This is an excerpt from Conditioning to the Core by Greg Brittenham & Daniel Taylor.
The muscular structures of the abdominal and back regions play a dominant role in postural control, lumbar stabilization, and proprioception (what we call total body balance). As we have said, a well-functioning core can help reduce the risk and severity of injury and promote greater efficiency. Precise movements such as lifting a baby from a crib or throwing a dart would not be possible without effective involvement of the core musculature. Tasks that demand synchronous strength, such as standing in strict military posture for an extended time or maintaining balance while exiting a ski lift, similarly require core involvement. In addition, power-based tasks such as sprinting, swinging a golf club, or dunking a basketball would be impossible without a stable core.
You might ask how the core is involved in throwing a dart. The answer is that we must use the deep stabilizers to isometrically and dynamically sustain the kinetic chain during energetic movements within all three planes of motion. More simply stated, stabilization provides a strong foundation through which an action (such as throwing a dart) can occur most efficiently, powerfully, and accurately. Action is never plane-specific. That is, even though your movement is taking place in one plane, the other two planes must be stabilized for the action to be successful. How accurate can a dart-throw be from a core foundation as wobbly as a cube of Jell-O? Force reduction, stabilization, and force production within all planes of movement is the template for training the entire kinetic chain. In training, as we have stated before, stability is trained before strength, and strength is trained before power.
A stable core is no doubt important to everyday activities, but for optimal athletic performance stabilizing the core is imperative. Eastern philosophers have been preaching core stability for thousands of years. Trunk and torso stabilization techniques are as much a daily ritual for them as are eating and sleeping. The view is that you enhance your quality of life through maximizing efficiency of physical function. Eastern martial artists routinely focus the greatest percentage of their training time on the development of the "Hara" (the core), the physical center of being.
Relaxation of the muscles promoted by a strong core allows for greater freedom of movement, better control of power within a movement, less extraneous movement, and most important, the conservation of energy through efficient movement. Controlled body movement is also a prerequisite for accuracyof skill. The power developed in the core must eventually travel through the musculoskeletal system to the more precision-oriented distal musculature of the extremities. Only after achieving this ability to channel energy can you begin to realize your tremendous physical potential - and it all starts with the core.
Characteristics of Good Balance
Balance is the result of correct body alignment and fully functioning sensory mechanisms. The proper synergism between the core and the legs, arms, feet, hands, and head is essential to achieving correct body alignment.
From an athletic perspective, someone who is standing and is balanced (in an athletic stance) typically demonstrates the following:
- The knees are flexed rather than straight, creating a slightly lower center of mass.
- The base of support is comfortably wide, with feet parallel.
- Body weight is slightly forward of the midpoint of the foot.
- The center of mass is dynamic; that is, the athlete continually uses rapid yet controlled motion to respond to sudden changes of direction.
The ability to accurately adjust to changes in your position or to an unstable equilibrium and to sense your limitations in the constant battle against gravity indicates accomplished balance. Most great athletes possess such balance without even realizing it.
Maintaining balance and stability is a dynamic process. With no conscious effort, your body's muscular system is continually contracting and relaxing in order to sustain sitting, standing, walking, running, or any other posture. Your body is continually trying to achieve a state of equilibrium. Several mechanisms within the body continually process information in an effort to attain this state. Two of the more athletically relevant sources of feedback include the vestibular apparatus within the inner ear and proprioceptors within the muscles and joints.
- The vestibular apparatus relays information to the central nervous system concerning the body's spatial awareness, including any deviations from the vertical position.
- Proprioceptors, such as the muscle spindle and Golgi tendon organ, sense the magnitude and speed of a stretched muscle and changes in joint angles.
These sensors provide input necessary to make immediate and essential adjustments in balance. A good example of your receptors at work is that disturbing feeling of just beginning to nod off, only to be abruptly jerked back to reality. For example, while sitting in the film room listening to an unbearably boring lecture on postural assessments and realizing that you can never possibly get back these wasted four hours of your life, you begin to doze off and your head starts to drop forward. The muscle spindles in the back of your neck sense the stretch placed on the neck musculature and quickly make a correction by firing those same muscles and returning your head to upright position. From a stabilization, balance, and postural standpoint, refining your proprioceptor sensors enhances athletic performance and reduces injury risk.
