The heat seems to induce muscle cramping in my thighs, esp. when I climb aggressively. I was on my descent down the mountain, where leg turn over is minimal, and the cramps set in hard. I quickly stopped, applied my Cramp911, and INSTANTLY those cramps were gone. Unbelievable! I have spent thousands of dollars going through testing to attempt to determine what causes the cramping during intense exercise for me – with no real success.