Possible Clues:

• After breather, energy to spring forward
• Quad-strengthening exercise move
• Thrust oneself suddenly forwards
• Exercise that stretches the hamstrings
• Thrust forward name for inclusion in Olympic event
• Push forward easily, initially, after breather
• Move suddenly forward in swim? Not at first
• Thrust using energy after breather
• Sudden thrust forwards
• Quadriceps-strengthening exercise