While inventing the osteogenic loading impact emulation medical devices called OsteoStrong, which John and I discussed in this podcast, John developed a deep understanding of the impact-ready ranges of motion. (“Impact-ready” refers to the ranges your reflexes would choose in order to absorb high forces experienced in hard contact with the ground.) Approaching the subject with the ultimate goal of stimulating bone growth required taking a different perspective than prior researchers. By determining where peak forces occur in relation to body placement on the OsteoStrong device, John was able to plot the strength curve throughout the range of motion in a way no scientist had before.
In our most recent podcast, John and I introduced the concept of the different ranges of motion, using a standard bench press as an example. The same can be done for any movement, whether single-joint or multi-joint.
Take a pushup, for example. The weakest range of motion is when your arms are bent and your nose is almost to the ground. Right before your arms come to full extension marks the strongest range of motion. Anyone who has ever attempted a pushup knows there is a vast difference in strength between these two positions.
For this reason, people often end up using only the top range of motion where the movement is easiest when doing pushups. Everyone subconsciously does this to maximize reps, even children. If you watch a high school physical education class, you’ll notice a percentage of kids won’t go all the way down to where their nose touches the ground. They only do what they see as the easy part at the top because that’s where more muscle is usable.
Let’s also look at a deadlift. The weakest position is when you’re bent over, the bar is near the ground, and your spinal erectors, hamstrings, and trapezius are elongated. The medium-range is in the middle of the movement, and the strongest is just before you’re standing up. I'm making the qualification of “just before” because if you lock out your joint, your muscles essentially turn off. Have you ever watched a professional mover move furniture and notice how they use moving straps? They change the length of the strap so they can engage with movements in just the optimized range.
The squat is another example. The weakest range is when your knees are the most bent and your body is closest to the ground. Just before full knee extension, as you approach the top of the lift, is the strongest range of motion. Sprinters subconsciously know this one. Does a sprinter use a full range of motion when contacting the ground to push off for the next stride? Absolutely not. A sprinter uses seven degrees of flexion behind the knee when contracting, yet has 180 degrees available. This is the range of efficiency where force delivery through the muscle is optimized.
Weights Are for the Weak
John was the first to discover there is a seven-fold difference between the weakest and strongest range, effectively demonstrating that muscular capacity is far greater than anyone ever realized. His findings also exposed the Achilles’ heel of weight lifting: Because the weight used is determined by the weakest range, there is a vast mismatch between the amount of weight lifted and actual muscular potential. What’s more, the stronger a lifter gets, the more cumulative damage to joints, since they are at their maximum possible capacities in the weakest range of motion. This causes pain and stops the muscle from contracting effectively through the process of neural inhibition (a concept covered in greater depth in John's new book).
Lifting a weight light enough to accommodate the weak range means the mid and strong ranges aren’t being worked to anywhere near their full capacity. Choosing a weight heavier than what your weak range can handle isn’t effective either because it ensures you can’t complete a single rep. It also increases your risk of injury. As a result, weight lifting ends up fatiguing the least amount of tissue possible based on the limitations of the weakest range of motion.
Some people think low force, high repetition exercise—doing three sets of fifty curls with two-pound weights, for example—is the solution to this problem. However, research shows muscle is not built through low forces. In fact, you can actually greatly diminish muscle exercising this way. In a 2016 study, researchers concluded that when it comes to training for muscle strength and hypertrophy, “a trend was noted for superiority of heavy loading.” What does this mean? It means that when you want to grow muscle in the most effective way possible, there is no getting around HEAVY.