SPEED WINDOWS

As a short recap to the last blog:

There are certain times during the body’s maturation that the biological sciences have shown that we can help enhance certain aspects of a child’s physical nature.

We call these “windows of opportunity” or “gates” that open and are prepared to be optimized. From the physical standpoint, there are speed, mobility, kinesthetic and vestibular awareness, endurance, strength and power windows. Mentally, there are times where we can best help a child improve ability to rationalize and process what happens each day.

We’ll discuss speed windows today.

For boys, the first speed window happens between a biological 6 to 9 years old, give or take a few months. Researchers, Wilmore and Costill, showed there is a slight rise in testosterone during that time.  In separate studies, several researchers showed an increase both strength and power in boys.  From a handgrip to shoulder, elbow, hip and knee flexion, Shephard and Lavallee as well as Malina and Roche showed that boys strength improved in that 6-9 age range.

What’s not known is how much neuromuscular facilitation, or the ability of the brain to make the muscles do what it actually wants them to do, is involved with the strength gains during this age range. However, given that more testosterone is actually added to the body at that point, it is not a huge leap to ascertain that doing activities that promote strength and speed will help form muscle fiber designed to, in fact, facilitate strength and speed.

Five different studies (Jones – 1949 (2 different studies), Beunen – 1988, Loko – 1977, Kemper and Verschuur – 1985), determined that the second window for strength and speed happens to boys from about 13 to 16.5-17 years old. That time frame is consistent with the pubertal growth spurt. Testosterone begins to increase during puberty. And at that peak of a boy’s growth (PHV or peak height velocity) testosterone comes in a huge way. (A quick side: research shows that the optimal time to introduce boys to external load strength training is roughly 18 months post PHV. However, we’ve found nothing biologically wrong with starting the athletes on external-load resistance training at PHV. If the athlete has been training since before puberty and has an excellent grasp of the exercise he is supposed to do, then there is nothing wrong with adding resistance to the movements he has been doing.)

Research shows that girls do not have the same dramatic growth as boys. However, the strength and speed gains are no less than that of the boys. In fact, a 1994 study by Shephard and Lavallee showed a more expansive increase in muscular strength in girls than in boys. Malina and Roche (1983) showed that the onset of those gains in girls was started earlier than boys, especially in the muscle groups used for pulling motions – forearm flexors, biceps, latissimus dorsi, posterior deltoids, trapezius, teres minor and makor and rhomboids.

As earlier stated, the second speed window happens during the pubertal growth spurt for boys and a little earlier for girls, who do not have as pronounced a growth spurt as boys.

From roughly 13 to about 16.5-17 years old, boys typically go through that radical growth according to studies including: Espenschade (1960), Clarke (1971), Guzalovski (1977), Shephard (1982), Saavedra (1991) and Froberg and Lammert (1996). As mentioned earlier testosterone hits boys in a huge way in the middle of that growth. That hormonal increase spurs a strength increase, too. More muscle fiber means the boy has a better chance of recruiting the muscle mass needed to perform movement at higher speeds.

Many of the same individuals and research teams studied girls, too, finding that the average onset of the second big strength improvement came about a year to 1.5 years before the boys. Girls grow more steadily than boys after the initial rapid growth that happens after birth. Their strength gains tend to progress more steadily, too, typically reaching full maturity before boys. Again, just as in the first speed window, the girls’ steady rate of strength improvement proved to equal to that of the boys’ rapid growth. The big difference is the testosterone – which makes the boys much stronger.