Tag Archives: positive

A Positive Study on Vibration With or Without Exercise

Abstract

Whole-body vibration effects on bone mineral density in women with or without resistance training.

Whole-body vibration exposure may translate into improved bone mass in young adult women. The primary focus of this study was to examine the effects of graded whole-body vibration or vibration exposure plus resistance training on bone mineral density (BMD), hematological measures for bone remodeling, and exercise metabolism in young women.
There were 51 healthy active women [mean (SD) age, 21.02 (3.39) yr; height, 165.66 (6.73) cm; body mass 66.54 (13.39) kg] who participated in the intervention. Subjects were randomly assigned to whole-body vibration (WBV), whole-body vibration plus resistance training (WBV+RT), or control (CONT) groups for 16 wk.
A repeated-measure ANOVA found no significant (P < 0.05) group differences in BMD at the completion of 16 wk. A significant within group change was apparent for the WBV (2.7% femoral neck) and WBV+RT (femoral neck 1.9%; vertebra 0.98%). WBV and WBV+RT experienced a significant (P < 0.05) 60% and 58% increase in adiponectin, 48% and 30% in transforming growth factor-beta1, and 17% and 34% in nitric oxide with an accompanying 50% and 36% decrease in osteopontin, 19% and 34% in interleukin-1beta, and 38% and 39% in tumor necrosis factor-alpha.
The results indicate graded whole-body vibration exposure may be effective in improving BMD by increasing bone deposition while also decreasing bone resorption. Whole-body vibration may also provide an efficient stratagem for young women to achieve peak bone mass and help stave off osteoporosis later in life and provide a novel form of physical training.

Humphries B, Fenning A, Dugan E, Guinane J…
Aviat Space Environ Med Dec 2009
PMID: 20027849

Similar Results From Minimal vs. High Resistance Exercise in Rats

Abstract

Increased training loads do not magnify cancellous bone gains with rodent jump resistance exercise.

This study sought to elucidate the effects of a low- and high-load jump resistance exercise (RE) training protocol on cancellous bone of the proximal tibia metaphysis (PTM) and femoral neck (FN). Sprague-Dawley rats (male, 6 mo old) were randomly assigned to high-load RE (HRE; n = 16), low-load RE (LRE; n = 15), or sedentary cage control (CC; n = 11) groups. Animals in the HRE and LRE groups performed 15 sessions of jump RE during 5 wk of training. PTM cancellous volumetric bone mineral density (vBMD), assessed by in vivo peripheral quantitative computed tomography scans, significantly increased in both exercise groups (+9%; P < 0.001), resulting in part from 130% (HRE; P = 0.003) and 213% (LRE; P < 0.0001) greater bone formation (measured by standard histomorphometry) vs. CC. Additionally, mineralizing surface (%MS/BS) and mineral apposition rate were higher (50-90%) in HRE and LRE animals compared with controls. PTM bone microarchitecture was enhanced with LRE, resulting in greater trabecular thickness (P = 0.03) and bone volume fraction (BV/TV; P = 0.04) vs. CC. Resorption surface was reduced by nearly 50% in both exercise paradigms. Increased PTM bone mass in the LRE group translated into a 161% greater elastic modulus (P = 0.04) vs. CC. LRE and HRE increased FN vBMD (10%; P < 0.0001) and bone mineral content (∼ 20%; P < 0.0001) and resulted in significantly greater FN strength vs. CC. For the vast majority of variables, there was no difference in the cancellous bone response between the two exercise groups, although LRE resulted in significantly greater body mass accrual and bone formation response. These results suggest that jumping at minimal resistance provides a similar anabolic stimulus to cancellous bone as jumping at loads exceeding body mass.

Swift JM, Gasier HG, Swift SN, Wiggs MP…
J. Appl. Physiol. Dec 2010
PMID: 20930128 | Free Full Text

Aerobic and Resistance Exercise May Increase Bone Formation in Young Women

Abstract

Influence of exercise mode and osteogenic index on bone biomarker responses during short-term physical training.

