What is the definition for a static contraction

source: HealthGuidance for better health

‘static’ – meaning still/motionless, and ‘contraction’ – meaning to tense the muscles and use them. So the idea then in static contraction is simply to force your muscles to work without actually moving. That might sound ridiculous, but it doesn’t mean simply standing on the spot tensing but using a different technique to work muscles without moving – pushing or pulling against an immovable force. F

which of what? i am confused