Phases: Concentric Vs. Eccentric
I see it every day. People come into the the gym and try to set speed records lifting low amounts of weight. They wonder why they aren’t making any progress towards their goals of losing weight or changing their body composition.
The problem is, they aren’t using the proper form to actually break down the muscle. You see, lifting weights doesn’t actually build muscle. Your goal in the gym should be to break down the muscles fibers by providing constant resistance. The muscle-building comes with proper nutrition (protein intake) and rest. When you slow down your reps, you break down the fibers to build greater muscle which, in turn, boosts metabolism. A higher metabolism will result in burning more fat for energy. That’s where the results come in the form of improved body composition.
There are two phases in a repetition. The concentric phase is the shortening of a muscle (against gravity). The eccentric phase is the lengthening of the muscle as gravity acts on the load. For instance, if you are doing a biceps dumbbell curl, the concentric action is lifting the dumbbells from the hanging position to the upward position. You are pulling the weight against gravity. The biceps muscles are shortening. The eccentric phase is when you lower the dumbbells back to their starting position. The amount of tension that you exert during the lowering (eccentric) phase, is what helps to break down the muscles fibers. There is also the isometric phase where there is no movement and the load is actually suspended. I use isometrics in my training, as well.
Here’s where most people fail. If they don’t lift enough weight, there is not enough resistance to tear the fibers. If they lift too fast, there is not enough force as the weight is acted on by gravity. Often, there is a combination of both – too little, too fast. When you use momentum to quickly move the weight by either “pushing” or “pulling”, you are actually “cheating” and not using the full range of motion. The American Council on Exercise (ACE), recommends a six-second repetition over 8-12 reps per set (2 or 3 sets are recommended). The concentric phase should be about two seconds while the eccentric phase should take about four seconds. When doing the biceps curls, I count “one, two” when I lift the dumbbell and “one, two, three, four” when I lower the weight. There is a slight pause at the top of the contraction. I do the same thing with my clients. I am always having to tell them, “slow it down” – if their goal is to build muscle and/or tone. You should also note that speed can also result in injury, especially if you don’t use proper form or manageable weight loads.
It’s also important to lift the proper amount of weight. If you can lift a load 15 reps for two sets, it’s probably too light. You need to increase the load so that you struggle to get the last few reps of a set of 12 reps. Then, when you improve to being able to lift two sets of 15 reps of the new weight, take the load up again to the next level or five to ten percent.
The caveat to this is if you are just trying to improve overall strength and power. People who focus on strength are lifting heavier loads for a fewer number of reps. For example, an Olympic weight lifter is only focused on lifting the heaviest weight possible, one time. People who want to improve power, will try to lift heavy weights as fast as possible. We all need power, but power does not necessarily improve muscle size or cause the changes that will result in fat loss or a more toned body.
To get that better-looking body, you may not necessarily have massive gains in strength and/or power. It’s a trade-off, of sorts. For me, I’m not out to set weight lifting records. I want to change my body composition by building muscle to improve my metabolism so that I burn more fat at rest. However, by building muscle (hypertrophy), you will see modest gains in strength. If you want more strength gains, you can always alternate between routines – go for muscle building over four weeks and then focus on strength or power over the next four. Some people like to alternate, just to shake things up.
The next time you go to the gym, be aware of your movements and your weight load. Slow it down a bit and feel the burn. If your muscles aren’t burning toward the end of each set, you’re not working hard enough. Oh… and shorten the rest time in-between sets to 30- to 60-seconds. You’ll start seeing results in just a few short weeks!
To Your Health!