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NECESSARY RELATIONSHIPS: VOLLEYBALL AND SPORT SCIENCE
I recently returned from USA Volleyball's Critical Thinking Seminar on Blocker Development. This was the third Critical Thinking Seminar organized by USAV and as a scientist, I found it to be the most challenging one to prepare for. In previous seminars on setter and hitter development, Dr. Jeff Broker (senior biomechanist with the USOC's Sport Science and Technology Division) and I have attempted to describe biomechanical aspects of various volleyball skills. Throughout the evolution of the Critical Thinking series, Dr. Broker and I have arrived at a format that has helped us organize and convey our thoughts in an effective and meaningful way. What I hope to do in this article is 1) describe what biomechanists do; 2) outline our approach to these seminars; and 3) encourage readers to contribute ideas and questions to the Sports Medicine and Performance Commission's (SMPC) Resource Advisory Teams. Of Biomechanics and Biomechanists Dr. Broker and I begin each presentation by describing the nature of biomechanics and what biomechanists do. Many sport biomechanists seek a level of understanding of human motion so that they can recommend technique changes that optimize performance or reduce severity and/or predisposition for injury. To accomplish this, we marry an understanding of functional human anatomy with the mechanical principles of motion. We use mathematics, engineering, and computers to create two- and three-dimensional simulations or re-creations of complex athletic performances. Disclaimer Volleyball is a dynamic and complex team sport. Therefore, it is important to understand that what may be optimal in terms of mechanical technique may be suicide in terms of real-life game-situation tactics.Expressed differently, mechanically optimal and tactically optimal. The "does not equal" symbol in this expression should be interpreted as "does not always equal". This is our disclaimer and we think it is an important one. An excellent example of the tradeoffs between mechanically optimal and tactically optimal techniques is found in middle blocking. We know that blockers can jump higher if they start from an upright position, lower themselves, and then reverse the downward motion to propel themselves up into the air. This technique is called a "countermovement" and we know that this results in much higher jumps than those beginning from a crouched or squatted position which do not involve a preparatory lowering phase. The reason for the improved performance in countermovement jumps seems to be related to increased force produced by the leg muscles at the beginning of the upward phase of the jump. For the middle blocker, there are two problems with the countermovement jump. First, it takes much longer. The time spent on the ground during a countermovement jump is significantly longer than during a "squat jump". Therefore, if the middle blocker is reacting to a ball that is set in the middle (not guessing or committing), the countermovement will take so long to complete that the blocker may still be lowering the body while the hitter is actually contacting the ball. Second, since the countermovement jump results in greater jump heights, the middle blocker will stay in the air longer. If the middle committed to the quick, and performed a countermovement jump, it is unlikely that they will be able to land in time to help with a set that went to the outside. Therefore, while the countermovement technique may be mechanically optimal in terms of maximizing jump height, it is likely to come at the expense of completely eliminating the middle from helping with a double block. What We Know and What We Think We Know Unfortunately, there is little published research on the biomechanics of volleyball and some of what has been published is not particularly useful. Therefore, when Dr. Broker and I try to describe our current state of knowledge of the biomechanics of volleyball and ask, "What do we know for sure?", "Not too much" is our typical answer. The good news is that while we may not know a lot about the science behind volleyball, we do know a lot about the science behind other skills that are either related to or are components of volleyball skills. Jumping is a good example. We know a lot about jumping even though few (if any) studies have specifically examined volleyball players jumping during volleyball game-like situations. Therefore, many times we are forced to make educated guesses about volleyball-related techniques based on non-volleyball-related data. Herein lies the idea behind, "What we think we know." Regarding jumping, I do not believe this is a serious limitation as long as tradeoffs between technique-related advantages are considered against tactical limitations of team play. For example, we know that jumpers that use a vigorous arm swing and a running approach (like attackers) will jump higher into the air than jumpers who use a restricted arm swing and no approach (like blockers). We know that, if all else is equal, one-legged takeoffs (like slide attacks) will result in greater overall jump and reach heights than two-legged takeoffs (like traditional attacks) because the body's center of mass is higher within the body at the instant of takeoff during one-legged jumps. We also know that jumpers who reach at the peak of their jump with one arm up, keeping the other arm down (like attackers), can reach to higher heights than jumpers who reach into the air with two arms up (like blockers). What Do We Need to Know? In the Critical Thinking Seminars, Dr. Broker and I have tried to describe "what we know" and "what we think we know" about the biomechanics of volleyball. However, we have struggled when addressing the question of "What do we need to know?". We both know volleyball reasonably well. We have both played competitively and I have coached for several years at various levels. We have arrived at questions like, "why do outside attackers land on one leg so often?"; "what is the optimum spacing between blockers?"; and "is there an optimum body position for back row defenders?" However, are these really the questions that YOU want to know most about? Although we have been encouraged to do so in the past, I do not feel that we should the only ones trying to answer the question of "What do we need to know?" And, I strongly believe that we should not be the ones trying to prioritize these questions. Here is where the reader comes in. In 1994, USA Volleyball formed the SMPC. Within the SMPC are four Resource Advisory Teams (RATs). The RATs comprise experts from the major disciplines of sports medicine and exercise science: psychosocial (sport psychology and sport sociology), medicine, exercise physiology, and biomechanics. The RATs serve as an information clearinghouse to members of the volleyball community. Therefore, we write articles like this one. However, a majority of the articles written by RAT members are on self-selected topics based on the expertise of the contributing member. To cite examples, I have written about jumping and Dr. Jill McNitt-Gray has written about landing. Now, there is nothing inherently wrong with this situation. Providing some expert perspective to a sport like volleyball that has a limited research foundation is better than providing none. I would argue, however, that the RATs could be more effective and better utilized if coaches were the ones posing questions and suggesting issues to be addressed in these articles. After all, coaches and athletes are the experts of the game. They are the ones closest to the sport and know better than anyone else the issues that are affecting coaching decisions and performances of athletes or teammates. A Call for Questions Help the RATs help coaches and athletes. Submit questions to the RAT leaders and ask them to devote their next article to issues most important to the sport of volleyball. There are two possible outcomes to this. Both are positive. First, RAT members may already know (or think they know) the answers to your questions. If this is the case, RAT members can write a short review of the relevant literature on the issue in question. Second, RATs may not know the answer (and no one else may know either). In this situation, the RATs can perform a literature search and communicate our lack of knowledge to you directly and/or address the lack of knowledge in this area in an article. Sometimes, an answer to a question may not exist. For example, there may not be a singular footwork technique that is best for every middle blocker. However, this information can be conveyed to you in a way that will help you make an informed decision. When enough questions are submitted, the RATs can begin to look for trends. Which questions keep arising? Which questions seem to have the greatest potential for improving performance or reducing injury? By understanding more about the needs of coaches and athletes, the USAV, the SMPC and their RATs can more effectively identify critical performance questions and can initiate research endeavors to answer those questions in priority of their potential impact to the sport. I believe programs like USAV's Critical Thinking Seminars are exceptional in that they allow coaches and scientists to interact. Coaches learn more about what scientists are capable of doing and what information and methods may be currently available to them. Scientists learn more about what coaches concerns and what tradeoffs they must consider in light of team play dynamics. Critical Thinking Seminars have been offered every other year, but by improving two-way communication between coaches and scientists now, a more mutual and meaningful learning process can be facilitated. The SMPC and RATs were established to serve the volleyball community. Use the interim between seminars and coaching conventions to ask questions. We will all learn something new. The opinions reflected here are solely those of the author and are not necessarily those of USAV or the SMPC. Please address any comments and concerns to:
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