Quality Strength for Human Athletic Performance
- 02-17-2003, 07:38 PM
Quality Strength for Human Athletic Performance
by Charles Staley
December 1, 1998 (Volume 1, Number 9)
Although most athletic skills and events depend upon a variety of physical qualities, speed strength (also called power) certainly rates among the most important. Whenever you need to accelerate yourself (as in running, cycling, swimming, skating, or skiing), an external object (such as a ball, a barbell, a javelin, or another person), or both (such as pushing a bobsled or driving through an opposing lineman in football), your ability to generate force with speed will be a primary determinant of your success.
As the duration of the event or skill becomes reduced, the need for speed strength (I'll abbreviate it as "SS" from this point on) increases. However, even triathletes rely heavily upon explosive strength as they sprint to the finish line. It's not a matter of whether or not you need to develop SS, but to what degree you need to prioritize it in your training.
SS is also a vital quality during emergency situations, such as when it becomes necessary to quickly dodge a car when walking across the street, or duck to avoid being hit by a stray ball. In fact, SS is the bodyís preferred method of force generationó the last time you had to lift a heavy object from the floor to a high shelf, did you accelerate the load to make the task easier, or did you make a concerted effort to lift the object with a constant speed?!
For bodybuilders, SS training methods are immensely valuable for their ability to improve intramuscular coordination (the ability to recruit high threshold motor units), which has significant payoffs during later training phases utilizing lower intensity loads. In other words, a two week training phase emphasizing accelerative training techniques will potentiate the ability to lift greater loads during a subsequent phase utilizing more "traditional" bodybuilding lifting technique (i.e., constant tension, avoiding joint lock-outs, etc).
Strength: the Multi-faceted Motor Quality
Of course, SS is simply one expression of force output, and strength as a bio-motor ability has many expressions. The following list briefly describes the types of strength available to athletes:
Absolute Strength (maximal strength)
Absolute strength is defined as the amount of musculoskeletal force you can generate for one all-out effort, irrespective of time or bodyweight.
This form of strength can be demonstrated or tested in the weight room during the performance of a maximal, single repetition lift. While only powerlifters need to maximize and demonstrate this type of strength in competition, all athletes need to develop absolute strength as a foundation for other bio-motor abilities such as SS, strength endurance, agility, and others.1 For this reason, absolute strength is brought to high levels in the preparatory period, and then "converted" to more event-specific forms of strength later in the macrocycle. Absolute strength can be displayed through three types of muscular actions:
1) Concentric Strength: the ability to overcome a resistance through muscular contraction, i.e., the muscle shortens as it develops tension.
2) Eccentric Strength: displayed when a muscle lengthens as it yields to a resistance. Eccentric strength is normally 30-50% greater than concentric strength, meaning that you can lower significantly more weight in good control than you can actually lift. This may be the result of increased intra-muscular friction (a concept not yet validated by science) during the eccentric portion of a lift. In eccentric muscular encounters with external resistances, there are two possible scenarios which can occur:2
a) The resistance encountered is less than oneís maximal isometric strength. In weight training applications, this applies to any load less than 1RM.
b) The resistance encountered is more than oneís maximal isometric strength. In weight training applications, this applies to any load more than 1RM (commonly called "eccentric training").
3) Static Strength: muscular contraction which does not cause external movement of the resistance, either because the athlete has chosen to produce exactly enough force to prevent the resistance from lowering, but not enough to lift it; or because the external resistance is immovable. Static strength is also observed during the momentary pause between the eccentric and concentric portions of a movement.
Absolute Strength Forms the Basis for Speed Strength
Despite the current preoccupation with plyometrics, specialized shoes, and the like, improving absolute strength remains the most efficient way to improve SS.3
In fact, Romanian strength & periodization specialist Tudor Bompa suggests that "No visible increments of power are possible without clear gains in maximal (absolute) strength."4
To appreciate the importance of absolute strength on SS, imagine a rocket weighing 1000 pounds, with an engine capable of 1200 pounds of thrust.
This rocket has only 200 pounds of reserve force to propel itself. The same rocket, when equipped with an engine rated at 3000 pounds of thrust, will have 2000 pounds of reserve thrust that can be used for propulsion.
