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Effect of dietary restriction and exercise on lower extremity tissue compartments in obese, older women: a pilot study.

ABSTRACT: Accumulating evidence suggests that both dietary restriction and exercise (DR + E) should be incorporated in weight loss interventions to treat obese, older adults. However, more information is needed on the effects to lower extremity tissue composition-an important consideration for preserving mobility in older adults.Twenty-seven sedentary women (body mass index: 36.3±5.4kg/m(2); age: 63.6±5.6 yrs) were randomly assigned to 6 months of DR + E or a health education control group. Thigh and calf muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) size were determined using magnetic resonance imaging. Physical function was measured using a long-distance corridor walk and knee extension strength.Compared with control, DR + E significantly reduced body mass (-6.6±3.7kg vs control: -0.05±3.5kg; p < .01). Thigh and calf muscle volumes responded similarly between groups. Within the DR + E group, adipose tissue was reduced more in the thigh than in the calf (p < .04). Knee extension strength was unaltered by DR + E, but a trend toward increased walking speed was observed in the DR + E group (p = .09). Post hoc analyses showed that reductions in SAT and IMAT within the calf, but not the thigh, were associated with faster walking speed achieved with DR + E (SAT: r = -0.62; p = .01; IMAT: r = -0.62; p = .01).DR + E preserved lower extremity muscle size and function and reduced regional lower extremity adipose tissue. Although the magnitude of reduction in adipose tissue was greater in the thigh than the calf region, post hoc analyses demonstrated that reductions in calf SAT and IMAT were associated with positive adaptations in physical function.

SUBMITTER: Manini TM

PROVIDER: S-EPMC4158399 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Effect of dietary restriction and exercise on lower extremity tissue compartments in obese, older women: a pilot study.

Manini Todd M TM Buford Thomas W TW Lott Donovan J DJ Vandenborne Krista K Daniels Michael J MJ Knaggs Jeffrey D JD Patel Hetain H Pahor Marco M Perri Michael G MG Anton Stephen D SD

The journals of gerontology. Series A, Biological sciences and medical sciences 20130516 1

<h4>Background</h4>Accumulating evidence suggests that both dietary restriction and exercise (DR + E) should be incorporated in weight loss interventions to treat obese, older adults. However, more information is needed on the effects to lower extremity tissue composition-an important consideration for preserving mobility in older adults.<h4>Methods</h4>Twenty-seven sedentary women (body mass index: 36.3±5.4kg/m(2); age: 63.6±5.6 yrs) were randomly assigned to 6 months of DR + E or a health educ ...[more]

PMID: 23682155

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Project description:Purpose:This study aimed to assess the effects of exercise with dietary restriction on arterial stiffness, central hemodynamics, and cardiac autonomic function in obese adolescents. Patients and methods:Twenty-one obese adolescents completed a 6-week exercise and dietary program. Body composition and metabolic parameters were measured. Carotid-femoral pulse wave velocity (cfPWV) and brachial-ankle pulse wave velocity (baPWV) were used to assess central and systemic arterial stiffness, respectively. Using applanation tonometry, the analyses of central hemodynamic parameters [central blood pressure, heart rate (HR), augmentation index normalized at 75 bpm (AIx75), and subendocardial viability ratio (SEVR)] were performed. To determine cardiac autonomic function, heart rate variability (HRV) was analyzed by standard deviation of normal R-R intervals (SDNN), root mean square of successive R-R interval differences (RMSSD), percentage of successive R-R intervals that differed by >50 ms (pNN50), total power (TP), low-frequency (LF) and high-frequency (HF) power, and LF/HF ratio. Results:Following the intervention, obese adolescents had reductions in body mass index, body fat percentage, brachial systolic and diastolic blood pressure, and HR; and they had shown improvements in lipid profiles. There were reductions in both cfPWV and baPWV following the intervention. Moreover, there were reductions in AIx75, aortic systolic and diastolic blood pressure and an augmentation in SEVR after intervention. The intervention increased cardiac autonomic function (determined by increased SDNN, RMSSD, pNN50, HF, and reduced LF/HF). Furthermore, we observed a correlation between increased cardiac autonomic function (SDNN, RMSSD, pNN50 and HF) and increased central hemodynamics, as measured by SEVR and AIx75. Conclusion:Obese adolescents had increased central hemodynamics and autonomic function with reduced arterial stiffness after exercise and dietary restriction. Moreover, a positive correlation between an enhancement of cardiac autonomic function and an augmentation in central hemodynamics was found after the intervention.

