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Program Design Concept and Physiology As can be easily surmised, the lactate and ATPPC systems are being targeted by the Frappier Acceleration Training program. This is accomplished by incorporating a series of high intensity, short duration exercises. Warmup sets are typically thirty seconds to two minutes in length, with no extended duration runs. Research has shown that "due to a small delay in reaching peak oxygen transport (the process is half completed in about twenty seconds), the steady delivery of oxygen accounts for 60 percent of energy requirements at two minutes, and 80 percent at five minutes" (Shepherd, p. 27). Once the oxygen transport system has been brought to peak it can be expected that all energy transport systems will be able to function optimally. Extended runs (of greater than two or three minutes) would at best be indifferent to the demands of the l Frappier Acceleration Training and may be counterproductive in that distance running typically develops patterns of flexibility and motor recruitment that tend to inhibit sprint development. Therefore, the workout sets themselves range from four to twenty seconds in length in order to specifically stress the phosphagen and lactic acid systems. Muscle contraction force is generated by the recruitment of a sufficient number of muscle fibers to meet the load demand placed on them. The Size Principle of Henneman, et al., relates slow twitch muscle fibers with relatively small, low threshold/low conductance nerve fibers, versus large, high threshold/high conductance fibers for fast twitch muscle. An increased intensity of contraction leads to an increased recruitment of fast twitch muscle fibers as the stimulus potential generated by the central nervous system rises. Additional stimuli may be supplied endogenously by sources within the muscle structures themselves. Researchers have suggested a system "centered on the stretch receptors in muscle spindles or Golgi tendon organs. Feedback could signal the need for adding or subtracting muscle fibers from the contraction" (Gollnick and Saltin, p. 204). Very slow, intense stretching of muscle fiber activates the Golgi tendon organs and results in a reflexive relaxation of muscular contraction. The muscle spindles, on the other hand, are sensitive not only to the length of the muscle fiber but also to the rate of change of length. Activation of the muscle spindles results in a reflexive increase (i.e., without central nervous system involvement) in contraction force from a muscle which is being stretched or lengthened, a phenomenon otherwise known as the Stretch Reflex (Fox and Mathews, p. 126). Faster change in length results in faster recruitment. The muscle is then better able to accommodate increased or sudden changes in strain. In fact, Garrett has shown that an activated muscle placed under strain can absorb 100 percent more energy than when the same muscle is passively strained (Garrett, p. 439). The eccentric contraction force that is generated by definition whenever the stretch reflex is initiated can then be countered by the activated muscle's contraction force rather than by its connective tissue structures. Physiological changes involving both the glycolytic enzymes and the mitochondrial enzymes within the muscle infrastructure have been demonstrated. Glycolytic enzyme contents of whole muscle have shown an adaptive response to training. Glycolytic enzyme concentrations (phosphorylase, phosphofructokinase, lactate dehydrogenase) were studied in trained versus untrained subjects and in sprint trained versus strength trained subjects. Adaptive response appears to be related to the duration of exercise. Little or no difference was observed when exercise intervals were kept to six seconds or less. When intensity was reduced so that effort could be maintained for up to thirty seconds PHOS and PFK were elevated 10 to 20 percent while LDH was unchanged. Crosssectional studies of other athletes shows a level of PHOS, PFK, and LDH within the range of sedentary subjects for strength related athletes (field event, weight lifters, etc.). Sprinters, jumpers, and 400800 M runners "usually have elevated levels of these enzymes" (Gollnick, p. 212). When training is targeted specifically towards increasing maximum strength, no change was observed in mitochondrial enzyme activity. In fact, extended strength training can lead to a "disproportionate proliferation of the contractile proteins, resulting in a dilution of the mitochondrial concentration in the muscle fiber, and the activities of the enzymes expressed per unit of muscle become lower than those of muscle from sedentary individuals" (Gollnick, p. 214). Chronic demand for high oxygen consumption, such as in sprint training or isometric strength training, leads to a significant elevation in mitochondrial enzyme concentrations. Further, this adaptation appears to be selective to the muscle groups placed under stress (Gollnick, p. 214). Physiologic goals for the Frappier Acceleration Training program may be stated as:
Application Increased recovery capacity is in itself insufficient to increase sprint performance. Power output also must be improved both for initial acceleration and for maintaining a higher end velocity. The only methods for humans to increase power output are to:
Activating the stretch reflex has already been discussed as one method of recruiting high threshold muscle fibers into a contraction. Force of contraction may be improved in at least two other ways. The obvious method is to increase the strength of the muscle group or groups involved in the required action. The second is more subtle, involving changes in the actual recruitment patterns of the neuromuscular system. The neuromuscular aspect will be discussed first. As was discussed earlier, contraction force of a muscle can be increased by placing it under a slight stretch. In Frappier Acceleration Training, the stretch reflex is utilized in several different ways. By having the athlete run at elevations up to 40 percent grade, foot plant occurs at a position that is normally nonweight bearing when running flat. In addition, the angle of inclination virtually precludes a heeltotoe gait. Initial foot plant is made before plantarflexion begins, or in the position of dorsiflexion that normally precedes heel strike. The athlete's weight is carried by the lower leg with the gastrocnemius/soleus complex in an elongated or stretched position, precisely what is required in order to activate the stretch reflex and initiate a more forceful contraction of this particular muscle complex during the subsequent toe off stage. The hip flexor group is activated through the elongated pushoff that accompanies running on grade. Additional loading and activation of the Golgi tendon reflex with the attendant requirement for voluntary maintenance of contraction is applied through the use of the Sprintcords. The Sprintcords, when used properly, will selectively and progressively load the hip flexors through their entire range of motion until maximum hip flexion is reached, at which time the quadriceps are loaded progressively through their ROM until the point of foot plant. Swingthrough and knee extension during the stride recovery phase are thereby facilitated. The continuous application of force pulling back against the hip flexors after toeoff results in accentuated extension of the hips before recovery begins. It should be clear that this also activates the stretch reflex mechanism of the hip flexors, causing a more forceful contraction of the hip flexors against the pull of the Sprintcords. Since this action is taking place while on the treadmill, the athlete is also forced to maintain a certain speed of recruitment. The other consequence of the continuous backwards pull is that a tendency for the pelvis to tip forward (or the feet to be pulled back and out from under the athlete) must be counteracted by the abdominals. Stride length can be inhibited by insufficient abdominal strength which can:
In addition to the stretch reflex effects of grade running an emphasized knee drive is required because of the elevated foot plant location. Repeated exercise under these conditions results in the acquisition of specific neuromuscular patterns of recruitment while engaged in sprint activities. In other words, optimizing the development of a motor engram The athlete will have learned to automatically maintain a high knee drive, proper pelvic position, forceful contraction of the lower leg, high foot carrythrough and full extension on every stride. Strength training is done in those areas that specifically apply to running/sprinting mechanics. Perhaps most significant is the work done on the multihip machine. Problems of femoral retro/anteversion, poor hip flexion or extension, and poor foot placement can be remedied or somewhat alleviated through strengthening and/or balancing of strengths in the hip girdle. A premium is placed on flexor/extensor strength and speed of recruitment, but these motions must be stabilized by the much smaller abductor and adductor groups. During lateral movement these stabilizing groups become essential to optimum performance. The need for well developed abdominal strength has already been discussed. Upper body strength is needed primarily in the shoulder flexion and extension movements, with stabilization provided by shoulder abduction/adduction. Good upper body sprint mechanics center around a relaxed, focused arm carry with a slight amount of forward lean in the trunk. Strength and flexibility are required in order to facilitate both speed and economy of movement of the upper body in concert with the lower body. Improper or deficient upper body mechanics and strength can have a tremendous effect on overall sprint capability. Although mentioned above, upper body flexibility seldom is a factor in running mechanics due to the natural flexibility of the shoulder complex. Lower body flexibility needs to be addressed again, both as to its requirements and its implications for sprint mechanics. The need for strong agonists is obvious. The need for equally strong antagonists and for enhanced range of motion is not always so apparent. Garrett notes that "stretching clearly led to a reduction in tension for a given amount of stretch and an increase in length for a given tensile force" (Garrett, p. 441). There are several implications for sprint activity here. It has already been shown that an activated muscle can absorb 100 percent more energy than a passively stretched one. In addition, it is now apparent that for a given amount of stretch, increasing a muscle's range of motion decreases the amount of passive tension generated. Decreasing the amount of tension present in one muscle group translates to less effort required by its antagonist at a given point in its range of motion. Increasing the ROM of a muscle group allows it to actively accommodate to contractile demands made upon it, rather than relying on the connective tissue units to prevent excessive excursion. Therefore, particularly in eccentric motions, more force can be absorbed without the plastic deformations or outright failure that would otherwise occur. Summary Bibliography Acceleration Information
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