H. M. Frost and E. Schönau, The "muscle-bone unit" in children and adolescents: a 2000 overview, J Pediatr Endocrinol Metab, vol.13, pp.571-590, 2000.

D. Courteix, E. Lespessailles, S. L. Peres, P. Obert, P. Germain et al., Effect of physical training on bone mineral density in prepubertal girls: a comparative study between impact-loading and non-impact-loading sports, Osteoporos Int, vol.8, pp.152-158, 1998.

S. K. Grimston, N. D. Willows, and D. A. Hanley, Mechanical loading regime and its relationship to bone mineral density in children, Med Sci Sports Exerc, vol.25, pp.1203-1210, 1993.

L. Maïmoun, O. Coste, and P. Philibert, Peripubertal female athletes in high-impact sports show improved bone mass acquisition and bone geometry, Metabolism, vol.62, pp.1088-1098, 2013.

L. Maïmoun, O. Coste, and T. Mura, Specific bone mass acquisition in elite female athletes, J Clin Endocrinol Metab, vol.98, pp.2844-2853, 2013.

M. L. Hetland, J. Haarbo, and C. Christiansen, Low bone mass and high bone turnover in male long distance runners, J Clin Endocrinol Metab, vol.77, pp.770-775, 1993.

M. K. Karlsson, H. Magnusson, C. Karlsson, and E. Seeman, The duration of exercise as a regulator of bone mass, Bone, vol.28, pp.128-132, 2001.

J. D. Macdougall, C. E. Webber, and J. Martin, Relationship among running mileage, bone density, and serum testosterone in male runners, J Appl Physiol, vol.73, pp.1165-1170, 1992.

N. Georgopoulos, K. Markou, and A. Theodoropoulou, Growth and pubertal development in elite female rhythmic gymnasts, J Clin Endocrinol Metab, vol.84, pp.4525-4530, 1999.

N. A. Georgopoulos, K. B. Markou, and A. Theodoropoulou, Height velocity and skeletal maturation in elite female rhythmic gymnasts, J Clin Endocrinol Metab, vol.86, pp.5159-5164, 2001.

T. Chevalley, J. P. Bonjour, S. Ferrari, and R. Rizzoli, Deleterious effect of late menarche on distal tibia microstructure in healthy 20-year-old and premenopausal middle-aged women, J Bone Miner Res, vol.24, pp.144-152, 2009.

S. A. Jackowski, M. C. Erlandson, and R. L. Mirwald, Effect of maturational timing on bone mineral content accrual from childhood to adulthood: evidence from 15 years of longitudinal data, Bone, vol.48, pp.1178-1185, 2011.

G. Theintz, B. Buchs, and R. Rizzoli, Longitudinal monitoring of bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels of lumbar spine and femoral neck in female subjects, J Clin Endocrinol Metab, vol.75, pp.1060-1065, 1992.

N. H. Golden and J. L. Carlson, The pathophysiology of amenorrhea in the adolescent, Ann N Y Acad Sci, vol.1135, pp.163-178, 2008.

J. P. Petrozza and K. Poley, Dysfunctional uterine bleeding, pp.241-264, 1999.

C. F. Njeh, M. B. Chen, and B. Fan, Evaluation of a gel-coupled quantitative ultrasound device for bone status assessment, J Ultrasound Med, vol.20, pp.1219-1228, 2001.

N. A. Georgopoulos, K. B. Markou, A. Theodoropoulou, D. Benardot, M. Leglise et al., Growth retardation in artistic compared with rhythmic elite female gymnasts, J Clin Endocrinol Metab, vol.87, pp.3169-3173, 2002.

S. M. Ott, Attainment of peak bone mass, J Clin Endocrinol Metab, vol.71, pp.1082-1082, 1990.

N. A. Georgopoulos, A. Theodoropoulou, and N. A. Roupas, Growth velocity and final height in elite female rhythmic and artistic gymnasts, Hormones (Athens), vol.11, pp.61-69, 2012.

C. Sultan, F. Paris, C. Jeandel, G. Attal, S. Lumbroso et al., Rev Int Pédiatr, vol.32, pp.9-10, 2001.

B. Towne, S. A. Czerwinski, E. W. Demerath, J. Blangero, A. F. Roche et al., Heritability of age at menarche in girls from the Fels Longitudinal Study, Am J Phys Anthropol, vol.128, pp.210-219, 2005.

O. Karapanou and A. Papadimitriou, Determinants of menarche, Reprod Biol Endocrinol, vol.8, p.115, 2010.

L. Dossus, M. Kvaskoff, and A. Bijon, Determinants of age at menarche and time to menstrual cycle regularity in the French E3N cohort, Ann Epidemiol, vol.22, pp.723-730, 2012.

A. B. Loucks, M. Verdun, and E. M. Heath, Low energy availability, not stress of exercise, alters LH pulsatility in exercising women, J Appl Physiol, vol.84, pp.37-46, 1998.

A. B. Loucks and J. R. Thuma, Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women, J Clin Endocrinol Metab, vol.88, pp.297-311, 2003.

N. I. Williams, D. L. Helmreich, D. B. Parfitt, A. Caston-balderrama, and J. L. Cameron, Evidence for a causal role of low energy availability in the induction of menstrual cycle disturbances during strenuous exercise training, J Clin Endocrinol Metab, vol.86, pp.5184-5193, 2001.

M. Burrows, A. M. Nevill, S. Bird, and D. Simpson, Physiological factors associated with low bone mineral density in female endurance runners, Br J Sports Med, vol.37, pp.67-71, 2003.

