• aerobic
• less force 
• more endurance
• greater blood supply
• greater number of mitochondria
• more myoglobin stores

• anaerobic
• more force
• less endurance
• greater diameter
• more glycogen stores (they run out of oxygen quicker)

• If too stretched, it has less strength (there's not enough actin and myosin attachments)
• If it's too contracted, less force

• Each action potential induces a twitch
• calcium is being relased to bind actin and myosin
• drop off= calcium is taken back into the SR
• incomplete tetanus= more calcium
• complete tetanus= calcium is not taken back up
• troponin causes tropomyosin to roll and move out of the way, calcium binds actin and myosin, myosin heads contract (energy is stroed in the myosin head, enabling it to contract), the head releases with the help of ATP, the head recocks
• need calcium and ATP to keep going

Smooth muscle contraction differences

• calcium activated myosin, instead of activating actin
• slower contraction, uses less energy
• force of contraction depends on calcium levels
• calcium comes from outside and SR