Performances in Vertical Jump and Horizontal Jump Tests Are Positive Determinants of Hip Bone Mineral Density in a Group of Young Adult Men

Abstract

Although osteoporosis is known to mainly affect postmenopausal women, there is enough evidence to support substantial bone losswith aging inmen aswell (1,2). Bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is the best single predictor of fracture risk in elderly subjects (1,2). Among all fragility fractures, hip fractures are the most important in terms of morbidity andmortality (1,2). Highermortality rates after hip fracture have been reported in men compared with women (3). Peak BMD attained at the third decade of life is a strong predictor of fracture risk later in life (4). An increase in peak BMD of 10% would delay the onset of osteoporosis by 13 yr (4). Long-term practice of weight-bearing physical activities stimulates bone formation and enhances BMD of stressed sites (5,6). According to the mechanostat hypothesis, bones adapt their strength tomechanical loads generated fromvoluntarymechanical usage (7). This has been supported bymany animal-based studies (8,9). In humans, it has been shown that body weight and lean mass are the strongest predictors of BMD in both sexes (10,11). Other human-based studies have shown that BMD is correlated to the performances done in some physical tests (12,13). Identifying simple determinants of BMD may be useful for the prevention and early detection of osteoporosis and/or osteopenia. The aim of this study was to explore the relationships between performances in different physical tests (vertical jump [counter-movement jump], standing long jump test, 3-jump test, and 5-jump test) and BMD of the total hip in a group of young adult men. We hypothesized that the objective measures of muscular strength would be correlated to BMD of the hip because hip BMD is strongly correlated to mechanical factors on one hand and the physical tests, which were used in our study to measure the strength and the power of the lower limbs, on the other hand. Ten healthy Lebanese males whose ages ranged from 18 to 30 yr participated in this study. Weight and height were measured, and body mass index (BMI) was calculated. Daily calcium intake, daily protein intake (DPI), and sleep quality were evaluated using