Why do you only Strength Train once per week?
The short answer is that once per week is all that it takes. If once per week is effective, why train more often? The long answer is that at first, we probably could tolerate more frequent workouts. But as you get stronger and more capable, it requires a more intense output of energy to stimulate any change. The natural consequence of the greater effort is a greater impact on the body, necessitating a longer rest peroid. We aim to teach people how to train intensely enough to justify such a low frequency right out of the gate. If a person would rather take it a little easier and come more often, the trainer could certainly do that; it just costs more to train more often.
How will this help me to lose fat?
A simple analogy works well here. Consider the fuel efficiency of a Toyota Prius vs. a Ford F150. The vehicle with a bigger engine and more horse power burns through more fuel. In this analogy, your muscles are the engine and calories are the gas.
Taking this thought experiment a bit further, the difference in fuel economy is there when both vehicles are idling at a stop light. What happens when the light turns green and both vehicles take off? Now the difference is much greater since the Prius consumes far less fuel. What about if both vehicles not only take off, but stomp on the accelerator? Now the diffence is huge, as the Ford barrels ahead of the Prius, practically watching the gas gauge drop.
Will Strength Training make me bulky?
No. That is, not unless you have the specific genetic characteristics required to get big muscles. It is a common misconception that anyone can and will get excessively large muscles from strength training. The truth is that we are all working with the genetic endowment passed to us from our parents. The length of our muscle bellies versus the tendons relative to the length of our bones and our muscle fiber density and composition are all inborn characteristics that cannot be changed by exercise. Women in particular have an unwarranted fear of growing their muscles for fear of getting too big. Very, very few women posess the genetic characteristics necessary to get truly bulky.
The truth is that what everyone really wants is to carry less body fat. Avoiding developing your muscles is not the answer. In fact, our muscles are what give us our shape (as fat is shapeless) and burn calories. The best long-term strategy is to develop your muscles as much as possible to keep your metabolism revved up and keep that youthful shape, while addressing your nutritional strategy, which is where the game is truly won or lost.
Will training effect my endurance?
Most will experience an improvement in endurance. There are two reasons for this:
1) When your muscles are stronger every stride or pedal stroke requires a lower percentage of effort, which means you can do it for longer.
2) Threshold training stimulates an increase in mitochondria, which is the key to sustained muscular effort.
Obviously there are some limitations to this rationale: if someone has the genetics to develop excessively large muscles, the increase in mass may negate the benefit of greater strength. Elite competitors may want to avoid hypertrophy (increase in muscle size) in general since they are looking for any edge. But for most people just looking to get more fit, strength training will actually improve their endurance.
The thing to keep in mind is that, as with anything else, if you expect to perform well, you must practice. Strength Training alone will not automatically translate into greater endurance. You must be conditioned to the very speciifc requirements of the activity in question.
What about Functional Training?
Functional Training is a buzz word right now. The idea is to use exercises that simulate the demands of daily life so as to better prepare your body for those particular demands. A classic example is the lifting, twisting and setting down of groceries. At first glance this makes a lot of sense. After all, you don't bench press groceries, right? The problem is that a pure functional training workout ignores a couple of important exercise principles.
First, the Overload Principle, which basically states that our tissues will only respond and fortify themselves when introduced to a challenge that exceeds present capactiy. In order to make functional movements intense enough to get a result you have to either add enough resistance (which can make such movements dangerous) or do many, many repetitions (which is the road to overuse injuries).
Second is the SAID principle, or Specific Adaptation to Imposed Demand, which basically states that our bodies will respond to training stress according to the specific conditions of that stress. This sounds like a an argument in support of functional training, except that you must ask "how specific does the stress need to be?" The answer: very specific, in fact, identical. A classic example is a weighted golf club. Many people believe that swinging a weighted club will strengthen the core specifically to the demands of the golf swing, making you better at it. The problem is that none of your clubs weigh that much in real life, so it's not actually going to improve your stroke from a skill standpoint and performing such a ballistic movement with added weight is risky.
We argue that you are better off to train your muscles and subsystems as safely and efficiently as possible and then actually do the things you want to be better at. Our nervous system responds very quickly. So long as your musculoskeletal system is ready and capable, you can learn any new skill or movement very quickly, without doing a million reps in the gym that "sort of" resemble the demands of your life.
All of that being said, there is some value to a lot of the balance challenges and bodyweight movements that one encounters in a functional training workout. The benefits are an improved sense of balance and kinesthetic awareness. Recognizing this, we have found ways to include these kinds of challenges in our workouts without relying on them to provide the stimulus alone.
Finally, the real value of functional training is in rehabilitation. When we become injured or when we spend prolonged periods of time doing repetitive motions, we develop muscle imbalances or deficiencies that can lead to greater injuries down the road. Adressing these very specific problems is beyond the scope of fitness trainers and is best treated by a physical therapist.