Clearly, it is not. The overriding concept is that, like all training methods, training to failure is a tool. No tool should be used all the time for all applications. But used judiciously, it can be a useful training method. Any training program which plans for progressive resistance, consistency, and variation is likely to produce success.
Recommendations
1) Plan and document your training. If your best effort in the bench press is 225 for five sets of five repetitions, your goal should be to surpass that effort- either by getting five more pounds for 5x5, or by getting a greater volume with the same weight. When you do, you'll progress, even if you don't go to failure on each and every set. Keeping a training log is a must in order to know what barriers you're trying to surpass. Use one!
2) Use and apply strictly defined technique parameters for yourself. Cheating (by utilizing co-contraction from non-targeted muscles) only encourages inefficient movement patterns, poor posture, and potentially, injuries. Your technique on the last rep should be identical to the technique you use on the first repetition.
3) Progress is a function of gradually increasing your training load over time- not how "trashed" you feel after a workout.
4) Careful attention to acute program variables can have a big impact on how much volume you can comfortably tolerate. Here are two examples:
a) Muscles can be worked more thoroughly by first training in an unstable environment (i.e, free weights) which challenge the stabilizers, and then moving to a stable environment (i.e, machines). To test this for yourself, first do a set of dumbbell bench presses to fatigue. Next, load a barbell with the same weight, and immediately do a set. You will find that you can lift this weight, despite failure on the DB bench. Next, go to a machine bench press, load it with the same weight, and you'll find that you can continue even further. This phenomenon is an example of "stabilizer failure";
b) Because fatigue is specific, greater workloads are possible if sets of contrasting exercises are performed back to back, as opposed to finishing all sets for a particular exercise before proceeding to the next. As an example, if you plan to perform bench presses and lat pulldowns in the same session, sets 1,3,5, etc., would be bench presses, and sets 2,4,6, etc., would be lat pulldowns. The more distant the two muscle groups are from one another, the greater the reduction in residual fatigue. Still another method of reducing fatigue is to alternate between low repetition sets, which fatigue primarily the nervous system, with high repetition sets, which fatigue primarily the metabolic system. The low repetition sets facilitate greater neural drive, which carries over to the high repetition set, allowing a greater overall workload to be performed.
c) Except for beginners, a linear progressions of training load, where the athlete attempts to add resistance each and every workout, result in early stagnation and loss of improvement. A more productive approach is a "three steps up, one step down approach" which allows for periodic regeneration and continued improvement.
5) For hypertrophy development, remember that muscles consist of more than just contractile fibers. Use a variety of repetition ranges to stimulate all elements of the muscle cell.
6) It is especially important to recognize the qualitative components of a good set- elements such as the feel, control, and overall mastery of the movement. Over-reliance on achieving the maximum number of repetitions at any cost is an invitation to injury and long-standing technique errors.
7) Stick to conventional or "basic" training methods until they no longer yield results.
