In most cases, heavy weight causes the injury. Ego lifting is an attempt to lift weights that are heavier than the weightlifter's capability. During ego lifting, the lifter's form will be twisted because the weight is too heavy, and if the weight is far beyond the lifter's strength, then there is a likelihood to suffer from biceps tears. Another injury caused by biceps curls is ulnar neuropathy, which lead to ulnar nerve conduction slowing at the elbow. This is caused by compression of the nerves against a weight bench during the exercise. Though unlikely, biceps curl can cause a rupture of the pectoralis major muscle, which is a severe injury that occurs in the chest. References Weight training exercises