The Relationships Between Skeletal Muscle Index and Bone Variables in a Group of Young Adults

International audienceThe purpose of this study was to investigate the relationships between skeletal muscle index (SMI) and bone variables in a group of young adults. Three hundred and thirty-five young adults (129 men and 206 women) whose ages ranged from 18 to 35 yr voluntarily participated in this study. Weight and height were measured, and body mass index (BMI) was calculated. Body composition, bone mineral content (BMC), bone mineral density (BMD), geometric indices of hip bone strength and trabecular bone score (TBS) were determined for each individual by Dual-energy X-ray absorptiometry (DXA). Appendicular skeletal mass (ASM, in kg) was calculated by summing the muscle masses of the 4 limbs, assuming that all nonfat and nonebone mass is skeletal muscle. Skeletal muscle index (SMI) was defined as ASM/height². In young men, SMI was positively correlated to WB BMC (r = 0.63; p < 0.001), WB BMD (r = 0.53; p < 0.001), L1-L4 BMC (r = 0.33; p < 0.001), L1-L4 BMD (r = 0.30; p < 0.001), L1-L4 TBS (r = 0.26; p < 0.01), TH BMC (r = 0.61; p < 0.001), TH BMD (r = 0.46; p < 0.001), FN BMC (r = 0.51; p < 0.001), FN BMD (r = 0.46; p < 0.001), FN cross-sectional area (CSA) (r = 0.56; p < 0.001), FN cross-sectional moment of inertia (CSMI) (r = 0.52; p < 0.001) and FN section modulus (Z) (r = 0.54; p < 0.001) but negatively correlated to FN strength index (SI) (r = -0.24; p < 0.01). In young women, SMI was positively correlated to WB BMC (r = 0.61; p < 0.001), WB BMD (r = 0.60; p < 0.001), L1-L4 BMC (r = 0.35; p < 0.001), L1-L4 BMD (r = 0.33; p < 0.001), L1-L4 TBS (r = 0.29; p < 0.001), TH BMC (r = 0.61; p < 0.001), TH BMD (r = 0.53; p < 0.001), FN BMC (r = 0.45; p < 0.001), FN BMD (r = 0.49; p < 0.001), FN CSA (r = 0.60; p < 0.001), FN CSMI (r = 0.52; p < 0.001), and FN Z (r = 0.40; p < 0.001) but negatively correlated to FN SI (r = -0.20; p < 0.01). The current study suggests that SMI is a positive determinant of bone mineral density and geometric indices of hip bone strength in young adults

Effects of Exercise Training on Bone Health Parameters in Individuals With Obesity:A Systematic Review and Meta-Analysis

International audienceBackground: Osteoporosis causes bone fragility, increasing the risk of fractures. Evidence suggests a strong correlation between obesity and fracture risk. Physical training is known to enhance bone resistance and protect from fracture; however, its osteogenic effect in the presence of obesity remains unknown.and nbsp;Objective: We sought to evaluate the influence of exercise training on bone health indices in individuals with obesity.and nbsp;Methods: This systematic literature search was conducted using common electronic databases from inception - December 2019. The following key terms (and synonyms searched for by the MeSH database) were included and combined using the operators &quot;AND, &quot; &quot;OR, &quot; &quot;NOT &quot;: [( &quot;body mass index &quot; OR obesity OR obese OR overweight OR fat mass) AND ( &quot;bone mineral density &quot; OR &quot;bone mineral content &quot; OR &quot;peak bone mass &quot; OR &quot;mechanical loading &quot; OR &quot;Osteoporosis &quot; OR &quot;bone geometry &quot; OR &quot;bone resistance &quot;) AND ( &quot;exercise training &quot; OR &quot;physical training &quot; OR &quot;strength training, &quot; OR &quot;resistance training &quot; OR &quot;aerobic training &quot; OR &quot;combined training &quot;)].and nbsp;Results: After screening, 10 studies (889 initial records) were included in the final analysis (8 different countries, 263 participants). Two studies investigated males, six females, and two, both sexes. The training duration was at least eight weeks with 2-3 sessions/week. Physical training displayed a significant trivial impact on the whole body (WB) BMD (0.13 SMD; 95% CI [0.00, 0.26], p = 0.046). Subgroup analyses indicated a significant small increase in the WB BMD (0.27 SMD; 95% CI [0.00, 0.53], p = 0.048) in the endurance training group, a non-significant trivial increase in the WB BMD (0.11 SMD; 95% CI [-0.06, 0.29], p = 0.203) in the resistance group, and a non-significant trivial increase in the WB BMD (0.03 SMD; 95% CI [-0.26, 0.32], p = 0.86) in the combined training group. In addition, a significant small decrease was found in the weight of trained subjects (-0.24 SMD; 95% CI [-0.42, -0.05], p = 0.011).and nbsp;Conclusion: Physical training has little to no effect on the WB BMD in subjects with overweight/obesity. Currently, insufficient evidence to advocate for any specific type of exercise for enhancing bone health exists for overweight/obese individuals. Investigations examining the impact of varying types of physical exercise on WB BMD of obese individuals are needed