C. C. Glüer, Monitoring skeletal changes by radiological techniques, J Bone Miner Res, vol.14, pp.1952-1962, 1999.

V. Gilsanz, J. Chalfant, and H. Kalkwarf, Age at onset of puberty predicts bone mass in young adulthood, J Pediatr, vol.158, pp.101-102, 2011.

D. Courteix, N. Rieth, and T. Thomas, Preserved bone health in adolescent elite rhythmic gymnasts despite hypoleptinemia, Horm Res, vol.68, pp.20-27, 2007.

C. E. Cann, M. C. Martin, H. K. Genant, and R. B. Jaffe, Decreased spinal mineral content in amenorrheic women, JAMA, vol.251, pp.626-629, 1984.

A. Heinonen, P. Oja, and P. Kannus, Bone mineral density in female athletes representing sports with different loading characteristics of the skeleton, Bone, vol.17, pp.197-203, 1995.

T. L. Robinson, C. Snow-harter, D. R. Taaffe, D. Gillis, J. Shaw et al., Gymnasts exhibit higher bone mass than runners despite similar prevalence of amenorrhea and oligomenorrhea, J Bone Miner Res, vol.10, pp.26-35, 1995.

J. Nilsson and A. Thorstensson, Ground reaction forces at different speeds of human walking and running, Acta Physiol Scand, vol.136, pp.217-227, 1989.

H. M. Frost, The role of changes in mechanical usage set points in the pathogenesis of osteoporosis, J Bone Miner Res, vol.7, pp.253-261, 1992.

C. M. Langton and D. K. Langton, Male and female normative data for ultrasound measurement of the calcaneus within the UK adult population, Br J Radiol, vol.70, pp.580-585, 1997.

T. Chevalley, J. P. Bonjour, S. Ferrari, and R. Rizzoli, The influence of pubertal timing on bone mass acquisition: a predetermined trajectory detectable five years before menarche, J Clin Endocrinol Metab, vol.94, pp.3424-3431, 2009.

A. D. Baxter-jones, M. Burrows, and L. K. Bachrach, International longitudinal pediatric reference standards for bone mineral content, Bone, vol.46, pp.208-216, 2010.

O. Johnell, B. Gullberg, and J. A. Kanis, Risk factors for hip fracture in European women: the MEDOS Study. Mediterranean Osteoporosis Study, J Bone Miner Res, vol.10, pp.1802-1815, 1995.

T. Chevalley, J. P. Bonjour, S. Ferrari, and R. Rizzoli, Pubertal timing and body mass index gain from birth to maturity in relation with femoral neck BMD and distal tibia microstructure in healthy female subjects, Osteoporos Int, vol.22, pp.2689-2698, 2011.

H. M. Frost, On the estrogen-bone relationship and postmenopausal bone loss: A new model, J Bone Miner Res, vol.14, pp.1473-1477, 1999.

H. Schiessl, H. M. Frost, and W. S. Jee, Estrogen and bone-muscle strength and mass relationships, Bone, vol.22, pp.1-6, 1998.

D. C. Cumming, Exercise-associated amenorrhea, low bone density, and estrogen replacement therapy, Arch Intern Med, vol.156, pp.2193-2195, 1996.

C. M. Snow-harter, Bone health and prevention of osteoporosis in active and athletic women, Clin Sports Med, vol.13, pp.389-404, 1994.

K. Christo, R. Prabhakaran, and B. Lamparello, Bone metabolism in adolescent athletes with amenorrhea, athletes with eumenorrhea, and control subjects, Pediatrics, vol.121, pp.1127-1136, 2008.

G. Karsenty, Convergence between bone and energy homeostases: leptin regulation of bone mass, Cell Metab, vol.4, pp.341-348, 2006.

L. Maïmoun, O. Coste, F. Galtier, T. Mura, D. Mariano-goulart et al., Bone mineral density acquisition in peripubertal female rhythmic gymnasts is directly associated with plasma IGF1/IGFbinding protein 3 ratio, Eur J Endocrinol, vol.163, pp.157-164, 2010.

L. Maimoun, O. Coste, A. Jaussent, D. Mariano-goulart, C. Sultan et al., Bone mass acquisition in female rhythmic gymnasts during puberty: no direct role for leptin, Clin Endocrinol (Oxf), vol.72, pp.604-611, 2010.

K. Christo, J. Cord, and N. Mendes, Acylated ghrelin and leptin in adolescent athletes with amenorrhea, eumenorrheic athletes and controls: a cross-sectional study, Clin Endocrinol (Oxf), vol.69, pp.628-633, 2008.

K. K. Miller, M. S. Parulekar, and E. Schoenfeld, Decreased leptin levels in normal weight women with hypothalamic amenorrhea: the effects of body composition and nutritional intake, J Clin Endocrinol Metab, vol.83, pp.2309-2312, 1998.

N. D. Roupas and N. A. Georgopoulos, Menstrual function in sports. Hormones (Athens), vol.10, pp.104-116, 2011.

O. O. Babatunde and J. J. Forsyth, Quantitative ultrasound and bone's response to exercise: a meta analysis, Bone, vol.53, pp.311-318, 2013.

F. Marín, J. González-macías, A. Díez-pérez, S. Palma, and M. Delgado-rodríguez, Relationship between bone quantitative ultrasound and fractures: a meta-analysis, J Bone Miner Res, vol.21, pp.1126-1135, 2006.

A. Moayyeri, J. E. Adams, and R. A. Adler, Quantitative ultrasound of the heel and fracture risk assessment: an updated meta-analysis, Osteoporos Int, vol.23, pp.143-153, 2012.