This week's guest blog post comes again from Dr./Coach Patrick Davidson. As usual its a solid piece providing a digestable "big picture" view of a modern training model. Enjoy!
The purpose of training is to create specific structural and functional adaptations that lead to the attainment of personal goals. The more closely the training mimics the exact nature of the sporting activity or personal goal, the more likely it is that adaptations will lead to improved performance for the desired outcome. Increasing the specific training volume over a multi-year developmental period is the optimal methodology for helping athletes reach the highest level of performance and competition. Every sporting movement has an accepted window of optimal biomechanics for performance. Individual anatomical, psychological, and emotional components lead to certain styles that athletes bring to the way in which they execute their sporting movements; however, the commonalities of sporting movement execution and the required muscle recruitment and sequencing of muscle firing are more prevalent than differences amongst elite performers. The aim of coaching is to teach the technical and tactical components of sporting movements to athletes that lead to the attainment of optimal biomechanics and kinetics to help the athlete reach their ultimate potential within their chosen sport. Coaches need to possess knowledge of how to correct faulty technique as well as outline training plans that maximize fitness while minimizing the chance of injury. While these aims of coaching seem fairly straight forward, in truth, they are only achievable if the coach possesses high levels of knowledge within anatomy, physiology, and hands-on performance of the sport itself. Keeping athletes healthy while maximizing the amount of training specificity is a very delicate balancing act within a dynamic, multi-variate environment.
Non-functional overtraining is a concept related to having athletes perform excessive amounts of fitness related work that does not directly translate over to improved performance in the desired sporting activity. Anatoly Bondarchuk, in his book, Transfer of Training was able to document the degree of carryover from different training activities to sporting performances in the world of track and field. Transfer of Training is a very interesting book that all performance based coaches should examine. One of the clear messages from the book is that the more elite the athlete, the more narrow the window of transferability from traditional fitness exercises to sporting performance. Another way of relating this message is to say, the worse the athlete, the greater the reward the athlete receives from traditional strength and conditioning training, and the better the athlete, the lower the reward from traditional strength and conditioning training. Another clear message from Transfer of Training is that certain exercises do in fact lead to performance improvements in some athletes (bench press for shot putters), while the same exercise may have no carryover to other sports (javelin). Transfer of Training provided an in depth evaluation of runners, jumpers, and throwers, and the degree to which an exercise might benefit one type of athlete while having no impact on another athlete was striking. This leaves the performance based community in a very interesting position, for we do have some references as to what works with track and field athletes; however, no such systematic review has been performed on traditional team based athletes, such as those who compete in baseball, football, basketball, and hockey. There is no definitive way to know whether you are choosing an exercise that leads to performance based improvements in these athletes from a reliable literature source that has specifically chronicled elite performers. Despite this knowledge gap, intelligent and thoughtful coaches can rest assured that increasing the amount of specific training for these athletes is still the methodology that will lead to improved performance. Analysis of sporting tasks from a biomechanical and energy systems demand perspective is the avenue through which training specificity can be gleaned. Concentrating the training workload on these regions will reduce the incidence of non-functional overtraining and avoid wasting the valuable and non-refundable training time that athletes need to invest within their short lived careers.
The warm-up/movement preparation component to the training session is the first area to examine when making decisions that will limit non-functional overtraining related exercise choices. The common denominator amongst the major professional sports in the United States is that they are locomotion dominant. Maximal locomotion velocity, change of direction, and the highest sustainable oxidative energy system driven velocity are all critical variables that should be maximized amongst these athletes. The keys to maximizing these locomotion components are helping the athlete achieve optimal gait mechanics, acquisition of maximal efficiency within gait , and the ability to create appropriate physiological recruitment strategies of the gait musculature. Analysis of gait is an area of study that has been taken up primarily by physical therapists as well as those who study developmental kinesiology. There is a great deal of information related to the gait cycle within the body of knowledge within these fields. Gait is a complex intra-organ, multi-system task that is highly regulated by the efferent and afferent communication strategies of the nervous system. Intervention strategies that lead to alterations in sub-conscious gait are highly specific and require true expertise on the part of the therapist/coach who is working with the target patient/athlete in question. Working within the confines of an objective testing battery specific to the gait cycle is a fundamental requirement of any practitioner who is attempting to induce actual change and improved performance within this motor program. Practitioners must understand exactly what their client is presenting them with in terms of gait dynamics in order to create the appropriate intervention/training strategy that will lead to positive outcomes.
