Identifying and Correcting Errors in Sport Skills

    This chapter will give you advice about observing an athlete's performance and using your knowledge of mechanics to pick out errors that need correcting. We have laid out what you must do as a series of five steps:
    Step 1: Observe the complete skill.
    Step 2: Analyze each phase and its key elements.
    Step 3: Use your knowledge of sport mechanics in your analysis.
    Step 4: Select errors to be corrected.
    Step 5: Decide on appropriate methods for the correction of errors.

Step 1: Observe the Complete Skill

    It's a good idea to plan how you intend to observe a skill. By deciding what to look at and where to stand, you can watch the skill or the elements in a phase of the skill as accurately as possible.
    Begin by observing (and videotaping) your athlete's performance from several different positions. Watch from the left and right, from the front and rear. In this way you can cross­ reference and double check the information you gather. Characteristics of the performance that are hidden from one point of view will be revealed from another. A good approach is to watch the whole skill in this manner several times and then home in on the skill's phases and key elements.
 

Observing Skills That Involve Distance and Height
    Observing skills that involve height and flight (e.g., gymnastics vaulting, ski jumping, and pole vaulting) can be more demanding than observing skills that contain much less movement (e.g., archery or power lifting). A gymnastics vault contains a long and fast approach, a takeoff, flight onto and off the horse, and finally a landing. These phases of the skill occur at high speed and cover considerable distance and height. To critically observe all aspects of the action, observe from positions that are at right angles and about 15 ft from the flow of the skill. Stand at right angles to the board, then the vaulting horse, and finally position yourself to the rear of the approach. You can also stand beyond the landing pads so that the athlete runs toward you. In this way you'll get several viewpoints of the takeoff, flight, and hand positions on the horse. This observational technique also works well for track events. Get closer when skills cover less distance and height and when you are focusing on particular phases and elements of the skill.
    Modern television gives us excellent slowmotion coverage of athletes viewed from above. You're probably familiar with the dramatic replays of hand changes on the high bar, swings to a handstand on the rings, and the incredible rotary skills of gymnasts on the pommel horse. In swimming, cameras on tracks on the sides and bottom of the pool give superb coverage of swimming strokes. If this additional visual information is available, it will help you tremendously with the assessment of your athlete's performance.
 

Ensuring Safety When Observing
    With many skills, you'll pick up much worthwhile information when you observe from in front of your athlete. But be particularly careful in this situation. You may center your concentration on your athlete's movements and not on what happens after. Viewing from the front is not recommended for the throwing events in track and field or for sports such as golf, where the velocity of the ball is exceptional. Unless you have a specially designed protective screen as is used in baseball, be satisfied with viewpoints that are from the side and the rear.
    With rotational skills such as discus, shot put, and hammer throw, it is best that you are well back behind a safety cage officially approved for the event. This is highly recommended for the discus and hammer throw. In the hammer throw, the 16-lb ball travels at phenomenal velocity; in the hands of a novice there is no certainty it will fly in the required direction. If you have no safety cage available, stand well back to the left rear (as you view the athlete from the rear) for hammer and discus throwers who rotate counterclockwise across the ring. In the shot put event (which normally does not use a cage), stand well back to the left rear of right-handed throwers and vice versa for left-handed throwers. As the athlete becomes a more competent shot-putter, you will be able to move closer without endangering yourself.
    If you are marking distances while you assess your athlete's performance, be aware that an implement in flight is extremely deceptive. Javelins viewed head-on have a habit of momentarily seeming to disappear from sight, and wind can dramatically alter flight paths. You must also allow for the distances that implements skid and bounce. A discus skidding across wet grass is extremely dangerous!

Finding Settings for Observation
    Try to avoid conditions that distract you and your athlete. Physical education classes and recreational settings disturb your concentration and that of your athlete because there are too many other activities going on. Any movement in the background can disrupt your attention from the details you want to analyze. If you are instructing a group, you cannot, and should not, pay attention to one athlete for very long. Other athletes need your supervision and encouragement. The best setting is one in which there are no distractions at all. Your athlete can concentrate on performing and you on observing and analyzing.

Getting Started With Your Observation

    Have your athlete warm up and perform the skill several times so you get a good overall impression. Don't concentrate on specific phases, even though a poor windup or a poor force-producing phase will obviously catch your eye. Try to get a feel for your athlete's rhythm, flow, and general body positions from the start of the skill to the finish. Your main objective at this stage is to get an overall impression of the athlete's performance.
 

Making Comments During Observation

    When you observe, don't distract your athlete by continually offering instruction. Watch without making any comments other than an occasional encouraging remark after the skill is completed. Try to keep him relaxed and enjoying having you as an enthusiastic and knowledgeable spectator. Your athlete should not struggle to impress you, be discouraged, or become so casual that he loses concentration. You want an accurate impression of his abilities, not a performance altered by tension or insufficient concentration. Above all, don't start listing aloud all the actions your athlete is doing wrong! This serves no purpose and destroys morale. You don't want your athlete to become tense or stressed in any way. Your job is to get a true impression of how he performs.
    While you observe, make a mental note if you think your athlete is lacking in strength, flexibility, or endurance. But remember that your athlete cannot change these characteristics during one training session, just as he cannot gain or lose weight on command. Take these factors into account by modifying your demands when you start correcting errors. In other training sessions you can get him to work on improving these areas.

