Sh*t things good coaches do

Sh*t things good coaches do

There are two kinds of coaches, broadly speaking:

  • There are shit coaches. This is, unfortunately, the majority in my experience. This isn’t usually due to the coaches themselves, though it often is. It’s due primarily due to the low quality of Level 3 PT courses, the lack of support that coaches get after doing these courses, and the impression that the public have of what a PT does
  • Most who aren’t in the industry see PT’s as either fitness bunnies who irritate everyone by exclaiming how happy they are all the damn time, and selling them detox plans, as meathead drill instructors that shout ONE MORE every now and then and berate their clients for not eating clean enough, or just fitness enthusiasts who work out for a living. This image allows people to think “I don’t want to sell stuff to people, and I’m no drill instructor – I’m DIFFERENT. I just love fitness”
  • Loving fitness isn’t enough to be a good trainer, though, and starting your career because you want to work out all of the time then doing a course that doesn’t really prepare you for what’s ahead is a recipe for disaster. A completely unprovable but regularly cited statistic is that the average Personal Trainer lasts 1-3 years in the industry before moving on to something else (1), and most of those dropping out don’t do it because they were great at their job
  • There are good coaches. These guys realise that PT’ing is about more than writing workouts and telling folks to eat kale. They understand that you need to understand programming, nutritional science, motivational science/psychology, behaviour change and interpersonal relationships. They see themselves as a support figure rather than a dictator, and they help their clients in every feasible way to ensure they achieve their goal. They wouldn’t be caught dead prescribing the same meal plans to everyone, chastising a client for not adhering to their dietary protocol, or for wanting an easy training session because life is a bit tough at the minute

    By reading this blog, I’d be happy to bet a decent amount of money that any trainers out there are type 2. If you’re not a coach but find yourself working with one (or thinking about it) then I hope you’re able to find a type 2 coach – they are few and far between, but definitely worth every penny they charge.

    They aren’t immune to doing shit things, though. We all have cognitive biases, intellectual blindspots and opinions we consider to be fact. Aleksandr Solzhenitsyn famously said that “the line dividing good and evil cuts through the heart of every human being”(2), and in my experience the line dividing good and shit coaching cuts through the mind of every personal trainer who believes that they have little else to learn.

    Below are some of the key things that great personal trainers do, but which are sometimes misguided, ineffective or downright rubbish. It’s not my intention to pass judgement on anyone here, of course (who the hell am I to judge?) but rather, to allow you to identify common mistakes made by those who wish to do well so that you’re better equipped to spot this in yourself, or in your coach.

    1. Refusing to write meal plans

    “I don’t write meal plans”

    “I educate you, rather than writing a meal plan”

    “Meal plans don’t work”

    “Meal plans don’t teach you anything”

    I’ve been guilty of saying all four of these things, and I’ve heard them echoed by a number of other coaches. In fact, it’s been incredibly popular for good coaches to denounce meal plans as ineffective, lazy approaches that leaves clients frustrated due to the ‘fact’ that they are an inherently useless idea.

    This is somewhat mistaken, though.

    Sure, some clients would absolutely not benefit from a meal plan whatsoever. These are clients for whom life is a bit ‘all over the place’ so eating out regularly is a hurdle; or simply clients that already have a decent handle on nutrition but who need their approaches to be fine-tuned. In this case, an approach whereby a coach provides macros/calories and checks in on adherence or makes suggestions for handling anomalous situations is a great option.

    This is not going to be the majority of clients that a typical coach comes across, though. According to HSE, 47% of Britons tried to lose weight in 2013 (3), that’s over 30 million people trying to shed some lbs, and a not-so-insignificant number of those people represent a large chunk of the PT target market.

    Simply, the most common goal that any PT will encounter is weight loss, and those who need help losing weight are generally not the kind of people mentioned above. Conversely, these are the kinds of people who need a lot of help. They need guidance. They need to know what to DO.

    As I’ll come back to, according to self-determination theory the three psychological requirements that people have for success in living healthfully are relatedness, autonomy and competence (4). I’ll get into the definitions of the other two later on, but competence should be a fairly self-defining term. In order for a client to be able to do something they need to think that they are able to do it, and because of this a large barrier faced by many clients (either nutrition-only or exercise based clients) is a lack of self-belief and a large amount of overwhelm.

