Complex sentence: Certain studies suggested a link between sporadic ALS, specifically in athletes, and a diet enriched with branched-chain amino acids, a common dietary supplement among athletes, which cause cell hyperexcitability resembling that usually observed in people with ALS.
Split into simpler sentences: Certain studies suggested a link between sporadic ALS, specifically in athletes, and a diet enriched with branched-chain amino acids. BCAAs, a common dietary supplement among athletes, cause cell hyper-excitability resembling that usually observed in people with ALS.