Now back to the gym: a 200 pound man capable of squatting 250 pounds for a single rep will have a mere 50 pounds of reserve strength available to propel his body upward during a vertical jump. Contrast this with a 200 pound elite-class powerlifter capable of squatting 600 pounds. Now weíve got 400 pounds of strength reserve available, and all things being equal, will have a vastly superior vertical jump compared to the novice squatter.
Whereas absolute strength refers to strength irrespective of bodyweight, relative strength is a term used to denote an athlete's strength per unit of bodyweight (his or her "pound for pound strength"). It can be used as a modifier for other categories of strength, such as speed strength or strength endurance. So, if two athletes of different bodyweights can power clean (a display of SS) 275 pounds, they have equal speed strength for that lift, but the lighter athlete has greater relative speed strength.
Athletes who compete in weight-class events depend heavily on relative strength, as do athletes who must overcome their bodyweight to accomplish a motor task (i.e., long jump, sprinting, etc.). Further, sports which have aesthetic requirements (figure skating, gymnastics, etc.) demand the development of strength without a commensurate gain in bodyweight.
As a side note, in the World of sport, lighter athletes have better relative strength than heavier athletes, whereas the heavier athletes get the nod for absolute strength. In Olympic weightlifting for example, elite-level athletes in light weight classes have lifted triple-bodyweight from the floor to an overhead position. World-class competitors in the superheavyweight division are unable to lift even double-bodyweight; however, the absolute poundages they lift are far greater than that of their lighter peers.
Since strength training targets the neuro-muscular system, strength can be developed through two very different meansó by applying stress either to the muscular or to the neural aspect of the system. The former method is usually accomplished through the application of "bodybuilding" methods (repetitions between 6-12 to exhaustion, using continuous tension techniques), and results in strength gains through an increase in muscle cross-section. The latter method employs higher intensity training (repetitions between 1 and 5 using accelerative technique and full recoveries between sets), and increases in strength are the result of the body's improved ability to recruit more of its existing motor unit pool.
Contrary to conventional wisdom, athletes who depend upon relative strength or SS should not completely avoid bodybuilding methods, which, when used judiciously, can be used to facilitate recovery between periods of intensive nervous system training. And, as you might expect, I strongly recommend that bodybuilders keep an open mind with regards to SS methods as well.
Now to the topic du jour: SS is defined as work divided by time, where work is defined as force x distance. Therefore, SS is defined as force x distance, divided by time. SS is characterized by three distinct components:
Starting strength: Defined as the ability to recruit as many motor units (MUís) as possible instantaneously at the start of a movement.4 Common examples include the lunge in fencing, coming off the line in football, and the start in short sprints.
Explosive strength: This quality refers to acceleration or rate of force development. In other words, once youíve recruited a maximal number of MUís, how long can you keep them recruited? In his seminars, Dr Fred Hatfield, co-founder of the International Sports Sciences Association and the first man to officially squat 1000 pounds, compares starting strength to the flash bulb of a camera, and explosive strength as a flash that stays on and becomes brighter and brighter the longer it stays on.
With regards to above distinctions, different sporting skills and events can be classified as either starting or explosive strength events, depending on the relative proportion of speed and strength required. The javelin event in track and field would be classified as a starting strength event because the implement is very light, which permits the athlete to impart a great degree of speed during the throw. Conversely, the shot is relatively heavy, which means that less speed can be achieved. This makes the shot put an explosive strength event. Thus, it logically follows that starting strength athletes emphasize relatively lighter weightloads in strength training than do explosive strength athletes.
Stretch Shortening Cycle (Reactive Strength): Although traditionally classified as a component of SS, reactive strength is more accurately thought of as an independent motor quality.5 It involves the storage of potential kinetic energy during the eccentric portion of a movement, which is then converted to actual kinetic energy during the subsequent concentric phaseó much like stretching and releasing an elastic band.
During many skills (jumping rope, for example), the working muscles attempt to maintain static contraction, with force output being provided by the storing and release of elastic energy through the tendons. Since static muscular activity requires less energy than dynamic muscular activity, reactive strength is an extremely energy-efficient way of movingó you can do more work with less calories. This is why novice exercisers can always be seen doing exercises in the easiest possible manner, using quick, choppy movements, whether itís on the bench press or the stair climber. Reactive strength is also the method of choice when someone who is tired and/or weak gets up out of a chair: instead of simply standing up, they will actually lean back first, and then quickly reverse this action, springing out of the chair. If you ask someone to rise out of a chair using pure concentric movement, it looks very unusual. To appreciate the effect of reactive strength on force production, perform a vertical jump in a normal manner, where you first crouch, and then rapidly switch and jump upwards as explosively as possible. Next, crouch, but pause for five seconds (this pause will dissipate most if not all of the stored potential kinetic energy), and then jump upward. You'll find that the jump where the crouch (or eccentric phase) was IMMEDIATELY followed by the jump results in a more successful attempt. The key to preserving as much potential kinetic energy as possible is to switch from eccentric to concentric as rapidly as possible.