Prescribing exercise based on intensity, frequency, and duration of loading may maximize osteogenic responses in bone, but a model of the osteogenic potential of exercise has not been established in humans. In rodents, an osteogenic index (OI) has been used to predict the osteogenic potential of exercise. The current study sought to determine whether aerobic, resistance, or combined aerobic and resistance exercise programs conducted over eight weeks and compared to a control group could produce changes in biochemical markers of bone turnover indicative of bone formation. We further sought to determine whether an OI could be calculated for each of these programs that would reflect observed biochemical changes. We collected serum biomarkers [bone-specific alkaline phosphatase (BAP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide fragment of type I collagen (CTx), deoxypyridinoline (DPD), 25-hydroxy vitamin D (25(OH)D), and parathyroid hormone (PTH)] in 56 women (20.3+/-1.8 years) before, during and after eight weeks of training. We also measured bone mineral density (BMD) at regional areas of interest using DXA and pQCT. Biomarkers of bone formation (BAP and osteocalcin) increased in the Resistance and Combined groups (p<0.05), while biomarkers of bone resorption (TRAP and DPD) decreased and increased, respectively, after training (p<0.05) in all groups. Small changes in volumetric and areal BMD (p<0.05) were observed in the distal tibia in the Aerobic and Combined groups, respectively. Mean weekly OIs were 16.0+/-1.9, 20.6+/-2.2, and 36.9+/-5.2 for the Resistance, Aerobic, and Combined groups, respectively. The calculated osteogenic potential of our programs did not correlate with the observed changes in biomarkers of bone turnover. The results of the present study demonstrate that participation in an eight week physical training program that incorporates a resistance component by previously inactive young women results in alterations in biomarkers of bone remodeling indicative of increased formation without substantial alterations in markers of resorption.

Lester ME, Urso ML, Evans RK, Pierce JR…
Bone Oct 2009
PMID: 19520194

45 Minutes of Resistance Exercise Reduces Resorption for 8 Hours

Abstract

Acute effects of moderate intensity resistance exercise on bone cell activity.

Resistance exercise has positive effects on bone mass, but little is known about the mechanisms by which this occurs. The purpose of this study was to determine if a single bout of moderate intensity resistance exercise alters biochemical markers of bone cell activity. Indices of bone turnover were measured in nine healthy, untrained men (21.9 +/- 1.2 yrs old), before and following a single 45 minute session of resistance exercise, and during a control trial. A cross-over design was used so that all participants performed both trials in random order. Blood samples were collected immediately before, immediately after, and at 1, 8, 24, and 48 hours post exercise and analyzed for bone-specific alkaline phosphatase (BAP), type I collagen propeptide (PICP), and type I collagen N-telopeptide (sNTX). Urine from the second morning void was collected over four days (day before, day of, and two days following exercise) and analyzed for type I collagen N-telopeptide (uNTX). Exercise resulted in a significant increase (p < 0.05) in the ratio of biochemical markers of bone formation to bone resorption eight hours post exercise, largely due to a decrease in sNTX. Markers return to baseline within 24 hrs. These data suggest that moderate intensity resistance training acutely reduces bone resorption, leading to a favorable change in overall bone turnover, for at least 8 hours post exercise in untrained young men. Further work is needed to determine if long-term benefits to bone strength follow with persistent training.

Whipple TJ, Le BH, Demers LM, Chinchilli VM…
Int J Sports Med Oct 2004
PMID: 15459829

Resistance Exercise Counters Bed Rest

Abstract

Resistance exercise as a countermeasure to disuse-induced bone loss.

During spaceflight, skeletal unloading results in loss of bone mineral density (BMD). This occurs primarily in the spine and lower body regions. This loss of skeletal mass could prove hazardous to astronauts on flights of long duration. In this study, intense resistance exercise was used to test whether a training regimen would prevent the loss of BMD that accompanies disuse. Nine subjects (5 men, 4 women) participated in a supine maximal resistance exercise training program during 17 wk of horizontal bed rest. These subjects were compared with 18 control subjects (13 men, 5 women) who followed the same bed rest protocol without exercise. Determination of treatment effect was based on measures of BMD, bone metabolism markers, and calcium balance obtained before, during, and after bed rest. Exercisers and controls had significantly (P < 0.05) different means, represented by the respective following percent changes:

lumbar spine BMD, +3% vs. -1%;
total hip BMD, +1% vs. -3%;
calcaneus BMD, +1% vs. -9%;
pelvis BMD, -0.5% vs. -3%;
total body BMD, 0% vs. -1%;
bone-specific alkaline phosphatase, +64% vs. 0%;
alkaline phosphatase, +31% vs. +5%;
osteocalcin, +43% vs. +10%;
1,25 dihydroxyvitamin D, +12% vs. -15%;
parathyroid hormone intact molecule, +18% vs. -25%; and
serum and ionized calcium, -1% vs. +1%.

