DYNAMICS OF SPORT COACHING

MICROFAILURE ZONE

CORE RIGIDITY?

DOES CORE STABILITY TRAINING EQUAL

ELASTIC REGION

Amount of deformation Figure 1: Deformation graph for a muscle under load

BOX 2: THE RELEVANCE OF ELASTIC DEFORMATION TO ATHLETICS TRAINING

ELASTIC REGION: Within the elastic region, stressed tissues become deformed, but return to their original size and shape at rest. When an athlete is getting used to a particular activity, the stress will induce the production of new stronger cells in the tissues used in that activity. Here training occurs within the athletes’ “comfort zone” whereby their tissues work within their stress tolerance levels. To move this region to the right, increasing their loading tolerance, they must train within the microfailure region.

MICROFAILURE REGION: To offer a change within an athlete’s tissue orientation, training needs to occur within this region to result in a change in his or her tolerance to activity therefore preventing injury and improving performance output. Injured tissues should be kept within the elastic region so the cells can rest as they repair.

PLASTIC REGION: Post-injury muscle cells in the microfailure zone are not ready to take any strain. If their repair mechanism is slowed down in any way they may enter the plastic region, in which they may become deformed. At this point, they will not return to their normal size and shape at rest, and this deformation can be permanent.

attempting to improve on their sprint times? Now let’s turn to another scenario.

A triple-jumper completes repetitive single-leg sit to stands and stand to sits at a slow speed, concentrating on the technique, obviously with the idea that this will improve single limb control. The concept in itself is sound – training unilaterally as opposed to bilaterally – but again we have to ask: Is this action specific enough? Will the skills gained in this exercise transfer through to the event itself? Interestingly, on observation this triple-jumper falls into valgus with pelvic rotation at full flexion. From our perspective it may be noted that before progression to speed- and load-specific unilateral landings, we would want this athlete to use support

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on either side, to work through a lesser range (regression) and to increase the load before taking away any support and increasing the range (progression). Such “regression” and

“progression” are necessary aspects of exercise in order to shift the so- called “elastic region” of the tissues to the right. Training that pushes tissues into the “microfailure” zone in which the muscle is deforming too much because it is being over-stressed, or over-training or incorrect training, will result in the athlete having to see someone like myself because of injury. See Figure 1 and Box 2 for more about deformation under load.

CORE STABILITY Training takes many forms, of course, and one of the “bread and butter”

PLASTIC REGION

formats undertaken by most athletes is some kind of core stability training. This often involves exercise balls and yoga- and Pilates-based positions. There are several concepts regarding the “core” (what it is and how to train it) but remember that most core training involves maintaining a rigid torso, usually without any limb movements. Consider whether making an athlete adopt a press-up position with his or her feet resting on a ball, or kneeling on a ball, is really ideal for skill transference into his or her sport? Would this offer stability throughout motion, and more importantly rotation at the trunk, that is necessary for propulsion? Or would this in fact result in “core rigidity” whereby the athlete is too rigid at the torso and then compensates by moving excessively into the coronal and transverse planes, and in doing so affecting structures at the knee and hip, for instance (4). Again, progression and specificity come into the picture. And we should ask ourselves, does core stability training equal core rigidity?

PLYOMETRICS Techniques in training are ever- changing, with the aim of improving performance. One well-used technique is that of plyometrics, in which the stretch–shorten cycle is augmented during jumping and bounding drills to elicit explosive gains in speed and jump athletes. It has been further used by Hewett et al (2001) in the USA to develop protocols for preventing knee injuries in young female athletes. The idea is sound. Upon landing, toe to heel, the knee and hip should be flexed at least 30 to 45o

with a slight amount

of forward spinal flexion. This allows for muscular lengthening and force attenuation, and leads subsequently to rapid shortening, so producing the jump. Figure 2 shows an incorrect landing. As a result knee valgus occurs – the plague of many a jump/running- based athlete. Yet, somewhat surprisingly, the

converse exists. Some coaches are advised to make their athletes land in an erect posture, with their spine in

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Increasing load