The effects of creatine supplementation and weight training on muscle mass in individuals with prostate cancer undergoing androgen deprivation therapy.

Study Design This is a double-blind randomised controlled trial designed to measure the effects of creatine (Cr) supplementation in addition to resistance training (RT) in prostate cancer (PCa) patients receiving androgen deprivation therapy (ADT). Both supplement (SUPP) and control (PLA) groups will receive a 12-week supervised exercise program comprising of RT undertaken three times per week. In addition, participants in the SUPP group will receive a daily dose of Cr: 20 g/day during the loading phase, 5g/d thereafter for the duration of the study. The PLA group will also receive a daily dose of a placebo of dextrose (following the same dosing protocol as SUPP). Participants Fifty-six men (n=56) with localised or locally advanced prostate cancer, who are currently on ADT (and expected to remain on ADT for the next three months) will be eligible to enrol in this study. Exercise Program Participants assigned to each arm will attend three (60-minute) clinic-based supervised RT sessions each week, for 12 weeks. RT will be prescribed using repetition maximums (RM), where participants will be required to perform 8 different exercises using major muscle groups (Chest press, Push Up, Seated Row, Shoulder Press, Lat Pulldown, Leg Press, Step Up, Leg Curl) at 8-12 RM (the maximal weight that can be lifted 8 to 12 times each set, equivalent to ~65-85% of 1RM) for 3-4 sets per exercise. Accredited Exercise Physiologists will supervise all exercise sessions. Supplement & Placebo protocol Participants in the SUPP group will receive 20g/day of Cr monohydrate for five days, divided into four equal doses throughout the day in the week prior to the start of the 12-week training program. Participants will then be given single daily doses of 5 grams for the remaining 12 weeks in the study. Participants in the PLA group will follow the same dosing protocol with dextrose. Participants will be asked to dissolve the supplements in 200-300 mL juice to mask the solubility of Cr and taste of dextrose. To increase compliance, participants will be asked to return empty packets to the research team once a week. Supplement packages will be coded so that neither the investigators nor the participants will be aware of contents. Supplementation with Cr or PLA will begin following baseline assessments.