures. The subjects also were placed into 1 of 3 categories—those whose pelvises tilted less than 4 degrees, between 4 and 7.9 degrees, and more than 8 degrees from the starting position.
Players were categorized by the total numbers of days missed during the season (fewer than 30 days or 30 or more days). The analysis showed that the chances of missing 30 or more days in the season were 3 times higher for the high-tilt group than for pitchers in the lowest-tilt group. It was also 2.2 times higher than for players in the moderate-tilt group.
Further analysis suggested that of the 108 (31.1%) participants who missed at least 1 day because of injury, the average number of days missed was significantly different among the 3 groups. On average, those with poor lumbopelvic control missed 99 days, those with moderate control missed 46 days, and the well-controlled group missed 44 days.
“The core could help prevent injury by spreading out the energy load, allowing pitchers to use their legs more and their throwing arm less,” Dr. Chaudhari said.