Concentric and Eccentric Muscle Contractions

Concentric and Eccentric Muscle Contractions (And Why It Matters)

Concentric (Positive) Contractions: Put simply, this contraction shortens your muscle as it acts against resistive force (like a weight). For example, during a biceps curl, the biceps contract concentrically during the lifting phase of the exercise.

Eccentric (Negative) Contractions: During these contractions, the muscles lengthen while producing force—usually by returning from a shortened (concentric) position to a resting position. Using the same example above, the lowering the weight back down during a biceps curl is an eccentric contraction for the biceps. Think of this as "putting on the breaks." You're basically slowing the descent of the weight back down instead of allowing the weight (and gravity) to just pull your arm back down passively.

So why does this matter?
It's a good idea to include both concentric and eccentric contractions in your strength-training program. Luckily, most traditional exercises include these movements—a lifting phase (using the shortening or concentric phase) and a lowering phase to return to the start position. However, how much time you spend in each phase can affect your results. Here are some facts:

• Your muscles can generate more force during the eccentric phase of an exercise. For example, you may only be able to lift a 10-pound dumbbell for a biceps curl. But likely, you could hold and lower (the eccentric phase) a 15 or 20 pound weight.
• By slowing down the negative (eccentric) phase of your exercise, you can help your muscles build greater strength. This is why, typically, people are advised to lower weights or return them to the start position slowly.
• Negative training is a type of strength training designed for greater strength gains. It involves using heavier weights than you could typically lift concentrically and focusing just on the eccentric phase of the exercise. This does pose a higher risk for injury and should not be practiced by beginners, however.
• You can also use negative training to your advantage—as a way to progress to exercises that are currently too difficult for you. For example, maybe you have a goal to perform real pull-ups but don't have the strength yet to lift yourself all the way up (concentric phase). You could help work up to that movement by focusing on the lowering phase. Stand on a box or step to come up to the "up" position and then work on slowly lowering yourself back down. After each lowering, step back up onto the box and repeat the lowering phase again. You'll be working the same muscles and still benefit from the exercise this way.

So next time you're in a class and the instructor tells you to lower the weights more slowly than you lifted them, you'll know that you're helping your muscles develop greater strength by doing so. And if you ever hit a plateau in your strength-training program focusing a little more on the negative part of your training can be just the ticket you need to make it to the next level.

20 Minute Cardio Challenge

Imagine you are a Child again, with Boundless Energy, and approach this Challenge with Enthusiasm!

Burpees no one likes these, for good reason, they are tough but my god will you see a difference in your bum, legs and thighs if you keep this up: from standing, crouch down, place palms on floor, jump legs back into full push-up position (add a push up if you wish), then jump legs back to crouch pose and stand up (or jump up). Repeat again.

When Marching swing your arms and lift your knees up high this is your Active-Rest between intervals.

Before Starting: Grab a stopwatch (I like my Gymboss timer) or an egg timer that will alert you when the time has passed, a bottle of water and a towel (for all the sweat that will be dripping off you!)


* March in place for 3 minutes (360 steps)
* 60 Jumping Jacks
* March 1 minute (120 steps)
* 60 Jumping Jacks
* March 1 minute
* 30 Burpees
* March 1 minute
* 30 Burpees
* March 1 minute
* 30 Burpees
* March 1 minute
* 30 Burpees
* March 1 minute
* 60 Jumping Jacks
* March 1 minute
* 60 Jumping Jacks
* March in place 2 minutes to cool down

Remember the Marching phase is your active-recovery to allow your heart rate to even out and muscles relax, thus allowing you to put all your intensity into your next round of Jumping Jacks and Burpees.

This is a challenge for those of you who have been regularly working out for a few months. 
If you are beginner or have any joint issues please consult with your doctor prior to performing these exercises!

What is a Fitness Plateau? How can break through it?

Plateaus of Weight Loss- Adaptive Thermogenesis  

Research done by Mike Roussell PhD 

Plateaus can be frustrating and detrimental to your fat loss if not dealt with swiftly and properly. Another way to look at weight loss plateaus is that they are actually your body settling in at a new body weight set point.

The set point theory is basically the idea that your body likes to be at a certain body weight and it will work to keep you there. Chances are you have experienced this in your own life. I’m talking about situations where you will gain or lose weight but inevitably after a couple weeks or months of trying to change you end up around the same body weight.

In order to break these body weight set points, it is important to understand the forces that you are working against (know thy enemy, right?). I’m talking about adaptive thermogenesis.

Adaptive thermogenesis is the seemingly automatic reduction in energy expenditure that occurs when you diet. Many think that this is the driving force behind people’s body weight set point.
This is important so I want to make sure I’m explaining it clear enough so here’s an oversimplified example.

You are currently eating 2000 kcal per day. Your body is currently burning 2000 kcal per day. You decided that you need to lose weight so you cut 500 kcal from your diet. So in theory your body should now have to dig up another 500 kcal from body fat to fuel the calorie difference???

EXCEPT ->>
It doesn’t work that way. Studies show that your body adjusts its energy output so that it can now function on only 1500 kcal per day. This is adaptive thermogenesis. It has been demonstrated that adaptive thermogenesis occurs with both severe and modest calorie cutting.

What is the driving force behind this? Here are some candidates:

• Changes in body weight
• Changes in Leptin
• Changes in Insulin
• Changes in Thyroid Hormones
• Depletion of Fat Stores

 Fortunately you can beat all of these, prevent adaptive thermogenesis, and keep the weight loss coming.

The answer?

Metabolic Training combined with diet.

We know from research and anecdotal evidence that not all exercise prescriptions work. What does work is intense metabolic resistance training...think HIIT and Tabata!

If you are currently stuck at a weight loss plateau, you need to break your body’s set point. To do this it is necessary to undergo a rigorous change in diet and training so that you can in essence shock your system.

Here’s what to do next. Once you break though your sticking weight, maintenance is very important. Get 5-15lbs below your old body weight set point and maintain that weight. Many people lose their fire and drive after they have lost the weight but you need to stay focused so that you can reset your body’s set point.

Maintain your new weight for 4 weeks (this is ideal) before you start losing weight again. This step wise approach will help reset your system to your new body weight and help fight its urge to return to the old set point. The key is keeping your body weight long enough so that your body ‘thinks’ that is the new normal.

Stay Focused and Invest in the Long Term - you'll get there!