What's Better: "Leg Days" and "Arm Days" or Full-Body Workouts? These Experts Have the Answer

It's hard not to love a good full-body workout, but you might also hear about "leg days" and "arm days," workouts that focus on certain muscle groups. Those are called split workouts, because you "split" up your weekly workout routine to dedicate an entire day to each muscle group. If you're trying to build muscle, both are effective as long as you're doing resistance training a few times a week, eating plenty of protein, and increasing your weight as you get stronger.

More on all of that later. Figuring out which is more effective, full-body or split workouts, is the first question you want answered.

Full-Body Workouts vs. Split Workouts

Full-body workouts are the best choice for most people, said exercise physiologist Tom Holland, MS, who's also a fitness adviser for Bowflex. The major reasoning behind that? Time efficiency. You won't have to work out as often if you do full-body workouts, Tom told POPSUGAR. "When time is the number one reason people give for not exercising, this is the best approach," he explained. "For the vast majority of people, whose primary goals are to increase their functional strength, fix muscular weakness and imbalances, and build lean muscle, full-body workouts make the most sense," Tom said.

Another positive, according to Jeff Monaco, MS, CSCS, fitness education manager at Gold's Gym: full-body workouts often use a lot of compound movements, which are exercises that combine one or two moves to work multiple muscle groups. Think: squat to overhead press or plank with row. This trains your muscles to work together instead of in isolation, he told POPSUGAR, which helps you with functional fitness in your day-to-day life. Plus, he said, it burns more calories than just working one muscle group at a time.

There's also one important factor in building muscle, Tom told POPSUGAR, which is "the number of times per week that you work the same muscle groups." Ideally, that would be two to three times per week for each muscle group. It's another reason full-body workouts are a good choice: you're trying to build muscle in the fewest amount of workouts per week.

Split workouts are best for the more advanced, Tom said — that is, "those who plan on lifting weights almost every day per week, and sometimes twice daily." Jeff added that they're also great if you're looking to build up one muscle group or correct muscle imbalances. Still, he agreed, "Split workouts require more time and days in the gym to get the same benefit as the full-body workout. This generally means anywhere from four to six days per week in the gym." Not in the cards for you? (Me neither.) Then you'll likely see the best results from your full-body routines.

Eat Protein and Rest to Build Muscle

Of course, if muscle-building is your goal, a few other factors come into play. "You must ensure that you're getting in adequate amounts of daily protein," Tom said. Registered dietitian and ACSM-certified Jim White told POPSUGAR in a previous interview that a muscle-building diet should be about 25 percent protein, so try to ensure that a quarter of your plate at every meal (and snack) is devoted to protein sources like lean meat, fish, or tofu. To build muscle, Jim said your other macros should be 55 percent carbs and 20 percent fat.

Rest and recovery are also crucial, Jeff told POPSUGAR. "The body has to have enough rest and recovery to adapt to the stress that is put on it during a workout," he explained. He recommended waiting 48 hours between strength-training workouts if you're a beginner, and more if your muscles are sore. "You'll do more good letting those muscles rest another day than putting them through another tough workout when they're still recovering from the previous workout," he said.

How Often Should I Do Full-Body Workouts?

For beginners, Jeff recommended starting with two full-body strength workouts per week and gradually working up to three. "It's always advisable to start slow and gradually increase the amount of exercises, sets, and repetitions in a given workout over time so the body can adapt properly," he told POPSUGAR. That means you should do them on nonconsecutive days, Tom said, and keep them to around half an hour in length. On your non-strength-training days, get in some steady-state cardio like running, swimming, or cycling. You could also throw in one or two HIIT workouts, but avoid doing more than that, as HIIT can be particularly draining on your body and muscles. To get that essential balance, check out this four-week workout plan that'll help you build muscle and lose weight.

As you get stronger, it's essential that you keep bumping up your weight to continue building your muscles and avoid a strength-training plateau. You can start with bodyweight routines like this 20-minute full-body workout, including simple but effective moves like push-ups and squats. Then, gradually incorporate resistance through machines or dumbbells. Pick weights that are challenging you through your last few reps without losing form, Tom said. "When the last few repetitions become easy, it's time to increase the weight." Just starting? We've got you covered with this guide on choosing the right weight.

That might seem like a lot to keep in mind, so we'll make it a little simpler: unless you plan on lifting weights every day, go with full-body workouts. Make sure your diet has protein aplenty to fuel your workouts and help your muscles grow. Gradually increase the weight in your strength workouts with progressive overload, and do your best to strength train two or three times a week.

Now is the fun part: picking out your new, full-body routines. We've got lots: try this 30-minute weightlifting workout that's perfect for beginners; pump up your heart rate with this strength-building, HIIT-style video; or grab a pair of dumbbells for this fast and effective muscle-building routine. Let's get that burn on.