The Importance of Good Posture
Poor posture affects not only balance but all other athletic performance variables. Keep in mind that force is more effectively transferred through a straight line. Obviously, there are natural curvatures throughout the body, but generally speaking, you should strive for proper body alignment between segments - particularly during the push or explosive phase of a movement. A person with poor posture lacks that straight line.
The preferred path of force transfer is through the skeletal system. Poor posture, however, causes detours in the force transfer because the smaller and weaker muscles outside the core must act as the force conduit. Much wasted energy results, and subsequent and usually more severe breakdowns are inevitable. Poor posture leads to countless mechanical and structural problems, some of which we touched on in chapter 3.
Training for Strength
We can break strength down into two categories: muscular strength and muscular endurance. In its strictest sense, muscular strength is the maximum amount of force that a muscle can generate against resistance in a single effort. In contrast, muscular endurance is the ability of a muscle or group of muscles to exert force for a sustained time, such as when running, raking leaves, or hitting hundreds of forehands over the course of a tennis match. From an athletic perspective, both muscular strength and muscular endurance are critical for
- performance enhancement,
- functional stabilization and dynamic postural control of the spine, and
- efficient biomechanical movement throughout the kinetic chain.
Most people think of strength in terms of how much can I lift? In fact, strength - and specifically core strength - is an integral protective mechanism that helps eliminate postural distortions that can lead to ineffective neuromuscular proficiency. Low strength levels at any point within the kinetic chain place the athlete at risk for compensation issues that can elicit extra stresses placed on the contractile and noncontractile tissues, which will adversely affect functional movement patterns and place the athlete at greater risk of injury. Conversely, strong muscles provide efficient dynamic stabilization, decrease the risk of serial distortion patterns, and transmit forces to the bones, acting as levers and resulting in precise and effectual movement.
Unfortunately, most coaches and athletes view strength in its absolute sense - the greater weight that can be lifted translates to heightened performance on the court or field. Strength is but one component within a complex system of a multisensory sport performance. Without stabilization, strength cannot be fully developed. Without strength, stabilization - or the lack thereof - will decrease performance and expose the weak link in the kinetic chain. Without both stability and strength and the refined neuromuscular efficiency associated with the systematic functioning of their relationship, athletes cannot hope to fully develop their power potential.
If you are new to strength training, we encourage you to take the same approach to training for strength as for the global development of all physiological processes. As we have mentioned, enhanced motor skill development evolved following a proximal-to-distal progression. Your strength training should follow a similar course, with emphasis on developing core strength before implementing extremity exercises. Once you have established a foundation of strength, you can then focus on the quality of technique and execution over quantity (with regard to load and repetitions). Quality is nearly impossible without the proper foundation from which to execute the activity. In addition, once foundational core development has been established, you can begin to focus on sport specific - related movements without risking deleterious technical inaccuracies.
Training for Power
Assimilating stability and strength is an important part of developing your center of power. Sport movements, however, typically require explosive, ballistic, and well-coordinated muscular actions. The ability to take strength gained from the weight room and apply it effectively on the playing field is the goal of any performance-enhancement program. Power and strength are not synonymous. As such, the strongest athlete is not necessarily the most powerful athlete. Power conditionally relies on the correlation between strength and speed - thus the clever phrase "speed strength." For athletes to maximize their power gains, they must include a speed component in their training. Simply put, power is a relationship between strength and speed. To this point we have discussed strength, but what exactly is speed? How important is speed? How is speed developed?
