Training for Power and Explosion: Criterion 2: Speed of the Movement. (Strength Training).

BECAUSE OF THE ON-going debate between the traditional (ballistic) and non-traditional (non-ballistic) schools of strength training, I believe that a spirited discussion and exchange of ideas can be valuable in educating, enlightening, and improving the level of understanding and respect between the two groups.

I have established six criteria through which to compare the two viewpoints. In my first article last month, I focused on the Muscle Recruitment Principles. My second (current) criterion involves The Speed of Exercise Movement.

The one indisputable fact about speed and resistance is that the heavier the resistance, the slower the athlete's speed, and the lighter the resistance, the faster his speed.

Obviously, the lighter the resistance used, the fewer the total number of MUs that have to be recruited. Thus, in order to recruit and overload a significant number of MUs when using relatively light resistance, the athlete must effect a maximum number of repetitions.

On the opposite end of the continuum, the heavier the resistance used, the greater the total number of MUs that have to be recruited -- which can only result in a slower speed of movement.

This is where much of the confusion exists in power training. It is assumed that the slower movement will not enhance the power equation because being "fast" is the goal.

I hear this quite often: "If you move a resistance slow, you'll only become slow." This simply is not true. Using a heavier resistance slowly (which you have to do since it is heavier) calls for the use of a greater number of MUs. This can create greater overload in a safer manner, as compared to moving a lighter resistance faster (all other factors being equal).

If the speed of the exercise were the paramount factor in power development, the lighter the resistance, the better would be the exercise. A fast movement could be attained with virtually no resistance at all, such as using a wooden broomstick for cleans, snatches, bench presses, etc. Although this would assure a fast movement, it would involve less than maximum motor unit involvement. Recall that Type 1 MUs alone are capable of high-speed contractions when the resistance is light.

Question: How fast do you have to move in strength training for optimal power development? Various studies conclude that moving "fast" may not be the answer. For example:

* A study by Schmidtbleicher and Haralambie supported the superiority of heavy loads for the development of muscular power. Two groups were tested: a heavy resistance training group using sets of 1-3 reps with 90-100% of maximum strength +1 kilogram, and a low-load training group using 5 sets of 8 reps with 45% of maximum strength.

* Both groups produced similar improvements in maximum force output, but the heavy-load group improved more in the rate of force development (RFD) and in maximum rate of rise in electrical activity.

* A study by Napier investigated the effects of five weeks of strength training incorporating seven exercises on 20-meter sprinting speed. One group was required to train with sets of 8 reps at 40-50% of 1-RM (light) as fast as possible, while another group performed sets of 1-3 reps at 80% of 1-RM (heavy).

The group training with the heavy loads produced a significant improvement in the 20-meter sprint, which the light-fast training failed to do. Based on these results, the investigator questioned the apparent emphasis now being placed on lightload training by sprint coaches.

* In a study by Young and Bilby using a barbell half-squat exercise (knee angle at 90 degrees) a "fast" group was instructed to lower the resistance slowly, then explode upward as fast as possible. A "slow" group was instructed to move slowly in both the descent and ascent. Both groups improved significantly in RFD and vertical jump, with no significant difference between them in any training parameter. The testers' hypothesis that the "fast" group would show greater improvements in muscular power measures was not supported by the results.

* Kaneko and colleagues worked out a task that involved lifting a weight as quickly as possible among subjects who trained with a resistance of either 0, 30, 60, or 100% of maximum isometric strength.

The results demonstrated a classic resistance-specific training effect: The heavier the resistances, the greater the increases in isometric strength, and the lighter the resistance, the greater the velocity.

The 30% resistance produced the greatest increase in force and power over the entire concentric-velocity range and also resulted in the greatest increase in maximum mechanical power.

It was hypothesized that increases in power are specific to the training resistance and velocity used. This may be the rationale behind the recommendation of the 30% maximum voluntary contraction (MVC).

Point: Based on this hypothesis, it might be logical to ask: If 30% MVC is the recommendation for optimal power development, what would happen if we used either a slightly heavier or lighter resistance?

For example, would using 25% MVC increase the speed of movement, all other factors being equal? Would using 35% MVC produce a slower speed of movement? Where does one draw the line on optimal resistance load and speed of exercise moment?

Consider the following:

* According to Young, training with heavy loads is effective and may even be preferable to light loads for power development, provided the contractions are performed as explosively as possible.

* Sale and MacDougal suggest that whenever maximum effort is used, the motor unit activation patterns will be similar, regardless of the external speed movement.

* Contraction speed is dependent on the rate of tension development, not the speed of external movement. In fact, an isometric contraction (zero movement speed) can be performed fast or explosively with maximum voluntary effort.

* Examination of muscle activation patterns showed no significant difference between explosive isometric and fast ballistic concentric contractions. It may thus be hypothesized that the conscious effort to produce fast, explosive contractions may be a major stimulus in the development of muscular power.

Point: Whenever a heavier resistance is being moved with great effort and the lifter is attempting to "explode," the movement will naturally be slow, but more MUs will be activated.

At the same time, it will minimize the dangerous accelerative forces, making the activity much safer.

* Most of the evidence from human studies indicate that in high-velocity contractions, the recruitment order of slow and fast motor units is not reversed and there is no selective activation of fast motor units in high-speed activities.

Therefore, both fast and slow motor units are active during maximum high-resistance training, regardless of the speed of movement. Ergo, coaches should not feel compelled to use light loads exclusively for fast movements in an attempt to develop speed/strength.

* Kanehisa and Miyashita reported that a slow-training group improved power at a wide range of testing speeds, whereas a fast-training group showed no improvement at slow speeds. The greatest absolute improvement in power at any speed was obtained by the slow-training group.

* If strength is more trainable than speed, heavy-load training can be expected to be more effective than low-resistance methods that emphasize speed in the development of mechanical power.

* Isometric training has produced more significant increases in movement speed as well as superior gains in power development than light dynamic training.

* Hakkinen and others have showed that heavy strength training not only increased strength, but also significantly decreased the time to reach a force of 2000 newtons, increased jumping height and produced fast-twitch fiber hypertrophy.

* Heavy squat training has proved effective in improving vertical jumping ability.

* Tidow explained that even though both light and heavy-load training with explosive contractions may require a high degree of neural input, the high-resistance efforts must result in slower movements and, therefore, a longer duration of muscular tension. The near-maximum loadings compel the motor neurons to fire high-frequency impulses for comparatively long times. This may be a superior training stimulus for speed/strength development.

* Behm and Sale have presented evidence that it is the intention to move quickly which determines the velocity-specific response, and that heavy resistance training may be effective if the athlete attempts to move the resistance as quickly as possible.

Implications for the Traditional Group:

Traditionalists emphasize that Olympic lifts naturally produce relatively faster speeds of movement and increased momentum. Since momentum reduces muscular tension, it can limit total motor unit recruitment and also increase accelerative forces that can potentially create muscle and/or joint injury. The slower-moving exercises that the traditional trainers also employ, such as basic pressing, rowing and squatting will recruit a greater number of MUs in a safer manner.

Implications for the Non-Traditional Group:

The non-traditional group uses a slower, controlled speed to recruit the maximum number of MUs. Its rationale is to safely target the higher-threshold Type 2B MUs to reduce the momentum and potentially dangerous wear-and-tear forces.

As an exercise set nears the point of maximum reps and fatigue begins to take its toll, the trainee begins "exploding" to move the resistance, but it is moving under control. All "fast" training is performed outside the weight room in an un-loaded manner; that is, body-weight only drills and exercises.