How early is “early”? According to the position stand of the National Strength and Conditioning Association (NSCA), “if a child is ready for participation in sport activities, then he or she is ready for some type of resistance training”. This can include children as young as 7 or 8 years of age. Some parents might think that a bit too early. Most, unfortunately, give the idea no thought at all.

For the vast majority of young athletes, their first exposure to resistance training comes during their freshman year in high school. Research shows that that may be a little too late – at least when it comes to injury prevention.

In looking at the graph above we can see that the incidence of anterior cruciate ligament (ACL) injuries spikes quite dramatically from 15-19 and more so in females. The reasons for this are quite varied and beyond the scope of this post but the take-home message is two-fold:

1. the liklihood of injury (especially ACL injury) is greatly reduced with a properly designed resistance training program
2. waiting too long to get started can be detrimental to your child’s health.

The idea that women who lift heavy weights will develop the same degree of muscularity as men violates basic physiology. Where this idea originated is unknown but I speculate that someone, somewhere, witnessed a drug-using female athlete lifting weights (most likely a bodybuilder) and drew their erroneous conclusion. It wasn’t long before the media popularized this as fact, coining such words as “toning” and “sculpting”, frightening women into a world of step aerobics and light-weight, high-repetition weight training.

Unfortunately, the female athlete is no less susceptible to this bias. Here is a quote from a recent interview with motocross athlete Sarah Whitmore: “…when I do lift weights, I use really light weights and high reps. But it stinks because I look kind of funny when I’m at the gym lifting five-pound weights…” Five-pound weights! How is someone going to get stronger using five-pound weights? I mention this not to single her out but to make the point of how pervasive this thinking has become. But, I digress.

Lost in all this misinformation is the FACT that the degree of hypertrophy (i.e. muscle growth) seen in female bodybuilders is possible only through the use of anabolic steroids (i.e. testosterone). Testosterone is one of the primary anabolic (i.e. growth promoting) hormones believed to be involved in the synthesis of new muscle tissue. Men have it in abundance – nearly ten times that of the average woman – which results in the development of greater muscle size and strength both inherently and with training. On average, untrained women are estimated to be 24% muscle (men are 40%) and have approximately half of the upper-, and approximately two-thirds of the lower-body strength of men. This disparity obviously places the female athlete at a tremendous disadvantage.

The beautiful thing is that, despite lower absolute strength levels, research has shown that women experience the same relative increases in strength following training. In other words, while women may never be as strong as their male weight-training counterparts, they typically see an identical percentage increase from training.

For example, let’s say that at the start of a training program Subject 1 (male) can bench press 150 pounds and Subject 2 (female) can bench press 75 pounds. Subject 1 has an absolute strength advantage twice that of Subject 2 (150 = 2 x 75). After several weeks of training, Subject 1 can now bench press 165 pounds and Subject 2 can now bench press 82.5 pounds. Subject 2 is still not as strong as Subject 1 but both experienced a 10% gain from training.

To allay your fears, these early increases in strength (first 6-8 weeks) are not accomplished by increasing muscle mass but rather by adaptations within the nervous system – primarily through improvements in coordination within and between muscles. In essence, trainees get better at recruiting existing muscle fiber. Only later does a strength increase arise from muscle hypertrophy and, even then, the onset and degree varies with the complexity of the exercises, the structure of the workouts and, as we’ve already discussed, gender.

Exercise Selection

Complex resistance exercises, such as those involving movement at more than one joint (i.e. the leg press), typically involve a longer neural adaptation phase compared with simpler single-joint exercises (i.e. the leg extension). This extended learning period can delay hypertrophy by several months. Furthermore, training three-dimensionally with free-weights (i.e the squat) demands even greater coordination between the stabilizing musculature and prime movers delaying the necessity for hypertrophy even further.

Workout Structure

An infinite number of strength-training programs can be designed by manipulating these variables:

• choice of exercises
• order of exercises
• number of sets
• number of repetitions
• resistance used (percentage of 1RM*)
• rest periods between sets and exercises

*1RM (one-repetition maximum) refers to the amount of weight that can be lifted only once for a given exercise.

Programs designed to induce muscle hypertrophy traditionally rely heavily on machines to isolate muscle groups, utilize more than one exercise to target the same muscle group in a given session, use 3 to 4 sets of 8 to 12 repetitions per exercise at approximately 60-75% 1RM, and prescribe short rest periods of one to two minutes between sets.

Programs designed for maximal strength, on the other hand, emphasize free-weights, focus on movements rather than muscles, utilize fewer exercises, use 5 to 10 sets of 1 to 5 repetitions at approximately 75-100% 1RM, with long rest periods of two to five minutes between sets.

By comparison, the typical weight training routines employed by most women usually include 2 to 3 sets of 15 to 20 repetitions at 50% 1RM or less. More often than not they include a mixture of free-weight and machine-based exercises often in circuit-type fashion. Circuits are a collection of exercises performed in succession with little or no rest between them. While not an ideal method for building strength, circuit training does a good job of developing muscular and cardiovascular endurance.

Taken together you can see that, contrary to popular belief, the program that maximizes muscle size does not necessarily employ the heaviest weights. Rather, hypertrophy-oriented programs maximize the amount of work done which, in turn, maximizes the amount of protein degraded (i.e. broken down) in a given workout. The greater the amount of protein broken down the greater the amount of protein resynthesized.

Protein Breakdown and Protein Synthesis

According to popular theory, what determines whether a muscle “grows” is the total amount of muscle that is broken down during a workout. This is a function of both the rate of protein breakdown and the total weight lifted. The rate of protein breakdown is determined by the load (i.e. the heavier the weight, the higher the rate of protein degradation) whereas, total weight lifted is calculated by multiplying sets x reps x weight.
 
Granted, while the rate of protein breakdown is high when training heavy, the total weight lifted is usually small due to the fewer number of repetitions performed. The opposite is true when using very light loads (>20 reps). The total weight lifted is high but, given the low resistance, the rate of protein breakdown is low. However, when training with moderate loads (8-12 reps) the rate of breakdown is average, the mechanical work is average, but taken together they result in a large amount of degraded protein. Given adequate rest and proper nutrition, such a program will yield the greatest amount of muscle gain.

Practical Application

Based on the above theory, we can now see why high-repetition resistance training minimizes the possibility of inducing muscle hypertrophy. Unfortunately, given the relatively light loads, these same programs also minimize gains in strength – a quality underdeveloped yet so vital to the female athlete.

So, what’s a girl to do?

• Concentrate on complex, multi-joint movements (i.e. squat, deadlift, bench press, pullups, etc.)
• Don’t be afraid to lift heavy (75-100% 1RM)
• Keep the circuits
• Ditch the machines

One of my preferred methods is to begin a training session with one or more compound movements, such as the deadlift, and finish with a full-body circuit. Use your imagination.

On a final note, studies have shown that combining both strength and endurance training in a given program diminishes the hypertrophy response observed when performing strength training alone. As most female athletes engage in some form of endurance training (as they should) you can feel safe knowing that your chances of getting big and bulky are slim.