Observing Skills Performed at Normal Speed
    When you observe a complete skill for the first time, it is best if your athlete performs the skill at normal speed. The reason for this recommendation is that skills performed at unnaturally slow speeds are dramatically different from those that occur at normal speed. Timing, coordination, and the feel for the skill are different. Slow-speed performances serve little purpose when you are looking for errors to correct. They give you a false picture of what is occurring. However, reducing speed is helpful when you teach new movement patterns. When the fundamentals are learned, the speed of movement can be increased.

Determining the Number of Times You Observe a Skill
    How often you watch your athlete perform depends on the physical demands of the skill. Skills that take considerable time, concentration, and effort for each repetition, such as diving and ski jumping, are by necessity viewed fewer times than a place kick, a volleyball serve, a pass in soccer, or the repetitive paddling actions of a kayaker. It is important, however, that you view the performance enough times so your athlete's pattern of movements becomes apparent. Skills such as diving and ski jumping may require more than one training session to develop an accurate impression of the athlete's abilities.

Noting Differences Between Beginners and Experienced Athletes
    As you observe, expect that a beginner's performance will change dramatically from one repetition of the skill to the next and that a beginner will tire more quickly than an experienced athlete. Novices make gross errors in which they miss several key elements in a phase, or even a whole phase of a skill. During your general observation you'll notice that their foot positions are incorrect at one moment and correct the next. You'll notice that the beginner may not use the large muscles of the body or shift the
body weight in the correct direction. You may even feel, after completing the observation, that the best course of action is to totally rebuild the skill. With novices you must accept this situation. It's part of coaching beginners!
    In comparison to beginners, elite athletes make fewer apparent errors. You'll see errors when you analyze a slow-motion video of the skill, or you'll catch them when you concentrate on specific elements in the skill. Perhaps you'll discover that your athlete's line of vision is incorrect or that his head is in the wrong position, upsetting his balance. You may dis­ cover that your athlete's overall performance is good except that the wrist action at the end of a pitch, throw, or hit is not as it should be. Unfortunately, you may also have to struggle through many training sessions to get an elite athlete to eliminate these seemingly minor errors. The reason for this difficulty is that an elite athlete has probably been performing the skill in the same way for years, and the incorrect action has become ingrained. How different it is when you coach a young novice. Every coaching session can be a giant leap forward! To your delight you'll find that the technique of most novice athletes is like clay that you can mold. Each coaching session can make a massive change in the quality of their performance. This is why many coaches find great pleasure in coaching novices.

Observing and Spotting
    If you are a novice coach, you may find it difficult to critically observe a performance when you are also involved in spotting. Your attention tends to focus on where you should give support (and perhaps on protecting yourself from the flailing arms and legs!) rather than assessing whether certain movements are performed correctly. In gymnastics, dividing your attention can be a risky practice. Experienced coaches can carry out both jobs at once, but even these coaches must concentrate on their spotting when more complex skills are attempted. If you are starting as a coach in a sport that has a high level of risk, play it safe and use competent spotters if you want to be free to observe. If spotters are not available, have an onlooker videotape the per­ former while you give the necessary assistance. Afterward, analyze and discuss the performance with the athlete.

Looking for Other Clues
    Part of your observation technique will be to look beyond your athlete for clues about the performance. The flight path, rebound, and roll of balls result from the movements and actions your athlete uses in the skill. Skate marks on ice, ski patterns on snow, and footprints on approaches, takeoffs, and landings are all clues to what's going on in the skill.
Don't forget to use your ears as well as your eyes when you look for clues! The rhythm of footfalls during an approach or during the repetitive bounding of a triple jump is an indication of stride length and stride cadence. The overemphasized thud of one of your athlete's feet during throwing events is a sure sign of poor balance and weight distribution. (It's also a sure sign that the hop or the step in the triple jump is too large.) The noise of bat and club on ball helps determine a direct or sliced impact. In volleyball, a slapping noise is a giveaway to the coach of a carried ball or some other incorrect contact. Almost every sport will give you visual and auditory signals that you'll be able to associate with good or bad performance. Use every source of information. Don't limit yourself in anyway.
 

Step 2: Analyze Each Phase and Its Key Elements

    After you have watched the complete skill several times, you are ready to concentrate on individual phases and their key elements. There are two ways to approach this task.
 

Start With the Result

    One method coaches commonly use with an athlete who is competent is to start with the end product and work back from there. Here's an example: A player in rugby is trying to spiral the ball for distance. There's enough force put into the kick but there's no spiral. So you concentrate on the action of the foot as it contacts the ball. Is the ball fed onto the player's foot correctly? Is the foot drawn across the long axis of the ball to produce the torque necessary to generate a spiral? On the other hand, if the ball's spiral is satisfactory but distance is lacking, then shift your attention to other phases and key elements in the skill. Ask yourself, "Is there an adequate shift of the player's body into the kick?" "Are the lower leg and kicking foot allowed to swing freely, or is the kicker tightening the leg muscles and eliminating any chance of a whiplash action occurring?" "Is flexibility a problem?" Inflexibility will restrict the range that the kicking leg swings through and reduce the force applied to the ball.
    In throwing, kicking, and striking skills, checking the result gives you a wealth of information. You might have a big, powerful athlete who ought to throw the shot a long distance, but there's no force behind the shot and you know the athlete should be throwing 5 ft farther. So you concentrate on the throwing stance that the athlete assumes after the glide across the ring is complete. When you examine the throwing stance, you ask yourself, "Is the athlete's body angled correctly?" "Are his shoulders still facing the rear of the ring when the glide is complete?" "Is the foot placement correct?" "Is the athlete rotating his hips toward the direction of throw, and are the massive muscles of the legs, seat, and back used before the chest, arm, and fingers?" (Figure 8.3 shows the actions that you should be looking for in shot put.) After critically examining the throwing stance, you may decide that the problem lies in a poor glide across the ring. Well-performed standing throws confirm your suspicion. The athlete's glide across the ring is ruining the remaining part of the throw! With the problem diagnosed, you and your athlete can now work on correcting the errors in this phase of the throw.

