The onset of back pain among runners may stem from a general weakness in their deep core muscles, new research indicates.
Such deep muscles are located well below the more superficial muscles typified by the classic six-pack abs of fitness magazine fame, the researchers noted.
Using computer simulations, they found that runners with relatively weak deep core muscles end up relying more and more on their superficial muscles to keep on running. The result is a higher risk for back pain.
“We measured the dimensions of runners’ bodies and how they moved to create a computer model that’s specific to that person,” said study lead author Ajit Chaudhari. “That allows us to examine how every bone moves and how much pressure is put on each joint.”
Chaudhari is an associate professor of physical therapy and biomedical engineering at Ohio State University’s Wexner Medical Center.
The investigators found that “when your deep core is weak, your body is able to compensate in a way that allows you to essentially run the same way,” Chaudhari said in a medical center news release, “but that increases the load on your spine in a way that may lead to low back pain.”
The study team said it’s not uncommon to find avid athletes who fail to put sufficient focus on their deep core strength, perhaps because superficial muscle maintenance tends to get a lot more public attention.
However, Chaudhari said, “working on a six-pack and trying to become a better runner is definitely not the same thing.
“If you look at great runners, they don’t typically have a six-pack, but their muscles are very fit,” he said. “Static exercises that force you to fire your core and hold your body in place are what’s really going to make you a better runner.”
The study was published online recently in the Journal of Biomechanics.
The American Academy of Family Physicians has information on low back pain.
SOURCE: Ohio State University Wexner Medical Center, news release, Jan. 3, 2018
Female runners with a low body weight are more likely to have stress fractures and take longer to recover from them, according to a new study.
Researchers from the Ohio State University Wexner Medical Center reviewed data on dozens of injuries suffered by female college runners. They found that runners with a body mass index (BMI) below 19 were more likely to suffer stress fractures than others. BMI is an estimate of body fat based on weight and height.
Women with a low body weight were also sidelined longer after an injury. Among those with the most severe stress fractures, recovery time was 13 weeks for women with a BMI of 19 or higher. That compared to more than 17 weeks for those with a BMI below 19, the study found.
“We found that over time, we were able to identify the factors that put female runners at an increased risk of developing a stress fracture,” said study co-author Dr. Timothy Miller, assistant professor of clinical orthopedic surgery and sports medicine.
“One of the most important factors we identified was low body weight, or low body mass index,” he said in a hospital news release.
Having too little lean muscle mass to dissipate the impact of repetitive pounding on hard surfaces makes the bones of runners’ legs vulnerable to injury, according to Miller.
“When body mass index is very low and muscle mass is depleted, there is nowhere for the shock of running to be absorbed other than directly into the bones. Until some muscle mass is developed and BMI is optimized, runners remain at increased risk of developing a stress fracture,” he explained.
Female athletes should maintain a BMI of 20 to 24, Miller suggested.
A woman who is 5 feet, 5 inches tall and weighs 120 pounds has a BMI of 20, according to the U.S. Centers for Disease Control and Prevention.
The BMI for an average American woman is 26, the CDC says.
To prevent injury, Miller said women should stay at a healthy BMI and include resistance training in their workout regimen to strengthen their lower legs, “even if that means adding weight from additional muscle mass.”
The study was published recently in the journal Current Orthopaedic Practice.