    Fat loss clients generally either have very little knowledge about nutrition, or they know enough to be overwhelmed by it. There is more information available to the general public than there was available to medical doctors only a few decades ago, but along with this general increase has come an increase in the ratio of noise:signal. Frankly, most information about nutrition and exercise that the general public gets is awful, because it primarily comes from salesmen, biased Netflix documentaries, the Daily Mail and stuff their mates say.

    Then if we come along as a personal trainer and ask them to plan their own food out using some guidelines we give them, the guidelines offered just get added to the pile of “stuff I know already” and the client is suddenly overwhelmed. They don’t know where to start – or they are given a small habit like ‘drink more water’ (which, in your head, is a great starting point from which to build a healthy lifestyle) and they start to resent paying you so much for the privilege of being told something they have been told since school.

    If, however, you sit down with your client and discuss a meal plan with them, you accomplish the parallel goals of:

    • Showing them how to plan food
    • Telling them how to plan food
    • Ensuring the foods that they plan in are appropriate for their goals (so they may not be ‘perfect’ immediately)
    • Giving them something to take away and action immediately, to great effect
    • Educating them about what a healthy diet looks like from buying to preparing to eating

    Once a client has their starting point, they are able to start actioning the things you ask them to without having to come up with ideas that, frankly, they wouldn’t have hired you if they were able to come up with themselves. Once the client has sat with you and created 3-4 meal plans for 3-4 weeks, they will be far better placed to start doing it on their own. The meal plan has worked, they have learned, and you have coached. Not a bad outcome for a ‘bad idea’.

    2. Advocating an approach whereby ‘no foods are off limits’

    The flexible dieting movement told us that ‘there are no good and bad foods’. It brought us around to the idea that a meal of equal calorie/macronutrient makeup has largely the same impact on the body regardless of whether it’s whole food based or highly processed (5), that the amount of fat or carbohydrate you eat doesn’t matter much so long as protein is kept steady (6) and that highly restrictive diets can lead to disordered eating behaviours (7).

    This has lead to coaches/trainers espousing the idea that ‘there are/should be no banned foods’, or that restrictive diets necessarily lead to eating disorders like orthorexia. It is my position, that while this is OBVIOUSLY said with the absolute best of intentions by great coaches who care about their clients, this is mistaken.

    When talking about restriction they are evidently talking about restriction in terms of food choice. Restriction per se is not considered a bad thing, as is evidenced by the fact that these coaches are happy to restrict their clients’ calories until they lose weight. Some coaches will also restrict their clients’ fat and/or carbohydrate intake to do so, too, by providing target ranges for their clients to aim to fall in to for each macronutrient.

    This may seem a semantic issue but it isn’t, what this is telling us is that some restriction is OK – that there is a level of restriction that these coaches fundamentally understand is not problematic. Therefore, my disagreement with them is not based on principle, rather it is based in the fact that I think their definition of what is unacceptable or harmful restriction is too broad.

    What I’d argue is twofold:

    First, there is the simple fact that some foods are really, really hard to resist. Hyperpalatability is a characteristic of modern manufactured foods that has not been present in the food chain throughout our evolutionary history. I love Cinnamon Swirls as much as the next guy, but as far as humankind is concerned they are a bit of a novelty and that might not be such a good thing.

    We have two primary drivers to eat (8). The first is known as the metabolic or homeostatic mechanism, governed by energy needs, activity levels and general maintenance of your present weight. If you undereat for a day you’ll be hungrier the next, and your appetite will be roughly matched to your daily calorie requirements so long as you focus on the foods that we evolved eating. This mechanism can therefore be faulty if we eat highly calorie-dense foods that pack a lot of energy into one bite, and we eat them quickly. This allows us to pile a lot more calories in than we need without feeling full until it’s too late.

    The other mechanism is probably the most deleterious for our health, though – the hedonic system. This system drives us to eat more and more even if our energy needs have been met, so long as the foods we are going for meet certain criteria (primarily a high amount of carbohydrate or fat, but also protein and salt). It’s not hard to see this in your own behaviour – how much pizza can you eat (in terms of calories) without getting bored, vs unseasoned chicken, undressed salad and plain steamed rice?