Bone mass in adolescents : effects of body composition, overweight and of an endurance training program

Les buts de cette thèse étaient d’explorer les effets de la composition corporelle, de la surcharge pondérale et d’un programme d'entraînement pluridisciplinaire en endurance sur le contenu minéral osseux (CMO) et la densité minérale osseuse (DMO) chez les adolescents. Au total 4 études ont été menées. La première étude avait comme but d’explorer la contribution relative de la masse maigre et de la masse grasse aux valeurs de DMO chez 35 filles et 65 garçons français. Celle-ci a montré que la masse grasse est un déterminant positif de la DMO chez les filles mais pas chez les garçons. En effet, la masse maigre était le meilleur déterminant de la DMO chez les garçons. La deuxième et la troisième étude avaient comme objectif d’étudier les effets de la surcharge pondérale sur le CMO et la DMO du corps entier, du rachis lombaire et de la hanche chez des adolescentes libanaises. Ces 2 études ont montré que la surcharge pondérale est accompagnée d’une augmentation des valeurs absolues de CMO et de DMO. Cependant, après ajustement par le poids, ces différences disparaissent. Dès lors, ces études suggèrent que la DMO des filles en surcharge pondérale soit bien adaptée à l’excès de poids. La quatrième étude a étudié les effets de 12 semaines d’entraînement en endurance sur le CMO et la DMO chez des adolescentes obèses, en surpoids et normo-pondérées. Cette étude a montré une augmentation des valeurs de DMO dans les 3 groupes alors que le CMO n’a augmenté que dans le groupe obèse. Cette étude confirme le rôle positif de l’exercice physique sur la DMO chez les adolescentes obèses et non obèses.The aims of this thesis were to explore the effects of body composition, overweight and of an endurance training program on bone mineral content (BMC) and bone mineral density (BMD) in adolescents. 4 studies were undertaken to achieve this goal. The first study explored the relative importance of lean and fat mass on BMD in a group of adolescent girls and boys. This study showed that fat mass is a positive determinant of BMD in girls but not in boys. In fact, lean mass was the best positive determinant of BMD in boys. The studies 2 and 3 aimed at studying the effects of overweight on whole-body, lumbar spine and hip BMD in Lebanese adolescent girls. These studies showed that the crude values of BMC and BMD were higher in overweight girls compared to controls. However, there were no differences in BMC or BMD between the two groups after adjusting for weight. Therefore, these studies suggest that the BMD of the overweight girls adapts to the increased body weight. The last study explored the effects of 12 weeks of endurance training on BMC and BMD in obese, overweight and normal-weighted sedentary adolescent girls. The BMD increased in the three groups. However, the whole-body BMC increased only in the obese group. This study confirmed the positive effects of physical exercise on BMD in obese and non-obese adolescent girls

