scholarly journals Training, muscle volume, and energy expenditure in nonobese American girls

2001 ◽  
Vol 90 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Alon Eliakim ◽  
Tim Scheett ◽  
Nicki Allmendinger ◽  
Jo Anne Brasel ◽  
Dan M. Cooper
Keyword(s):  
Energy Expenditure ◽  
Body Mass ◽  
Summer School ◽  
Muscle Volume ◽  
Thigh Muscle ◽  
Cross Sectional ◽  
Brief Training ◽  
Allometric Analysis ◽  
Sectional Analysis ◽  
Prepubertal Girls

Little is known about the relationship among training, energy expenditure, muscle volume, and fitness in prepubertal girls. Because physical activity is high in prepubertal children, we hypothesized that there would be no effect of training. Forty pre- and early pubertal (mean age 9.1 ± 0.1 yr) nonobese girls enrolled in a 5 day/wk summer school program for 5 wk and were randomized to control ( n = 20) or training groups ( n = 20; 1.5 h/day, endurance-type exercise). Total energy expenditure (TEE) was measured using doubly labeled water, thigh muscle volume using magnetic resonance imaging, and peak O2uptake (V˙o 2 peak) using cycle ergometry. TEE was significantly greater (17%, P < 0.02) in the training girls. Training increased thigh muscle volume (+4.3 ± 0.9%, P < 0.005) andV˙o 2 peak (+9.5 ± 6%, P < 0.05), effects surprisingly similar to those observed in adolescent girls using the same protocol (Eliakim A, Barstow TJ, Brasel JA, Ajie H, Lee W-NP, Renslo R, Berman N, and Cooper DM, J Pediatr 129: 537–543, 1996). We further compared these two sample populations: thigh muscle volume per weight was much lower in adolescent compared with prepubertal girls (17.0 ± 0.3 vs. 27.8 ± 0.6 ml/kg body mass; P < 0.001), and allometric analysis revealed remarkably low scaling factors relating muscle volume (0.34 ± 0.05, P < 0.0001), TEE (0.24 ± 0.06, P < 0.0004), andV˙o 2 peak (0.28 ± 0.07, P < 0.0001) to body mass in all subjects. Muscle and cardiorespiratory functions were quite responsive to brief training in prepubertal girls. Moreover, a retrospective, cross-sectional analysis suggests that increases in muscle mass andV˙o 2 peak may be depressed in nonobese American girls as they mature.

Muscle Strength, Size, and Composition Following 12 Months of Gender-affirming Treatment in Transgender Individuals

2019 ◽  
Vol 105 (3) ◽  
pp. e805-e813 ◽  
Author(s):  
Anna Wiik ◽  
Tommy R Lundberg ◽  
Eric Rullman ◽  
Daniel P Andersson ◽  
Mats Holmberg ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Muscle Function ◽  
Treatment Initiation ◽  
Hormone Replacement ◽  
Knee Extensor ◽  
Muscle Volume ◽  
Muscle Size ◽  
Thigh Muscle ◽  
Cross Sectional ◽  
One Year

Abstract Context As many sports are divided in male/female categories, governing bodies have formed regulations on the eligibility for transgender individuals to compete in these categories. Yet, the magnitude of change in muscle mass and strength with gender-affirming treatment remains insufficiently explored. Objective This study explored the effects of gender-affirming treatment on muscle function, size, and composition during 12 months of therapy. Design, settings, participants In this single-center observational cohort study, untrained transgender women (TW, n = 11) and transgender men (TM, n = 12), approved to start gender-affirming medical interventions, underwent assessments at baseline, 4 weeks after gonadal suppression of endogenous hormones but before hormone replacement, and 4 and 12 months after treatment initiation. Main outcome measures Knee extensor and flexor strength were assessed at all examination time points, and muscle size and radiological density (using magnetic resonance imaging and computed tomography) at baseline and 12 months after treatment initiation. Results Thigh muscle volume increased (15%) in TM, which was paralleled by increased quadriceps cross-sectional area (CSA) (15%) and radiological density (6%). In TW, the corresponding parameters decreased by –5% (muscle volume) and –4% (CSA), while density remained unaltered. The TM increased strength over the assessment period, while the TW generally maintained their strength levels. Conclusions One year of gender-affirming treatment resulted in robust increases in muscle mass and strength in TM, but modest changes in TW. These findings add new knowledge on the magnitude of changes in muscle function, size, and composition with cross-hormone therapy, which could be relevant when evaluating the transgender eligibility rules for athletic competitions.

scholarly journals Fitness, Training, and the Growth Hormone→Insulin-Like Growth Factor I Axis in Prepubertal Girls1

2001 ◽  
Vol 86 (6) ◽  
pp. 2797-2802 ◽  
Author(s):  
Alon Eliakim ◽  
Timothy P. Scheett ◽  
Robert Newcomb ◽  
Subburaman Mohan ◽  
Dan M. Cooper
Keyword(s):  
Growth Factor ◽  
Training Program ◽  
Muscle Volume ◽  
Thigh Muscle ◽  
Insulin Like Growth Factor ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Prepubertal Girls

