Effect of Resistance Training on Musculoskeletal Endocrine Interactions

Early adolescence (pre-puberty) is associated with many physiological changes with the intersection of metabolic pathways and body composition at the core. Lifestyle behaviors provide substantial influence and the rise of sedentary behavior particularly among this population can exert profound disruption. Metabolic dysfunction associated with limited activity and thus limited strain on the muscles and bones is associated with poor musculoskeletal health. Metabolic disturbance within the system during critical periods of development such as pre-puberty confers long-term health consequences.

Communication across systems is reliant upon various hormones which interact on the regulation of glucose homeostasis, bone metabolism, and muscle development. While it is well-established that bone and muscle growth are dependent upon fuel utilization, factors secreted by bone and muscle have been recently shown to play an interactive role in glucose homeostasis. Data derived primarily from animal models have demonstrated maintenance of physiological levels promote optimal growth and development, whereas these hormones appear to have adverse effects when levels are altered. While the data in animals is compelling, translation in humans has not been conducted.

Speculatively, impaired glucose homeostasis, much attributable to decreased strain on the musculoskeletal system, promotes impairments in physiological roles of these hormones. As a result, disordered development may be of consequence, such that the bones grow bigger yet have impaired quality, and delivery of fuel to muscle is compromised. Obesity-induced perturbations in metabolism and tissue partitioning may be an added stress to the system, impairing muscle function, power, performance and overall quality. Strategies that optimize the protective effects of the musculoskeletal system may be encompassed by forced stress on the system via resistance training, known to influence synthesis and release of hormones involved in fuel delivery and utilization by muscle and bone. The strategy proposed will target optimization of musculoskeletal health, promoting synthesis and release of musculoskeletal-derived signals providing protection on metabolic health at a critical period of development.

Inclusion criteria

• overweight
• early pubertal boys (Tanner stage <3)
• ages 7-12 years
• self-identified as Non-Hispanic Black.

Exclusion criteria

• type 1 or 2 diabetes
• musculoskeletal disorders
• disturbances in glucose or lipid metabolism
• use of thyroid medication, diuretics, beta-blockers, or any medication that potentially could affect body composition, the lipid profile, insulin sensitivity, or blood pressure
• allergy to EMLA cream
• history of eating disorders, cancer, kidney disease, endocrinopathy, liver disease, heart disease, or thyroid disease
• medically determined not to be able to engage in resistance training