Project description:BACKGROUND AND PURPOSE:There is limited evidence regarding risk factors for lower extremity overuse bone injury (LEOBI) in collegiate athletes. The purposes of the study were to: 1) determine incidence of LEOBI in selected sports and its impact on athletic participation and ADL, 2) assess risk relationships between LEOBI and selected risk factors, and 3) establish the viability of using calcaneal densitometry as a screening tool to identify risk for LEOBI. STUDY DESIGN:Prospective analytical cohort design. METHODS:Collegiate athletes in selected sports (swimming/diving, women's soccer, field hockey, cross-country/track) at one university were invited to participate. Consenting athletes completed an initial questionnaire including demographic information, history, and menstrual function. Measurements included height/weight, hip abductor strength, foot posture index, and calcaneal bone mineral density. Athletes were monitored for potential LEOBI for nine months and an algorithm was used to determine if physician referral was required. The primary outcome of interest was the occurrence of physician-diagnosed LEOBI. If LEOBI was diagnosed by the physician, the athlete completed a follow-up visit including a repeat bone mineral density scan. All athletes were invited for a repeat scan at the end of the year and completed a final questionnaire. Athlete demographics were summarized using descriptive statistics and differences in continuous risk factors were analyzed using t-tests and ANOVA. Finally, risk relationships for categorical variables were analyzed using chi-square and relative risk. RESULTS:84 athletes (64 female, 20 male) consented to participate. Over the study period, eight athletes (one male, seven females) were diagnosed with LEOBI (LEOBI group), five with stress fractures and three with medial tibial stress syndrome. The other 76 athletes who did not have a diagnosis of LEOBI were placed in the non-LEOBI group. Five of the eight were cross-country/track athletes; no swimming/diving athletes had bone injury. Sport (cross-country/track) had a significant relative risk value of 2.26 (95% CI = 1.18-4.32) for LEOBI. There was no association between LEOBI occurrence and sex, hip abductor strength, body mass index, foot type, and menstrual function. There was no difference in bone mineral density at initial or follow-up measures between LEOBI and non-LEOBI groups (p>.05) when analyzing all athletes. When analyzing ground-based athletes only at follow-up (n=44), athletes with LEOBI had lower bone mineral density of right (p = .05) and left (p =.07) calcaneus. The relative risk for developing LEOBI based on calcaneal bone mineral density below the mean of the study participants was 2.1 (95%CI = 1.09-3.35) on the left and 1.53 (95% CI=.80- 3.06) on the right. CONCLUSION:The incidence of LEOBI in this population of athletes was approximately 10%. Risk factors were sport (cross-country/track) and decreased left calcaneal bone mineral density. This study supports the use of calcaneal bone mineral density as a screening measurement for LEOBI risk and suggests the need for further investigation into additional LEOBI risk factors. LEVEL OF EVIDENCE:2.

Project description:Context The extent to which lower extremity lean mass (LELM) relative to total body mass influences one's ability to maintain safe landing biomechanics during prolonged exercise when injury incidence increases is unknown.Objectives To examine the influence of LELM on (1) pre-exercise lower extremity biomechanics and (2) changes in biomechanics during an intermittent exercise protocol (IEP) and (3) determine whether these relationships differ by sex. We hypothesized that less LELM would predict higher-risk baseline biomechanics and greater changes toward higher-risk biomechanics during the IEP.Design Cohort study.Setting Controlled laboratory.Patients or other participants A total of 59 athletes (30 men: age = 20.3 ± 2.0 years, height = 1.79 ± 0.05 m, mass = 75.2 ± 7.2 kg; 29 women: age = 20.6 ± 2.3 years, height = 1.67 ± 0.08 m, mass = 61.8 ± 9.0 kg) participated.Intervention(s) Before completing an individualized 90-minute IEP designed to mimic a soccer match, participants underwent dual-energy x-ray absorptiometry testing for LELM.Main outcome measure(s) Three-dimensional lower extremity biomechanics were measured during drop-jump landings before the IEP and every 15 minutes thereafter. A previously reported principal components analysis reduced 40 biomechanical variables to 11 factors. Hierarchical linear modeling analysis then determined the extent to which sex and LELM predicted the baseline score and the change in each factor over time.Results Lower extremity lean mass did not influence baseline biomechanics or the changes over time. Sex influenced the biomechanical factor representing knee loading at baseline (P = .04) and the changes in the anterior cruciate ligament-loading factor over time (P = .03). The LELM had an additional influence only on women who possessed less LELM (P = .03 and .02, respectively).Conclusions Lower extremity lean mass influenced knee loading during landing in women but not in men. The effect appeared to be stronger in women with less LELM. Continually decreasing knee loading over time may reflect a strategy chosen to avoid injury. A minimal threshold of LELM may be needed to safely perform landing maneuvers, especially during prolonged exercise when the injury risk increases.

Dataset Information

Effect of dietary restriction and exercise on lower extremity tissue compartments in obese, older women: a pilot study.

Publications

Effect of dietary restriction and exercise on lower extremity tissue compartments in obese, older women: a pilot study.

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