Consommation d’oxygène chez des cyclistes confirmés lors d’une séance composée d'intervalles courts (30 s/30 s) sur bicyclette ergométrique

Introduction : L’entraînement par intervalles courts de type 30 s/30 s est très utilisé en athlétisme et en sports collectifs afin d’améliorer la consommation maximale d’oxygène (VO2max). Cependant, à notre connaissance, aucune étude ne s’est intéressée à détecter son éventuelle efficacité sur le développement de la VO2max chez les cyclistes. Le but de cette étude était de vérifier si l’entraînement par intervalles courts de type 30 s/30 s (20 répétitions) à puissance maximale aérobie (PMA) et avec une récupération passive permettait de passer beaucoup de temps à une intensité proche de VO2max chez des cyclistes confirmés. Méthodes et résultats : Sept cyclistes confirmés ont participé à cette étude. Les sujets ont d’abord réalisé un test maximal à charges croissantes sur bicyclette ergométrique afin de mesurer leur consommation maximale d’oxygène. Après une semaine, les sujets ont réalisé 20 répétitions de 30 s/30 s (30 secondes à la puissance maximale aérobie suivies de 30 secondes de récupération passive). Ce type d’effort n’a permis à aucun cycliste d’atteindre 90 % de VO2Max. Conclusion : L’entraînement par intervalles proposé (20 fois 30 s/30 s à PMA et en récupérant passivement) ne permet pas d’atteindre 90 % de la VO2max chez les cyclistes confirmés

Composite Indices of Femoral Neck Strength in Middle-Aged Inactive Subjects Vs Former Football Players

International audienceThe purpose of this study was to compare composite indices of femoral neck strength ((compression strength index [CSI], bending strength index [BSI], and impact strength index [ISI]) in inactive middle-aged men (n = 20) and middle-aged former football players (n = 15). 35 middle-aged men participated in this study. Body composition and bone variables were evaluated by dual-energy X-ray absorptiometry. Composite indices of femoral neck strength (CSI, BSI, and ISI) were calculated. Handgrip strength, vertical jump, maximum power of the lower limbs (watts), horizontal jump, maximal half-squat strength, maximal bench-press strength, sprint performance (10 meters), and maximum oxygen consumption (VO2 max, ml/min/kg) were evaluated using validated tests. CSI, BSI, and ISI were significantly higher in football players compared to inactive men. Vertical jump, horizontal jump, maximal half-squat strength, VO2 max and sprint performance were significantly different between the 2 groups. CSI, BSI, and ISI remained significantly higher in football players compared to inactive men after adjusting for physical activity level. The current study suggests that former football practice is associated with higher composite indices of femoral neck strength in middle-aged men

La masse osseuse de l'adolescent (effets de la composition corporelle, de la surcharge pondérale et d'un programme pluridisciplinaire d'entraînement en endurance)

