The original GOOD cohort was found to be representative of the general young male population in Gothenburg , and the cohort at the follow-up visit was found to be representative of the initial population . The study was approved by the Regional Ethical Review Board at the University
of Gothenburg. Written and oral informed consent was obtained from all study participants. Present physical activity A standardized self-administered questionnaire, based on a validated physical activity questionnaire to measure the effect of mechanical strain on bone mass  with amendments, was used to collect information about patterns of present physical activity in sports and exercise. Information www.selleckchem.com/products/z-devd-fmk.html on the type of physical activity as well as duration (in hours per week) and number of years spent on all present physical activities in relation to sports and exercise was collected. Subjects were divided into two groups according learn more to their main present activity: resistance training (n = 106) or soccer (n = 78). Seven subjects (6.6 %) in the resistance training group and 72 subjects (92.3 %) in the soccer-playing group find more classified themselves as being competitive athletes. Subjects
who had never been active in sports, with neither competitive nor recreational purpose, were used as nonathletic referents (n = 177). We did not record information regarding kinds of resistive exercises, loading levels, number of sets, or number of repetitions performed in the resistance training group. Information on occupational physical loading (in metabolic equivalent
of task), sedentary behavior (total time (in hours per week) sitting down, e.g., watching TV or using a computer), and type of daily transportation (walking, bicycling, or passive transportation, e.g., public transportation, driving a car or motorcycle) was also collected by questionnaire. Anthropometrics, calcium intake, and smoking status Height and weight were measured using standardized equipment. The coefficient of variation (CV) values were <1 % for these measurements. A standardized Exoribonuclease self-administered questionnaire was used to collect information about calcium and smoking (yes/no). Calcium intake (in milligrams per day) was estimated from dairy product intake. Grip strength Grip strength was assessed using a Jamar hydraulic hand dynamometer (5030J1, Jackson, MI, USA) with adjustable handgrip. The subjects sat in a standard chair with both the forearm and dynamometer resting on a table. The subjects were asked to hold the dynamometer firmly and in an upright position, and then squeeze the handle as hard as they could. Three trials of each hand were performed. The results were recorded in kilograms of force, and the mean value of the three results for the nondominant hand was used in this study.