A warm-up that focuses on improving the gait cycle appears to be an effective strategy for preparing athletes for training that will carry over to injury reduction and performance enhancement. Such a warm-up is based on individual assessment of the gait cycle of an athlete and a determination of which exercises appear to result in the greatest observable objective changes for improved gait efficiency. The testing battery provided by the Postural Restoration Institute (PRI) provides objective tests that analyze gait, categorize the individual tested, and provide a systematic corrective exercise algorithm to reposition, retrain, and restore the athlete/client/patient. Other models exist, and ultimately all models are based on the authentic anatomy and physiology of the human organism; however, at this time, the PRI model appears to be the most complete and usable system available to practitioners. Learning this system, and possessing the knowledge, skills, and abilities associated with optimizing gait appear to be the best practice methodology for driving demonstrable change into people you are coaching during the phase of training that prepares individuals for higher intensity exercise, particularly if the goal is to maximize locomotion capacities in athletes.
The traditional dynamic warm-up which features many drills from the track and field community (high knees, butt kicks, straight leg marches, and varieties of skips) will increase body temperature and recruit large muscles involved with the thorax, pelvis, and limbs; however, it is highly unlikely that these drills will alter objective tests associated with improving the gait cycle. Time may be better spent by the coach and athlete by discovering what drills lead to objective change in tests and then focusing on those drills during the warm-up as opposed to following a traditional dynamic warm-up.
Following a warm-up supported by positive outcomes on objective locomotion tests, it is important to try to maximize mechanical work that induces physiological fitness adaptations during the training session. Adaptations are organ and system specific. Examples of adaptations to exercise include, eccentric and concentric cardiac hypertrophy, increased capillary and mitochondrial density in cardiac and skeletal muscle, increased stores of glycogen at skeletal muscle, improved acid buffering capacities within cells and blood vessels, and protein synthesis of skeletal muscle. The degree of mechanical work which is specific to the requirements involved with inducing these types of adaptations should be maximized within the time frame of the training session.
Eccentric and concentric hypertrophy of the cardiac tissues are considered to be central adaptations within cardiovascular training. Eccentric hypertrophy involves increasing the volume of the ventricular chambers of the heart, and concentric hypertrophy involves an increase in the thickness of the cardiac musculature which makes up the walls of the heart’s chambers. Eccentric cardiac hypertrophy is considered to be a volume induced phenomenon, whereas cardiac hypertrophy is a pressure induced phenomenon. Rhythmic exercise that does not involve a great deal of sustained skeletal muscle tension increases venous return to the heart via an action referred to as the skeletal muscle pump. This increased venous return to the heart puts more blood into the ventricle with each beat. More blood in the ventricle stretches the chamber in a manner similar to filling a balloon with water. If the heart receives more blood on a consistent basis with each beat, the size of the chamber will grow. Concentric hypertrophy is brought on when the heart is forced to eject blood from the left ventricle to the body when blood pressure is elevated considerably. Exercise involving considerable skeletal muscle contractile activity creates this pressure overload due to the muscle tension clamping down on blood vessels. As you may be gleaning from reading this, the two types of cardiac adaptations are vastly different from one another, and it is therefore fair to say that different modes of exercise can create different forms of cardiac adaptations. Discerning the type of and degree of cardiac adaptation that a specific athlete needs for success in their sport is important when determining the optimal training plan.
Increasing the capillary and mitochondrial density of a tissue is highly specific to the tissues used during training. The same can be said of protein synthesis and increasing substrate stores (glycogen). These types of adaptations are considered to be peripheral, or local adaptations to exercise. Only those fibers that are recruited and fatigued during a training bout are able to experience adaptations to training. If you are attempting to improve running performance and see an increase in glycogen, capillaries, and mitochondria in the running muscles, a swimming training regime will not provide the desired outcomes. Only running will induce the previously mentioned peripheral adaptations based on the principle of specificity.
