Even so, the back squat does differ in important ways from the vertical jump. Primarily, it involves a much greater trunk extension turning force, because of the barbell weight on the upper back, and this likely contributes to the more hip-dominant nature of the squat over the vertical jump. Secondly, it is often performed to a deeper depth, which can alter the relative contribution of each of the hip extensors to the movement, because of their different leverages at each joint angle. And thirdly, it only involves accelerating up to midway through the movement, while the vertical jump involves accelerating right up until take-off. This also affects the relative contribution of the hip extensors, as force production will be required in the jump even when the hip is nearly fully extended, while this is unnecessary in the squat.
Jonathan Chait escribió en The New Republic que Klein "presta, sorprendentemente (pero, habida cuenta de sus premisas, no es de sorprender), poca atención a las ideas de derecha. Ella reconoce que el neoconservadurismo se encuentra en el corazón del proyecto guerra de Irak, pero no parece saber qué es el neoconservadurismo, y no hace ningún esfuerzo para averiguarlo".16
Unfortunately, I’m not the 6' 7" son of a Hall of Famer, so I had to resort to desperate devices—like Hennessy, an infamous and inexpensive cognac that, according to one of the two NBA players who recommended it to me, “will give you that Yah! That bounce. That little bit of meanness you need.” The little minibar-sized bottle that I downed 30 minutes into an intense session of dunk attempts on a sweltering day last summer, had no effect other than scorching my esophagus, giving me a headache and releasing from my pores an aura that, as my six-year-old put it that evening, “smells like medicine.”
I just got the bike on Friday and used it twice over the weekend so this isn't a long-term review but my initial impression is highly favorable. I am a "serious" cyclist, which is not to say I'm a professional or anything like that but I log a lot of miles on my road bike and use high-end equipment. I've always hated hooking a bike up to an indoor trainer and I've avoided that type of training for many years. I finally went in on a spinning bike and I am very impressed with the results.
About 100 yards away from this 9' 10" breakaway rim (which came to sound, each time I grabbed and released it, like someone closing the metal baby gate at the top of our stairs) was a brown, oxidized, immobile 9' 1" version, a hand-ruining iron maiden where, in front of the occasional puzzled onlooker, I practiced (and practiced) the timing and the hand and wrist work required to dunk. I knew early on that my regulation dunk, if it ever came to pass, would have to come from a lob of some sort—a bounce to myself, either off the blacktop or underhanded off the backboard—after which I would hypothetically control the ball with one hand just long enough to flush it. Mastering the placement and the delicate timing of such lobs would prove to be a quixotic pursuit in and of itself. But it was necessary, not just because of my hand size (7 ¾ inches) but also because I needed to keep my arms free so I could swing them at takeoff, adding much-needed lift to my leap.
A common, low-tech plyometrics method is performing box jumps, where the athlete jumps repeatedly from the floor to the top of the box and back again. By concentrating on the mechanics of the jump, directing propulsion from the balls of the feet and thrusting with an explosive extension of the legs, the ability of the athlete to land lightly and immediately return to the floor enhances motor control over the movement.
An important component of maximizing height in a vertical jump is attributed to the use of counter-movements of the legs and arm swings prior to take off, as both of these actions have been shown to significantly increase the body’s center of mass rise. The counter-movement of the legs, a quick bend of the knees which lowers the center of mass prior to springing upwards, has been shown to improve jump height by 12% compared to jumping without the counter-movement. This is attributed to the stretch shortening cycle of the leg muscles enabling the muscles to create more contractile energy. Furthermore, jump height can be increased another 10% by executing arm swings during the take off phase of the jump compared to if no arm swings are utilized. This involves lowering the arms distally and posteriorly during the leg counter-movements, and powerfully thrusting the arms up and over the head as the leg extension phase begins. As the arms complete the swinging movement they pull up on the lower body causing the lower musculature to contract more rapidly, hence aiding in greater jump height. Despite these increases due to technical adjustments, it appears as if optimizing both the force producing and elastic properties of the musculotendinous system in the lower limbs is largely determined by genetics and partially mutable through resistance exercise training.