If you are an experienced lifter then this definitely applies to you but even if you are a rookie to the weights and stick mostly to machines, you have probably still noticed that your muscle fail at the same spot during certain exercises. I have heard this attributed to genetic factors like limb length, height and body weight but the true culprit is generally the body’s natural strength curve. While those genetic factors can slightly manipulate the degrees of someone’s strength curve, this isn’t a subjective thing, everyone and every exercise has one. If you learn how to manipulate the resistance of certain exercises, you can combat that strength curve and grow stronger in a more complete range of motion.

  I will do my best to keep the anatomy to a minimal and articulate this in a way everyone can understand. A muscle contains two protein filaments, one is thick and made up of Myosin, the other is thin and made of Actin. When these two filaments slide over one another, this is muscular contraction. A muscle has two ends of spectrum, fully contracted and fully lengthened. As you would assume, a muscle is strongest in it’s fully contracted position and weakest in it’s fully lengthened position. This lady’s and gentleman is the reason why your body has a natural strength curve.

To better illustrate my thoughts, lets use some examples of popular exercises that demonstrate the strength curve. We will begin with the most common exercise (among young males anyway), the Barbell Bench Press.

Anyone who has spent time in the gym has been witness to the high pitch cries of a teenage boy pinned to a bench by a barbell twice his body’s weight. In all my years in the gym, I could count on one hand the number of times I have seen someone fail on a bench press once the bar is half way up or higher. This is a perfect example of the strength curve to a bench press. The prime mover in the bench press is the pectoral muscles. When you descend in the movement, the muscle of the pec lengthens and when you elevate upwards, they contract. Making you strongest at the top portion and weakest at the bottom portion of the movement.

  For this example, we will use a video of the Band Resisted Bench Press:

Next, lets use the example of a Chin-Up. If we are using the wide grip variation for this example, then the prime mover is the Latissimus Dorsi or the “lats”. A fully lengthened position of the lats is when you are in the bottom portion of a chin up, with your arms fully extended. A fully contracted position would be at the top of the movement with your elbows tucking in toward the sides of the body. Thus meaning, you would be weakest at the bottom and as you contract upwards you would become stronger.

For this example, we will use a video of the Band Assisted Chin-Up:

  If you can learn to combat this strength curve and challenge yourself where you are weakest, you can create a more well rounded strength for both aesthetics and athletics.