The questions about Aaron Rodgers and his injury are mounting. Was it turf-related? Did his calf strain make him vulnerable? Was it a fluke, or could it have been prevented? Can Achilles’s tears be predicted? A torn Achilles is often considered one of the most feared injuries in sports due to its lengthy and grueling rehabilitation process, with no guarantee of a full recovery. While there are more common injuries, Achilles tears are often career-ending.

Experts in Achilles tendon injuries offer some insights. Connecting Rodgers’ injury to his previous calf issues may seem logical, but it’s not supported by the facts or science. Dr. Nigel Hsu notes that while calf injuries can contribute to Achilles ruptures, Rodgers’s injury seems unrelated to his calf strain.

When it comes to MetLife Stadium’s turf, it may cause injuries, but it’s unlikely to have caused Rodgers’s Achilles injury; at least, that’s what Dr. Hsu says, so discussion shifts to facts and considerations like that Achilles tendon tears are more common in late-30s to early-40s male recreational athletes, a category that doesn’t quite fit Rodgers. However, as athletes age, their tendons weaken, making them more susceptible to such injuries.

Sudden bursts of activity, common in recreational athletes or those returning from injury, can also increase the risk. The narrative of athletes returning from injury and then suffering Achilles tears is not uncommon. Dr. David Geier suggests that prior injuries and periods of inactivity might play a role in Achilles injuries.

Preventing Achilles injuries in elite athletes could have significant financial and performance benefits for teams and players. Implementing individualized training regimens focused on flexibility and strength could be a proactive approach to reduce the risk.

While this may not be all the answers, Aaron Rodgers’ injury highlights the need to explore ways to minimize the risk of Achilles tears in professional athletes. It’s a discussion worth having, as even a small reduction in injury risk could have substantial benefits for athletes and teams.

For many competitors, completing the Boston marathon is a life-changing experience. The same is true of the bacteria that live in the guts of athletes.

In a new study published in an online journal, researchers examined how the bacteria in the digestive tracts of 15 Boston marathon participants altered following the race, and how this may provide an edge to some athletes.

The researchers, the majority of whom are based in Boston, regarded the yearly event as an ideal opportunity to examine endurance athletes’ microbiomes. “Boston is a city that values physical activity,” said molecular scientist Jonathan Scheiman, the study’s first author. “There was considerable interest in taking part in this investigation.”

To conduct the research, scientists took daily samples of solid waste from participants one week before and one week after the marathon. “For two weeks, I drove around in a zipcar for seven hours a day collecting feces,” explained Scheiman, who was then a postdoctoral researcher at Harvard University’s Wyss Institute for Biologically Inspired Engineering. “That was fun.”

More About the Gut Research

They were able to isolate a specific genus of bacteria, Veillonella, that was more numerous in the athlete’s gut following the 26.2-mile marathon but not in the guts of ten non-runners, using a powerful DNA sequencing approach. Scheiman and his colleagues discovered that Veillonella bacteria feed primarily on lactate. Lactate is created by the muscles and released into the bloodstream during exercise. Additionally, it is responsible for the sensation of muscular burn.

To corroborate their findings, scientists examined stool samples from 87 more athletes, including rowers preparing for the Olympic trials and ultramarathon runners who run up to 100 miles at a time. They discovered that the prevalence of Veillonella bacteria rose in these athletes following exercise. Additionally, they discovered that post-exercise gut bacteria had enhanced expression of genes involved in the breakdown of lactate to propionate, a short-chain fatty acid.

“This is groundbreaking work,” said Jeffrey A. Woods, a kinesiologist at the University of Illinois at Urbana-Champaign who was not involved in the new study. “This is one of the first studies to examine the effect of a single session of exercise on the microbiome.”

The researchers next investigated if the Veillonella bacteria had any effect on running performance by isolating one strain, V. atypica, from one of the marathon runners and implanting it into the gut of mice. Animals implanted with the organism ran 13% longer on a treadmill than mice implanted with another species of bacteria, L. bulgaricus, which does not consume lactate. Woods points out, however, that the researchers’ test is not indicative of a human marathon.

In a separate experiment, Scheiman and colleagues demonstrated that lactate may move from the bloodstream to the stomach in mice, implying that gut bacteria could degrade it to propionate, although this was not demonstrated in the study. Propionate has been shown in a previous study to raise heart rate and oxygen consumption while regulating blood pressure in mice, which may explain why the mice with Veillonella bacteria ran better.

The Problem that Many Marathon Runners Have

Related to the fact that marathon runners occasionally get gastrointestinal disorders such as colitis as a result of the rigorous training, Woods hypothesizes that the lactate leaking into the gut observed in mice is due to a disturbance of the gut barrier. “It is not always a positive thing,” he stated. Additionally, Woods desired that the researchers demonstrate that the leaking lactate is truly transformed into propionate.

The new study provides extensive information on how chemicals generated during exercise might modify the composition of the microbiome and how this alteration can affect athletic performance. Woods and colleagues have demonstrated, however, that exercise increases the growth of multiple bacterial species, not just one. “I believe the tale is oversimplified,” he stated. “They’re making a huge deal out of this single bacterial strain, and I believe there’s more to the tale.” He believes the researchers are concentrating their efforts on Veillonella because they are interested in commercializing it as a probiotic.

Giovanni Messina, a physiologist at the University of Foggia in Italy who was not involved in the new research, told Inside Science that researchers would need to continue their work before developing items for athletes to ingest to boost athletic performance. Scheiman and many of the study’s co-authors created Fitbiomics with the goal of conducting additional research on elite athletes and their microbiome. They recruited Olympic winners with the intention of profiling their microbiomes and isolating additional beneficial microorganisms.