General > General Technical Chat
Gym Exercise Physics Quesion
EEVblog:
--- Quote from: bostonman on April 06, 2022, 01:47:19 am ---Technically it seems holding 25kg in each hand hanging vertical would exert the same force on each shoulder regardless if elbows are bent or not, but common sense, years of going to the gym, and this thread, it makes sense that it causes other muscles to change the direction of forces.
--- End quote ---
The shoulder is an incredibly complicated piece of biomachinery.
bostonman:
You're correct and I believe it's one of the most involved joint - I'm just unfamiliar with the many names and know the basic names.
BTW, great picture.
jpanhalt:
If your question is related only to the amount of weight/force, then as others have said, 25 kg doesn't change. However, if you are concerned about forces on the shoulder, particularly the rotator cuff, then the situation is more complex. Relative to the scapula only and ignoring the acromion/clavicle, some muscles in the shoulder originate on the scapula and insert on the head of the humerus (1). Other muscles (e.g., biceps) originate on the scapula and insert in the upper forearm (2).
Dead weight on a fully relaxed arm and shoulder puts stress on the rotator cuff. When appropriate muscles are flexed, that force on the rotator cuff is shared with the scapula.
Anyone who has had serious rotator cuff injury can describe for you the ease with which that shoulder may feel slightly dislocated and is uncomfortable. Flexing the muscles puts it back where it belongs.
1) https://www.ortho.wustl.edu/content/Patient-Care/3127/Services/Shoulder-Elbow/Overview/Shoulder-Arthroscopy-Information/The-anatomy-of-the-shoulder.aspx#:~:text=The%20rotator%20cuff%20connects%20the,by%20pulling%20on%20the%20tendons.
2) https://en.wikipedia.org/wiki/Biceps#:~:text=The%20biceps%20or%20biceps%20brachii,attached%20to%20the%20upper%20forearm.
Bud:
--- Quote from: MicahWiggins on December 15, 2022, 01:46:11 pm ---Since my early childhood, I have been practicing many different sports. One of them was running. Growing up, I ended up practicing only this one. Now, I'm keen on waking up every morning and running for at least half an hour. Also, I started understanding that if you want to lose weight or get fit, you should take some products that help you get the best results.
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And in your next post can we expect you giving us links to weight loss products you sell?
bostonman:
Hahahah
This wasn’t about shoulder injuries, it was about forces.
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