Observe Each Phase of the Skill in Sequence

    Another method of observation that coaches commonly use is to start by critically observing the first phase in the skill, then progress to the second, third, and so on. The first phase contains preliminary movements and your athlete's establishment of a mental set. In the first phase, look at such elements as your athlete's stance and weight distribution. Take note of her head position, her line of vision, and the way she concentrates for the actions that will follow.
    In the second phase, when your athlete winds up or performs a backswing, examine her weight transference from one foot to the other. Check the position of the implement and your athlete's body at the end of the windup. Make a mental note if she appears stiff and needs to improve flexibility.
    When you examine the force-producing phase, remember that in many skills this phase is made up of several distinct sections, such as an approach and a takeoff in jumps and vaults; an approach, glide, spin, and throw in throwing events; or an approach, hurdle step, board flexion, and takeoff in springboard dives. In free­ style, it can be the "catch" of the water at hand entry followed by a long pull and push from the hand and forearm. Break these complicated force-producing phases into key elements, and concentrate on each key element in sequence.
    In most skills, the follow-through is the least important of all phases. Your athlete has applied force, and the follow-through safely dissipates her momentum and kinetic energy. But be sure to observe what happens during the follow­ through and, of course, what happens to the implement and your athlete immediately after­ ward. Her actions and the implement's flight are clues to what has happened earlier. Check your athlete's arm and hand actions during the follow-through on a jump shot in basketball or a volleyball spike. In these skills, a follow-through can indicate the amount and direction of force and spin that's applied to the ball.
    In some sport skills, insufficient control during the force-producing phase produces a follow-through that violates the rules of the sport. A field hockey player swings the stick too high, or a volleyball player hits the net after spiking or blocking. So don't disregard the follow-through; consider it an important phase that gives you clues about what happened during the windup and force-producing phases that occurred earlier.
    In cyclic, repetitive skills such as swimming, remember that the follow-through is a recovery action that sets your athlete up for another force­ producing phase. Check that these recovery actions are mechanically efficient and not wasting your athlete's energy. A misdirected arm recovery in freestyle, in which the swimmer's arm swings across the midline of the body, produces poor body alignment, generates excessive form drag, and affects the efficiency of the force-producing phase that follows (see figure 8.4). Cyclists talk of the need to spin the pedals, meaning that proper pedaling technique is a rotary motion, not just a push downward with a rest on the way up. Check that your athlete is pulling up and around with one leg while pushing down and around with the other. Proper pedaling technique is the ultimate in cyclic, repetitive action.

Step 3: Use Your Knowledge of Sport Mechanics in Your Analysis

    As you observe each successive phase and its key elements (from preliminary movements and mental set to follow-through, or recovery), you must put your knowledge of sport mechanics to work. In particular, concentrate on how your athlete applies muscular force to produce a desired action in a skill. You must carefully assess the mechanical efficiency of your athlete's actions and the way he competes against gravity, friction, drag, air resistance, and the forces generated by opponents, whatever the opposition might be. In this way you can pick out technical (i.e., mechanical) errors that your athlete commits. What should you be looking for as you examine the elements in each phase? Here is a series of important questions you can ask yourself as a guide:
 

Does your athlete have optimal stability when applying or receiving force?
A wide base and correctly positioned center of gravity are essential for applying and receiving force. Check the position of your athlete's center of gravity and the way she sets up a base of support. Ask yourself the following questions:
    "Is her base of support extended in the direction it should be?"
    "Is the base too narrow or too wide?"
    "Is she standing too erect instead of squatting down?"
    "Is her center of gravity too dose to the edge of the base when it should be centralized?"
 

