Relationships among body weight, joint moments generated during functional activities, and hip bone mass in older adults

Abstract

Objective-To investigate the relationships among hip joint moments produced during functional activities and hip bone mass in sedentary older adults.Methods-Eight male and eight female older adults (70-85 yr) performed functional activities including walking, chair sit-stand-sit, and stair stepping at a self-selected pace while instrumented for biomechanical analysis. Bone mass at proximal femur, femoral neck, and greater trochanter were measured by dual-energy X-ray absorptiometry. Three-dimensional hip moments were obtained using a six-camera motion analysis system, force platforms, and inverse dynamics techniques. Pearson's correlation coefficients were employed to assess the relationships among hip bone mass, height, weight, age, and joint moments. Stepwise regression analyses were performed to determine the factors that significantly predicted bone mass using all significant variables identified in the correlation analysis.Findings-Hip bone mass was not significantly correlated with moments during activities in men. Conversely, in women bone mass at all sites were significantly correlated with weight, moments generated with stepping, and moments generated with walking (p < 0.05 to p < 0.001).Regression analysis results further indicated that the overall moments during stepping independently predicted up to 93% of the variability in bone mass at femoral neck and proximal femur; whereas weight independently predicted up to 92% of the variability in bone mass at greater trochanter.Interpretation-Submaximal loading events produced during functional activities were highly correlated with hip bone mass in sedentary older women, but not men. The findings may ultimately be used to modify exercise prescription for the preservation of bone mass.

Bone health in ambulatory individuals with multiple sclerosis: Impact of physical activity, glucocorticoid use, and body composition

“…One research group found that in individuals without MS aged 30 to 49, hip joint moments can explain up to 58 percent of variance in BMC, more so than variance in BMD, independent of body size [59]. An even stronger correlation was found in another study of older adults without MS, for whom dynamic hip load independently predicted up to 93 percent of variance in BMC and 73 percent of variance in BMD [60]. However, other researchers have reported that current physical activity does not affect BMD in postmenopausal women without MS [63] and BMD of the PF is not associated with dynamic hip load in young women without MS [64].…”

“…That physical activity and exercise positively affect BMD in healthy women across the lifespan is well established [55][56][57]. Several studies in non-MS populations have shown that PF BMD and BMC, in particular, are strongly associated with dynamic load on the hip [43,[58][59][60] and with accelerometer counts [41,[61][62]. One research group found that in individuals without MS aged 30 to 49, hip joint moments can explain up to 58 percent of variance in BMC, more so than variance in BMD, independent of body size [59].…”

Effects of excess body mass on strength and fatigability of quadriceps in postmenopausal women

“…The reduced quadriceps fatigability observed in the present study may be a result of the obese women having adapted to greater body mass because the excess body mass constantly carried by these obese individuals (weight-bearing effects) during daily activities and leisure creates a prolonged level of muscular exertion that mimics an exercise load, inducing favorable fatigue-resistant effects. 8,30 Conversely, the reduced amount of fast powerful movements secondary to excess body mass may contribute to a loss of fast-twitch motor units (type IIb), resulting in a loss of strength. 12,27,28,31,32 We also found a correlation between fatigue and carbohydrate intake, which may be linked to the fact that high intensity exercises mainly use anaerobic metabolism (glycolysis), recruiting type II muscle fibers (glycolytic fibers).…”

Gender differences exist in the hip joint moments of healthy older walkers

“…For walking, the peak adduction moment is of particular interest as it is a large component of the inter-segmental moments at the hip that must be balanced by internal muscle forces throughout stance. It occurs in the same time region as the peak-resultant joint force and bending moment, as measured in vivo (Bergmann et al, 1995), and has been used previously as a surrogate measure of the joint loading (Schipplein and Andriacchi, 1991;Hurwitz et al, 1998;Moisio et al, 2004;Andriacchi and Mundermann, 2006;Wang et al, 2006;Thorp et al, 2006). The simplified marker set used in this study was selected on the basis of the specific questions addressed which focused on the three-dimensional external joint moments at the hip and sagittal and frontal plane hip motions.…”