In short yes, the percentage of slow/fast fibres will vary with muscle group. Pectoralis major tends to be about 60% fast-twitch fibres. "Legs" is a bit of a generalisation - your soleus, in common with other postural muscles, is predominantly slow-twitch fibres, other leg muscles contain more fast-twitch fibres (taken from this study):
Soleus 70% ...
Yes it is possible for two people of similar builds to have different flexibilities and I simply think this is because the amount of stretching and the consistency and repetition of that stretching. I doubt it's something that is a natural occurrence, it's like confidence, there's no way you can be born with it. If you take a look at gymnasts and how they do ...
I like a number of the answers above (in particular the one from @user31548). One other thing that I'd like to add is that some people get stronger more than they get bigger.
I look reasonably fit, but not like the guy you call to move a fridge. I can lift more than you'd think by looking at me. Using more or less the same programs, intensity,... other ...
If you want something to grow, work it hard. If you want it to not-shrink, work it at least a little.
The only way I can interpret your question in a way that makes sense to me is "When I'm not exercising a variety of muscles, is there any way to control which of them degrades first/fastest?". Is that what you're asking? ...
Bending forwards: Rectus abdominis (the "6 pack" muscle)
Bending backwards: Erector spinae group (the muscles running up your back either side of the spine)
Bending sideways: Abdominal oblique muscles (these are on the sides, in two layers, running between the hips, rib cage, and the centre of the abs)
Twisting: Also abdominal oblique muscles
So basically you have three types of muscle fibre:
Type I (slow-twitch)
Type IIa (fast oxidative)
Type IIx (fast glycolytic)
Most people are generally born with roughly a 50/50 split between types I and II. Top level endurance athletes can have up to 90-95% type I fibres, whereas strength/power athletes can have 60-80% type II. It's generally believed that ...
An efficient squatter mainly uses the glutes to extend the hips, not the hamstrings.
As can be seen from this image the hamstrings crosses both the hip and knee joint:
They therefore have two functions: extending the hips and flexing the knee.
If you use the hamstrings to extend the hips in the squat you also get a flexing torque at the knee. This means ...
I think this question has more to do with why a person with a lot of fast-twitch muscle types have higher stamina. Especially if you pair it with this question.
First, there are actually three types of muscle fibers. Type 1 (slow-twitch), type 2a (fast-twitch), and Type 2b (super-fast-twitch. Also called Type 2x). Type 2a is kind of an in between between ...
I'm not able to answer your question definitely, but here's a thought experiment with squats.
Strong person has a squat PR of 200kg
Weak person has a squat PR of 40kg
Who do you think will manage more reps with a weight of 40kg?
So i'd say, all else equal then yes, the stronger person also has more stamina.
We need to clarify some terms. "Extension" means movement of a joint which increases the angle between two body parts. So elbow extension is the movement that increases the angle between the humerus and radius/ulna, i.e. straightening the elbow. The opposite of extension is "flexion", which is a movement of a joint which decreases the ...