What is the cause of fatigue for the alactacid system? (A) Lack of essential amino acids (B) Lack of muscle glycogen stores (C) Inability to re-synthesise phosphate creatine (D) Inability to convert carbohydrates to glycogen - HSC - SSCE Personal Development and Physical Education - Question 10 - 2015 - Paper 1

The primary cause of fatigue in the alactacid system is the inability to re-synthesise phosphate creatine. The alactacid system, also known as the ATP-CP system, relies on creatine phosphate (CP) to rapidly regenerate ATP during high-intensity activities. When CP stores are depleted, the system cannot maintain ATP production, leading to fatigue. This system is predominant in short bursts of activity, typically lasting up to about 10 seconds.