We recently demonstrated that a brief endurance type training program led to increases in thigh muscle mass and peak oxygen uptake (V̇O2) in prepubertal girls. In this study, we examined the effect of training on the GH→insulin-like growth factor I (GH→IGF-I) axis, a system known to be involved both in the process of growth and development and in the response to exercise. Healthy girls (mean age 9.17 ± 0.10 yr old) volunteered for the study and were randomized to control (n = 20) and training groups (n = 19) for 5 weeks. Peak V̇O2, thigh muscle volume, and blood samples [for IGF-I, IGF-binding proteins (IGFBP)-1 to -6, and GHBP] were measured. At baseline, IGF-I was significantly correlated with both peak V̇O2 (r = 0.44, P &lt; 0.02) and muscle volume (r = 0.58, P &lt; 0.004). IGFBP-1 was negatively correlated with muscle volume (r = −0.71, P &lt; 0.0001), as was IGFBP-2. IGFBP-4 and -5 were significantly correlated with muscle volume. We found a threshold value of body mass index percentile (by age) of about 71, above which systematic changes in GHBP, IGFBP-1, and peak V̇O2 per kilogram were noted, suggesting decreases in the following: 1) GH function, 2) insulin sensitivity, and 3) fitness. Following the training intervention, IGF-I increased in control (19.4 ± 9.6%, P &lt; 0.05) but not trained subjects, and both IGFBP-3 and GHBP decreased in the training group (−4.2 ± 3.1% and −9.9 ± 3.8%, respectively, P &lt; 0.05). Fitness in prepubertal girls is associated with an activated GH→IGF-I axis, but, paradoxically, early in a training program, children first pass through what appears to be a neuroendocrine state more consistent with catabolism.

scholarly journals Endocrine and Clinical Correlates of Myostatin Serum Concentration in Men—the STRAMBO Study

2012 ◽  
Vol 97 (10) ◽  
pp. 3700-3708 ◽  
Author(s):  
Pawel Szulc ◽  
Michael Schoppet ◽  
Claudia Goettsch ◽  
Martina Rauner ◽  
Thomas Dschietzig ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Fat Mass ◽  
Insurance Coverage ◽  
Muscle Growth ◽  
Serum Levels ◽  
Health Insurance Coverage ◽  
Cross Sectional ◽  
17Β Estradiol ◽  
Sectional Analysis

Abstract Context: Myostatin is expressed mainly in skeletal muscle cells and acts as an inhibitor of muscle growth and differentiation. However, data on the determinants of serum myostatin concentrations in humans are limited. Objective: The aim of the study was to assess the correlates of serum myostatin concentrations in men. Design: We conducted a cross-sectional analysis of the STRAMBO cohort. Setting: Men holding private health insurance coverage with Mutuelle de Travailleurs de la Région Lyonnaise were included in the study. Participants: A total of 1121 male volunteers aged 20–87 yr participated in the study. Interventions: Nonfasting blood samples were collected. Main Outcome Measures: We measured the association of the investigated variables with circulating myostatin levels. Results: Serum myostatin levels increased slightly with age until 57 yr and then decreased. Circulating myostatin levels showed circannual variation, with the highest concentration in spring. In men older than 57 yr, serum myostatin levels decreased across increasing quartiles of body mass index and of total central and peripheral fat mass (P &lt; 0.05 to &lt; 0.001). Serum myostatin levels were positively correlated with serum levels of 25-hydroxycholecalciferol (25OHD), even after adjustment for season. Average myostatin levels were 0.47 sd higher in men with 25OHD above 40 ng/ml, compared with those with 25OHD below 20 ng/ml (P &lt; 0.05). Current smokers had lower myostatin concentration. Neither current physical activity nor serum levels of PTH, testosterone, and 17β-estradiol were associated with myostatin concentrations. Conclusions: In men, circulating myostatin levels show seasonal changes and are associated with age, body mass index, fat mass, smoking, and 25OHD levels.

scholarly journals Effect of exercise intervention on thigh muscle volume and anatomical cross-sectional areas-Quantitative assessment using MRI

2010 ◽  
Vol 64 (6) ◽  
pp. 1713-1720 ◽  
Author(s):  
Martin Hudelmaier ◽  
Wolfgang Wirth ◽  
Maria Himmer ◽  
Susanne Ring-Dimitriou ◽  
Alexandra Sänger ◽  
...  
Keyword(s):  
Quantitative Assessment ◽  
Exercise Intervention ◽  
Muscle Volume ◽  
Thigh Muscle ◽  
Cross Sectional

scholarly journals Annual Observation of Changes in the Angle of Trunk Rotation. Trunk Asymmetry Predictors. A Study from a Scoliosis Screening in School Adolescents

2020 ◽  
Vol 17 (6) ◽  
pp. 1899
Author(s):  
Katarzyna Adamczewska ◽  
Marzena Wiernicka ◽  
Ewa Kamińska ◽  
Joanna Małecka ◽  
Agata Dąbrowska ◽  
...  
Keyword(s):  
Body Mass ◽  
Stepwise Regression ◽  
Body Height ◽  
Stepwise Multiple Regression ◽  
Trunk Rotation ◽  
Primary School Students ◽  
School Students ◽  
Cross Sectional ◽  
Sectional Analysis ◽  
Scoliosis Screening

Adolescent forms of idiopathic scoliosis are commonly encountered deformities of the thoracic and lumbar spine. They affect a significant number of adolescents, yet their cause is still unknown. The presented research is a cross-sectional analysis of 3933 volunteers (2131 girls and 1802 boys). The participants were primary school students aged 9 to 13 years old. This study determined a relationship between predictors such as: body mass, body height and body mass index (BMI) (independent variables) and angle of trunk rotation (ATR) value (dependent variable). Moreover, a stepwise multiple regression with backward selection was conducted to determine to what extent the dependent variable is explained by body mass, body height and BMI. In the group of 11,12,13-year-old girls, the analyzed results of multiple stepwise regression were statistically significant. Among the all studied predictors, it has been shown that body mass in the 11-year-old girls and body height in 12- and 13-year-old girls are major correlates of a 1-year ATR increase in proximal and main thoracic spine levels.

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