Speed can be broadly defined as the elapsed time it takes to move from point A to point B. The distance between point A and point B could be the 26.2 miles of a marathon, the 10 feet from the floor to the basketball rim, or, when at bat, from the "cocked" position to the contact point with the ball. Once you combine speed with strength, the long hours of strength training in the weight room start to pay off, and sport-specific, or functional, strength starts to translate to power. Thus power is the product of force (the weight room) and velocity (the functional application). It should come as no surprise that all of this begins at the core.
Developing the speed component of power differs dramatically from standard programs designed to enhance strength. Typically, you increase your muscular strength through consistent and progressive overload training (increasing load). Training for enhanced speed can certainly be influenced by regular trips to the weight room; however, the level of change is more often a predisposition of unseen factors. These considerations, along with diligent workouts, determine the ultimate level of speed development. These factors are
- individual genetic characteristics and
- the physiology of the muscular system.
Individual Genetic Characteristics and Their Relation to Speed
An athlete's proportional configuration of muscle fiber type (i.e., muscle cell types) has a profound influence on his or her potential for speed. For our purposes here, we will simplify the physiology and discuss two types of muscle fiber: fast-twitch and slow-twitch.
Fast-twitch muscle fibers exert great power but fatigue quickly. The body generates the energy required to contract a fast-twitch fiber anaerobically, or without oxygen. These fibers are best suited for short, explosive actions, such as sprints, Olympic lifting, or volleyball spikes. In contrast, slow-twitch muscle fibers require oxygen for sustained contraction and are thus ideal for endurance activities, such as cross-country skiing, marathon running, or road cycling.
Athletes who participate in endurance sports typically have a higher percentage of slow-twitch fibers. Conversely, the muscles of athletes whose sports require explosive actions tend to contain a higher percentage of fast-twitch fibers. Most elite-level athletes gravitate toward sports that are compatible with their genetic makeup (remember that we are simplifying the physiology).
All of us were born with a certain ratio of fast-twitch to slow-twitch fibers. Even if your muscles are predominantly slow-twitch, however, does not mean you are destined to remain slow. Clearly, you will never become as fast as a cheetah, but you can always become faster than you are right now. You simply learn to maximize what you have inherited.
Muscle Physiology and Its Impact on Speed
Power performance is a consequence of the relationship between muscles and the nervous system. The muscles provide the gas to generate the force, and the nervous system monitors how much gas is needed to execute the task. One way to tap into your vast reservoir of power is to further develop your naturally occurring physiological processes - to "step on the gas." Training the core's neural response mechanisms helps to facilitate this speed component. (Keep in mind that we are not talking about winning a race, necessarily, but, rather, drawing on your vast potential of untapped athleticism.)
The neural adaptation to strength training takes the shape of increased activation of the primary movers, or the agonist muscles. The neural response also includes a heightened involvement of the synergist muscles - the muscles that support the prime movers. Common sense suggests that the opposing torque developed by the coactivation of the antagonist muscles would decrease the net torque intended by the agonists, but on the contrary, it is the antagonist that provides the stability - primarily within the acting joint or joints - necessary to elicit maximum force and, from a power perspective, the rate of that force. Thus for performance to have a chance of success, the agonists (prime movers), synergists (coordinators), and antagonists (stabilizers) must work in concert, and when they do, great things can happen. All of this must occur against a backdrop of sensory feedback in the form of perception and reflexes.
The Stretch Reflex
The speed component of power is directly influenced by a highly trainable attribute called the stretch reflex. Within a bundle of muscle are tiny sensory mechanisms called muscle spindles. These spindles are about the size of a muscle fiber (or cell) and are located in, among, and parallel to the muscle fibers (figure 4.1). A spindle's primary duty is to prevent injury to its associated muscle fibers in situations in which the fibers might be placed on an excessively rapid or overly forceful stretch - well beyond the muscle's tolerance. An extreme stretch such as this can certainly occur as a result of the ballistic nature of many athletic movements.
Muscle spindles located within the muscle fibers.