Les buts de cette thèse étaient d explorer les effets de la composition corporelle, de la surcharge pondérale et d un programme d'entraînement pluridisciplinaire en endurance sur le contenu minéral osseux (CMO) et la densité minérale osseuse (DMO) chez les adolescents. Au total 4 études ont été menées. La première étude avait comme but d explorer la contribution relative de la masse maigre et de la masse grasse aux valeurs de DMO chez 35 filles et 65 garçons français. Celle-ci a montré que la masse grasse est un déterminant positif de la DMO chez les filles mais pas chez les garçons. En effet, la masse maigre était le meilleur déterminant de la DMO chez les garçons. La deuxième et la troisième étude avaient comme objectif d étudier les effets de la surcharge pondérale sur le CMO et la DMO du corps entier, du rachis lombaire et de la hanche chez des adolescentes libanaises. Ces 2 études ont montré que la surcharge pondérale est accompagnée d une augmentation des valeurs absolues de CMO et de DMO. Cependant, après ajustement par le poids, ces différences disparaissent. Dès lors, ces études suggèrent que la DMO des filles en surcharge pondérale soit bien adaptée à l excès de poids. La quatrième étude a étudié les effets de 12 semaines d entraînement en endurance sur le CMO et la DMO chez des adolescentes obèses, en surpoids et normo-pondérées. Cette étude a montré une augmentation des valeurs de DMO dans les 3 groupes alors que le CMO n a augmenté que dans le groupe obèse. Cette étude confirme le rôle positif de l exercice physique sur la DMO chez les adolescentes obèses et non obèses.The aims of this thesis were to explore the effects of body composition, overweight and of an endurance training program on bone mineral content (BMC) and bone mineral density (BMD) in adolescents. 4 studies were undertaken to achieve this goal. The first study explored the relative importance of lean and fat mass on BMD in a group of adolescent girls and boys. This study showed that fat mass is a positive determinant of BMD in girls but not in boys. In fact, lean mass was the best positive determinant of BMD in boys. The studies 2 and 3 aimed at studying the effects of overweight on whole-body, lumbar spine and hip BMD in Lebanese adolescent girls. These studies showed that the crude values of BMC and BMD were higher in overweight girls compared to controls. However, there were no differences in BMC or BMD between the two groups after adjusting for weight. Therefore, these studies suggest that the BMD of the overweight girls adapts to the increased body weight. The last study explored the effects of 12 weeks of endurance training on BMC and BMD in obese, overweight and normal-weighted sedentary adolescent girls. The BMD increased in the three groups. However, the whole-body BMC increased only in the obese group. This study confirmed the positive effects of physical exercise on BMD in obese and non-obese adolescent girls.ORLEANS-SCD-Bib. electronique (452349901) / SudocSudocFranceF

Geometric Indices of Hip Bone Strength in Obese, Overweight, and Normal-Weight Adolescent Girls

International audienceThe aim of this study was to compare hip bone strength indices in obese, overweight, and normal-weight adolescent girls using hip structure analysis (HSA). This study included 64 postmenarcheal adolescent girls (14 obese, 21 overweight, and 29 normal weight). The 3 groups (obese, overweight, and normal weight) were matched for maturity (years since menarche). Body composition and bone mineral density (BMD) of whole body, lumbar spine, and proximal femur were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at the femoral neck (FN) at its narrow neck (NN) region, the intertrochanteric (IT), and the femoral shaft (FS) by the HSA program. Cross-sectional area and section modulus were measured from hip BMD profiles. Total hip BMD and FN BMD were significantly higher in obese and overweight girls in comparison with normal-weight girls (p < 0.05). However, after adjusting for weight, using a one-way analysis of covariance, there were no significant differences among the 3 groups regarding HSA variables. This study suggests that in obese and overweight adolescent girls, axial strength and bending strength indices of the NN, IT, and FS are adapted to the increased body weight

Muscular power and maximum oxygen consumption predict bone density in a group of middle-aged men.

The purpose of this study was to explore the relationships between several physical performance variables and bone parameters in a group of middle-aged men. 50 middle-aged men participated in this study. Body composition and bone variables were evaluated by DXA. Bone mineral density (BMD) was measured at the whole body (WB), total radius (TR), lumbar spine (L1-L4), total hip (TH) and femoral neck (FN). Geometric indices of femoral neck (FN) strength were also calculated by DXA. Handgrip strength, vertical jump, maximum power of the lower limbs (watts), maximal half-squat strength, maximal bench-press strength, sprint performance (10 m) and maximum oxygen consumption (VO max, L/min) were evaluated using validated tests. VO max (L/min), maximum power of the lower limbs, maximal half-squat strength, maximal bench-press strength, handgrip and lean mass were positively correlated to many bone parameters. Lean mass was the strongest determinant of WB BMC. VO max (L/min) was the strongest determinant of WB BMD, TH BMD and FN BMD. Maximum power was the strongest determinant of total radius BMD. The current study suggests that VO max (L/min), lean mass and maximum power of the lower limbs are the strongest determinants of bone variables in middle-aged men

Site-specific effects of trunk fat mass on bone mineral density in a group of adolescent girls

Eesti Arst 2011; 90(8):38