Recruitment and fatigue of muscle fibers is the method that will induce peripheral adaptation. Recruitment is a neurological phenomenon. Typically training based science only focuses on the force production requirement associated with recruitment, and load is considered to be the primary variable to manipulate for this effect; however, neurological processes are multi-variate in nature. Reciprocal inhibition is a major player involved with the ability to recruit specific fibers. Most skeletal muscles have an antagonist muscle that performs an opposite movement. When an antagonist muscle is firing, the nervous system inhibits the agonist muscle so that movement can occur. If the agonist and antagonist were to fire equally, static tension would be induced, and no joint rotation and subsequent movement would take place. This same phenomenon takes place when we discuss muscle slings and chains, which are groups of muscle that are recruited to perform more global based actions. Chains can exist in a right/left situation, or different chains can create an anterior/posterior arrangement of agonistic and antagonistic behavior. One of the fundamental muscle chains within the PRI system is the Anterior Interior Chain (AIC). The AIC consists of the hemi-diaphragm, psoas, iliacus, tensor fascia latae, vastus lateralis, and biceps femoris. There is a left and right AIC. The AIC is considered to be the lumbo-pelvic-femoral locomotion chain. Recruitment of the right AIC can be compromised if it is the victim of reciprocal inhibition from an overly active antagonistic left AIC. Alternatively, we could also say that there is an inability to inhibit the left AIC in such a situation. From a training perspective, we could say that it is relatively easy to recruit and fatigue the fibers involved with the left AIC, thus driving significant tissue adaptations into them, while the right AIC would lag behind due to a difficulty in recruiting its fibers. Techniques that inhibit the left AIC would reduce the reciprocal inhibition strangle hold being placed on the right AIC, thus allowing the right AIC to be recruited, which would set the stage for potentially providing physiological adaptation to this chain.
Proper biomechanics for a sporting task, and the recruitment of the correct musculature that drives those joint actions is a critical factor in driving adaptations into the proper tissues. When proper biomechanics are found within an athlete, the training aim shifts towards maximizing the fitness of the tissues that drive sporting actions. Training that recruits sporting muscle fibers in similar vectors and ranges of motion as that which occurs during the sport performance has the potential to improve sporting performance. Training that is performed at or near the intensity level and duration of the performance of the sport has the potential to improve the bioenergetics capacities of the sporting musculature. Thus, a good overall model for training can be said to involve a systematic procedure that begins with assuring the potential to perform sporting actions optimally, and then increasing the mechanical work capacity of the tissues that drive appropriate biomechanics.
Mechanical work capacity is based on the force and the ability to sustain force production capacities of specific tissues. Adaptations that lead to increased force production are a combination of enhanced recruitment and rate coding of muscle fibers as well as increasing protein synthesis in those fibers. Recruitment of muscle fibers tends to follow the Size Principle, wherein fibers are recruited in a gradation format beginning with slow twitch fibers, and as force increases, more and faster twitch fibers are recruited. When a fiber is recruited once, it becomes easier to re-recruit that fiber. Thus training that recruits a previously unused fiber for a specific task, “unlocks” that fiber for subsequent performance in that task. If the unlocked fiber can be fatigued within the performance of an activity, that fiber will improve in fitness by undergoing stereotypical adaptation responses. If an athlete improves the ability to recruit and utilize more fast twitch fibers in their sporting movement, the force production demonstrated in the sporting movement will improve. If an athlete improves the fatigue resistance of the fibers used in sporting movements, the ability to reproduce optimal sports movements will be enhanced.
This article has presented the reader with a, “theoretical big picture” of a modern training model. The primary aim was to discuss the fact that major American sports are locomotion dominant sports. The ability to run faster and to sustain high locomotion velocities are a dominant factor in determining success in American sports. Narrowing the focus of the warm-up and training process towards a more thorough understanding of improving a specific function appears to be a reasonable approach to take in developing athletes. Utilizing objective test results for determining the relevance of exercise selection is a progressive step towards reducing the number of training movements that do not translate over to improving performance or reducing injuries, thus reducing non-functional overtraining, and saving more training time for exercises that lead to positive physiological outcomes for athletes.