    If your athlete stumbles or gets thrown one way as the implement goes the other, or if she is too easily knocked off balance by an opponent, you'll know there's an error in this area. So check through the mechanical principles associated with balance and stability. Remember that stability is one turning effect (i.e., torque) battling another. To remain stable, your athlete may have to reposition her feet and center of gravity to apply more leverage and more torque.
    In many skills, your athlete must be able to move quickly and react in an instant. When she is receiving a serve, playing in goal, or reacting to the moves of an opponent, the objective is not maximum stability but rather a level of stability that allows her to move in a flash in any direction. We discussed these principles in detail in chapter 5.
    In particular, be sure to carefully check the size and alignment of your athlete's base of support and the position of her center of gravity during a skill's force-producing phase. An inadequate base not only makes your athlete unstable but, equally important, also reduces the distance and time over which she can apply force.
Is your athlete using all the muscles that can make a contribution to the skill?
    Athletes produce inferior performances when they do not apply force with all the muscles they can and should use in a skill. This may seem a strange state of affairs! After all, why not use the leg muscles, or any other muscle group, if they can make a contribution to the performance? If the performance of a skill requires the muscles of the legs, trunk, chest, and arms, and your athlete uses only the muscles of the chest and arms, then the total force put into the skill will be below optimal level. How can you tell if your athlete is using all the necessary muscles? Usually this is easy because in dynamic skills muscle contractions produce actions. If a limb segment or some other part of the body moves, you know muscles are contracting. Here's an example of what we mean. When a child throws a ball for distance for the first time, the youngster frequently stands still with his feet close together, then throws with his arm alone. There's no wide throwing stance. The throwing arm is not taken back, and the shoulders aren't rotated away from the direction of throw. In the force-producing phase of the throw, the muscles in the legs, trunk, and chest make no contribution. This error doesn't occur only among children. You'll see it happening among adults as well.
    Top-flight athletes always aim to have all the required muscle groups contributing to the skill. Elite rowers make sure that the muscles of the legs, back, shoulders, and arms play their part in the stroke. Elite speed skaters make sure that their leg muscles contribute optimally in powering them along the ice. The muscles working their arms and shoulders make their own contribution in counterbalancing the actions of the legs. Imagine how poor the performance would be if a speed skater failed to use her quadriceps muscles adequately to extend her legs, or if she skated with her arms hanging straight down instead of forcefully swinging them back and forth! The same principle applies to all skills. Make sure that all members of your athlete's "muscular team" are making a contribution by moving the body segments that they are responsible for moving. Think of your athlete's muscles as a tug-of-war team. If a team is made of eight members, why have one or more of the team resting on the rope without pulling?
 

Is your athlete applying force with the muscles in the correct sequence?
    If a world champion weightlifter performs a clean and jerk, and you critically examine the key elements of the clean (in which the athlete pulls the bar up to the chest), you'll see that the muscles of the legs, back, shoulders, and arms are contracted at about the same time. The extension of the legs is closely linked to an extension of the back and a strong upward pull with the arms. On the other hand, if you examine the key elements in the force-producing phase of a pitcher's fastball, you'll see a well­ defined sequence of actions, starting from the big muscles that accelerate the athlete's body and the large, more massive body segments and finishing with the high-speed movement of smaller, less massive body segments (i.e., the throwing arm and hand). All great pitchers step forward as the throwing arm is drawn back and the shoulders are rotated away from the batter. When they have stepped out into the pitching stance, their bodies rotate toward the hitter in a whip-like sequence that starts from the legs, shifts to the hips, then to the chest, and ends with a tremendous acceleration of the throwing arm. The pitcher's body acts like the handle of a whip that is being cracked. The hand gripping the baseball is the tip of the whip. A volleyball spike or a tennis serve uses a similar whip-like sequence of actions.
    This comparison between the actions used in a clean and jerk and a baseball pitch demonstrates opposite extremes in the sequence that an athlete's muscle contractions occur. When you examine each phase in your athlete's performance, check that the movement of his limb segments occurs in the correct sequence. If it does, then you know that muscle contractions are occurring in the correct sequence as well. A common fault for many athletes in throwing and hitting skills is to use the small muscles of the shoulders and throwing arm long before the big muscles of the legs, back, and trunk have done their job. The result is that the big muscles never get the heavier parts of the body moving ahead of those that are lighter. It's impossible to crack a whip if you don't accelerate the whip handle first.
 

Is your athlete applying the right amount of muscular force over the appropriate time frame and distance?
    You'll recognize this statement as our old friend impulse, which we discussed in chapter 3. Remember that impulse refers not only to the amount of force that your athlete uses but also to the time period that your athlete applies force.
    If your athlete uses the right amount of force for the right amount of time, his limbs move at the required speed through the required range of movement. When this occurs and all muscle contractions are sequenced correctly, you'll see movements that are fluid, smooth, rhythmic, graceful, and well coordinated. When an athlete applies force indiscriminately and haphazardly (and this is what novices do!), you'll see actions that are jerky and awkward. What you are seeing is the difference between a polished and well-practiced technique and one that is not.
    Practice helps your athlete establish how much force each muscle involved in a skill must exert. When they are learning, many athletes apply too much or too little force at the wrong time, and as a result, their technique will look jerky and awkward. You can help your athlete correct this situation by giving rhythmic cues that provide an idea of the speed at which he should perform the actions. You can also provide coaching tips such as "Step out long and low, and as soon as your foot hits the deck, thrust your hips toward the direction you are throwing" or "Stretch up at takeoff and swing your arms upward as fast as you can."
    Keep in mind that what is correct in a mechanical sense is not always possible in an anatomical sense. In other words, mechanical principles must fit with the design of your athlete's body. For example, athletes do not apply maximum force over the longest possible time frame even in hitting skills that require maximum velocity at impact or in jumping skills that require maximum velocity at takeoff. In these skills, good technique is characterized by limbs that are slightly flexed at the start of the skill and fully extended from maximal muscular contraction when impact and takeoff occur. Look for this action when you examine the final elements of the force-producing phases in golf driving, baseball batting, tennis serving, and track and field throwing.
    In skills that require accuracy, such as a volley in tennis or a drop shot in squash, look for controlled force applied over a specific range. Too much force or too great a range of movement defeats the purpose of the skill. When too much force or too great a range of movement occurs, the volley puts the ball out of the court. Likewise a drop shot in squash rebounds too high from the front wall, making the "get" easy for the opponent.
    A word of advice in relation to force and the time frame that force is applied. No one expects young novices to be able to produce the same force as adults, and likewise, you cannot expect novices to assume the same body positions and apply force over the time frame and distances elite athletes use. Make allowances when you watch your young athlete perform. Less force applied over a limited range of movement is not necessarily an error but a stage in the developmental process. More force and a greater range of movement will come with increased strength, flexibility, endurance, and coordination-all of which are carefully molded by your good coaching.
 

