Weight Training Two Separate Body Parts in One Day

If you're in a hurry, the most time-efficient way of strength training is to work all your major muscle groups in one workout. But if you have more time and focus to spend on lifting weights, a two-body-parts-a-day workout plan offers some extra benefits.

To get stronger and bigger, your muscles need adequate rest between workouts. The science on this is solid and, as numerous organizations including Harvard Health Publishing explain, each muscle group needs at least 48 hours of rest time between strength-training workouts — more if you're still notably sore when the next workout rolls around. Your muscles get stronger not during your workouts, but in that between-workout rest and recovery period.

With that said, the Department of Health and Human Services physical activity guidelines for Americans note that for optimal health, you should strength-train all your major muscle groups at least twice a week. If you're training all your major muscle groups at once and giving yourself adequate rest time, that means no more than three days in the weight room during a typical week.

While that's a bummer for anyone who really loves the weight room, its real significance for your muscles is that if you have to subdivide your strength-training workouts to address all your major muscle groups, that limits the number of sets, and overall time under tension, you can do for each individual muscle group.

That, in turn, limits the muscles' potential for growth. As a systematic review published in the June 2017 issue of ‌Journal of Sports Sciences‌ notes, there's a clear dose-response relationship between the number of strength-training sets you do and increases in muscle mass for the body parts being worked. Or to put it another way, more sets means more muscle.

So if you're lifting for general health or pressed for time, doing full-body workouts twice a week is more than adequate. But if you're really serious about making gains in muscle strength, size or both, then adopting a two-muscles-a-day workout routine allows you to boost your gains by maximizing how many sets you do for a given muscle group.

Depending on exactly how you want to subdivide your "body parts," there are several ways you can craft a two-body-parts-a-day workout plan. One of the most common splits for working two body parts a day is the chest/back/legs division:

• Sunday: Rest
• Monday: Chest/triceps
• Tuesday: Back/biceps
• Wednesday: Legs/core
• Thursday: Chest/triceps
• Friday: Back/biceps
• Saturday: Legs/core

This type of two-muscles-a-day workout routine has a few key characteristics. You only get one real break from the weight room — on Sunday — but each muscle group has at least 72 hours of recovery time before you work it again.

Also, this type of split depends on grouping muscles that typically work together into each workout. There's a natural partnership between your chest and triceps, because the two engage powerfully together in most pushing/pressing exercises. And the same holds true for your back and biceps, which engage together on almost every pulling exercise.

But that's not the only way you can go about working out multiple muscle groups in a weight-training split. Another common split pairs push/pull muscles from the same general region of your body:

• Sunday: Rest
• Monday: Chest/back
• Tuesday: Triceps/biceps
• Wednesday: Legs/core
• Thursday: Chest/back
• Friday: Triceps/biceps
• Saturday: Legs/core

Did you notice that your shoulders don't get their own entry in either of the splits described? That's because they help out with the pushing/pulling motions of your chest, back and arms, so depending on your lifting goals, you might not need to dedicate specific exercises to your shoulders. However, if you're bodybuilding, you might want to add some shoulder-specific exercises on upper body days to help you meet your aesthetic goals.

Where to put your shoulders is fairly intuitive if you take the back/biceps and chest/triceps approach of the first split example; you'll put exercises that work the front or middle section of your deltoids on chest day, because those parts of your shoulders are so often involved with pressing exercises. Place your rear deltoids on back/biceps day, because they help with pulling exercises.

But if you're doing the second example split, there's a little more flexibility in interpreting exactly where your shoulders should go — there's a feasible argument for putting them with chest/back and another for putting them with arms (biceps/triceps). So go with whichever method feels best.

Regardless of whether you're a power-lifter, training for general health or lifting to help meet a specific sports goal, following a few basic weight training principles will help you avoid injury and get the most out of your workouts. These principles include:

‌Always warm up before your workouts.‌ This means doing 10 to 15 minutes of aerobic activity or dynamic warm-ups with the same body parts you plan to work in the weight room — or if you're doing your strength training on the same day as your cardio workouts, just do the cardio first so your body is already warm when you hit the weights.

‌Cool down after your workout.‌ Lifting weights is intense exertion; taking the time to cool down with at least another five or 10 minutes of gentle activity helps ease your body back into a state of rest.

‌Do post-workout stretches.‌ Don't fall into the stereotype of a muscle-bound lifter with no flexibility. Basic stretching can improve your range of motion during lifts and reduce your risk of injury. After your workout, when your muscles are still warm, is the perfect time to do this.

‌Choose sets and repetitions strategically.‌ How many sets and repetitions you do, and how much weight you lift, determines how your muscles will develop. Beginners should start with one to three sets of eight to 12 repetitions, as recommended by the Department of Health and Human Services.

For intermediate and advanced exercisers with a specific goal in mind, those numbers change. As the American College of Sports Medicine explains, if you're lifting for size you'll typically start with a weight that's 70 to 85 percent of your one-rep max or 1RM, and lift with the same one to three sets of eight to 12 reps a novice would use. Once you're more advanced, you can add additional sets (up to six) for each muscle group, and consider adding maximal lifts if they're appropriate.

For strength, the ACSM recommends the same sets and reps for novice and intermediate lifts, but using just 60 to 70 percent of your 1RM. As you become more advanced, you can build up to as many as six sets per muscle group, drop your repetitions to eight or below, and consider doing maximal lifts.