Runners often obsess about speed and mileage, but an aspect of fitness that is often overlooked is flexibility.
It could be due to ignorance or even confusion from conflicting views, but flexibility is key to becoming a better runner.
"Flexibility is important for runners," says Mr Justin Wee, senior physiotherapist at Tan Tock Seng Hospital's Sports Medicine and Surgery Clinic. "The body usually attempts to compensate (for inflexibility) by transmitting the load to other joints, ligaments or muscles, which may lead to other injuries."
Flexibility also correlates to stride length and step frequency, two factors in faster running.
To improve flexibility, stretching or repeated movement through a joint's range of motion will work to increase joint range and prevent loss of motion respectively, according to Ms A. Lynn Millar, a professor of physical therapy and a fellow of the American College of Sports Medicine (ACSM), in a column on the ACSM's website.
"Stretching increases the flexibility of muscles and tendons, facilitating resting length of muscles, which may be tight due to habitual postures we adopt or due to ageing," says Mr Wee.
When and how to stretch, however, is still a point of contention. For a long time, experts believed that static stretching - holding a position that produces a slight pull but not to the point of pain - increased flexibility and boosted performance.
But about a decade ago, studies found that it actually caused performances to suffer. Experts started advocating dynamic stretching - which takes the joint and muscles through the full range of motion, often repeatedly.
"Studies on static stretching right before sporting activities show that the rates of injuries are not reduced, while speed and power seem to reduce," says Mr Wee.
"Dynamic stretching also allows muscles to warm up by increasing blood flow and temperature, hence it is preferred."
However, he says that since long-distance running may not require a lot of power and speed, static stretches may not be detrimental to performance.
Keeping pre-exercise stretching routines to less than eight minutes may not significantly alter lower leg strength. In fact, it appears to temporarily improve joint range of motion, according to a study of moderately active individuals in the August 2008 issue of the ACSM journal Medicine & Science In Sports & Exercise.
"Our findings...suggest that for these muscles, there may be a 'threshold' of stretching between eight and 10 minutes that would be necessary to decrease muscle strength," said study author Joel T. Cramer, an ACSM fellow.
Offering another perspective on the stretching debate, a study presented at the 2011 annual meeting of the American Academy of Orthopaedic Surgeons found that stretching before a run neither prevents nor causes injury. However, runners who typically stretch should continue or they risk injury, say the researchers.
More than 2,700 runners who run 16km or more per week were involved in the study. About half were randomly assigned to a group that stretched their quadriceps, hamstrings and calves for three to five minutes just before running; the other half did not stretch.
"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," said Dr Daniel Pereles, study author and orthopaedic surgeon.
Mr Wee notes stretching is beneficial only when done to tight muscles - not every muscle would be tight. He says the muscles or areas typically tight in runners are: quadriceps, hamstrings, calves, hip flexors, iliotibial band, piriformis and lower back.
"Stretching should be stopped if symptoms of tingling or numbness are experienced. Stretching muscles that are not tight should be avoided as that may do more harm than good," says Mr Wee.
This story was first published in The Straits Times on July 20, 2013
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