Is your athlete applying force in the correct direction?
    This principle may seem hardly worth mentioning, yet you should look for this factor, particularly in the force-producing phase of the skill. Elite sprinters drive down and back with each leg thrust so that they travel forward at the greatest possible velocity toward the finish line. The direction of each leg thrust gives these superb athletes the exact amount of vertical and horizontal thrust required by each sprinting stride. The result is optimal forward propulsion. You'd have no trouble deciding that there was some­ thing terribly wrong with a sprinter's technique if her leg thrust was directed out to the side, or if her arms swung sideways across her body rather than forward and backward! Errors like these in the force-producing phase of sprinting indicate that the athlete is wasting force and not applying it in the correct direction.
    In your analysis of the performance of sport skills, you'll notice that inexperienced athletes apply force in many different directions. They waste much of their muscular effort, and so it makes no contribution to their performance. Look also for inexperienced athletes to thrust and push in the correct direction with one part of their bodies and in an incorrect direction with another part. You see this often with novice downhill skiers. Young shot-putters of­ ten complain that putting the shot bends their fingers backward. A careful examination of the arm action in their throws indicates that they are not pushing directly behind the center of gravity of the shot. The thrust is in some other direction, and the result is that the shot bends their fingers back. Likewise, a hammer thrower or discus thrower who spins on the spot instead of traveling across the ring, or who falls sideways out of the ring when he releases the implement, is obviously misdirecting his force! Poorly directed force produces inadequate rotation at takeoff for gymnasts, divers, and figure skaters; mishits in sports that use dubs, bats, and rackets; miskicks in sports that use kicking skills; and poor propulsion in swimming skills.
 

Is your athlete correctly applying torque and momentum transfer?
    Many sport skills require your athlete to generate and control rotation. Rotation is applied to your athlete's body, an opponent, a ball, or an implement such as a discus. To initiate rotation your athlete must apply the turning effect of torque. The more spin required, the more torque he has to apply. In your analysis, check how much force he is generating and the distance this force is applied relative to the axis of rotation. In judo, look at the position of the axis of rotation that your athlete sets up for a hip throw and where he applies force to the opponent. Is your athlete strong enough to apply tremendous force? If not, is there any way of increasing the force arm (Ie., the distance from the axis to where force is applied)? The larger this distance, the less effort he must apply.
    In gymnastics, diving, and figure skating the number of rotations your athlete performs depends on how much torque he generates and how much momentum transfer he uses at takeoff. Momentum comes largely from arm and leg actions that are transferred at takeoff to his body as a whole. A skater who performs a double spin when intending to perform a triple may say, "I don't think I got enough spin." However, after you've analyzed the skater's takeoff you may disagree. Check the actions of the arms and the free leg to see whether they make an adequate contribution to rotation. You might decide that sufficient torque was applied at takeoff, and in fact it was overemphasized. Your analysis may indicate in­ stead that there was not enough upward thrust at takeoff and that the arms and free leg were not swung vigorously enough to provide any transfer of momentum in an upward direction to the skater's body.
 

Is your athlete decreasing rotary resistance to spin faster and increasing rotary resistance to spin slower?
    If a skill requires your athlete to spin faster, turn quicker, or swing the limbs at high speed, she must decrease her rotary resistance (i.e., rotary inertia) by pulling her body in toward her axis of rotation. The requirements of the skill determine the tightness of this position. Arms flexed at the elbows help produce a fast and efficient arm swing for sprinters and speedskaters. A tight tuck for gymnasts and a compressed body position for figure skaters when they spin around their long axis helps produce the required number of rotations. Extended body positions oppose a fast spin and slow down rotation. Is your athlete not tucking tight enough because of insufficient flexibility or lack of muscular strength, or is the problem inadequate knowledge of the correct timing in the skill? Your careful analysis of each phase and its key elements can pinpoint the source of the problem.
    Keep in mind that when your athlete rotates and extends the arms, her body slows but her arms and hands travel faster. Put a racket or a bat in your athlete's hand and the head of the implement travels fastest of all. Many skills require a combination of hip and shoulder rotation coupled with full extension of the arm (particularly at impact or release). For example, a tennis serve and a golf drive require full arm extension when the racket or club hits the ball. A discus thrower must release the discus with the implement as far from the body as possible. In your analysis, look for extension at release and impact and for some flexion and tighter body positions earlier in the skill.

