3 ms·

> In either case, it appear that humans have specifically evolved for throwing, with most of the energy coming from the shoulders, not from long or cord-like te

> In either case, it appear that humans have specifically evolved for throwing, with most of the energy coming from the shoulders, not from long or cord-like tendons. that's not really true. as someone who can throw a baseball quite fast, you really want relaxed shoulders. tense shoulders are a great way to get injured. from my experience throwing, most of the throwing power is generated from the hips. then it comes up your lats on your back which generates a whipping motion through the shoulder. you want this energy transfer from the hips to the arm to be as smooth as possible, hence loose shoulders. near the end of the throw, the triceps and then forearm engage to complete the whip. other than knowing this from throwing, it's pretty easy to know because these are the muscles that are sore when i haven't thrown in a long while.

maxerickson 9y ago
Even someone without a practiced throwing motion can demonstrate the importance of the hips in the motion; just try throwing with arm only while standing flat footed.
eesmith 9y ago
No, it's not "really true". I summarized the summary, and didn't include all of the details. Here are quotes from the summary which show it isn't only the shoulder involved, but that the shoulder is a key component. "The shoulder and arm and the rest of the body involved in the throwing motion must be storing elastic energy," "Several developments in anatomy allowed humans to throw this way, he said, including a waist that allows twisting and a relatively open shoulder, compared with those of other primates like chimpanzees." "“You’re storing energy in your shoulder,” Dr. Roach said, ... “It works just like a slingshot would. You’re actually stretching the ligaments.” "What is new in Dr. Roach’s study, say anatomists, is the idea of the shoulder’s functioning like a slingshot, and tying the specific anatomical changes to the fossil record." "“I don’t believe that Homo erectus had the broad shoulders that would have given him the ability” to throw the way humans do." Note that I said nothing about tense vs. relaxed shoulders. The NYT summary links to the actual paper, which is at http://www.nature.com/nature/journal/v498/n7455/full/nature12267.html http://www.nature.com/nature/journal/v498/n7455/full/nature1... . Some quotes from it: "Here we use experimental studies of humans throwing projectiles to show that our throwing capabilities largely result from several derived anatomical features that enable elastic energy storage and release at the shoulder." "Throws are powered by rapid, sequential activation of many muscles, starting in the legs and progressing through the hips, torso, shoulder, elbow and wrist. Torques generated at each joint accelerate segmental masses, creating rapid angular movements that accumulate kinetic energy in the projectile until its release. It has been shown that internal (medial) rotation around the long axis of the humerus makes the largest contribution to projectile velocity." I wasn't sure, so I looked up humerus. Wikipedia says "The humerus ... is a long bone in the arm or forelimb that runs from the shoulder to the elbow." "Calculations of the maximum power-production capacity of all of the shoulder’s internal rotator muscles indicate that these muscles can contribute, at most, half of the shoulder rotation power generated during the throwing motion" "We propose that several evolutionarily novel features in the human shoulder help to store and release elastic energy to generate much of the power needed for rapid humeral rotation during human throwing." Those seem to say that most of the power comes from the shoulder, though the hips and other parts of the body of course play a role.

maxerickson 9y ago

Even someone without a practiced throwing motion can demonstrate the importance of the hips in the motion; just try throwing with arm only while standing flat footed.

eesmith 9y ago

No, it's not "really true". I summarized the summary, and didn't include all of the details. Here are quotes from the summary which show it isn't only the shoulder involved, but that the shoulder is a key component. "The shoulder and arm and the rest of the body involved in the throwing motion must be storing elastic energy," "Several developments in anatomy allowed humans to throw this way, he said, including a waist that allows twisting and a relatively open shoulder, compared with those of other primates like chimpanzees." "“You’re storing energy in your shoulder,” Dr. Roach said, ... “It works just like a slingshot would. You’re actually stretching the ligaments.” "What is new in Dr. Roach’s study, say anatomists, is the idea of the shoulder’s functioning like a slingshot, and tying the specific anatomical changes to the fossil record." "“I don’t believe that Homo erectus had the broad shoulders that would have given him the ability” to throw the way humans do." Note that I said nothing about tense vs. relaxed shoulders. The NYT summary links to the actual paper, which is at http://www.nature.com/nature/journal/v498/n7455/full/nature12267.html http://www.nature.com/nature/journal/v498/n7455/full/nature1... . Some quotes from it: "Here we use experimental studies of humans throwing projectiles to show that our throwing capabilities largely result from several derived anatomical features that enable elastic energy storage and release at the shoulder." "Throws are powered by rapid, sequential activation of many muscles, starting in the legs and progressing through the hips, torso, shoulder, elbow and wrist. Torques generated at each joint accelerate segmental masses, creating rapid angular movements that accumulate kinetic energy in the projectile until its release. It has been shown that internal (medial) rotation around the long axis of the humerus makes the largest contribution to projectile velocity." I wasn't sure, so I looked up humerus. Wikipedia says "The humerus ... is a long bone in the arm or forelimb that runs from the shoulder to the elbow." "Calculations of the maximum power-production capacity of all of the shoulder’s internal rotator muscles indicate that these muscles can contribute, at most, half of the shoulder rotation power generated during the throwing motion" "We propose that several evolutionarily novel features in the human shoulder help to store and release elastic energy to generate much of the power needed for rapid humeral rotation during human throwing." Those seem to say that most of the power comes from the shoulder, though the hips and other parts of the body of course play a role.