Research Says Don't Bother With Stretching Before You Run

Stretching before a run neither prevents nor causes injury, according to a study presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).  More than 70 million people worldwide run recreationally or competitively, and recently there has been controversy regarding whether runners should stretch before running, or not at all.

This study included 2,729 runners who run 10 or more miles per week. Of these runners, 1,366 were randomized to a stretch group, and 1,363 were randomized to a non-stretch group before running. Runners in the stretch group stretched their quadriceps, hamstrings, and gastrocnemius/soleus muscle groups. The entire routine took 3 to 5 minutes and was performed immediately before running.

The study found that stretching before running neither prevents nor causes injury. In fact, the most significant risk factors for injury included the following:
  • history of chronic injury or injury in the past four months;
  • higher body mass index (BMI); and
  • switching pre-run stretching routines (runners who normally stretch stopping and those who did stretch starting to stretch before running).
"As a runner myself, I thought stretching before a run would help to prevent injury," said Daniel Pereles, MD, study author and orthopaedic surgeon from Montgomery Orthopedics outside Washington, DC. "However, we found that the risk for injury was the same for men and women, whether or not they were high or low mileage runners, and across all age groups. But, the more mileage run or the heavier and older the runner was, the more likely he or she was likely to get injured, and previous injury within four months predisposed to even further injury," he added.

Runners who typically stretch as part of their pre-run routine and were randomized not to stretch during the study period were far more likely to have an injury. "Although all runners switching routines were more likely to experience an injury than those who did not switch, the group that stopped stretching had more reported injuries, implying that an immediate shift in a regimen may be more important than the regimen itself," he added.

The most common injuries sustained were groin pulls, foot/ankle injuries, and knee injuries. There was no significant difference in injury rates between the runners who stretched and the runners who didn't for any specific injury location or diagnosis.

Source: American Academy of Orthopaedic Surgeons

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Cherry Juice At The Marathon Finish Line

Congratulations, you actually made it to the finish line after 26.2 miles of agony. You are exhausted and need some kind of recovery drink to pick you back up. Reach for the Gatorade? Chocolate milk? Water? No, your best bet is a big glass of tart cherry juice!

Dr Glyn Howatson, exercise physiologist and Laboratory Director in the School of Psychology and Sports Sciences at Northumbria University, examined the properties of Montmorency cherries in a study that found that athletes who drank the juice recovered faster after Marathon running than a placebo controlled group.

In the investigation, 20 marathon runners drank either a tart cherry blend juice or a placebo drink twice a day for five days before taking part in the London Marathon and for two days afterwards.

The findings indicated that the group who drank the cherry juice recovered their strength more rapidly than the control group over the 48-hour period following the marathon. Inflammation was also reduced in the cherry juice group, as was oxidative stress, a potentially damaging response that can be caused by strenuous physical activity, particularly long distance endurance exercise.

The study, which was run in collaboration with PhD student Jess Hill of St Mary's University College, concluded that cherry juice appears to aid recovery following strenuous exercise by increasing total antioxidative capacity, reducing inflammation and oxidative stress, hence aiding in the recovery of muscle function.

Dr Glyn Howatson(Credit: Image courtesy of Northumbria University)
Dr Howatson said: "Participating in long-distance endurance events, such as the London Marathon, causes a degree of muscle damage and inflammation for the runners. It takes several days to recover and during that period the runner's ability to conduct physical activity can be vastly inhibited.

"The phytochemicals, in particular, anthocyanins found in Montmorency cherries have anti-inflammatory and antioxidating properties, which the research has shown to be effective in helping exercisers to recover from strenuous physical activity."

Although it remains to be examined, Dr Howatson believes that the findings will not only benefit marathon runners but could also have serious implications in the treatment of people living with inflammatory diseases, such as arthritis.

He said: "If funding can be secured to embark on a further study, we can determine whether the use of tart cherry juice has implications for the management of some clinical pathologies that display high levels of inflammation and oxidative stress, such as rheumatoid arthritis and fibromyalgia.

"People are increasingly looking at natural remedies, or neutraceuticals, to treat their conditions, and scientific studies, such as the research into tart cherries, examine the potentially untapped treatments held in natural resources, that can provide adjunct therapy for the management of disease, which can help reduce negative symptoms and improve quality of life."

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Source:  Northumbria University and Howatson et al. Influence of tart cherry juice on indices of recovery following marathon running. Scandinavian Journal of Medicine and Science in Sports, 2009; DOI: 10.1111/j.1600-0838.2009.01005.x

Bad Air Affects Women More Than Men In Marathons

Poor air quality apparently affects the running times of women in marathons, according to a study by Virginia Tech civil and environmental engineer Linsey Marr.  Her findings come from a comprehensive study that evaluated marathon race results, weather data, and air pollutant concentrations in seven marathons over a period of eight to 28 years.

The top three male and female finishing times were compared with the course record and contrasted with air pollutant levels, taking high temperatures that were detrimental to performance into consideration.

Higher levels of particles in the air were associated with slower running times for women, while men were not significantly affected, Marr said. The difference may be due to the smaller size of women's tracheas, which makes it easier for certain particles to deposit there and possibly to cause irritation
"Although pollution levels in these marathons rarely exceeded national standards for air quality, performance was still affected," Marr said.

Her work, done in collaboration with Matthew Ely, an exercise physiologist at the U.S. Army Research Institute of Environmental Medicine, appears in the official journal of the American College of Sports Medicine, Medicine and Science in Sports & Exercise.

Her studies were conducted where major U.S. marathons are located, such as New York, Boston, and Los Angeles, where pollution tends to be highest. Although the person might not be significantly impacted by low-yet-still-acceptable air quality, marathoners are atypical because of their breathing patterns, she said.

"Previous research has shown that during a race, marathon runners inhale and exhale about the same volume of air as a sedentary person would over the course of two full days," Marr said. "Therefore, runners are exposed to much greater amounts of pollutants than under typical breathing conditions."
Particulate matter appeared to be the only performance-altering factor in air quality, with carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide levels not impacting race times.


Source: Virginia Tech and Marr, Linsey C.; Ely, Matthew R. Effect of Air Pollution on Marathon Running Performance :. Medicine & Science in Sports & Exercise, 2010; 42 (3): 585 DOI: 10.1249/MSS.0b013e3181b84a85

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