    These hedonic properties are bad enough, but then we need to consider that the drive to eat hyperpalatable foods is not equal between individuals. Obese people experience a far greater response in the corticolimbic areas of the brain upon eating than do healthy-weight people(9). This area is responsible for emotion, learning, reward and addiction meaning that these actions are more likely to be repeated. Conversely, obese people also show a reduced level of activation in the caudate nucleus – an area associated with reward – due to decreased dopamine (the ‘happy neurotransmitter’) receptor sensitivity (10), meaning that while some areas of the brain respond really well to make obese people feel great upon eating, other areas are far slower off the mark, meaning that more food is needed to satiate desire.

    That desire, incidentally, is at least in part caused by activity in the gustatory cortex and somatosensory regions, and activity here in response to food cues (so seeing or thinking about food) is far higher in obese individuals than healthy weight folks (10).

    Putting all this together, some foods taste so good that we want to eat more of them. Obese people who are shown these foods (bare in mind that they are omnipresent in modern society) crave them more than healthy-weight people. Then upon eating, an area of the brain associated with reinforcing behaviour is way more active, but an area of the brain associated with feeling that a craving has been sated is activated to a reduced degree. More cravings, more reinforcement, more food needed. Neurologically, these foods are just not a great idea for people that find themselves in this situation, and so it’s no wonder that many overweight people have ‘trigger foods’ or things that they just can’t portion control. It’s not at all unreasonable to suggest that foods that are highly sweet, salty or fatty should be heavily reduced or even temporarily eliminated in the diet of someone who finds it very hard to resist them. Sure, if eating out there’s no harm in a client fitting some dessert into their macros, but for a lot of people, one or two cookies just doesn’t cut it.

    Then there is the more straightforward issue at hand – these individuals don’t need fat loss because their eating has been historically restrictive. Rather, they have been eating an unrestricted diet for far too long, and that’s why they are in a situation that justifies hiring a coach in the first place. If you were to tell them that there are no unhealthy foods, or that they can eat whatever they want and lose weight, their response is going to be less than enthusiastic. That’s what they’ve been doing all along (and let’s face it, WeightWatchers have been giving that same message for years, it’s not new). Quite often those who are ardently against any kind of food restriction are reacting to a historic oversimplification of the issue from the world of fitness, where ‘eating clean’ was the done thing.

    These people are either evidence based folks who want to battle the belief that nobody really has anymore outside of cultish ‘healthy eating’ circles like FoodBabe followers, or they are people who have themselves been stung by overly restrictive dieting (or a smaller third group, who work with the latter on a regular basis). These people bought into the idea that you had to eat clean and it didn’t work for them, it gave them eating issues, or something else, and now they are fighting the good fight so that their clients don’t need to fall into the same fate.

    This is potentially projection, though. Unless your clients are having these issues, there’s no real need to avoid restriction in all it’s forms, just because some (and perhaps you) have the kind of personality and mindset that renders it destructive. Many clients coming to a coach are CRYING OUT for a little restriction. They want structure, and they want something that changes the status quo. There’s nothing stopping you adding these things back in later, and it’s DEFINITELY a good idea to educate them on the context behind the idea that they should maybe not eat ice cream for a while – but advocating an approach where ‘anything goes’ might not be the best idea, all of the time either.

    3. Giving all of the answers

    As a coach it’s hard not to consider yourself the expert in the relationship with your client. It’s self-evident that the client has come to you for the answers because they don’t know what do to, and therefore they are paying to give answers to them, right?

    Well, yes and no.

    As above, you need to give a certain amount to your clients because the truth of the matter is they don’t know exactly where to start and exactly what to do. That lack of understanding the practical first step is what leads to overwhelm and inaction, but the story does not end there.

    As I noted above, there are three facets to motivation, competence, belonging and autonomy. That is, a client needs to know they can do what they need to do, they need to belong to a wider support network of people who have the same interests as them, who have their back and to whom they can turn for support when they need it, and they also need to be the masters of their own fate.

    Self determination theory posits the simple truth that most people know roughly what constitutes a health-promoting behaviour:

    • People know broccoli is better for you than crisps

    • People know water is better for you than coke

    • People know fruit is a better daily snack than cake

    • People know they shouldn’t drink to excess

    • People know they shouldn’t smoke

    People know all of this, the problem is they are either not ready to change their behaviour, or they aren’t aware of HOW they go about doing what they need to do. If someone isn’t ready, they aren’t ready, and in the interests of keeping this blog under 10,000 words I’ll just advise that and coaches/trainers reading this look back to the Transtheoretical Model of change taught at Level 3, or just watch this video.