The difference in net calcium balance was also significant (+21 mg/day vs. -199 mg/day, exercise vs. control). The gastrocnemius and soleus muscle volumes decreased significantly in the exercise group, but the loss was significantly less than observed in the control group. The results indicate that resistance exercise had a positive treatment effect and thus might be useful as a countermeasure to prevent the deleterious skeletal changes associated with long-duration spaceflight.

Shackelford LC, LeBlanc AD, Driscoll TB, Evans HJ…
J. Appl. Physiol. Jul 2004
PMID: 15220316 | Free Full Text

Weight Belt, Step-Ups, Chair Rises, Elastic Band, and Dumbbells + HRT

Abstract

Home-based resistance training improves femoral bone mineral density in women on hormone therapy.

This study tested whether moderate resistance training would improve femoral bone mineral density (BMD) in long-term users of hormone therapy with low BMD. The study was a 2-year randomized, controlled, trial (RCT) of moderate resistance training of either the lower extremity or the upper extremity. Eighty-five women participated in a 6-month observation period. The setting was center-based and home-based training. The participants were 189 women aged 59-78 years, with total femur T-scores from -0.8 to -2.8 and on hormone therapy (HT) for a minimum of 2 years (mean 11.8 years); 153 completed the trial. Lower extremity training used weight belts (mean 7.8 kg) in step-ups and chair rises; upper extremity training used elastic bands and dumbbells. Measurements were BMD and body composition [dual-energy X-ray absorptiometry (DXA)], bone turnover markers. Total femoral BMD showed a downward trend during the observation period: 0.35%+/-0.18% (P=0.14). The response to training was similar in the upper and lower groups in the primary outcomes. At 2 years, total femoral BMD increased 1.5% (95% CI 0.8%-2.2%) in the lower group and 1.8% (95% CI 1.1%-2.5%) in the upper group. Trochanter BMD increased 2.4% (95% CI 1.3%-3.5%) in the lower group and 2.5% (95% CI 1.4%-3.6%) in the upper group (for both analyses time effect P<0.001). At 1 year, a bone resorption marker (C-telopeptide) decreased 9% (P=0.04). Bone formation markers, bone-specific alkaline phosphatase, decreased 5% (P<0.001), and N-terminal type I procollagen peptide decreased 7% (P=0.01). Body composition (percent lean and percent body fat) was maintained in both groups. We concluded that long-term moderate resistance training reversed bone loss, decreased bone turnover, increased femur BMD, and maintained body composition. The similarity of response in upper and lower groups supports a systemic response rather than a site-specific response to moderate resistance training.

Judge JO, Kleppinger A, Kenny A, Smith JA…
Osteoporos Int Sep 2005
PMID: 15754082

Weight Belt Walking Maintains Bone

Abstract

An aerobic weight-loaded pilot exercise intervention for breast cancer survivors: bone remodeling and body composition outcomes.

Weight gain and bone loss are commonly reported in breast cancer survivors. The purpose of this pilot study is to assess feasibility and explore the effect of an aerobic weight-loaded exercise intervention on bone remodeling, weight, and body composition.
A one-group pre-posttest design was used to test a 16-24-week supervised walking exercise intervention among women within 2 years of menopause. Through Weeks 1-4, time and weight were progressively increased. By Week 5 and through the end of the intervention, a waist belt was loaded with 5 lb and participants spent 45 min on the treadmill 3 times/week. Bone remodeling was measured by serum biomarkers (N-terminal propeptides of type I collagen [NTX] and serum osteocalcin). Dual-energy absorptiometry scans assessed body composition. Data were collected at baseline and 16 and 24 weeks.
The majority of the 26 participants were married, well educated, and employed, with a mean age of 51.3 years (SD = 6.2). The high adherence (M = 88.2%, SD = 6.8) demonstrated feasibility. There were no significant changes in serum osteocalcin (p = .67), serum NTX (p = .31), lean muscle mass (p = .08), or percent fat mass for the group as a whole (p = .14), but fat mass increased for women on adjuvant endocrine therapy (p = .04). The women maintained their weight.
This novel exercise intervention for breast cancer survivors was feasible, and women otherwise at high risk for weight gain and bone loss maintained their weight and bone mass.

Knobf MT, Insogna K, DiPietro L, Fennie C…
Biol Res Nurs Jul 2008
PMID: 18705153

Running Improves Calcium Balance in Rats

Abstract

Hypokinesia-induced negative net calcium balance reversed by weight-bearing exercise.

