I don't usually do this but I saw a book that should be published this fall you all should know about.  I have yet to see it but if it's like any of their other *.Anatomy  series, it will be terrific.  It's called "Swimming Anatomy" published by Human Kinetics.  Here's the description published with permission of Human Kinetics.

"See how to achieve stronger starts, more explosive turns, and faster times! Swimming Anatomy will show you how to improve your performance by increasing muscle strength and optimizing the efficiency of every stroke.

Swimming Anatomy includes 74 of the most effective swimming exercises, each with step-by-step descriptions and full-color anatomical illustrations highlighting the primary muscles in action.

Swimming Anatomy goes beyond exercises by placing you on the starting block, in the water, and into the throes of competition. Illustrations of the active muscles for starts, turns, and the four competitive strokes (freestyle, breaststroke, butterfly, and backstroke) show you how each exercise is fundamentally linked to swimming performance.

You’ll also learn how exercises can be modified to target specific areas, improve your form in the water, and minimize common swimming injuries. Best of all, you’ll learn how to put it all together to develop a training program based on your individual needs and goals.

Whether you are training for a 50-meter freestyle race or the open-water stage of a triathlon, Swimming Anatomy will ensure you enter the water prepared to achieve every performance goal."

What's the sport in triathlon where technique plays the largest part?  Swimming.  It's easy to get caught up in Swim-Bike-Run and throw in some resistance training in between when you can.  I hired a coach a few years ago, the first thing he added to my schedule was resistance training.  He said it might help in injury prevention and structural integrity.

When you're at the gym next, take a look around and focus on one piece of equipment.  Without leering, watch different people use it.  Do they all have the same technique?  The magic 8-ball says, "Very doubtful."

Why do their techniques vary?  Do they all know something you don't?  The magic 8-ball says, "Don't count on it."  You might see a wide range of people using the machine with different levels of experience and backgrounds.  Some might know how to use it, some might not.  How can you tell which is better technique?  By reading Optimal Muscle Training.

This book explains in detail how to assess if you're ready for the exercise, assess your flexibility needed to perform the exercise correctly, and then show you several correct techniques for various results.  It comes with a DVD that covers in great detail most of the topics, assessments, and exercises covered in the book.

With the permission of Human Kenetics, I reprint part of an excerpt and link you the remaining portion of it because it has terrific images with explanation of risk/reward benefit of different techniques.

"Risk–Benefit Ratio of Specific Weight-Training Exercise Techniques

Each weight-training exercise can be performed in various ways. Some techniques are beneficial for the development of strength, while other techniques are more suited for muscular hypertrophy. The benefit and inherent risk of each exercise
modification such as grip width, foot position, arm position, range of motion, head position, and trunk motion will alter dependent on the person’s experience, body type, and outcomes desired. The exercise modifications should always be done to
increase the stress on the muscles and not the joints, ligaments, or capsules. The following pages review variations in technique for each weight-training exercise to offer guidelines for the optimal implementation in an individual training program. Remember that high risk does not automatically mean that the person will be injured. It means that the potential for injury may be higher due to specific techniques needed for increased strength and development."
Click here for the pdf

"Analyzing the Risk–Benefit Ratio of Weight-Training Exercises

Along with a good understanding of muscle biomechanics, knowing how muscles function in weight-training exercises is also important. This knowledge enables the selection of the optimal technique while decreasing the risk of injury. Starting a weight-training program is similar to undertaking other types of physical fitness activities. All fitness activities carry a risk. The risk depends on the activity, the equipment, the environment, the athlete’s level of expertise, focus, conditioning, level of fatigue, the state of the athlete’s tissues, previous injuries, and biomechanical factors. A coding system should be created to indicate the level of difficulty relative to the person’s experience and needs to avoid injuries. Certain sports, such as downhill skiing, surfing, and boating, have an established system of coding the level of difficulty to allow people to decide the activity risk based on their self-assessed experience level. For example, in downhill skiing, ski trails or runs are marked with colors and shapes as follows: green circles indicate the easiest beginner trails that present a low difficulty level and risk of injury, blue squares mark intermediate trails with a medium difficulty level and risk of injury, and black-diamond runs are for advanced and expert skiers and present a high difficulty level and risk of injury.

Each level also offers a certain level of enjoyment, personal satisfaction, and accomplishment, known as the benefit of skiing. Black-diamond trails have the highest potential benefit, blue-square trails have a medium potential benefit, and green-circle trails have low potential benefit for the skier to aspire to. A beginner skier belongs on the green runs. If he or she takes a black-diamond run, the risk of being injured is high. But an advanced skier can go down the same black-diamond run with minimal risk of injury because of his or her higher skill level and get the benefit of a sense of adventure and fun. The advanced skier may find a low-risk green run too easy and thus derive less benefit of excitement from it."
Click here for pdf

With one sport, you can understand how which days to train hard.  The following is an excerpt printed with permission from Human Kinetics book, Run Strong, by Kevin Beck.  It covers running only but the concepts cross sport lines.  Understanding training rules of thumb will put you on the path to designing your own training patterns.

Based on my experience as an athlete and a coach, I believe that the most valuable tool for any self-coached runner is an outline to guide decisions regarding which workouts are appropriate. The various types of training, ...

This is an excellent excerpt reprinted from Burke's book with permission with permission from Human Kinetics, High-Tech Cycling-2nd Edition.

"Human physiology is affected in different ways at high altitude. In general, the various systems of the human body—pulmonary, cardiovascular, endocrine, skeletal muscles—respond and adjust in an effort to provide enough oxygen to survive in the hypoxic environment of high altitude. Some of these life-supporting physiological responses may also enhance athletic performance, particularly in endurance sports.

Hematological
The scientific rationale for using altitude training for the enhancement of aerobic performance is based on the body’s response to changes in the partial pressure of inspired oxygen (PIO2) and the partial pressure of oxygen in the arterial blood (PaO2). PIO2 at sea level is equal to 149 mmHg. At Mexico City (2300 m, 7544 ft), PIO2 drops to approximately 123 mmHg. At the summit of Mt. Everest (8852 m, 29,035 ft), PIO2 is approximately 50 mmHg or only about 30% of sea level PIO2.