P90X3 Isometrix Review
- Sean Arenas
- Dec 11, 2017
- 3 min read
Isometrix is one of my favorite Beachbody exercises, and I'm going to show you why!
Introduction
A strength building routine great for joints, stabilizer muscles, and balance.
Duration: As with all P90X3 workout routines, Isometrix is 30 minutes long

Who Appears in Isometrix
Tony Horton
Nate
Ted
Dreya
Equipment Needed
Water
Towel
Yoga Mat*
Although the yoga mat is optional, if you have a hard floor like I do, I highly recommend one. You will spend some time with one hand or two hands or your elbow on the ground, and the mat provides padding to protect your hands and elbows.
However, during the parts where you are standing on one foot, I recommend standing to the side of the mat as opposed to on it, as you will find more stability.
Exercise Details
This routine involves Yielding Isometric work - your joint and muscles are held in a static position during muscle contraction. Yielding Isometric exercise involves concentric and eccentric actions, unlike Overcoming Isometric exercise, which involves only Isometric action.
Isometric comes from the Greek words "Isos" and "metria" (equal and measuring). The length of the muscle and the angle of the joint do not change, though contraction strength may change.
The results of the type of Isometric exercise that Tony Horton uses in Isometrix won't increase your speed or range of motion, but will increase the strength of all of primary muscles used in all of your other activities, as well as secondary, stabilizing, and supporting muscles, which many other exercises aren't good at.
After performing Isometrix several times, you will find that you perform other fitness activities much better. I don't mean that they will become easier to perform, or that you can accomplish them with less effort. I mean that you will reach new heights in the other activities as all of your other muscles reach parity.
Check out the calories burned per routine, and the heart rate achieved in these Isometrix workouts:
Muscle Parity
I have my own term for what happens when all of your muscles are at an ideal fitness level: Muscle Parity.
This means that your primary, secondary, stabilizer, and supporting muscles are all equally fit. It also means that your left and your right sides, and your upper and your lower halves, are equally fit. This allows you to achieve greater success at sports, other fitness training routines, any physical demands required by your job, and your daily life.
(Read more about Muscle Parity here)
Isometrix helps you find and strengthen all of those muscles that you don't get a chance to work during your other activities.
Experiencing Isometrix
Your first few times through it, you might not notice a huge improvement from session to session. You're struggling to hold each pose, and several of them seem impossible.
After you get through it a few more times, you will notice that your ability to attain and maintain the poses increases, but that does not mean that the exercises become easier! On the contrary, the longer you are able to hold a pose, the longer you are taxing the muscles required to hold the pose. You are tearing them down faster, they require more oxygen, and they generate more heat.

After several more passes through the routine, you will notice different parts of your body becoming 'involved' in the poses than you previously noticed. What previously may have taxed your arms or your legs will now tax your lower back - that's because those unused muscles in your arms and legs have strengthened up, and now your lower back is receiving the work it needs.
The next major of challenge (I mean that in the best possible way) isn't in how long you can hold a pose, but perfecting the pose. When doing the Royal Dancer, for instance, can you do the pose exactly like the Dreya? Stretch just a little farther, pull that leg up a little higher? As you push a little more, you find the sweat coming on more, and the results show that same amount more!
Finally, Tony has "modifiers" and "intensifiers" for most of his routines. Modifiers are what you do when you're first learning the routine and can't hit all of the poses; it's an easier way to get through the routine. Intensifiers, however, are the adjustments that make the poses tougher. After you're feeling good at this routine, watch the students in the class and see which ones are doing more advanced moves, and try to follow along with them. That extra effort, as usual, means extra results for your body!
Benefits of Isometrix
Isometrix is great for finding your weak spots, and strengthening them. This routine along with X3 Yoga and Pilates X gives you a great route to balancing the fitness of all of your muscles.
The results are being a better athlete, or having athletic performance in all of your fitness routines and your day-to-day activities.
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