How Muscles Produce Force
1) MU recruitment (intramuscular coordination): All muscle fibers are one component of what physiologists call "motor units." A MU is defined as a motor neuron (or nerve cell) and all the muscle fibers it innervates or "recruits." Without going into excruciating detail, there are several essential bits of information that athletes and coaches should understand about the functioning of MUís:
All the fibers of a MU tend to have the same characteristics.5 When all the fibers are type II, the motor unit is said to be a high threshold or "fast" MU. If the fibers are Type I, it is a low threshold or "slow" MU. See Table 1 for an in-depth description of fiber types.
The all or none principle: When an action potential is sent from the cell body to the muscle fibers, one of two events will occur. If the action potential is strong enough, all the fibers of that motor unit will contract maximally. If the action potential is not strong enough, nothing will happen. In a nutshell, muscle fibers either contract all the way, or not at all. When the body needs to apply more force, it simply recruits more MUís. Generally, untrained people have limited ability to recruit high threshold MUís because they are unfamiliar with high-tension efforts.
The size principle: MUís are recruited in order of sizeó small to large. This explains why we can use the muscle to pick up something light (a pencil) or heavy (a dumbbell). As resistance increases, the body recruits more MUís.
2) Intermuscular coordination: the ability of different muscles to cooperate during the performance of a motor task. Muscles can function in several different ways depending on the task at hand. The most fundamental roles that muscles assume are listed below:
Prime Mover: The primary muscle responsible for a movement around a joint at any given point in time. For example, during the bench press exercise, the pectoralis major is the biggest and strongest muscle involved, and as such it provides the most force during most of the exercise.
Synergist: A synergist is a muscle which dynamically assists the prime mover. Going back to the bench press example, the front deltoid muscle and triceps would be considered synergists in this exercise.
Stabilizer: Stabilizers are muscles which anchor or stabilize one part of the body (through static activity), allowing another part to move. In other words, they assist the prime mover and synergists through static or "isometric" muscular contraction. The stabilizer role of muscles can be trained with exercises conducted in an unstable environment, which might involve dumbbells, Swiss balls, wobble boards, or other devices designed for this purpose.
For clarification, be aware that prime movers, synergists, and stabilizers are not different types of musclesó they are ways in which muscles perform. A single muscle might be a prime mover in one situation, and a stabilizer in another situation.
Agonist/antagonist relationship: (Not to be confused with the roles described above). For every muscle in the body, there is another muscle capable of resisting its force. If this were not the case, controlled human movement would not be possible. When you throw a punch for example, your tricep is one of the primary agonists (you can distinguish between these two terms by remembering that "the agonist is the one inagony"), as it is the muscle which extends the elbow. The primary antagonist during punching is the biceps, which acts eccentrically to control the extension force created by the triceps so that you donít hyper-extend your elbow at the end of the movement.
3) Rate Coding: The nervous system can vary the strength of muscular contraction not only by varying the number of MUís recruited, but also by varying the firing rate of each MU, called rate coding. The tension that a MU develops in response to a single action potential from the nervous system is called a "twitch." As the stimulus from the nervous system becomes stronger and stronger, the twitches per millisecond become more and more frequent until they begin to overlap, causing greater amounts of tension to be generated by the muscle fiber. The mechanism behind rate coding is very similar to the way in which increased vibrational frequency of a sound increases itís pitch.
As an example, a muscle comprised of 100 MUís would have 100 graded increments available to it. In addition, each MU can vary itís force output over about a 10-fold range by varying its firing rate (e.g., from 10 to 50 impulses per second). For any set of conditions, the force of contraction is maximal when all MUís have been recruited and all are firing at the optimal rate for force production.
