A study of baseball pitchers by Ohio State University researchers finds that those with strong core stability are less likely to miss 30 or more days in a single season from injury, compared with pitchers who have poor muscle control in their lower back and pelvis.
Image credit: Ohio State University
In the study, the researchers assessed the lumbopelvic control of 347 pitchers between the ages of 18 and 22 during spring training.
The researchers placed an iPod-based tilt sensor on the sacrum of each participant, where the spine and pelvis meet. The sensor allowed them to measure by how much of an angle the pitchers tilted their pelvis as they lifted a single foot up by about 10 cm.
This stepping motion is similar to the beginning of a pitch, or stepping a foot up onto a curb.
The researchers say that when a pitcher raises their knee to pitch, the pelvis has to tip. However, they were not as interested in measuring this as much as measuring how well the pitcher can control their pelvis before it has to move.
Once the researchers had recorded these measurements, they divided the pitchers into three groups, based on how far their pelvises tilted from the starting position. These groups were:
- Pitchers whose pelvises tilted less than 4 degrees
- Pitchers whose pelvises tilted between 4 and 7.9 degrees
- Pitchers whose pelvises tilted more than 8 degrees.
Throughout the season following spring training, the medical staff from each baseball organization recorded any days the players had missed.
For the purposes of the study, a missed day was defined as any day on which a pitcher could not complete their scheduled work because of a baseball-related injury.
Analyzing their data, the researchers found that participants in the high-tilt group were three times more likely to miss 30 or more days in the season than pitchers in the lowest-tilt group. Pitchers in the moderate-tilt group were 2.2 times more likely to miss that many days than the lowest-tilt group.
The researchers say that the group who tilted the most had poor lumbopelvic control and those who tilted the least were well controlled.
Lead researcher Ajit Chaudhari, PhD, associate professor at Ohio State’s School of Health and Rehabilitation Sciences, explained to Medical News Today:
“Decreased pelvic tilt in our test is a sign of a stable core because it means the person is able to properly sense movement and stop it with his/her muscles. In the test, we ask the person to keep the waist horizontal, so having increased pelvic tilt would mean either that they couldn’t tell they were tilting or they couldn’t figure out how to stop it.”
On average, the poorly controlled group missed 99 days of the season due to injury, the moderate-control group missed 46 days, and the well-controlled group missed 44 days.
Chaudhari says the reduced injury in the well-controlled group may be because a well-controlled core minimizes interference of energy moving through the body, from the legs to the throwing arm.
“I think the best way to think about how being able to minimize pelvic tilt might help spread the energy load is to imagine trying to throw a ball while sitting in a rowboat,” he told Medical News Today.
“If you push off of the rowboat hard, the boat will just tip, so you can push the ball as hard. On the other hand, if someone held the boat firm for you, then you could really use your whole body to push against the rowboat and throw the ball, which allows each individual muscle to do less while the end result is the ball going faster.
And with a stable core, the pelvis can redirect that force from the legs in the right direction to push the torso and so on all the way up the kinetic chain to the hand. Again, the more that you can get energy from the legs into the ball, the less you have to generate from the shoulder and arm muscles.”
While the results from the study are most directly applicable to baseball pitching, Chaudhari says that – because the test itself is like lifting a leg to step up onto a curb or stair – there are likely to be similar variations among people who do not play baseball.
“We believe that it’s possible people with poor core stability may have a greater risk of injury when lifting boxes,” he says, “or children, when reaching for a heavy dish in the cupboard, or in other daily activities. We are researching these other more everyday activities now to figure this out.”