Of all the manipulative variables involved in workout, variation must rank near the top. Decisions such as how long, how many reps/sets, how much weight to lift, what angle, bench, machine, are made to form a workout.
Too often though, the majority of people still end up doing the same thing and get stuck in a rut with limited results. The body they hope and work so hard for does not appear, injuries happen, the worker-outer gets bored, gives up, and has a hard time getting back in the groove. I've seen it hundreds of times throughout my exercise career.
Some exercisers do employ some type of variation by changing the machine they exercise on, the amount of weight they use, or the number of reps, but variation is far more than how many or how much. In fact, variation's two most important aspects to explore are intensity and modality.

Intensity
Take your old friend the treadmill for example. If you were to observe 20 people working out on a treadmill, you would most likely see:
1. A brief warm-up of 3-5 min
2. An increase of speed, or possibly some jogging, for 15 or more min
3. A cool down
Factor in Intensity and you might see:
1. A brief warm-up of 2min
2. Add in a 4 degree hill and bump the speed up to just under jogging tempo, possibly 3.8mph for 3min
3. Drop the hill to 2 deg and jog at 5.0 for 1m
4. Walk at 3.5 for 1m
5. Repeat #'s 3 and 4 increasing the speed .5mph on each and adding a 1 deg hill for a total workout of 12-15m

A few things to note about workout number two:
- This is an example of Interval Training: 1m intervals with a 1m recovery. The body loves intervals, thrives on intervals, and this push it-recover routine is sure to crank up your metabolism.
- Pushing yourself is the only way to promote change. The same thing/speed/intensity every time equals the same body.

- Resistance exercises like squats or lunges for example are actually forms of intervals themselves. In fact, if you check your heartrate following a set of squats, I'll bet it's higher than it was on the elliptical! Now, which one was 'Cardio' again?

Modality
Think of Modality as the same exercise done many different ways or with different equipment. Let's take Pressing as an example.

The gold standard for pressing is the bench press, yet when looking at the exercise, and the people who do it on a regular basis, it's always the same old thing: flop on the back and load the bar up. What about:
-  A standing single arm press with a rubberized tube
- Push-ups (check these variations out HERE)
- Dumbbell Press: flat, multiple levels of incline, slight decline, lying on a ball, together, alternating, wide, narrow...
- Bowflex (if you haven't used a  Bowflex for pressing you're missing out!)
- Various machine presses (some manufacturers better than others)
- Cables: standing, lying, together, alt, traditional cable crossover, or Free Motion

In each of the examples, the goal of shoulder and elbow motion, or pectoral, anterior deltoid, and triceps muscle training is being accomplished. The major difference, as you can see, is how the body is positioned and stabilized and what you're using to train the joints/muscles/nervous system. Add to this other manipulative variables such as a change in tempo, range, reps, resistance, frequency, rest interval, and you can create unlimited workouts and never repeated the same one twice.

The Nervous System

All of these minute changes in Intensity and Modality are very much promoting nervous system strength and integrity. How the brain, nerves, and the rest of the complex nervous system negotiate exercise and overcome resistance is really the overriding success parameter. Muscles and joints pretty much just do what they're told! Even with the slightest change, the benefits can be huge. Challenging the body employing different modalities and intensities strengthens nervous system capabilities making the body stronger as a whole. Variation and its partners Intensity and Modality: incorporate them into your exercise strategy today.