You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Crucifixion_of_Jesus

Context:
In his book The Crucifixion of Jesus, physician and forensic pathologist Frederick Zugibe studied the likely circumstances of the death of Jesus in great detail. Zugibe carried out a number of experiments over several years to test his theories while he was a medical examiner. These studies included experiments in which volunteers with specific weights were hanging at specific angles and the amount of pull on each hand was measured, in cases where the feet were also secured or not. In these cases the amount of pull and the corresponding pain was found to be significant.

Question:
How did Zugibe try to prove his theories?

carried out a number of experiments over several years