Joints can sprain
A muscle "strain" is when muscle fibers get stretched too far and/or some fibers tear. People generally call it a tear if enough fibers break, leading to some bleeding and swelling inside the muscle, resolving later with some healed scar tissue and some tightness in the area (less elastic).
A joint sprains when its ligaments (whitish fibers) are stretched too far and break. Muscles don't "sprain