Can you squat one day then spin the next, or should you skip legs? Here, the expert verdict.

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You may know it's not best to bench on back-to-back days, but how bad is it really to squat then spin? Or HIIT it hard every day? We turned to the experts for tips on just how aggressively you can stack your workout plan before it backfires. (See: Reasons You Actually Shouldn't Go to the Gym.)

Generally speaking, yes, it's fine to work out the same muscles on back-to-back days—as long as you're not going to failure on either of those says, says Lindsay Marie Ogden, a certified personal trainer and TEAM training manager at Life Time Athletic in Chanhassen, Minnesota. By "going to failure" she means getting to a point where you literally can't execute the move because your muscles are that tired. While this most commonly happens when you're strength training (you know the "I can't even do one more rep" feeling), your legs probably feel the same type of way after a weekly long run or an especially brutal HIIT class.

And, actually, there are some perks to training the same muscle group two days in a row, if you follow the right protocol: "It can facilitate recovery and lengthen the duration of protein synthesis—meaning it increases the window of time your body spending building muscle," says Ogden. The idea is to hit a muscle group hard one day with heavy weight and lower reps (3 to 8 range), then hit that same muscle group the next day with lighter weight, higher reps (8 to 12 range), she says. "The goal is to activate the cells that promote hypertrophy (a.k.a. muscle growth) and get nutrients to the muscles." But you don't have to hit the gym two days in a row to get those muscle-building benefits: "Proper sleep, stress management, and nutrition also aids in this," she says.

Wan the full run-down? Here's what you need to know about doing the same workouts and training the same muscles on back-to-back days.

Strength Training

The most important aspect here? Recovery. Toned triceps take time—and not just time in the gym.

"You don't get better during strength workouts—you get better between them," says Neal Pire, an exercise physiologist at HNH Fitness in Oradell, New Jersey. Muscles take a beating during training, then over a day or two they recuperate and rebuild stronger than before. Many variables affect how quickly your muscle fibers recover after weight training (i.e., your level of fitness, how much weight you're lifting, and how many reps you complete). But for the average Jane, Pire recommends training the same muscle group no more than twice a week, leaving at least 48 hours between each. So, no, you probably shouldn't strength train the same muscle group two days in a row.

Jen Hoehl, an exercise physiologist based in New York City, suggests hitting larger muscle groups (like chest, back, shoulders, quads, and hamstrings) with heavier weights earlier in the week. Then later in the week, when you're more likely to feel tired, work on smaller muscle groups (like arms and calves) with lighter weights and higher reps. Doing this allows you to be fresh when you're going hard and heavy, while building endurance later. (Related: How Often Should You Do Heavy Weight Lifting Workouts?)


Doing cardio—whether it's running or spinning—mutiple days in a row usually isn't that risky, as long as you're not going zero to 60 with your training intensity and frequency, according to Jacqueline Crockford, an exercise physiologist at the American Council on Exercise, as previously reported in Is It Bad to Do the Same Workout Every Day?. Slowly increase your training and listen to your body to avoid any overuse injuries.

But is it bad to lift those three-pound dumbbells in spin class every day? Not really—since those spin and barre class exercises aren't exactly considered strength training.

"Spinning and the light upper-body dumbbells some classes call for don't add enough resistance to break down the muscle—the high-rep, low-weight movements are designed to add some variety and increase intensity and heart rate," says Hoehl. So feel free to spin daily. But if you want to truly get buff biceps, unclip from those pedals and try barbell weight training at least twice a week.

HIIT Training

"High-intensity, total-body workouts (like burpees) don't provide the same muscular stress as classic strength workouts, so it's OK to do them on back-to-back days," says Pire. However, "if you’re doing compound or multi-joint movements, you’re hitting multiple muscles groups at one time—which can also be taxing and require more recovery," says Ogden.

That's why, if you do too much HIIT training, you may experience overtraining syndrome. To prevent that, rotate HIIT days and strength days—with low-intensity active recovery days, of course. "A mix of HIIT and heavy weight lifting will help you look lean," says Hoehl. (See: Here's What a Week of Perfectly Balanced Workouts Looks Like.)

Abs Workouts

"Ab work is generally about conditioning, or endurance, more than strength, so feel free to tack it on to your workouts daily," says Pire. Just make sure to mix things up. "Your core is always keeping you stable, so ab muscle recovery happens fast," says Hoehl. Abs quickly acclimate to stress, so do a different abs exercise every day, he adds.

The One Rule to Follow—No Matter What Kind of Workout

Overworking your body or hammering one muscle group, in particular, will likely sacrifice your form and put you at a higher risk of injury. "If you’re training total body day after day or trying to work your glutes, for example, each session, it can become difficult to manage the intensity and focus," says Ogden. "That, in turn, will cause more stress, calling for more recovery time." (See: How to Work Out Less and Get Better Results.)

That's why both Pire and Ogden agree: Regardless of your workout or which muscle group you're training, there's one rule of thumb: Let your body be your guide. "If you're too sore from the previous weight workout, push today's back and do cardio instead," says Pire.