    If someone is ready to change but not entirely sure how to go about it, you have two options available to you but most coaches are drawn to only one, especially a good, caring coach who really wants to help. This option is to dictate to the client what they need to do as an expert.

    For example, consider a client who snacks really regularly on crisps. We know that these aren’t helping them stay full, they aren’t providing much in the way of useful nutrition, and they are contributing a significant number of calories the client can do without. The coach may say to them “Next week, why don’t we see if you can cut your crisp intake down to 2 or three packets, and see how you feel?”

    This seems reasonable, right? The coach has opened up a discussion with their client, and hasn’t simply given an order. What they have ALSO done, though, is to place themselves as a figure of authority to whom the client needs to pay attention. They have implied that the client is at their whim, and they are now banking on the client doing as they are told. This is a risky proposition, and it also doesn’t provide the client with a valuable opportunity for self reflection.

    The ‘expert trap’ is exceedingly hard to avoid because it seems so natural, but imagine that instead of this approach, the coach had simply sat with the client and looked at their food diary and said:

    “OK, you didn’t lose as much weight as you wanted this week. As you know, the key thing we need to do is reduce your calorie intake a bit and create a deficit. What do you think would be the easiest place to drop some calories from your day?”

    All of a sudden the client is in the driving seat. The client has been asked to look at what they are doing and make a judgement. This is powerful because eventually the client is going to stop working with you and they need to be able to do this, but more than that, the client is no longer placed on an inferior platform – they are made equal to the coach who is positioned as an advocate and an advisor rather than an expert. The client is far more likely to do what they have thought of themselves, than they are to do what the coach has told them to do – even if the coach knew what they wanted and lead the horse to water, and even if the action is the same.

    This technique is called ‘Motivational Interviewing’, and I would urge anyone who wants to improve their communication skills with clients, to check out this book.

    4. Going for slow and steady fat loss, every time

    “Crash dieting is unhealthy, unsustainable and ineffective” say thousands of well-meaning coaches every day, and just like every pervasive myth, there is some truth to this. Hella low calorie diets have obvious drawbacks, including increased hunger, greater feelings of fatigue and a potential risk of nutritional deficiencies due to the sheer lack of food. That’s not to mention the fact that people who tend to crash diet regain the weight really quickly.

    There’s a lot more to this story, though.

    First of all, nobody is saying that very low calorie diets are sustainable, but the idea that a diet NEEDS to be sustainable long-term is mistaken. Low calorie diets need only be maintained for the amount of time that it takes someone to achieve their fat loss goal, and so just because ‘you won’t be eating like that a year from now’ that doesn’t mean that you’re not going to be able to stick it out for 16 weeks before going back to a higher, maintenance calorie intake.

    Then, within that, there is the assumption that a calorie deficit must be equal all of the time, and that is false. A rapid fat loss approach could be used to create a great deal of initial fat loss (hello feelings of competence) before a period of more slow progress involving more food. A recent study (11) that compared continuous energy restriction to intermittent restriction (one group ate 67% of maintenance calories for 30 weeks, one did 7 rounds of 2 week restriction to 67% and 2 weeks at maintenance) showed that the intermittent option yielded greater results – even though they were prescribed more calories throughout. If someone is looking for rapid fat loss, including 1-2 week periods involving a big deficit alongside 2-3 weeks of a moderate one could be a means of increasing the rapidity with which they reach their goal, in a way that is more effective than just slashing calories across the board.

    Finally, consider that yes – most crash dieters regain the weight – but most dieters IN GENERAL do. We only notice the crash dieters because, in the general public, that’s most of them. When comparing the recidivism of overweight people who diet quickly or slowly, there is no difference in rates of regain so long as fat free mass is preserved (12) and in fact rapid initial fat loss predicts success in weight loss maintenance when compared to a slow and steady approach (13). For those concerned, it’s also the case that lean body mass can be preserved very well on very low calorie diets so long as protein intake is adequate (14) and resistance training is performed (15). Worthy of note, is that this approach can have significant utility for obese, non-insulin dependent diabetics, too (16).