The size of a given muscle may in part determines the relative role of rate coding to total muscular force development.6
In small muscles, most MUís are recruited at a level of force less than 50% of maximal force capacity. Forces requiring greater tensions are generated primarily through rate coding. In large proximal muscles (such as the pectoralis and lats), the recruitment of additional MUs appears to be the main mechanism for increasing force development up to 80% of absolute strength and even higher. In the force range between 80% and 100% of absolute strength, force is increased almost exclusively by intensification of the MU firing rate.
Training Methods for Speed Strength
Since SS is comprised of speed and strength, it becomes important to consider what can be done to improve these two qualities independently, since an improvement in either aspect will improve the whole.
"Traditional" Strength Training
Since speed is primarily a genetically-inherited characteristic of the nervous system, it responds poorly to training, as compared to strength, which is perhaps the easiest motor quality to improve. For this reason, and because safer methods should be considered before more risky ones, the starting point for all athletes who wish to promote SS is traditional strength training. (I use the term "traditional" to refer to common weight room exercises performed in a traditional bodybuilding manner using a variety of intensities).
Compensatory Acceleration Training (CAT)
CAT training is a distinct form of accelerative lifting coined by Dr. Fred Hatfield. It refers to compensatorily speeding up your movement in such a way that improved leverages are compensated for. For example, when ascending out of a deep squat position, mechanical leverage begins to improve once you pass the "sticking point." This improving leverage reduces the tension on the working muscles, and in turn, the training stimulus is compromised. Deliberately accelerating through this movement path serves to increase muscular tensions. CAT technique takes time to master, because the acceleration must continue past the sticking point, yet end before the antagonist muscles are triggered into decelerating the movement in an effort to prevent joint hyperextension or loss of control. This "braking" action would be detrimental to normal coordination patterns involved with common athletic skills such as hitting, throwing, jumping, and kicking.
William Kraemer, perhaps this countryís most respected and prolific strength researcher, uses the term "ballistic training" to describe movements that are "accelerative, of high velocity, and with projection into free space."7 Ballistic training involves plyometrics, modified Olympic lifting, jumping, throwing, and striking movements (such as punching or kicking a heavy bag).
Kraemer argues that, in traditional barbell training, a significant portion of the movement path (specifically, the end of the concentric phase) is spent decelerating the baró a protective measure assumed by the antagonists to maintain joint integrity (in upper body movements such as bench pressing), or to prevent the athlete from leaving the ground in exercises such as the squat. If Kraemerís contention is correct, one would choose to gradually reduce the volume of traditional barbell drills as the training cycle progresses, in favor of ballistic exercises which lack this deceleration phase, making them easier to learn and much more coordination-specific for most athletes.
The modified Olympic lifts
The sport of Olympic weightlifting (sometimes called "weightlifting") contests two separate lifts: the snatch, where the barbell is grasped with a wide grip, and explosively pulled to an overhead position in a single movement; and the clean and jerk, where the barbell is grasped with a narrower grip, "cleaned" to the shoulders, and finally "jerked" to an overhead position.
Competitive lifters reach very deep squat positions as they struggle to get under ponderous weights prior to achieving the overhead position. But when slightly lighter weights are used, the lifter can manage to get under the weight without going below parallel, meaning that the top of the thighs never goes past the point of being parallel to the floor. When a lifter can accomplish this, the lift is called a power clean (or power snatch). The term "power" indicates that the load was not maximal, since the lifter didn't have to squat to rock bottom to get under it. Thus, a power clean has less of a force component and more of a speed component than a competitive "squat clean."
Arthur Dreshler, MSS, author of The Weightlifting Encyclopedia, eloquently describes the benefits of Olympic lifting and its derivatives for athletes:8
1) Olympic lifts teach an athlete how to explode (to activate a maximum number of motor units rapidly and simultaneously).
2) Olympic lifts teach the ability to apply force with his or her muscle groups in the proper sequence (i.e., from the center of the body to the extremities). This is a valuable technical lesson for any athlete who needs to impart force to another person or object.
3) Olympic lifts teach how to accelerate objects (including other people) under varying degrees of resistance.
4) Olympic lifts teach how to effectively receive forces from another moving body.
5) The actual movements performed while executing the Olympic lifts are among the most common and fundamental in sport.
6) The Olympic lifts are commonly used to measure an athlete's force output capabilities.
