Stretching has gone hand in hand with exercise for years, but one influential sports figure isn’t a fan. Bob Wylie, offensive line coach for the Cleveland Browns and a breakout star of HBO’s Hard Knocks, has made it very clear on the show that he thinks stretching is “overrated.”

“Did you know in World War I and World War II, all those guys that fought in that war, they did pushups, jumping jacks, sit-ups, [climbed up] and ran, but none of this fancy s***, and they won two world wars, two world wars by doing jumping jacks, pushups and sit-ups, two world wars,” he said in a recent episode. “You think they were worried when they were running across Normandy about f***ing stretching? Are you kidding me? … Give me my rubber band to stretch so I can run across that f***ing beach. You’ve got to be kidding me.”

In another scene, Wylie told a fellow staffer, “I’d rather watch a plant grow than stretch.”

People are obsessing over Wylie’s comments online:

In another scene, Wylie told a fellow staffer, “I’d rather watch a plant grow than stretch.”

Clearly, Wylie has some strong opinions when it comes to stretching, and, while they’re intense, they’re not out of left field. Stretching has been viewed as somewhat controversial in athletic circles thanks to mixed research on its effectiveness. One meta-analysis published in the journal Research in Sports Medicine in 2017 found that stretching poses “no significant advantage” to endurance runners and that it can’t help improve performance or reduce the number of injuries a person suffers. Another review and meta-analysis published in the British Journal of Sports Medicine in 2014 found that stretching had no effect on whether people got injured while working out.

However, other research has found that stretching can help range of motion in elderly people and people who are moderately flexible are less likely to become injured than those who are either highly flexible or not flexible at all.

“It’s hard to make a blanket statement that stretching is good or bad,” Albert Matheny of SoHo Strength Lab and Promix Nutrition, tells Yahoo Lifestyle. “Context matters.”

There are different types of stretching, like static stretching (where you hold a stretch in a certain challenging position for several seconds), dynamic stretching (which are active movements of a muscle that cause a stretch but aren’t held in place), and proprioceptive neuromuscular facilitation (PNF) stretching, which involves stretching and contracting a particular muscle group that’s being targeted, Matheny explains. And again, context matters. “Stretching is important and can be beneficial if done correctly, and for the right reasons,” Jim Pivarnik, a professor of kinesiology at Michigan State University, tells Yahoo Lifestyle.

In the short term, the right stretching can warm up a person’s muscles; in the long term, it can increase their range of motion around a joint, Pivarnik explains. But, he adds, there’s “very little research supporting a significant increase in performance” due to stretching.

Ultimately, the type of stretching someone does in a particular situation matters. In the context of football, dynamic stretches like high knees and other motion-based warmups are likely to be the most effective, Matheny says. “For runners, I would suggest doing a bit of a walk first, then a bit of a stretch, then the run, then walk to cool down, followed by a light stretch,” Pivarnik says.

But if you’re planning to do a sprint workout or heavy lifting, you’ll really want to avoid static stretching. “Before activities, especially power-based activities, static stretching is not helpful and may even be harmful,” Matheny says.

Whether stretching can be a benefit and the type of stretching you need really depends on the activity you’re planning to do. “It needs to be specific to the sport, activity, and timing,” Matheny says. “But in most cases, you’ll get better and more specific benefit from doing a full warmup.”