Muscles that get tight when Sitting?

Which muscles get tight when sitting? I'm asking because every time I take a break from sitting I will do a couple of stretches but I'm not sure if I'm targeting the right muscles. 

Hip flexors, glutes (piriformis) and I've found my calves and lower back also suffer

I agree with Santiago. Spending adequate time stretching out each part of the body is key. Specially calves. 

Thanks you

Hamstring becomes extremely tight ,also abs and lower ribs limiting the spine extension.

Hi @James Coppola, here are three GB Blog articles about stretches to do after sitting for extended periods of time:

1. "Two Stretches to Counteract the Effects of Sitting"
2. "Mobility for Desk Workers: Table Rocks"
3. "Front Splits for Flexibility in GST™ and Daily Life"

Best,

Chris

11 hours ago, Chris Garay said:

Hi @James Coppola, here are three GB Blog articles about stretches to do after sitting for extended periods of time:

1. "Two Stretches to Counteract the Effects of Sitting"
2. "Mobility for Desk Workers: Table Rocks"
3. "Front Splits for Flexibility in GST™ and Daily Life"

Best,

Chris

Thanks for these links, extremely useful!