What are the effects of performing an activity after completing a warm-up versus not doing a warm up?

Which of the following can be a community opportunity to play a team sport? basketball hang gliding hiking rollerblading which of the following breaks a safety rule? going to the gym while you have a contagious condition, like the flu or pink eye ignoring people who have been waiting to use your basketball court talking on your phone or texting during a yoga class walking out of a fairway sand trap without raking your footprints