Fitness expert challenges idea that strength training reduces flexibility

The popular notion that strength training with weights makes a person less flexible may not be true, according to a study conducted at UND.

The research shows that strength training over a full range of muscles and joints can improve flexibility more than conventional static stretching, said Jim Whitehead, associate professor of Physical Education, Exercise Science and Wellness and supervisor of the graduate student who conducted the study.

Former graduate student Sam Morton ran the study comparing stretching and strength training as part of his master’s thesis in kinesiology. Morton is now the wellness director at the Missouri Valley Family YMCA in Bismarck, N.D.

“The results are of very practical interest to people involved in fitness,” said Whitehead, who is the second author on the study, which has received a lot of national attention. “The old dogma was that if you do strength training, it’s going to tighten you up. Surprisingly, until now, nobody had done a study to back that up.”

“The results suggest that carefully constructed, full-range resistance training regimens can improve flexibility as well as—or perhaps better than—typical static stretching regimens,” Whitehead said.

He cautioned that the research results are preliminary and that additional research with more participants is needed to verify them. However, the study called into question some widely accepted ideas on flexibility and exercise.

“With strength training, flexibility gains were greater, and you’re going to get stronger as well as more flexible,” Whitehead said.

In addition to other research on stretching, the study added to the data suggesting that intense stretching before strength training is probably unnecessary and possibly counterproductive.

“In practical terms, it doesn’t mean that you probably don’t need to do static stretches in warm-ups,” Whitehead said. “Doing callisthenic-type exercises to get warm is likely a better choice before you strength train.”

Whitehead presented the results of Morton’s research in June during the American College of Sports Medicine’s 57th annual meeting in Baltimore. Out of thousands of presentations, it was one the organization chose to highlight. WebMD, a Swedish fitness magazine, and several other sources have published columns on the UND study.

When it comes to exercise, Whitehead said, more research is needed to separate myth from reality.

“Exercise science is a young area of applied science,” he said. “Stretching has been the neglected area of research. A large amount of information is based on what we think is correct and not scientific research.”

— Patrick Miller, writer/editor, University Relations, 777-5529, patrick.miller@und.edu.