The purpose of this study is to compare the effectiveness of acetaminophen extended release caplets to placebo in treating the muscle aching and pain (soreness) that occurs after a marathon.

This is a randomized, double-blind, placebo-controlled study to compare the effectiveness and safety of acetaminophen and placebo in treating muscle aching and pain (soreness) that occurs in subjects who complete a marathon. Subjects are randomized to receive acetaminophen extended release caplets, 3900 mg/day (two 650 mg caplets taken three times a day, for four days) or placebo (two placebo caplets taken three times a day, for four days). The primary measurement of efficacy is the average change from baseline in muscle soreness, on Day 1, the day of the marathon. Safety assessments consist of monitoring adverse events, and a physical examination at the screening visit, including vital signs, weight, a medical history review, and a urine pregnancy test for females of childbearing potential. The hypothesis of the study is that acetaminophen is more effective than placebo in the relief of post-race muscle aching and pain (soreness) score on the evening of the race. Two acetaminophen 650 mg extended release caplets, taken by mouth, three times a day over a four day period or two placebo caplets, taken by mouth, three times a day over a four day period.

Inclusion Criteria:

• Patients must be able to comply with the study schedule
• be able to swallow the study medication
• complete the marathon
• not take any analgesics after completing the marathon and before their eligibility to participate in the study has been determined
• rate their muscle soreness at least a 4, on a 0 - 10 point scale

Exclusion Criteria:

• Previous diagnosis of osteoarthritis
• currently have or have had a medical condition that may be relevant in one's eligibility to participate in the study
• known hypersensitivity to acetaminophen
• unable to understand or follow the instructions for the study
• taken any investigational medication within 30 days of the marathon