Negative calcium balance and bone loss occurring with immobilization and hypokinesia have been attributed to a lack of weight bearing on bones. The effects of weight-bearing exercise for promotion of calcium balance after hypokinesia were examined. Rats were randomly assigned to either hypokinetic suspension for 28 d or to a control sedentary group, free to move about their cages at will. After 28 d, the rats in each group were randomly subdivided to either post-hypokinetic forced running (HR), post-hypokinetic sedentary (HS), control forced running (CR), or control sedentary (CS) groups. Net calcium balance was then determined for 25 consecutive days. Net calcium balance of HR was negative for the first 5-d period of recovery and then became positive; that of HS was negative for 25 d; that of CR and CS remained essentially positive. Net calcium absorption paralleled net calcium balance. Forced running was effective in reestablishment of positive net calcium balance after 28 d of decreased weight bearing.

Lutz J, Chen F, Kasper CE
Aviat Space Environ Med Apr 1987
PMID: 3579816

Exercise + HRT = Bone Synergy

Abstract

Additive effects of weight-bearing exercise and estrogen on bone mineral density in older women.

The separate and combined effects of weight-bearing exercise and hormone replacement therapy (HRT) on bone mineral density (BMD) were studied in 32 women, 60 to 72 years of age. HRT consisted of continuous conjugated estrogens 0.625 mg/day and trimonthly medroxyprogesterone acetate 5 mg/day for 13 days. Exercise consisted of 2 months of low-intensity exercise followed by 9 months of more vigorous weight-bearing exercise approximately 45 minutes/day, > or = 3 days/week, at 65-85% of maximal heart rate. Lumbar spine and proximal femur BMD were significantly increased in response to exercise and to HRT, and total body BMD was significantly increased in response to HRT; neither exercise nor HRT had an effect on wrist BMD. The combination of exercise + HRT resulted in increased BMD at all sites except the wrist, with effects being additive for the lumbar spine and Ward’s triangle and synergistic for the total body. Based on reductions in serum osteocalcin levels, it appears that increases in BMD in response to HRT and exercise + HRT were due to decreased bone turnover. The lack of change in serum osteocalcin and IGF-I in response to exercise alone suggests that increases in BMD were due to decreased bone resorption and not increased formation. Results indicate that weight-bearing exercise + HRT may be effective in preventing and/or treating osteoporosis. It is likely that the additive effects of weight-bearing exercise and HRT on bone mineral accretion, coupled with other adaptations to the exercise (i.e., increased strength and functional capacity), could effectively reduce the incidence of falls and osteoporotic fractures.

Kohrt WM, Snead DB, Slatopolsky E, Birge SJ
J. Bone Miner. Res. Sep 1995
PMID: 7502701

Olive Oil, but Not Nuts, May Protect Bones

Abstract

A Mediterranean diet enriched with olive oil is associated with higher serum total osteocalcin levels in elderly men at high cardiovascular risk.

The intake of olive oil has been related to the prevention of osteoporosis in experimental and in in vitro models. Very few prospective studies have evaluated the effects of olive oil intake on circulating osteocalcin (OC) in humans.
The objective of the study was to examine the longitudinal effects of a low-fat control diet (n=34), a Mediterranean diet enriched with nuts (MedDiet+nuts, n=51), or a Mediterranean diet enriched with virgin olive oil (MedDiet+VOO, n=42) on circulating forms of OC and bone formation markers in elderly men at high cardiovascular risk.
Longitudinal associations between baseline and follow-up (2 yr) measurements of total OC, undercarboxylated osteocalcin, C-telopeptide of type I collagen, and procollagen I N-terminal propeptide (P1NP) concentrations were examined in 127 elderly men randomized to three healthy dietary interventions.
Baseline characteristics (age, body mass index, waist circumference, lipid profile, fasting insulin levels, and bone formation and resorption markers) were similar in all intervention groups. The total osteocalcin concentration increased robustly in the MedDiet+VOO group (P=0.007) in parallel to increased P1NP levels (P=0.01) and homeostasis model assessment-β-cell function (P=0.01) but not in subjects on the MedDiet+nuts (P=0.32) or after the control diet (P=0.74). Interestingly, the consumption of olives was associated positively with both baseline total osteocalcin (r=0.23, P=0.02) and the 2-yr osteocalcin concentrations (r=0.21, P=0.04) in the total cohort.
Consumption of a Mediterranean diet enriched with virgin olive oil for 2 years is associated with increased serum osteocalcin and P1NP concentrations, suggesting protective effects on bone.

Fernández-Real JM, Bulló M, Moreno-Navarrete JM, Ricart W…
J. Clin. Endocrinol. Metab. Oct 2012
PMID: 22855341

Interestingly, nuts did not show a benefit.