Smithing Biomechanics | EVERYTHING ELSE OFF TOPIC | Forum

Larry L;17865 wrote: Alec uses the weight of the hammer, he grips it right up by the head, the farther you hold down the handle the lighter hammer can be used to accomplish the same amount of work. A hammer that was half the weight swung at twice the speed would produce 8 times the result ( I think, I am too lazy to look it up to verify so someone prove me wrong)

Yes, I've seen that work equation quoted many times, but I think there's another equation that's important that never gets talked about and that's F=ma. Work is a different unit than Force, which is what's needed to break the friction between the molecules and actually get the metal moving. Work will allow the metal to keep moving once it starts. If you let go of the hammer at the strike like Hofi says, your accelaration of the hammer head drops to that of the force of gravity, 9.8m/s² if I remember correctly, then going to zero when the hammer hits the metal and then into negative values (in relation to direction of movement that we are going for) as the rebound occurs, so the force of the blow decreases. If you were to keep using your muscles to push the hammer head, you can continue to add to gravity's accellaration of the hammer to at least slow down the drop in force to zero, theoretically moving more (or cooler) molecules. Not a healthy thing to do, however. Which brings us to your next point:

Larry L;17865 wrote: The point being there is no correct way, only what works. It works for him now, it might not later. But dont think you need to swing a 7 lb hammer to be a blacksmith...

I cant say that I have any chronic pain. I have had issues that took months and months to work though but my experience to date has been that swinging the hammer is the best therapy ... All of my children are considerably older than Alec, maybe by the time I have grandchildren his age I will have some pain to complain about (I hope not but I am counting on it)

I believe and what I'm trying to compile is that there is a 'correct' way to do this, but I'm looking more at a detailed ergonomic, long-term muscle and joint health and pain-free smithing perspective. Two different examples of ruining your rotator cuff:

1. If you are using your rotator cuff (I'm talkling the actual 4 muscles of the rotator cuff: Supraspinatus, Infraspinatus, Subscapularis and Teres Minor) to move your arm, instead of the muscles that SHOULD be moving the arm: Bbiceps, Triceps, Deltoid, Lats, you're going to run into problems.

2. If you're using the right muscles to move the arm, but the scapular stabilizers (mainly the serratus anterior) aren't doing thier job, the bony prominences on the scapula will tear up our rotator cuff.

The one thing that I notice that long time Smiths have in common is that they do what I tell all of my patients to do, and that's: pay attention to your body and if it hurts, don't do it.

Keep the info/suggestions coming.

Hi Lee, and I hope what I post is more helpful than confusing.

Not sure what pictures you are looking for, if its the specific muscles, my suggestion is buy a used anatomy atlas (if I remember correctly, Netter's is the one with drawings, and Yamaguchi's is actual pictures). Netter's would probably be easier to understand.

As far as some of my terminology, I'm not sure there's an industry standard, but PTs who focus on muscle imbalances and posture and biomechanics recognize that most muscles can be categorized as primarily a mover of a certain joint, or a stabilzer of a joint. Some muscles need to move one joint while stabilizing another, some move a joint with certain actions and stabilize the same joint with other actions. In general, your stabilizers are smaller, deeper muscles, close to the joint, whereas your movers are generally more superficial, bigger and often cross multiple joints.

Like I said earlier (perhaps it was on IForgeIron) I'm a fan of yoga, Tai Chi or any stretching that takes the body through it's entire repitoir of movements throughout the full range of motion GENTLY. Remember, "use it or lose it!"