This is aimed mostly at those of you who lift for girls (lol @ u).
First of all, let me remind you that if you care mostly about aesthetics, 70-80% of your results will come from being lean. There's just no way you can waddle around at 20% body fat and not look like the Pillsbury dough boy. That's the brutal honest truth. If you could, you wouldn't be on this forum. If you're above 15% body fat, put an end to that now. Leanness should be your #1 priority.
But let's assume you have that taken care of already.
If you're like most gymcels, you probably care most about your biceps, trapezius, pectorals, and abdominals. The first three are most readily apparent in a shirt while the latter is most impressive in a beach or pool scene. You probably don't care much if at all about your legs or most of your back, but here's a list of these muscle groups and explanations for why they're important.
Triceps
You may or may not consider these "show" muscles, but chances are you neglect them in favor of biceps. However, they're actually a larger muscle group, and will fill out your shirt sleeves much more effectively than biceps. They, especially the lateral head, make your arms more visually impressive from the side. Functionally, they are an antagonist for the biceps, and neglecting them too much can cause a strength imbalance, which can cause injury and posture issues. If your arms have a tendency to stay bent with your hands hanging out in front like some giant extinct lizard, chances are you have such an imbalance.
Rhomboids
These are your middle back muscles and get the most activation with any horizontal pulling motion. They work with the latissimus dorsi as antagonists to the pectorals; they help keep you stable during those pushing exercises you do for your show muscles. Visually, once they are properly developed, they help give a rippling effect to the back when it's lean. Underdevelopment of the back muscles will cause your shoulders to roll forward, giving you a hunchback appearance and contributing to nerd neck. Along with taking an inch or two off your height and lowering your overall aesthetic appeal, this can cause middle and upper back pain, and injury during your pressing movements.
Spinal erectors
This is your lower back and an antagonist to your abdominus recti, i.e. your six pack, i.e. your abs. This muscle group is responsible for protecting and stabilizing your spine; keeping your posture erect. They don't contribute much visually, at least not on the surface, so if you're purely chasing aesthetics, this is probably high on your list of muscle groups to neglect. However, especially if you train your abs directly, neglecting your spinal erectors can cause anterior pelvic tilt, which will give you a pot-bellied look even at a low body fat percentage, and cause lower back pain and injury, especially during exercises that put any sort of load on the spine, like the squat or the deadlift.
Hamstrings
There's a good chance you neglect legs in general, but if you don't, your routine is most likely quadricep-heavy. However, your hamstrings work as antagonists to your quadriceps, and neglecting them will limit your range of motion during compound leg exercises like the squat, increasing your risk for injury and limiting your ability to grow your glutes and quads. Neglecting your legs in general will make you very top-heavy, making it easy for you to get knocked down to the ground, and harder for you to carry yourself and external objects up any sort of incline. It also makes doing simple tasks like moving furniture more difficult; females will choose the man who can move furniture over the one who can't. Underdeveloped legs also ruins your physique's overall harmony, giving you an uncanny valley look and distracting from your developed upper body. There is absolutely no good reason not to train your legs.
First of all, let me remind you that if you care mostly about aesthetics, 70-80% of your results will come from being lean. There's just no way you can waddle around at 20% body fat and not look like the Pillsbury dough boy. That's the brutal honest truth. If you could, you wouldn't be on this forum. If you're above 15% body fat, put an end to that now. Leanness should be your #1 priority.
But let's assume you have that taken care of already.
If you're like most gymcels, you probably care most about your biceps, trapezius, pectorals, and abdominals. The first three are most readily apparent in a shirt while the latter is most impressive in a beach or pool scene. You probably don't care much if at all about your legs or most of your back, but here's a list of these muscle groups and explanations for why they're important.
Triceps
You may or may not consider these "show" muscles, but chances are you neglect them in favor of biceps. However, they're actually a larger muscle group, and will fill out your shirt sleeves much more effectively than biceps. They, especially the lateral head, make your arms more visually impressive from the side. Functionally, they are an antagonist for the biceps, and neglecting them too much can cause a strength imbalance, which can cause injury and posture issues. If your arms have a tendency to stay bent with your hands hanging out in front like some giant extinct lizard, chances are you have such an imbalance.
Rhomboids
These are your middle back muscles and get the most activation with any horizontal pulling motion. They work with the latissimus dorsi as antagonists to the pectorals; they help keep you stable during those pushing exercises you do for your show muscles. Visually, once they are properly developed, they help give a rippling effect to the back when it's lean. Underdevelopment of the back muscles will cause your shoulders to roll forward, giving you a hunchback appearance and contributing to nerd neck. Along with taking an inch or two off your height and lowering your overall aesthetic appeal, this can cause middle and upper back pain, and injury during your pressing movements.
Spinal erectors
This is your lower back and an antagonist to your abdominus recti, i.e. your six pack, i.e. your abs. This muscle group is responsible for protecting and stabilizing your spine; keeping your posture erect. They don't contribute much visually, at least not on the surface, so if you're purely chasing aesthetics, this is probably high on your list of muscle groups to neglect. However, especially if you train your abs directly, neglecting your spinal erectors can cause anterior pelvic tilt, which will give you a pot-bellied look even at a low body fat percentage, and cause lower back pain and injury, especially during exercises that put any sort of load on the spine, like the squat or the deadlift.
Hamstrings
There's a good chance you neglect legs in general, but if you don't, your routine is most likely quadricep-heavy. However, your hamstrings work as antagonists to your quadriceps, and neglecting them will limit your range of motion during compound leg exercises like the squat, increasing your risk for injury and limiting your ability to grow your glutes and quads. Neglecting your legs in general will make you very top-heavy, making it easy for you to get knocked down to the ground, and harder for you to carry yourself and external objects up any sort of incline. It also makes doing simple tasks like moving furniture more difficult; females will choose the man who can move furniture over the one who can't. Underdeveloped legs also ruins your physique's overall harmony, giving you an uncanny valley look and distracting from your developed upper body. There is absolutely no good reason not to train your legs.
