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“If you’re young, if you’ve never hurt your back or injured a joint, there is what we call a feed-forward mechanism, an automatic contraction of muscles that are really close to joints and stabilize their position so you can follow through and do a motion,” Saliba explained.

Part of the feed-forward mechanism is the body’s setting of core muscles and the diaphragm in preparation for movement. That may result in an often involuntary, audible expression.

In other words, you groan.

“Your body is actually doing what it needs to do to create a muscle contraction to stabilize all the joints in your spine so that when you bend over or pick something up, you can do it without hurting yourself,” Saliba said.

The groan is even heard among the active and healthy, she said.

“At a tennis match, you hear the player grunt in a serve or volley, or the yell – the ‘kiai’ – in taekwondo and martial arts,” Saliba said. “That’s designed to create a solid cylinder, an isometric contraction of all the muscles in your core.”

You may grunt on occasion in your 20s. You may groan more often in your 30s. By the time you reach middle age, the sound you emit during exertion can become almost a habit. That’s because the core muscles involved in the feed-forward mechanism lose strength and tone due to life’s variety of injuries, strains and disuse over time.

Susan Saliba, a professor and co-director of the Education School’s Exercise and Sports Injury Laboratory, says that physical therapy targeting weak core muscles can help quiet the middle-aged groan. (Photo by Lathan Goumas, University Communications)

“Say, for instance, you’ve had an injury. Or maybe it’s just living life, because honestly, that’s what it comes down to. There are a lot of things that we’ve done during our lives that could account for weaker muscles or injuries, especially in your spine,” Saliba said.

But wait. There’s hope. Physical therapy can help quiet the groan.

“The normal method to work on that is to reteach those muscles how to contract before bending over,” Saliba said. “That’s what a physical therapist is going to do; spend time retraining those muscles to work in synchrony with the entire movement.”

Training the deeper muscles to stabilize the spine, as you did in your teens, can help you bend over and continue breathing while making nary a sound. Ultrasound imaging, biofeedback and exercises can help reinstate the “normal, pre-conditioning” of muscles and the feed-forward mechanism.

“And then, when we advance your exercises, we’re teaching you to breathe on top of it, so you can maintain that contraction without having to use all of the muscles that create that exhale,” Saliba said.

With therapy, you can repulse the middle-aged groan. But once you start strengthening exercises, you should not stop, lest it return.

“The biggest risk factor for any musculoskeletal injury is the previous injury of that particular joint,” Saliba said. “If you’ve sprained your ankle, you have a higher chance of spraining your ankle than people who have never sprained their ankle. You’re trying to retrain the muscles in your brain and your entire neuromuscular system, but it’s a lifelong type of thing.

“You want to maintain that strength, and if you don’t use it, you’re going to lose it,” she said. “It’s like brushing your teeth. You don’t just do it once, and then you’re done. You have to do it every day.”