In the past, I’ve shared my top secret exercises to help you lose fat faster by doing total-body exercises that use tons of muscles in each move that you do.
Whether it’s compound movements for your upper body (e.g. push-ups, pull-ups, rows, dips, etc.), lower body (squats, dead-lifts, lunges, etc.) or core (plank holds and rotational core exercises) these "many muscle" exercises provide the biggest bang for your buck during your workouts requiring MINIMAL time, but giving you MAXIMUM results.
Today though, I want to talk to you about something different. Today, let’s bring our focus on the WORST exercises you could ever add to your training routine.
I believe that a lot of women turn to these "easy" exercises because they just don’t know what else to do or are intimidated by the free-weight room at their gym.
You’ll never see me perform these movements because it’d give half the results in double the time and probably hurt me in more ways than one.
I truly believe that sometimes learning what NOT to do is just as beneficial as learning what you SHOULD do.
So let’s get to the three exercises that you would never want to do in your life!
1.) The Abs Machine
Crunches and sit-ups aren’t necessarily deadly; but because most people do them all the time, it creates a lot of bad force on your low-back and neck which will cause you many awkward pains ranging from your neck to low back.
Do you want to know whats worse?
When you add weight and use a machine that isn’t specifically made for your body. It’s made for the average person on about 5’6". Even if you are 5’6", do you have the exact same arm/back/leg length that the machine was made for?
With all those factors it’s no wonder that it trains you in an unnatural front and back motion. Plus you are in a seated position that demands minimal use of your core, meaning even more room for injury.Now add to that that we already mimic a crunch in life. For example: look at most people who stand or sit with poor posture, don’t they resemble someone before a sitting crunch or someone on an ab machine? Add even more crunches and sit-ups and you’ll just get triple the disaster on your back.
You may be saying, "But I feel the BURN!" And I’ll say, there’s better ways to make your abs work, rather than literally tearing up your spine. It’s a high risk exercise, only meant to be used for certain circumstances.
Remember, your core is meant to stabilize you when you are standing and when you are moving so you can stand nice and tall from your hips and to your shoulders in any way you can move (front to back, side to side and if you rotate).
21 Century Training Upgrade: For rock hard, Greek goddess abs, focus on plank stabilization exercises like from, side and back planks, as well as ground based rotational core work like chops variations and upper body twist. Also work on your diet. Without the diet, you’ll never see the washboard abs that you can do laundry off of.
2.)The Back Machine –
As you can tell, I am not a fan of the abs machine, so it figures that I am also not a fan of the reverse of it, the back machine. This is another exercise you should avoid for more reasons than I have fingers to count on.Here’s just one:
You probably already use too much "back" on most movements because your butt and hips aren’t working like they’re supposed to. Meaning they are too weak to do what they are supposed to do, so other muscles have to take over.
An easy way to think about it is when you are moving a heavy couch that needs 4 people to lift it. First four
people lift it, then say one person decides not to hold it up anymore, so now there’s only three people lifting. How much heavier is it for each person? Now imagine another person decides to stop lifting and you only have two people holding the couch. Imagine how your back is now. Your butt and your hips are those two people that decided to rest. Your back and arms are left over, trying to take the slack.
So instead of focusing on your back, let’s focus on strengthening your hips, especially the front part of your thighs by focusing on squat based movements that really get you using your butt, big time.
21 Century Upgrade: For a strong, stable back, work on deadlift and good morning variations while 
simultaneously focusing on the corrective stretching and self-massage of the Lumbo-Pelvic-Hip (LPH) complex, meaning you back, butt and front/back/inner/outer thighs. A prone cobra or airplane as it it sometimes called is also a great exercise to improve your back endurance while also improving your upper back strength and stability.
3.) The Leg Extension Machine
This exercise is a personal one for me. When I first started lifting weights, I abused this exercise like few others.
Most women love to abuse this machine like crazy. They see the pictures of the lean sculpted fitness models sitting on this and think this is the machine for them to bring out those cuts in their legs.
Here’s the truth-if you want knee replacement surgery, use this exercise 3 times a week for a year. If you 
don’t want your knees to be wrecked and have horrible stabbing pain that will lead to arthritis, avoid this machine like the plague.
21 Century Training Upgrade:For strong, stable knees, focus on both knee-dominant (lunge, step-up, and single-leg squat variations) AND hip-dominant single-leg exercises (single-leg hip extension, deadlift, and good morning variations) to keep the strength of both legs the same AND to help keep the front and back thighs and your inner and outer thighs balanced between each other. With balanced muscles comes stability, and with stability comes strength.