Step 4: Select Errors to Be Corrected

    After you've analyzed each phase and its key elements, you have the task of deciding what sequence to follow in correcting errors. Like any enthusiastic coach, you'd like to correct every error in the first training session. The difficulty you'll face is that inexperienced athletes commit numerous errors, some of which are major and some minor. What is a major error and what is a minor error?
    A major error will be the absence or poor performance of any item that we've discussed under step 3 in this chapter. So, errors that destroy your athlete's stability or the optimal use of his muscular force are major errors. A minor error is an action that only partially detracts from the performance of the skill. Examples of minor errors include a backswing in golf that needs to travel a few degrees farther back, a throwing stance that needs to extend a little farther, and an arm swing at takeoff in a jumping event that needs to be more vigorous. To an elite athlete, minor errors of this nature make the difference between a good performance and a world record. To a coach working with a beginner, these errors can be placed on the back burner while other more important errors are corrected.
    The simple method to follow when selecting errors is to forget those that are minor and pick out those that are major. When you've picked out the major errors, select the one that has the most adverse effect on the skill and work on this error first. If you still have trouble deciding which error to choose, home in on major errors in your athlete's stance and body position-particularly in the preliminary stance and in the force-producing phase. Get the preliminary stance straightened out and then shift to the force-producing phase. Why? Because an athlete cannot apply force correctly unless stance and body position are correct. In throwing, hitting, and striking skills and in contact sports, poor position and lack of balance destroy everything! An incorrect stance will ruin a golf stroke, and an incorrect body position simply sets a wrestler up for a countermove. In swimming, a body position where the athlete is not horizontal in the water creates tremendous form drag. Keeping the head down and improving the leg kick can correct this. It's amazing how much faster a swimmer will travel when drooping legs are raised into a horizontal position.

Step 5: Decide on Appropriate Methods for the Correction of Errors

    The final step leads you from sport mechanics into methods of teaching and coaching sport skills. Errors in skill performances vary in complexity. At their most complex, errors can be mistimed sequences of high-speed arm actions occurring in flight as a diver combines a somersault with a twist. At their simplest, a young novice might put the wrong leg forward when throwing a softball. If you are coaching the diver, you have the options of discussion, video analysis, and demonstration of the correct arm actions from the side of the pool. If you are lucky enough to coach at a pool with high-tech equipment, with a press of a button you can foam up the water
with air bubbles so your diver can work on the arm actions knowing that she's not going to get hurt if she fails. You might also decide that the correct arm actions need to be reinforced over and over on the trampoline with your diver in a spotting belt. But once your diver is in flight there's no possibility of hands-on help from you, and your athlete has no chance of slowing the skill in any way. It's the same when you coach a basketball lay-up or a start in swimming. It's obviously easier when you teach a youngster to throw a softball. You can demonstrate and say, "Put your left leg forward, and turn your right shoulder to the rear as you take your arm back. " You can even move the youngster's limbs into the correct position. It's impossible to do this with a diver in flight or a swimmer leaving the blocks.
    Because sport skills vary so much and errors are so diverse, it's impossible to offer a single method that works for the correction of all errors. But we can provide a step-by-step sequence that will help in most situations you'll encounter.
 

Steps in Error Correction
    •  If possible, separate the phase that contains the error from the rest of the skill. Treat this phase and its key elements as a skill in itself.
    •  Break the phase and its elements into smaller parts. For example, if the error is poor synchronization of footwork and arm actions, consider teaching the footwork first. Then teach the arm actions. Later add the two together. Use verbal counts and rhythmic cues to assist your athlete.
    •  Design a practice or a specific activity that is useful for teaching the correct movements. This practice should be easy to perform and, if possible, novel and interesting to the performer. Above all, be creative and flexible in your approach. If the practice activity you have designed doesn't help correct the error, then change it. What works well for one of your athletes may not work so well for another.
    •  Whenever possible have your athlete perform new movements slowly.
    •  Walk your athlete through the required body positions, pausing wherever appropriate. Again, use a verbal count for rhythm.
    •  Increase the speed of performance slowly.
    •  Always be prepared to repeat a step in this progression if speed reintroduces errors.
    •  When you have decided that the actions you wanted to correct are learned well enough, put them back into the phase they came from, and check your athlete's performance. If you are satisfied, attach additional phases from the skill at either end of the one containing the correction. Check how your athlete integrates the new movements. If problems persist, reinforce earlier steps in this sequence.
    •  Attempt the complete skill at reduced speed and effort with the corrected movements in place.
    •  Progressively increase speed and effort.
 

Safety in Coaching High-Risk Skills

    As we mentioned earlier, in many skills it's impossible for the athlete to pause halfway through to rethink movements. These skills usually involve flight and often have a high element of risk. A back somersault in gymnastics floor exercises is such a skill. With skills of this nature we recommend the following sequence:
    •  Maximize safety with spotters, overhead spotting rigs, safety belts, crash pads, pits filled with foam rubber, or any other specialized equipment that fully protects the performer. In this way your athlete can perform the required actions with confidence and without danger.
    •  With highly complex skills, go back to a known skill that contains elements of the movement patterns you wish to correct. Use this skill to reinforce the correct actions.
    •  Progressively remove spotters and other specialized equipment as the skill is learned.
    •  When your athlete attempts the skill alone, provide experienced spotters who can assist if necessary.
 

Your Attitude During the Correction Process
    During whatever process of correcting errors you use, remain positive and praise good effort and correct performance. Your objective is to help your athlete persevere through those difficult periods when he feels that the correct action will never be mastered. The progress he makes will depend on the amount of practice, the complexity of the required actions, and how long it takes you and your athlete to mold the corrected action into the total skill.
 