    The suitability of very low calorie diets, intermittent rapid fat loss approaches or ‘sharp shock’ initial weight loss incorporated into a standard long-term approach will depend entirely on the client, of course, and those who have high performing jobs, a lot of lifestyle stress or other factors that might preclude them from dramatic change might be better off opting for a slow and steady approach every time.

    That’s not everyone though. Only a Sith deals in absolutes.

    5. Talking during a client’s set

    The final shit thing that great coaches do, is trying to communicate to a client during a set. This could be counting out loud, giving generic ‘good rep’ motivation that doesn’t mean anything, or (my personal bugbear) correcting form mid-set. There are other examples, but I’ll deal with each of these individually to illustrate my point in a moment.

    The main reason that this is a really bad idea comes down to the theory of attentional capacity, perhaps first popularised by Kahneman in 1973 with his book ‘Attention and Effort’ (17). The quote that best illustrates the problem is this:

    “It is the taking possession in the mind, in clean and vivid form, of one out of several simultaneous possible objects or trains of thought. Focalization, concentration of consciousness are of its essence. It implies withdrawal from some things in order to deal effectively with others”

    Put simply, attentional capacity is the idea that we can only focus on so many things at a time, and that focusing on one thing necessitates the withdrawal of attention from something else. To sum up the points below, every time you talk to a client, you are taking them out of ‘the zone’, even if you are talking in order to motivate them. Intention and outcome aren’t the same, and a ‘great rep’ is just as distracting as anything else you could say to them. On to specifics:

    Counting your client’s reps out loud accomplishes two things very well: it reduces your client’s autonomy, and it distracts them. There’s nothing wrong with saying ‘good, two more’ when the client completes rep six of 8, as this allows them to ‘not’ focus on counting for the whole set, and instead concentrate on their lifting. It also gives them the autonomy to count those last two reps so they feel involved with the process. If your client is doing 12, though, and you count from 1-12, you’re wasting breath, distracting the client, and also kinda implying your client can’t count.

    Telling the client that every other rep was good, great, nice, perfect, or any other words PT’s seem to be unable to stop saying tells the client nothing. They don’t know why it was good, they don’t know what was good, and now they are listening to you. Instead, tell them at the end of the set what specifically was good about it, or don’t say anything at all. Creating an abundance of something immediately devalues it, and if your client is being praised 2-3 times per set for 15-20 sets, 2-3 times per week, all of a sudden it doesn’t mean anything anymore.

    Finally, let’s talk about fixing form during a set. Of all the things PT’s do, this is the single biggest distraction. Not only does your client need to listen to you, they need to process what the hell ‘keep a neutral spine’ means, or how they are supposed to ‘tuck their elbows’, do that thing, then work out how to perform the rep in their new position. This is going to be very difficult, and even if the client DOES manage it, they won’t really remember what they have done for the next set. A note to ‘lock it out’ or ‘look up’ is fine if the client usually does it then their form breaks down due to fatigue, but for any great changes in technique – save it until after the set (of course, unless the client is going to get hurt, in which case just kill the set and talk).

    The only real time that talking to a client is a good idea, is either in the example above where a small cue is needed to get the client to do what they know they need to do and usually would do, but stop because they are tired, in the example above of indicating the number of reps left – OR in the instance that the client is going for a really hard rep or two. Perhaps they are doing 8 reps with their true 8 rep max, and after rep 6 they stop and pant. Here a ‘Come on!’ or a ‘You got it, two more!’ may come in handy, but other than that?

    Shut up and let your client train.

    Final thoughts

    If you’ve made it this far, congratulations. As I mentioned in the preface, any PT reading this is likely to be a pretty damn good coach in their own right, and any great PT who reads an article like this obviously wants to improve, so I’ll congratulate you there!

    If you feel like you have fallen for any of the above, identifying it is 75% of the battle. Changing what we do as practitioners over time is one of the most important thing that I think a PT can do if they want long-term success, and the above points aren’t bad places to start. A lot of the points above are mentioned on the Advanced Nutrition Coaching Course. Any coach who decides to sign up for an online nutrition course is obviously one who wants to help, and so we endeavour to allow our students to do that in the most effective way possible.

