Muscles respond to overload by increasing in size and by becoming stronger. Resistance training in combination with good nutrition gives muscles the stimulus and building blocks they need to grow. Muscles grow by an increase in muscle fiber size rather than by hyperplasia where muscle fibers increase in number.
How easily an individual develops muscle is partially determined by genetics, but genetics aren’t destiny. With training and good nutrition, even a person who’s not genetically gifted can develop greater strength and an increase in muscle size in your upper and lower body. Some people simply have to work harder than others.
If you have small arms and shoulders, you might be mainly focused on getting upper body definition, whereas if you have scrawny legs, your goal might be to increase their size through resistance training. This raises the question – is one set of muscles easier to “grow” than the other?
Muscle Development: Upper Body versus Lower Body
When you first start a weight training program, you’ll likely see development in your upper body first. Several studies show hypertrophy happens to the upper body before the lower. On the other hand, women ultimately have more success building muscle in their thighs and glutes than they do their shoulders, biceps, and triceps. In addition, women start out with less muscle in their upper body relative to their lower body. So, developing biceps and triceps muscles that “pop” is a challenge for many women.
Strength disparities between men and women are greater in the upper body too. Research shows women have about 52% of the strength of men in their upper body and 66% in the lower body. Why the difference? Men have larger muscle fibers and more muscle mass in their upper body relative to women. Combine that with the fact that they have more testosterone to promote muscle growth than women. The fact that women have more of their lean body mass in their lower body also means most women don’t excel at pull-ups.
Not to say you can’t develop strong, defined muscles in your upper body or learn to do a pull-up, but it takes hard work and patience. You won’t achieve these goals training with light weights and high reps.
Building Upper Body Mass
If you have weak or undefined arms, how can you build more lean mass and definition? Use heavy resistance when you work your upper body, but work your lower body too! It sounds counterintuitive, but it works. When you work large muscle groups in your lower body with compound exercises, like squats, lunges, and deadlifts, it elicits more of an anabolic hormonal response than working small muscle groups like your biceps and triceps. You still have to train your upper body, but you’ll get better results when you focus a portion of your training on large muscle groups in your lower body. Doing so will boost growth hormone and testosterone release to help all of your muscles grow. In other words, if you want more defined biceps and triceps, don’t just focus on exercises that target those muscles.
When you work your upper body, be sure to include compound movements like bent-over rows, pull-ups and bench press that work more than one muscle group at the same time. When you do an upper body isolation exercise like biceps curls, sometimes combine it with a lower body movement like squats to increase the number of muscle groups you’re working. You’ll get more of an anabolic response and increase the calorie burn by doing this.
Another tip – begin your upper body routine with exercises that target the muscles in your back and chest first, the bigger ones. Then focus in on smaller muscles like your biceps and triceps. Smaller muscles fatigue more quickly. Once they’re fatigued, they won’t provide as much support when you work the larger muscle groups. Don’t forget to include push-ups as well as push-up variations. Push-ups are one of the most effective bodyweight exercises for building chest, shoulder and triceps definition.
Muscles in your upper body need to be maximally challenged to grow. In other words, they need to “feel the burn.” Give them additional stimulation they need with drop sets. Once you’ve reached the final rep in a set, drop the weight by 20% and continue until failure. Then drop the weight again and do another set, assuming your muscles aren’t spent.
Drop sets are effective because they recruit more muscle fibers. You’ll recruit a certain number of fibers during the first set and when you drop the weight for the second set, you recruit additional muscle fibers. Plus, drop sets increase the time your muscles are under tension. This is ideal for promoting the growth of stubborn muscles that are reluctant to grow.
Is Body Fat Blocking the View?
One reason you may think you lack definition is that you have a layer of body fat covering your arm muscles. Women tend to store fat in the hips, thighs and along the back of the arms, over the triceps muscles. If there’s a layer of fat covering your triceps, focus on the composition of your diet and add more high-intensity cardio to your exercise routine to burn fat. “Chicken wings” that flap, when you wave, may be a sign that your body fat percentage is too high for the muscle underneath to show. If you can pinch more than an inch when you grab the tissue between your elbow and shoulder, the underlying triceps muscle will be hard to see.
The Bottom Line?
When you first start training, you may notice changes to your upper body first, but all in all, you’ll probably have an easier time building lower body strength and lean mass. When training your upper body, don’t be afraid to use a heavy resistance. You can’t build arm definition with 5-pound weights. Vary your workouts so you’re stimulating the muscles in your upper body in different ways, and don’t underestimate the importance of working your lower body too. Working large muscles with compound exercises will give your upper body the hormonal boost it needs to grow.
References:
J. Strength Cond. Res. 24(10): 2857-2872. (2010)
Eur J Appl Physiol Occup Physiol. 1993;66(3):254-62.
Related Articles By Cathe:
Is a Weak Upper Back Making You Look and Feel Older?
Resistance Training: Getting Lagging Body Parts to Respond
5 Ways to Make Bodyweight Exercises More Effective
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