Okay so,1st thing, i am a male, i am 170 punds, 5"9 & A half, And i am 16 years old of age. my 1st question->> I just started exercising, and when i do pushups, my arms start to shake alot. and about after 3 to 4 pushups my arms give out and fall to the floor. and when i do situps, my shins on...