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High Impact vs. Bone Growth

Here's an e-mail reply to one of our customers. We present the actual text, because the points are good. The customer wrote in that her husband didn't want her son playing football (American football) until he was done growing. Her son insisted football was great exercise. She wanted to know who was right.

Here's the reply:


Your son should listen to his father, especially on this issue since you are 100% right. Any osteopathic surgeon will tell him high impact exercise is one of the worst things you can do to growing bones.

One effect of chronic high impact is it causes the bone ends to "seal." That is, they change to the mature state. This means no more growing. This is why teens should never lift heavy weights--the pressure brings on this very thing. High impact exercise brings it on even sooner.

So, instead of stimulating bone growth he's signaling for it to stop.

Bone growth is stimulated by hormones. Testosterone is a key hormone in this process, as it signals the bones to store calcium. Jogging depresses testosterone. So, he's also working at being less muscular in addition to having weaker, smaller bones. Probably not what most teenage boys aspire to.

Jogging is nearly worthless in terms of health benefits. It's a low-intensity, high impact exercise--so, it combines the worst and leaves out the best.

A. Low intensity exercise can help you maintain some minimum baseline level of fitness, but you get vastly more cardio response from 10 minutes of interval training than you do from an hour of jogging. This is why coaches have kids run bleachers rather than jog.

B. Low intensity exercise that's prolonged (more than about 30 minutes) changes the hormonal environment so it's negative to muscle and both growth and positive to fat retention. The body goes into a defensive mode at this stage, shedding metabolically expensive tissue. The hormone that signals this is that good old stress hormone, cortisol.

You can convince him if you have him use our testosterone test kit. Buy two kits, so you can do a "before" and an after". Have him do the test to see where he is now (with all his jogging). Then, replace the jogging with high-intensity, low-impact exercise. I suggest "sissy squats" (not really for sissies, but called that because you don't use weighs) once a week and no other exercise. Do these no more than once a week, or effect is counterproductive. So, 4 sets of 6 reps done slowly and with concentration on the movement, being sure not to let the knee come past the toe. Ask me if you don't know what this exercise is.

He will see marked improvement in his musculature and his cardio health will improve. After a month of this regimen, test his testosterone again. It should be much higher. The reason for the boost is two-fold:

1. No more counterproductive jogging.

2. Deep sissy squats boost testosterone production (as do bench presses, back squats, deadlifts, etc.--any of the major compound exercises).

I'm 48. See my photo here:

Here's the testosterone kit:

(get 2 of them)


Kids do not get a second chance to make up for the premature stop of bone growth. Parents are not doing their kids any favors by letting them engage in activities that result in permanent, and significant, damage to their bodies.


Article Authorship

The articles on this site are authoritative, because:

  • Every contributor is an expert in his or her field.
  • The articles comply with the accepted principles of the bodybuilder literature.
  • The articles comply with the teachings of such luminaries as 8-time Mr. Olympia Lee Haney.

 Where an article is not bylined with a specific author's name, it was written by Mark Lamendola (see photos on home page and elsewhere on this site). Mark is a 4th degree blackbelt, has not been sick since 1971, and has not missed a workout since 1977. Just an example of how Mark knows what he's talking about: In his early 50s, Mark demonstrated a biceps curl using half his body weight. That's a Jack LaLanne level stunt. Few people can even come close. If you want to know how to build a strong, beautiful body, read the articles here.

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