The answer would be Microfilaments.
Strech until it starts burning then ease up
"Shin splints" or medial tibial stress syndrome.
Wearing wornout shoes, along with all of the impact from triple jump and the poor flexibility, eventually leads to differences in movement. This leads to shin splints
Answer: Maintain flexibility
Explanation: If you maintain flexibility throughout your life, then you'll have to stretch often in order to keep fit.