Want to Get Stronger? Improve Your Mind-Muscle Connection.

This article originally appeared on Triathlete

Think back to your last lifting workout -- were you 100 percent focused on the task at hand, or were you contemplating what to make for dinner, stewing about work or daydreaming about a vacation? It's easy to let your mind wander while doing an activity you've done a thousand times before (more biceps curls -- zzz ...), but switching your brain to autopilot could be negatively impacting your results and may be making that elusive mind-muscle connection even harder to establish.

"Some fitness enthusiasts are skeptical about the mind-muscle connection and think it's bro-science quackery," explains kinesiologist Jessica Kasten, MS, NSCA-CSCS, CPT. "But it's been used for years by bodybuilders who swear by its effectiveness, and new research backs up their claims."

RELATED: Multisport Mobility Bootcamp

They're called "concentration curls" for a reason

Visualization is used by athletes of all levels, and the pros spend a lot of time mentally improving their performance by seeing the basketball go into the hoop, feeling their skis carve perfect turns and watching themselves cross the finish line first to win their 5K. A mind-muscle connection is a little different, however, and occurs when you actively think about and focus on feeling a target muscle contract and extend as you are actually doing a movement.

"The mind-muscle connection brings conscious awareness to a working bodypart or movement pattern that is free of distraction," says Matthew Zanis, DPT, physical therapist at the U.S. Olympic Performance Center. "For example, directing your attention to flexing and squeezing the biceps [in a curl] focuses your brain on that exact muscle, resulting in the body pumping more blood, making neural connections and releasing chemical mediators that set the stage for higher levels of performance in the form of strength, size and power."

his is also known as an "internal focus of attention" and is a beneficial skill if you're looking to develop size and strength. An external focus of attention, on the other hand, is task-oriented and involves cues such as driving through the floor with your heels or moving the weight as slowly as possible. These are more beneficial for motor control, performance and athleticism.

RELATED: Strength Training for Triathletes

Where focus goes, chemistry flows

So how does all this work, exactly? Imagine that your muscles and nerves speak different languages; a neurotransmitter called acetylcholine is the translator that helps them communicate. The better the communication, the more muscle fibers are recruited and the greater the muscular contraction. "Acetylcholine is released into the neuromuscular junction, a small space between a nerve and a muscle fiber, telling the muscles to turn on," Kasten says. "This molecular signaling ... contributes to greater muscle growth and adaptation."

"When the mind is connected well with the body, high levels of three important neurotransmitters are released: brain-derived neurotrophic factor, vascular endothelial growth factor and fibroblast growth factor," Zanis adds. "Together, these help develop bigger and more connected nerves and enhance neuroplasticity -- the ability of the brain to adapt, grow and evolve with new movement patterns -- making us more coordinated, stronger and better movers."

Honing in on your mind-muscle connection also can ingrain stronger muscle memory, which can work to your advantage if you're injured or are forced to be sedentary. "Consciously thinking about moving and engaging a target muscle can actually strengthen that muscle with no exercise at all," says Kasten, citing a study in the Journal of Neurophysiology in which participants wore surgical casts on their wrists for four weeks: Half were instructed to imagine flexing their wrists for 11 minutes per day, five times a week. The other half did nothing. When the casts were removed, the group who imagined flexing their muscles had double the strength of the control group.

A study published in the European Journal of Sport Science compared the effects of applying an internal (mind-muscle) versus an external focus of attention to resistance training on muscle adaptations such as hypertrophy and strength. After eight weeks, subjects in the internal focus group demonstrated significantly greater biceps growth -- 12.4 versus 6.9 percent -- than those with an external focus.

RELATED: Take Control of Your Triathlon Focus

Practice makes perfect

Improving your mind-muscle connection is all about repetition. Here are Kasten's tips to help you construct a strong connection, starting from ground zero.

  • Begin with a single-joint exercise. Practicing with a move such as a biceps curl or a leg extension makes it easier to identify and isolate a specific muscle on which you should focus.

  • Use a moderate load. Going too heavy automatically shifts your focus from internal to external, negating your potential benefits. Choose a weight that is 60 percent or less of your one-rep max, and complete between 12 and 20 reps for best results.

  • Perfect your form. Sloppy technique requires additional muscles to engage in order to perform an exercise, which ultimately distracts you from paying close attention to the movement of the target muscle.

  • Focus on each rep from start to finish. As you begin your lift, consciously activate and shorten the muscle on the way up (concentric), squeeze it hard at the top (isometric), then consciously feel it engage and resist on the extension as it lengthens (eccentric). Move slowly to best pinpoint your focus.

  • Limit your distractions. Put away your phone or pause your music so you can give your full attention to the exercise.

  • Flex between sets. Contracting and focusing on the target muscle helps improve the mind-muscle connection by allowing you to feel it and activate it even while you're not lifting. It also gives you a bit more of a pump and allows you to sneak a little more volume into your workout.

RELATED: Fitter & Faster Podcast: Everything Triathletes Need to Know About Strength Training

For exclusive access to all of our fitness, gear, adventure, and travel stories, plus discounts on trips, events, and gear, sign up for Outside+ today.