Resistance Training and Pioglitazone Lead to Improvements in Muscle Power During Voluntary Weight Loss in Older Adults

Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC 27109-7868. .
The Journals of Gerontology Series A Biological Sciences and Medical Sciences (Impact Factor: 5.42). 01/2013; 68(7). DOI: 10.1093/gerona/gls258
Source: PubMed


The prevalence of obesity in older adults is increasing but concerns exist about the effect of weight loss on muscle function. Demonstrating that muscle strength and power are not adversely affected during "intentional" weight loss in older adults is important given the wide-ranging negative health effects of excess adiposity.

Participants (N = 88; age = 70.6 ± 3.6 years; body mass index = 32.8 ± 4.5 kg/m(2)) were randomly assigned to one of four intervention groups: pioglitazone or placebo and resistance training (RT) or no RT, while undergoing intentional weight loss via a hypocaloric diet. Outcomes were leg press power and isometric knee extensor strength. Analysis of covariance, controlling for baseline values, compared follow-up means of power and strength according to randomized groups.

Participants lost an average of 6.6% of initial body mass, and significant declines were observed in fat mass, lean body mass, and appendicular lean body mass. Compared with women not randomized to RT, women randomized to RT had significant improvements in leg press power (p < .001) but not in knee extensor strength (p = 0.12). No significant differences between groups in change in power or strength from baseline were detected in men (both p > .25). A significant pioglitazone-by-RT interaction for leg press power was detected in women (p = .006) but not in men (p = .88).

In older overweight and obese adults, a hypocaloric weight loss intervention led to significant declines in lean body mass and appendicular lean body mass. However, in women assigned to RT, leg power significantly improved following the intervention, and muscle strength or power was not adversely effected in the other groups. Pioglitazone potentiated the effect of RT on muscle power in women but not in men; mechanisms underlying this sex effect remain to be determined.

Download full-text


Available from: Anthony P Marsh,
1 Follower
20 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A complication of cardiovascular disease (CVD) and the metabolic syndrome (MetS) among older adults is loss of mobility. The American Heart Association has identified weight management as a core component of secondary prevention programs for CVD and is an important risk factor for physical disability. The American Society for Nutrition and the Obesity Society have highlighted the need for long-term randomized clinical trials to evaluate the independent and additive effects of diet-induced weight loss (WL) and physical activity in older persons on outcomes such as mobility, muscle function, and obesity related diseases. Here we describe the rationale, design, and methods of a translational study, the Cooperative Lifestyle Intervention Program-II (CLIP-II). CLIP-II will randomize 252 obese, older adults with CVD or MetS to a weight loss only treatment (WL), aerobic exercise training (AT)+WL, or resistance exercise training (RT)+WL for 18months. The dual primary outcomes are mobility and knee extensor strength. The interventions will be delivered by YMCA community partners with our staff as trainers and advisers. This study will provide the first large scale trial to evaluate the effects of diet-induced WL on mobility in obese, older adults with CVD or MetS as compared to WL combined with two different modes of physical activity (AT and RT). Because uncertainty exists about the best approach for promoting WL in older adults due to concerns with the loss of lean mass, the design also permits a contrast between AT+WL and RT+WL on muscle strength.
    Contemporary clinical trials 08/2013; 36(2). DOI:10.1016/j.cct.2013.08.006 · 1.94 Impact Factor
  • Source
    The Journals of Gerontology Series A Biological Sciences and Medical Sciences 11/2013; 69(1). DOI:10.1093/gerona/glt185 · 5.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Peroxisome-proliferator-activated receptor (PPAR) delta and adenosine monophosphate (AMP)-activated protein kinases (AMPKs) regulate the metabolic and contractile characteristics of myofibres. PPAR proteins are nuclear receptors that function as transcription factors and regulate the expression of multiple genes. AMPK has been described as a master metabolic regulator which also controls gene expression through the direct phosphorylation of some nuclear proteins. Since it was discovered that both PPARdelta agonists (GW1516) and AMPK activators (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, known as AICAR) are very effective performance-enhancing substances in sedentary mice, the World Anti-doping Agency (WADA) included AICAR and GW1516 in the prohibited list of substances as metabolic modulators in the class 'Hormone and metabolic modulators'. Thiazolidinediones are PPARgamma agonists that can induce similar biological effects to those of PPARdelta and PPARdelta-AMPK agonists. Thus in this study, the effects of pioglitazone on mitochondrial biogenesis and performance were evaluated. Blood glucose levels and the protein expression of the intermediates involved in the mitochondrial biogenesis pathway and the citrate synthase activity were determined in both gastrocnemius and soleus muscles. Maximal aerobic velocity (MAV), endurance capacity, and grip strength before and after the training period were also determined. The MAV endurance capacity and grip strength of trained animals significantly increased. We found that the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and the nuclear respiratory factor-1 (NRF-1) protein content and citrate synthase activity significantly increased in the soleus muscle of trained animals. No effect of treatment was found. Therefore in our study, pioglitazone administration did not affect mitochondrial biogenesis signaling pathway. Copyright © 2013 John Wiley & Sons, Ltd.
    Drug Testing and Analysis 09/2014; 6(9). DOI:10.1002/dta.1587 · 2.51 Impact Factor
Show more