Giving Advice to Your Athlete

    How you and your athlete communicate deter­ mines how much success you gain when you attempt to correct errors. Don't befuddle a young athlete with needless technical jargon. Translate your mechanical know-how into instructions that fit the age, intelligence, and physical ability of the athlete. Some athletes will be genuinely interested in the mechanical principles behind a movement. Statements such as "Push forward when you contact the ball-it'll help you apply more force" are excellent because they indicate in easy-to-understand language the mechanical reasons behind a body position. But for most athletes, comments about angular momentum, momentum transfer, kinetic energy, and rotary inertia are meaningless. For most athletes, the less cluttered their minds, the freer they are to perform. This recommendation also relates to the amount of information you give at anyone time in your instructions. Give simple, short, easy-to-understand instructions that are to the point. No athlete wants to stand around while the coach talks endlessly about what could or should be done.
 

Improving Feedback

    Few sports use mirrors the way that body building does. Besides providing bodybuilders with continuous aesthetic assessment, mirrors pro­ vide instant visual feedback on how they per­ form an exercise. In the highly dynamic actions of most sports, the nearest you can get to a mirrored image is an immediate playback on a video machine. The machine tells your athlete, "This is what you looked like." However, neither the machine nor a mirror can say, "This is what the movements should feel like." Your athlete is the only one who actually feels the movement. As a coach observing and assessing the skill, you can­ not feel what your athlete feels although you can describe what it should feel like to your athlete. To be able to provide this kind of information requires considerable experience from you, first as an athlete and then as a coach.
    Sometimes you'll be surprised at the response when you ask, "What did you feel at that moment in the skim" Many novices have no idea what happened, and they have no sense of where their limbs are as they attempt a skill. Elite athletes differ considerably. Most of them have a well-developed kinesthetic sense and are aware of what their bodies are doing during a performance. Teach young athletes to develop this sensory awareness. It becomes an invaluable resource in helping them master sport skills.
 

Consider the Time Available for Correcting Errors

    One factor that considerably influences error correction is the time you have available to work with your athlete. Can you plan a training program that stretches over several months or a year, or are you working with a three- to six-week block before the competitive season starts? When you are restricted by time, it affects your choice of errors and the methods you use to correct them. You may feel that all you can do is correct some minor errors because major changes initially make your athlete perform poorly, and this downtime can carry into the competitive season. Whenever an athlete has to think about what he is doing in one or more phases of a skill, the effect is a drop in performance. The correct action must become second nature-an unconscious action. Remember that correcting a minor error can affect performance considerably. Be satisfied with that! Save large changes in technique for the off-season.
 

Getting Additional Help

    You must gather information from many different sources if you want to become a good coach in your chosen sport. In the area of analysis and skill correction, you should be ready to do the following:
    •  Read texts on your sport that offer successful teaching methods and techniques for correcting errors. The best texts should offer excellent illustrations of lead-ups and teaching progressions. A quality text contains lists of common errors that occur in the skills of your sport, with explanations on how to correct them. Look also for safety recommendations, not only for individuals but also for group activities. This is particularly important when you are teaching skills that have a high element of risk.
    •  Plan to attend coaching seminars and work­ shops. Here you can listen to presentations on coaching from experienced coaches and experts who do research in your area. You can discuss problems in your sport with coaches who are aware of the latest coaching techniques. Join your local and national coaching association so you can regularly receive the latest newsletters.
    •  Modem video and computer technology now gives you the opportunity to analyze performances in super-slow motion and to place elite performers on the same screen as novices. This is of tremendous assistance when you want to look at differences in technique. Computer advances in virtual reality now offer you and your athlete a "virtually real" method of experiencing the movement patterns of a skill while remaining static. Previously, downhill skiers and luge competitors would close their eyes and imagine steering through the curves and straight-aways. With virtual reality your athlete can put on a specially designed helmet that feeds a 3-D image containing an accurate representation of the bends, twists, and straight-aways that exist on the course. When applicable, a computer will have worked out the best course to follow relative to temperatures and other weather conditions.
    •  Read beyond this book and improve your knowledge of mechanics as it applies to your sport. Take an interest in other sports as well. It will make you more of an expert in your own!

SUMMARY

    •  There are five steps to the effective observation, analysis, and correction of errors in sport skills: (1) Observe the complete skill, (2) analyze each phase and its key elements, (3) use your knowledge of sport mechanics in making an analysis, (4) select errors to be corrected, and (5) decide on appropriate coaching techniques for the correction of errors.
    •  Observe skills from several different positions; avoid settings in which you and your athlete are distracted. Use video recordings to assist in your analysis.
    •  Do not concentrate on skill analysis while you are involved in spotting the performer.
    •  Once you have a good overall impression of an athletic performance, analyze each successive phase of the skill together with its key elements.
    •  Use your knowledge of sport mechanics for analyzing performance. Ask yourself mechanical questions (e.g., Does the athlete have maximum stability when applying or receiving force?).
    •  Divide the performance errors you see into major and minor categories. Major errors seriously detract from the optimal performance of the skill, whereas minor errors have minimal effect on performance. Follow the sequence outlined in this chapter for correcting errors.
    •  Use the very best safety techniques when correcting errors in skills that contain a high level of risk.
    •  Maintain a positive attitude during the correction process. Avoid using excessive technical jargon during coaching sessions.
    •  Teach athletes to develop sensory awareness to assist them in error correction.
    •  Be aware of the time you have available for correcting errors. Do not attempt massive changes in technique if time is limited.
    •  Attend coaching seminars and read texts on your sport that offer top-quality teaching methods and techniques for the correction of errors. Be alert to any advances in computer and video technology that can assist you in coaching. Expand your knowledge of sport mechanics, not only in your sport but in other sports as well.

