In an effort to bring Racer X Online readers the best information available regarding MX fitness, postings on this website are open to anyone with a specific and proven expertise in the fitness field. I came across one such person as I was surfing the net one day for MX-related fitness articles. Normally, when I visit so-called MX fitness websites, I am greeted with the same old stuff: outdated articles, files that don’t load, poor writing skills, and testimonials about guys they trained in the early '90s. Steven Bubel’s website is none of that and a whole lot more, and according to the bio page, he has more degrees than a thermometer. That’s nothing new, but what is new and refreshing is that Steve is good at getting his thoughts from his head to the paper, a rare gift. His training expertise is based not only on real-world experience but, more importantly, on cutting-edge scientific research. Virtual Trainer contacted Steve and he agreed to work on a few articles with us. Look for more articles from Steve in the future, but until then, be sure and check out his website at www.mxconditioning.com. This is part two of his series on Training the Female Athlete.

Aubriana Dunn

In Part I of this series, we challenged the notion of the fat-burning zone, widely touted as the optimum exercise intensity for maximizing fat loss. It was firmly established that, not only is the prescription misleading, it's practically useless for individuals training for the extreme physical demands of motocross.

Although it has unnecessarily biased a generation of exercisers against intense cardiovascular exercise, given the scope of the research upon which it is based, it is understandable how such conclusions were drawn. Part II, on the other hand, looks at another popular myth that is based on nothing more than anecdote and unsubstantiated rumor.

Myth #2: Lifting heavy weights will make you big and bulky

The idea that women who lift heavy weights will develop the same degree of muscularity as men violates basic physiology. Still, it remains the most common fear among female trainees beginning a resistance training program. 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 words such as "toning" and "sculpting" and frightening women into an exercise 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 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.

Tania Satchwell

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 10 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 percent muscle (men are 40 percent) 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 percent 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

Tara Gieger

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 percent 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 percent 1RM, with long rest periods of two to five minutes between sets.

Sarah Whitmore

By comparison, the typical weight-training routines employed by most women usually include 2 to 3 sets of 15 to 20 repetitions at 50 percent 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 percent 1RM)

• Keep the circuits

• Ditch the machines

One of my preferred methods is to begin a training session with one or more compound movements 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 motocross 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.

Good luck with your training and as always, VT can be reached anytime at crytset@comcast.net. In addition, be sure and check out the Racer X archives section, your complete one-stop information zone for motocross fitness. Archives before November, 2005 can be found here.