NCT04063813

Parameters of Exercise to Prevent Osteoporosis

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 40 (actual)
• Sponsor: University of Michigan · Academic / Other
• Sex: Female
• Age: 50 Years – 65 Years
• Healthy volunteers: Accepted

Summary

The principal goal of this study is to determine parameters of walking in terms of peak mechanical vertical force, bout duration, and bout spacing that can preserve or increase bone mineral density (BMD) in postmenopausal women. Release of pulses of parathyroid hormone (PTH), growth hormone (GH), and of markers of bone resorption and bone formation will be used as indicators of the osteogenic effects of a short exposure to exercise. When secreted in pulsatile fashion, GH stimulates osteoblast proliferation, particularly in cortical bone (27, 28). Like GH, the pattern of PTH secretion determines the nature of its effect on bone. When it is secreted in pulsatile manner, PTH contributes to bone formation through activation of bone lining cells, differentiation of osteoprogenitor cells, and suppression of bone cell apoptosis .

Detailed description

A. Hypotheses and specific aims: Specific aim 1. Measure plasma concentrations of anabolic hormones (parathyroid hormone (PTH) and growth hormone (GH), at sufficient frequency to define the area under the curve (AUC), and of markers of bone formation (osteocalcin, carboxyterminal propeptide of type 1 procollagen (CICP), and bone-specific alkaline phosphatase (ALKP)), and markers of bone resorption (immunoreactive carboxyterminal telopeptide of type I collagen (CTX)) after 40-minutes of treadmill exercise at the relative intensity of 125% of the ventilatory threshold (VT) corresponding to about 1.78 m/sec (4 miles/h), and two intensities of mechanical loading (724, and 1411 N), in healthy postmenopausal women. Hypothesis 1. Bone formation, as assessed by increases in markers of bone formation and decreases in markers of bone resorption, will be higher in response to dynamic exercise at a level of mechanical loading that produces increased secretion of PTH and GH than to exercise at other loading intensities. Specific aim 2. Measure plasma concentrations of anabolic hormones), at sufficient frequency to define the area under the curve (AUC), and of markers of bone formation as in specific aim 1, after two 20-minutes of treadmill exercise, separated by 7 h, at the relative intensity of 125% of the ventilatory threshold (VT) corresponding to about 1.78 m/sec (4 mi/h), and two intensities of mechanical loading (724, and 1411 N), in healthy postmenopausal women. Hypothesis 2. A 7-hour interval separating the two bouts of exercise will have greater bone anabolic effect than the equivalent volume and intensity of exercise performed in a single bout.

Conditions

• Osteoporosis, Postmenopausal

Interventions

Type	Name	Description
BEHAVIORAL	Experimental: 40 minute up trial
BEHAVIORAL	Experimental: 40 minute down trial
BEHAVIORAL	Experimental: Two 20 minute up trials
BEHAVIORAL	Experimental: Two 20 min down trials
BEHAVIORAL	Active Comparator: Sedentary trial

Timeline

• Start date: 2007-05-15
• Primary completion: 2010-08-19
• Completion: 2010-08-19
• First posted: 2019-08-21
• Last updated: 2019-08-21

Locations

1 site across 1 country: United States