REVIEW QUESTIONS

    1. What is a good sequence to follow when analyzing each phase of a sport skill?
    2. What is the mechanical difference between the recovery in a swimming stroke and the follow-through in a throwing skill?
    3. What is the common appearance of a skill when an athlete tries to use more than the optimal number of muscles in a performance? Give a common example of an athlete applying muscular force in the wrong sequence to perform a skill.
    4. Why is it important for an athlete to apply the right amount of force over the appropriate time frame with each of the muscles involved in a sport skill?
    5. What does this text refer to as major errors in the performance of a skill?
    6. What resources can you use to help you become a better coach in your sport?

PRACTICAL ACTIVITIES

Using video clips, analyze the following sports (and sport skills) using the questions listed underneath each sport as a guide to your analysis.
 

Freestyle wrestling competition. Watch one competitor for the duration of the clip and then repeat the clip watching the other competitor. The following questions will guide your analysis.
    a. How did the attacker increase or decrease his stability during an attack?
    b. How did the attacker attempt to increase the torque and lever action applied against the opponent?
    c. What did the defender do to increase his stability and counter the attack?
    d. When there was a successful attack that overcame the defense, what mechanical factors made the attack successful?
    e. When there was a successful defense that overcame an attack, what mechanical factors made the defense successful?
 

A mount on the beam in women's gymnastics. Watch five elite athletes run and mount onto the beam in a gymnastics competition. The following questions should guide your analysis.
    a. How big was the base of support of each athlete at the instant of landing on the beam?
    b. Did the skills used for the mount provide any specific methods for enlarging the athlete's base of support? If so, describe what these actions were.
    c. Did the athletes regulate their height and line of gravity to improve their stability? If so, what actions did they make?
    d. What actions did the athletes make with their arms, head, or legs to maintain stability?
    e. Did the athletes move quickly into the next skill in their routine? If so, did this help or detract from the performance of the mount?
 

A fastball pitch in baseball. Watch an elite athlete pitch several fastballs. Then use the following questions to guide your analysis.
    a. How did the athlete increase the size of the pathway over which the baseball was accelerated?
    b. What was gained from stepping forward toward the hitter? How does this compare with the actions used by a javelin thrower?
    c. Outline the sequence of limb and body movements used by the athlete to achieve the great release velocity of the baseball.
    d. What relationship is there between the sequence of limb movements that the athlete uses and the mass, inertia, and length of these limbs?
    e. Explain how linear and rotary motion are combined in the pitch.
 

A volleyball spike. Watch elite volleyball players spiking the ball. Then use the following questions to guide your analysis.
    a. What is gained from the steps used in the approach? Why perform the approach to the takeoff in the volleyball spike?
    b. What changes occur in body position and also the position of the athlete's center of gravity in the penultimate (next to last) and last steps (or strides) of the approach?
    c. How is momentum transfer employed in the takeoff?
    d. What particular differences exist between the volleyball spike and the high jump? (Compare the approach and the takeoff).
    e. Is all of the athlete's force used to direct the athlete in a vertical direction? If not, what occurs?
    f. What happens to other parts of the athlete's body when the striking arm is positioned ready to spike, and immediately after contact has occurred?
    g. How does the athlete generate the tremendous velocity of the striking hand?
    h. If the athlete spun the ball, explain how it was achieved.
 

Long jump. Watch elite athletes performing the long jump takeoff. Then use the following questions to guide your analysis.
    a. What is gained from the approach in the long jump?
    b. What changes occur in body position in the penultimate and last steps (or strides) of the approach?
    c. How does the body position of the athlete performing the long jump takeoff differ from that of athletes performing the high jump and the volleyball spike?
    d. What are the mechanical reasons for the changes in body position of the long jumper in the penultimate and final strides prior to takeoff?
    e. How is momentum transfer employed in the takeoff of the long jump? Compare with the high jump and the volleyball spike.
    f. What is the approximate angle of takeoff of the long jumper? Compare with the angle of takeoff used by the high jumper and the volleyball spiker.
    g. Is all of the athlete's force used to direct the athlete through the air in a horizontal direction? If not, what occurs?
 

Sprint starts in a 100-meter race. Watch elite athletes performing a sprint start in the 100 meters. Then use the following questions to guide your analysis.
    a. Is the athlete in a position of maximum stability or minimal stability in the set position?
    b. Comment on the line of gravity, the position of the center of gravity, and the area of the supporting base in the set position.
    c. What is the position of the leading leg and the arms immediately after the gun is fired? Why is there an acute angle at the knee and at the elbows?
    d. What is the position of the leg driving back at the blocks immediately after the gun is fired?
    e. Where is the center of gravity of the athlete just prior to the recovery of the leg that is driving back at the blocks? What is the reason for its particular position?

    f. Are the accelerative strides of the athlete long or short as she comes out of the blocks and sprints the first 5 meters?

    g. What is the cadence of the accelerative strides of the athlete coming out of the blocks? Is it fast or slow?
    h. What differences exist in the length and cadence of the strides between those used over the first 5-10 meters and those used in the middle portion of the race?
    i. Comment on the rise and fall of the athlete's center of gravity once the athlete is running at full speed.

FROM: SPORT MECHANICS for COACHES --- Chapter 8 --- by GERRY CARR