WHEN YOU’VE GOT your eyes on the prize—bigger muscles, a faster marathonimpressive strength, more efficient cycling, or improved athleticism in a sport—it’s easy to feel like you should only focus on the workouts proven to get you there. And therein lies the problem.

“It’s great to be spectacular in a specific activity, sport, or style of training, but we must also take into consideration that our bodies will eventually adapt and become super-efficient at whatever the primary movements involved are,” says Sean Alder, C.S.C.S., a personal trainer and team educator at SOLDIERFIT in Maryland. “We must also understand that the other parts or systems of the body are being neglected, increasing the likelihood for muscle imbalances from overuse or overtraining.”

An easy enough fix: Break out of your routine by cross-training once a week. The change-up will round out your ability without hurting your specialty, while also enhancing your overall results.

Pick one of these outside-your-wheelhouse workouts based on your goals, and get training.

Goal: Hypertrophy

When more mass is your aim, you’re probably combining heavy multi-joint lifts with isolation exercises to target specific muscles, and you’re likely doing two muscle groups a day, hitting each one once a week. What can happen, though, is that the muscles get less adept at working together in functional ways. Plus, because you’re aiming for gains, you may be short-shifting the cardio your heart and lungs crave for fear of burning off essential calories you’re consuming.

Cross-training workout: A fast-paced, high-rep, bodyweight functional circuit

Throwing together a few supersets such as stepups + pushups and alternating lateral lunges + pullups will work your muscles in synergy while getting your heart rate up and boosting your metabolism for improved mobility and lean muscle gains. Think of it as functional strength.

Goal: Running faster

With race day in sight, it’s hard to think you should be doing anything other than running for your workouts. And while long runs, recovery runs, tempo workouts, and speed and hill work are essential to your prep, exclusively running at the expense of other forms of training is an overuse injury waiting to happen.

Goal: Hypertrophy

When more mass is your aim, you’re probably combining heavy multi-joint lifts with isolation exercises to target specific muscles, and you’re likely doing two muscle groups a day, hitting each one once a week. What can happen, though, is that the muscles get less adept at working together in functional ways. Plus, because you’re aiming for gains, you may be short-shifting the cardio your heart and lungs crave for fear of burning off essential calories you’re consuming.

Cross-training workout: A fast-paced, high-rep, bodyweight functional circuit

Throwing together a few supersets such as stepups + pushups and alternating lateral lunges + pullups will work your muscles in synergy while getting your heart rate up and boosting your metabolism for improved mobility and lean muscle gains. Think of it as functional strength.

Goal: Running faster

With race day in sight, it’s hard to think you should be doing anything other than running for your workouts. And while long runs, recovery runs, tempo workouts, and speed and hill work are essential to your prep, exclusively running at the expense of other forms of training is an overuse injury waiting to happen.

Cross-training workout: Targeted strength

“We use both legs when we run, but we use them one at a time,” Alder says. “I recommend all runners do single-leg strength work, along with some upper body and core to help make them more efficient.”

Choose legs exercises such as reverse lunges, split squats, or single-leg box squats; upper-body row variations such as single-arm cable rows, bentover rows, and single-arm TRX rows plus pushup progressions (incline, flat, decline); and core work that focuses on anti-rotation and anti-flexion, such as planks (any type), and cable core presses.

Goal: Strength

Good news for you: “As long as there’s good variation in your programming, this is one of the best general ways to stay fit,” Alder says. That’s because strength training works both the muscles and the neuromuscular system responsible for recruiting them to work together to generate optimal force.

Still, Alder says, “we also must make sure we have proper range of motion as well as challenge other areas of our nervous system.”

Cross-training workout: Metabolic training

High-intensity intervals are the ticket for challenging coordination and boosting calorie burn to keep you strong and lean. Alder recommends selecting eight exercises—two for upper body, two for lower, two for core, and two conditioning—and doing a harder-core modified tabata: 23 seconds of work, seven seconds of rest for each move, twice through. Rest for about five minutes, then do the eight moves through once more. Example exercises: sled push, TRX rows, overhead medicine ball slams, and bear crawls.

Goal: Efficient cycling

Whether you’re a Tour de France contender or an indoor-cycling addict, you already know the benefits of purposeful pedaling, from cardio gains to major calorie burn with less joint impact than running. But between the repetitive motion and the not-so-awesome body positioning, you could be in for a world or hurt if long or intense rides are all you do.

Cross-training workout: Stretch sessions

To unfurl tight hips, rounded shoulders, and tight, well, everything, incorporating regular stretching is essential. That could mean a weekly yoga session or a regular date with a foam roller, targeting the hips, glutes, quads, calves, and middle back. Alder’s rolling recommendation: 10 to 15 minutes, three to five days a week.

Goal: Athletic prowess

From recreational soccer to pick-up basketball to MMA fighting or boxing, it’s easy enough to get focused on the games or specific skills needed to participate. While they rightly say that practice makes perfect, too many repetitive motions without support work to condition the entire body can lead to injury.

Cross-training workout: Speed, agility, and power training

Alder recommends general conditioning in the form of a metabolic workout (as he prescribed for strength trainers), but for athletes, he emphasizes plyometrics for power and agility. A workout that includes exercises like hurdles, box jumps, lateral skaters, ladder drills, suicide sprints (including side shuffles and reverse running), and band-resisted sprints all have a place in improving overall athleticism.