Men’s workout shorts Men's gym shorts made from nylon/spandex Machine wash Made in USA California Muscle style CM322 California Muscle has recreated the ultimate men's workout shorts. Available for a limited time, these authentic workout shorts are a must-have for any serious athlete – or for those who simply love to look good when they're at the gym, running, or performing any other athletic activity. The California Muscle Lava men's workout shorts feature a fiery-hot asymmetrical design in masculine colors of navy and black with red accents.