We don't have any clinical tests investigating this question, but most doctors tell their patients not to bend over for four hours after Botox injections. Some physicians don't restrict their patients because Botox is bound to its local tissue quickly after injection, but I still tell my patients of this four hour rule, to be safe. Weight lifting can cause significant elevation of blood pressure and this might induce delayed and significant bruising if one were developing a small bruise regardless of performing exercise. So if it is important to a patient to minimize the chance of swelling and bruising after Botox, then I would advise them not to do strenuous exercise for two days after Botox injections.The information provided in Dr. Shelton's answer is for educational purposes only and is not intended to constitute medical advice. The information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs.