Experimental design
pain
LEINER
This study was a double-blind, placebo-controlled, randomized study designed to examine the effects of 3, 6, and 9 months of CP supplementation on joint function, pain, and mental/social health in older life-long physically active males and females. Participants were asked to abstain from food and caloric beverages (12 h), caffeine (12 h), alcohol (24 h), and physical activity (24 h) prior to all study visits. At baseline visit, participants reported to the Institute of Sports Sciences and Medicine (ISSM) at Florida State University (FSU), where written informed consent to participate in the study intervention was obtained and participants were randomized to one of the three treatment groups: 0 g/d (PLA), or 10 g/d or 20 g/d CP (SOLUGEL® Collagen Peptides, PB Leiner, part of Tessenderlo Group, Vilvoorde, Belgium). Participants were randomized and stratified into one of the three treatment groups by sex, using the computer-generated randomization function in Microsoft Excel (Microsoft Corporation, Redmond, WA.).At baseline, participants completed three questionnaires evaluating pain and function, mental/social and physical health, and physical activity levels. Participants completed a three-day food record (2 weekdays and 1 weekend day) following the visit. All participants (