Some of the best body builders in the world have used body part splits, so it’s no wonder how they’ve become so popular. Hell, they’re still more popular in most commercial gyms than taking a movement based approach. There ain’t nothing wrong with a week long split, except that you may see yourself make far better progress training with more frequency.
If you’re taking the traditional body-part split approach, it’s likely that you’re putting a heavy bar on your back (squat) or in your hands (deadlift) once a week. If you have training partners using the same approach, y’all might be like these ladies:
Once-per week lower body training is fine, but you’ll see way better progress if you’re actually picking up heavy shit on a regular basis. Think about it this way: You’re probably training your upper body 2-4 times per week, but training your lower body once. The biggest muscles in your body are in your lower body, and they’ll have the greatest impact on metabolism and have the biggest potential to grow. Use your legs more, dammit!
There are some instances when body-part splits are necessary, but I prefer full-body routines or lower/upper splits for the vast majority of trainees. In fact, I’ve found that most people are comfortable training their glutes and upper back in almost every training session, 4-5 per week. Woahhh, Harold, that’s crazy talk!
When your training frequency is that high, your training volume drops, but if you’re doing it right, training intensity needn’t drop that much. You’re creating a more frequent stimulus for muscle growth, benefiting from an increased metabolism, and enjoying picking up heavy shit on a regular basis. It’s a win-win for everybody.
Balancing out training stressors can be tricky business, and that’s why I still like the strategy of Hard days and Easy Days. When it comes to training I think of these as high-load days and low-load days, where you can balance out activities with high neural load with those with less of a load. Perhaps on a Wednesday you sprint and squat and on Thursday you push the Prowler. It’s heavy and it ain’t easy, but it’s not as neurally demanding as maximal effort movement.
The one specific rule that I’ll give you is that I prefer lower body training days with a rest day before them, and upper body biased days after. This gives your neuromuscular system a day to get ready for what should be your heavier lifting, and still lets you train the upper body aggressively. For example, I know you want a great looking back:
You’ll get better back development from rocking out your deadlift than you will from doing inverted rows or reverse flies, so hit your heavier deadlifts when you’re fresh. The next day, you can include all of the chin-ups and dumbbell rows that your heart desires, including the volume that may be necessary for serious muscle growth.
Awesome. Pick up heavy shit, do it a few more times, and jackedness will ensue.
If you’re splitting lower body work among days, it may behoove you to group lower-back intensive work so that you don’t join the legion of those proclaiming, “Deadlifting hurt my back.” No it didn’t, deadlifting with poor posture hurt your back.
I’d greatly enjoy if you had a day that included more axial loading, think squat and deadlift, and a subsequent day with hip extension and unilateral work. Perhaps on your ‘hard’ day you include a deadlift and a front squat variation, and then on your ‘easy’ or ‘less-hard’ day you include a split squat or a glute bridge. There should be less mashy-mashy* on your joints, so you spend less time on the coach eating your pain and feelings ice cream and more time buying pants to fit around your gorgeous glutes. (Ice cream may help you on that quest.)
Look, I know that frequent leg training, or a big change to your training in general can be hard. A slow change is best for your body, and it’s important to focus on including more work when appropriate. Perhaps you’re adding kettlebell swings several times per week, or you’re doing extra lunges every day. Hell, take the stairs every chance you get. A little bit more frequently can go a long way for your physique.
If you have training partners, don’t blind-side them with your madness. Invite them to try it on themselves and see what it’s all about it. Sure, they may get mad, but…
Squat more. Deadlift more. Split Squat, Lunge, Reverse Lunge, Leg Curl, Kettlebell Swing, and have dance parties more. Your legs include the biggest muscles in your body, and you’re limiting your progress by training them once per week. Use your legs more!
*Mashy-mashy is definitely a technical term. Science, Bitch!
Harold Gibbons 
When I first started lifting, I only did legs once a week. I resisted the increase SO bad – I thought my legs were muscular enough (lolz) and wouldn’t be able to recover from two workouts per week (it used to take me 5 days to stop feeling sore). I did legs solidly twice a week for a year, before switching to my current approach: one full legs day, with three full body days. If you’d have told me two years ago that I’d be hitting legs 4 times a week, I’d have run away! But it does make so much more sense to think of your body as a complete machine and train it as such. At it happens, I rarely feel DOMS in my legs anymore – it doesn’t mean I’m working less, just that my body is recovering smarter 🙂
Tara, there is some cool evidence suggesting that women respond better to high-frequency training and that they have faster recovery time from DOMs. There’s also some cool (less scientific) evidence that anybody can train their legs that frequently if they simply acclimate to the training stress and modify what’s necessary so that it’s appropriate for them. Based on what we’re accustomed to, I don’t have a problem with somebody doing some sort of squat/lunge/swing/thrust variation every day of the week… provided that they recover appropriately and aren’t interfering with their primary training goals.
I’m so glad your’e on the high(er) frequency training train! It’s so much more fun, ain’t it?!