Complex sentence: Slalom is an alpine skiing and alpine snowboarding discipline, involving skiing between poles (gates) spaced much closer together than in giant slalom, super giant slalom (super-G) or downhill, necessitating quicker and shorter turns.
Split into simpler sentences: Slalom is an alpine skiing and alpine snowboarding discipline, involving skiing between poles or gates. These are spaced more closely than those in giant slalom, super giant slalom and downhill, necessitating quicker and shorter turns.