An interventional study of Experimental: 40 minute up trial and Experimental: 40 minute down trial in Osteoporosis, Postmenopausal, sponsored by University of Michigan. Completed at 1 site in United States. Open to female participants aged 50 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2019-08-21.
Sponsored by University of Michigan · Not applicable, Interventional, and Basic science
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 .
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.
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This study's enrollment of 40 is below the median of 95 across 1,133 interventional studies indexed under Osteoporosis.
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Exclusion Criteria:
Subjects were subjected to 40 minutes of treadmill exercise at a 6 degree incline and at 75% of maximal effort between 8:00 and 8:40 am. Isocaloric meals were provided at 7:00, 13:00. and 19:00 h.
Behavioral: Experimental: 40 minute up trial
Subjects were subjected to 40 minutes of treadmill exercise at a 6 degree decline and at 45% of maximal effort between 8:00 and 8:40 am. Isocaloric meals were provided at 7:00, 13:00. and 19:00 h.
Behavioral: Experimental: 40 minute down trial
Subjects were subjected to two 20 minutes of treadmill exercise separated by 7 h at a 6 degree incline and at 75% of maximal effort, the first one between 8:00 and 8:40 am and the second one between 15:00 and 15:20 h..Isocaloric meals were provided at 7:00, 13:00. and 19:00 h.
Behavioral: Experimental: Two 20 minute up trials
Subjects were subjected to two 20 minutes of treadmill exercise separated by 7 h at a 6 degree incline and at 45% of maximal effort , the first one between 8:00 and 8:40 am and the second one between 15:00 and 15:20 h. Isocaloric meals were provided at 7:00, 13:00. and 19:00 h.
Behavioral: Experimental: Two 20 min down trials
No exercise day with isocaloric meals provided at 7:00, 13:00. and 19:00 h.
Behavioral: Active Comparator: Sedentary trial
Also known as: 40 minutes of uphill exercise divided into two 20-minute trials separated by 7 h
Also known as: 40 minutes of downhill exercise divided into two 20-minute trials separated by 7 h
Also known as: 40 minutes of uphill exercise separated in two 20-min bouts 7 h apart
Also known as: 40 minutes of uphill exercise separated in two 20-min bouts 7 h apart
Also known as: A control no-exercise trial
Ground reaction forces
Sum of pressures on mechanosensitive Novel-Pedar shoe insoles
Time frame: During last 5 minutes of treadmill walking
Serum osteocalcin
Concentration of osteocalcin measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
Serum CICP (c-terminal propeptide of type 1 collagen
Concentration of CICP measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
Serum CTX (c-terminal telopeptide of type 1 collagen
Concentration of CTX measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
Relative aerobic capacity
Percent of maximal aerobic capacity used during uphill and downhill exercise
Time frame: 1 day (measured throughout treadmill exercise bouts)
Serum insulin
Concentration of insulin measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
Serum cortisol
Concentration of cortisol measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
Serum GH (growth hormone)
Concentration of GH measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
serum PTH (parathyroid hormone)
Concentration of PTH measured in serum samples
Time frame: Hourly blood draws between 8:00 and 22:00 hours
This study is completed, as verified in Aug 2019. You cannot join it, but the record below documents what was studied.
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University of Michigan