If you are unfamiliar with the Olympic lifts and their derivatives. I strongly suggest that you find either an ISSA-Certified Specialist in Sports Conditioning, or a USA Weightlifting Certified Coach in your area who can assist you with these exercises. These lifts, though not beyond the capabilities of most athletes, are more complex than the majority of strength training exercises.
Although "plyos" are overused by many athletes in their quest for the "magic pill" solution to their training problems, plyometric drills performed with bodyweight, weighted jackets, light resistances such as medicine balls, logs, sand sacks and gymnastic equipment can be a valuable component of a SS development program.
Plyometric training programs must be designed with sufficient recovery periods to ensure that fatigue does not take the "elasticity" out of the athleteís movements, since it is this repeated elastic neuromuscular control of impact which provides the training effect.
Testing Your Speed Strength: The Max Jones Quadrathlon.9
Few athletes are aware of this unique and very useful testing implement created by the English track & field coach of the same name. The MJQ can be used to regularly monitor your level of speed strength, and can also used as a fun competition several times a year. This test is very easy to administer (youíll need to do this at your local high school or college track) and involves only a tape measure and a stop-watch. One note of caution, however: The four test drills, although relatively simple, will take a toll on your body (particularly your hip flexors) if you have never done them before, or if itís been years since youíve done them. If you fall into this category, I strongly suggest you practice these drills for before going at them "full bore." Start with very low volume (just a few repetitions of each drill) and progress gradually over a series of 4-6 sessions.
The test drills are as follows:
Three Jumps: Feet together, hop three times and land in a long jump pit. Measure from your starting position to the closest disturbance of the sand where you landed.
Standing Long Jump: Standing at the edge of a long jump pit, with toes slightly over the edge of the board, perform a standing long jump into the pit. Measure from the lip of the board to the closest disturbance of the sand where you landed.
Thirty Meter Sprint: Using starting blocks (you may also have a partner place his or her foot behind your lead foot to simulate a block), start on the command of a timer at the finish line. The timer starts the watch when your back foot makes contact with the ground on the first step, and stops it when you break the finish line.
16lb Overhead Shot: Standing on top of a shot put stopboard (your back to the pit), dip down (much like the preparatory crouch for a vertical jump), swing the shot between the legs, and then extend and throw the shot overhead backwards. It is not necessary to remain on the stopboard. Measure from the lip of the stopboard to the first point of impact.
Please see Table 2 for the quadrathlon scoring tables. Simply convert your scores into the numerical scores provided, and total for your MJQ rating.
A Periodized Training Program for SS Development: The Rule of Thirds
Since fatigue is specific to the motor quality being trained, when microcycles with different objectives and varying demands follow each other, it promotes enhanced recovery, allows for maintenance of maximal strength and body composition during periods devoted to SS (and vice versa), and protects against "overuse" types of injury. The "rule of thirds" is a planning concept which partitions each mesocycle into thirdsó the first two thirds are spent training the targeted motor ability; the final third is spent training a complementary motor ability to provide recovery and balance to the program.
In this program, maximal strength is the targeted motor ability for the first six weeks, while SS is the focus of the final six weeks.
Note: Before initiating this training program, complete the MJQ and record your score. At the completion of the program, re-take the quadrathlon to assess the effects of the training.
Citius, Altius, Fortius!
A Periodized Training Cycle for SS Development
1) Hatfield, F.C. (Ed.)(1998). Fitness: The Complete Guide. Santa Barbara, CA: International Sports Sciences Association.
2) Dick, F.W. (1997). Sports Training Principles. London: A&C Black.
3, 5) Komi, P.V., (Ed.) (1992) Strength and Power in Sport. London: Blackwell Scientific Publications
4) Bompa, T. O. (1993). Periodization of Strength. Toronto: Veritas Publishing, Inc.
5) Hatfield, F.C. (1989). Power: A Scientific Approach. Chicago: Contemporary Books.
6) Zatsiorsky, V.M. (1995). Science and Practice of Strength Training. Champaign: Human Kinetics Publishers.
7) Kraemer, W.J., & Newton, R.U. Muscle Power. Muscular Development, March, 1995
8) Drechsler, A. (1998). The Weightlifting Encyclopedia. Flushing, NY: A is A Communications.
9) Dunn, G.D., & McGill, K. (1994). The Throws Manual (2nd. Ed.), Mountain View, CA: Tafnews Press
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