    From understanding motivational theory and the psychology behind overeating, to the applied practices of programming for nutritional interventions and personalising approaches, our students learn everything they need to be the best damn coaches they can be – with one lesson being paramount:

    Never stop learning.

    Thanks for reading

    References

    1. Hogen, R. (2010). Career lifespan of the personal trainer. [online] Fitness Trainer Network. Available at: http://www.fitnessnetwork.com.au/_blog/Network_Blog/post/Career_Life_Span_of_the_Personal_Trainer/ [Accessed 10 Oct. 2017].
    2. Solzhenitsyn, A. (1998). The Gulag Archipelago, 1918-1956. Boulder, Colo.: Westview Press.
    3. Piernas, C., Aveyard, P. and Jebb, S. (2016). Recent trends in weight loss attempts: repeated cross-sectional analyses from the health survey for England. International Journal of Obesity, 40(11), pp.1754-1759.
    4. Selfdeterminationtheory.org. (2017). selfdeterminationtheory.org – Theory. [online] Available at: http://selfdeterminationtheory.org/theory/ [Accessed 10 Oct. 2017].
    5. Bray, G., Most, M., Rood, J., Redmann, S. and Smith, S. (2007). Hormonal Responses to a Fast-Food Meal Compared with Nutritionally Comparable Meals of Different Composition. Annals of Nutrition and Metabolism, 51(2), pp.163-171.
    6. Sacks, F., Bray, G., Carey, V., Smith, S., Ryan, D., Anton, S., McManus, K., Champagne, C., Bishop, L., Laranjo, N., Leboff, M., Rood, J., de Jonge, L., Greenway, F., Loria, C., Obarzanek, E. and Williamson, D. (2009). Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates. New England Journal of Medicine, 360(9), pp.859-873.
    7. Masheb, R. and Grilo, C. (2000). On the Relation of Attempting to Lose Weight, Restraint, and Binge Eating in Outpatients with Binge Eating Disorder. Obesity Research, 8(9), pp.638-645.
    8. Yu, Y., Vasselli, J., Zhang, Y., Mechanick, J., Korner, J. and Peterli, R. (2015). Metabolic vs. hedonic obesity: a conceptual distinction and its clinical implications. Obesity Reviews, 16(3), pp.234-247.
    9. Dimitropoulos, A., Tkach, J., Ho, A. and Kennedy, J. (2012). Greater corticolimbic activation to high-calorie food cues after eating in obese vs. normal-weight adults. Appetite, 58(1), pp.303-312.
    10. Stice, E., Spoor, S., Bohon, C., Veldhuizen, M. and Small, D. (2008). Relation of reward from food intake and anticipated food intake to obesity: A functional magnetic resonance imaging study. Journal of Abnormal Psychology, 117(4), pp.924-935.
    11. Byrne, N., Sainsbury, A., King, N., Hills, A. and Wood, R. (2017). Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study. International Journal of Obesity.
    12. Vink, R., Roumans, N., Arkenbosch, L., Mariman, E. and van Baak, M. (2016). The effect of rate of weight loss on long-term weight regain in adults with overweight and obesity. Obesity, 24(2), pp.321-327.
    13. Nackers, L., Ross, K. and Perri, M. (2010). The Association Between Rate of Initial Weight Loss and Long-Term Success in Obesity Treatment: Does Slow and Steady Win the Race?. International Journal of Behavioral Medicine, 17(3), pp.161-167.
    14. Bryner, R., Ullrich, I., Sauers, J., Donley, D., Hornsby, G., Kolar, M. and Yeater, R. (1999). Effect of Resistance vs. Aerobic Training Combined with an 800 Calorie Liquid Diet on Lean Body Mass and Metabolic Rate. Journal of the American College of Nutrition, 18(2).
    15. Donnelly, J., Jakicic, J. and Gunderson, S. (1991). Diet and body composition. Effect of very low calorie diets and exercise. Sports Medicine, 12(4), pp.237-49.
    16. Henry, R., Wiest-Kent, T., Scheaffer, L., Kolterman, O. and Olefsky, J. (1986). Metabolic consequences of very-low-calorie diet therapy in obese non-insulin-dependent diabetic and nondiabetic subjects. Diabetes, 35(2), pp.155-164.
    17. Kahneman, D. (1973). Attention and effort. Englewood Cliffs, N.J.: Prentice-Hall.

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