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A study on the effects of resistance exercises on the bodys production of hormones

RT indicates Resistance Training. The RT was able to increase the calcium and phosphorus concentrations in bones. Significantly higher MMP-2 activity pro and active isoforms in the following comparison: Data are expressed as arbitrary units AU.

The increase in body weight of ovariectomized animals was accompanied by reductions in the calcium and phosphorus concentrations and bone MMP-2 activity, demonstrating the relationship between ovarian hormones and bone biochemical markers. These biochemical changes reflect negatively on biomechanical analyzes stiffness a study on the effects of resistance exercises on the bodys production of hormones strengthreducing the quantity and the quality of tissue. Interestingly, RT increased the concentrations of calcium, phosphorus and MMP-2 activity, which may contribute to greater strength and tissue remodeling.

Furthermore, the absence of ovarian hormones promotes the reduction in the ability to repair bone tissue microfractures maintain the integrity of the mineral phase.

This phase is composed of hydroxyapatite crystals and reflects the bone mineral content BMC and bone density BD. In the study, the levels of calcium and bone phosphorus were higher in trained animals that underwent HR. The RT and HR are effective to promote the deposition of these minerals in bone tissue, contributing to higher levels of strength and toughness. Training and HR was able to increase the stiffness, strength and load of bone fracture. Several mechanisms that influence the activity of osteoblasts and osteoclasts, and interfere with the bone remodeling process may explain this finding.

Renal damage affects the metabolism of calcium and phosphorus, influencing the activity of osteoblasts and osteoclasts in the process of bone remodeling 26. Estrogen promotes tubular reabsorption of calcium, and the rise in bone resorption at the lack of hormones could be accounted for, at least in part, by the effect of estrogen deficiency on the kidney.

Journal of Archives in Military Medicine

A rise in urinary calcium in the absence of ovarian hormones is the factor that contributes to the development of osteopenia 5. On the other hand, it is known that mechanical stress produced by exercise training improves the bone mass 2728mediated by the release of insulin-like growth factor-1 IGF-1 by osteoblasts, which promotes the proliferation of these cells.

The markers of the extracellular matrix are also involved in the remodeling of the bone tissue. Isaksson, Tolvanen 19 observed that the running exercise in rats for six months was capable of increase strength and toughness of the bone tissue increasing the mineral deposition and formation of the collagen network. Shiguemoto, Prestes 3 reported that the training was effective to enhance the biomechanical capabilities of bones by increasing bone resorption.

The increased activity of MMPs is indicative of matrix degradation - a process necessary for tissue growth. The MMP-2 to its active form 62kD preserves bone mass. The decrease in MMP-2 destroys the bone tissue, favoring osteoporosis 7. Collagen type I is found abundantly, promoting elasticity and strength to the bone 12.

Therefore, change in collagen, as occurs in osteoporosis, may affect the mechanical property of the tissue, making it susceptible to a study on the effects of resistance exercises on the bodys production of hormones 19. The bone demineralization and the decrease of collagen are associated with the high rate of bone remodeling negative bone balancethereby promoting reduction in the biophysical and biomechanical properties of bones 3.

Our results showed a marked reduction in MMP-2 activity and its isoforms, pro and active, a study on the effects of resistance exercises on the bodys production of hormones OVX Sed, when compared to the other groups. On the other hand, the training and hormone replacement was able to increase the activity of both forms of MMP-2. Thus, it can be noted that ovariectomy favors dramatic increases in bone turnover, followed by rapid loss of bone mass.

Ramage, Nuki 27 showed that mechanical stress, together with the signaling of pro inflammatory cytokines, stimulate bone chondrocytes in cartilage. Thus, we can state that the proposed resistance training is effective in reducing the damaging effects caused by ovariectomy on bone tissue.

Importantly, the lack of ovarian hormones in bone marrow might promote bone resorption because marrow adipocytes, much like fat cells elsewhere secrete inflammatory cytokines capable of recruiting osteoclasts 12. Moreover, there is a complex interplay between estrogens and fat within the bone tissue 12.

Evely, Bonomo 28 exhibited that there was a marked fatty bone-marrow infiltration in rats following ovariectomy, proposing that estrogen must play an important role in regulating adipocyte recruitment. These results have been observed in other studies with intact rats 3demonstrating that a study on the effects of resistance exercises on the bodys production of hormones training and high intensity exercise affect bone mass in intact rats. A limitation of the present study is the lack of bone collagen, pro-inflammatory cytokines and markers of osteoblast and osteoclast differentiation analysis, since, this has a significant function of promoting elasticity and strength to the bone.

In conclusion, we present evidences that ovariectomy imposes drastic and negative changes in MMP-2 activity, decreasing the biophysical and biomechanical properties of bone intrinsically mimicking the deleterious effects of menopause on bone remodeling. However, RT in our study was effective in preventing the deleterious changes on the bone tissue of OVX rats.

When there was a joint RT with HR, these results were even more favorable to the health of the bone tissue. New factors controlling the balance between osteoblastogenesis and adipogenesis. Effects of resistance training on matrix metalloproteinase-2 activity and biomechanical and physical properties of bone in ovariectomized and intact rats. Scand J Med Sci Sports. The calcium deficiency model for osteoporosis. Short- and long-term effects of calcium and exercise on bone mineral density in ovariectomized rats.

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Physical exercise improves properties of bone and its collagen network in growing and maturing mice. Resistance training improves body composition and increases matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles of diet-induced obese rats.

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Methods for long-term 17beta-estradiol administration to mice.

Three-point bending and acoustic emission study of adult rat femora after immobilization and free remobilization. Different training volumes yield equivalent increases in BMD. Signalling cascades in mechanotransduction: Structural requirements for the action of parathyroid hormone-related protein PTHrP on bone resorption by isolated osteoclasts. J Bone Miner Res. Estrogen, exercise, and the skeleton.

July 27, 2017; Accepted: October 04, 2017 Corresponding author: Markus Vinicius Campos Souza.