However, muscle spindles can also be used to the athlete's advantage to generate a more powerful muscle contraction. For example, during the drop or descent of a jump (the countermovement phase), those muscles that span the shoulder, hip, knee, and ankle joints are placed on a rapid stretch, primarily as a result of gravity and body weight. Because the muscle spindles lie parallel to the muscle fibers, they too experience a rapid stretch. The spindles consequently "sense" the stretch and send a message to the central nervous system (brain or spinal cord). In turn, the central nervous system instructs the stretched muscles to contract forcefully, relative to the speed and magnitude of the prestretch. If this sensory mechanism did not exist or for some reason was not functioning, the rapid stretch could possibly exceed the extensibility of the fiber and would most certainly result in an injury to the muscle. The muscle spindle response, subsequently combined with an intended voluntary contraction, can maximize peak force with athletic movements.
Stored Elastic Energy
Another important physiological phenomenon of muscle is the process of stored elastic energy. Think of stretching a rubber band. Imagine that the elasticity of the rubber is similar to the elastic properties of muscle (the fibers and its tendon). As you stretch the rubber band, energy is stored in the elastic properties of the rubber. When you release one end, you release that energy stored. However, there is an essential difference between a rubber band and muscle fiber. With the rubber band, the longer the stretch, the more energy is stored and then released. But with muscle fiber, it is not the magnitude but rather the speed of the eccentric stretch that determines how much energy can be used during the immediate ensuing concentric contraction.
Athletes can take advantage of this inherent elastic quality of the muscle tendon unit. The baseball batter cocking the body with the bat held high just before swinging or the discus thrower snapping (rotating the hips) just prior to release are prime examples of this stretch-shortening cycle. The elastic energy is stored in the active muscles as a result of a rapid prestretch. This physiological process is trainable, and most progressive regimens employ drills and activities designed to enhance it.
Additionally, the stretch-shortening cycle (muscle spindle response) can help facilitate the recruitment of a greater percentage of muscle to perform a given task. With greater motor unit involvement, the potential for intensified power output is thus more thoroughly exploited. Superior power in the core region directly enhances all athletic movements. Remember that no matter what your current ability, you can improve. Training the speed component is one more weapon in the training arsenal.
Transfer of Power
Without the efficient transfer of your newfound power potential, your core training might as well be focused on beach abs. Thus the number one training objective for every athlete should be to develop an efficient coupling system in which the tremendous power potential of the core can be expressed distally to the extremities, the goal being to functionally transfer this core power through progressively smaller and weaker musculature without a contemporaneous loss of energy. For example, if you were to lock your elbow and wrist and extend your index finger, and then attempt to push your friend, the force generated from the pelvic muscles will efficiently transfer from your core through your straight arm to your fingertip with little energy loss. The resulting push would cause at least minor discomfort, if not knock your friend off balance. If, however, you were to bend one of the joints along the chain, such as your elbow, the force generated by the core would dissipate through the bend in the elbow. The strong muscles of the core would become less effective, and the resulting push might feel like an aggressive tickle.
Today's flaccid approach to athletic development, which is often prescribed by physiotherapists and trainers, alienates us from our individual health and fitness goals, and of more critical concern, our athletic potential. We have become a collective ethos in which coddling and the sedentary methodology concerning athletic development has led to a generation of athletes whose performance is declining. Many athletes will experience some degree of intensified physical and structural breakdown on a regular basis during their career. In contrast, intelligently organized and purposefully executed training regimens that are progressively challenging will help maintain proper, efficient, and synchronous functioning of all body systems. Freedom of movement in harmony with the body's design, without the constraints of poor posture and unresponsive modalities, will help eliminate inferior function, thereby enhancing performance.
You must regain control of your fitness and performance potential. Proactivity, as opposed to passivity, will lead to a greater influence over your stability, strength, and power. Motion will become robustly efficient with a minimum of wasted energy, leading to enhanced control and spectacular performance. This controlled energy enables you to deal better with the physical and emotional stress of competition and to perform at a higher intensity for a longer duration with less fatigue - in other words, more productive time competing and less pampering time in the training room.
Read more from Conditioning to the Core by Greg Brittenham and Daniel Taylor.