Effect of resistance exercise training on cortical and cancellous bone in mature male rats

1998 ◽  
Vol 84 (2) ◽  
pp. 459-464 ◽  
Author(s):  
Kim C. Westerlind ◽  
James D. Fluckey ◽  
Scott E. Gordon ◽  
William J. Kraemer ◽  
Peter A. Farrell ◽  
...  

Westerlind, Kim C., James D. Fluckey, Scott E. Gordon, William J. Kraemer, Peter A. Farrell, and Russell T. Turner.Effect of resistance exercise training on cortical and cancellous bone in mature male rats. J. Appl. Physiol. 84(2): 459–464, 1998.—The effect of resistance training on tibial cancellous and cortical bone was evaluated in rats by using static histomorphometry and Northern analysis. Five-month-old male Sprague-Dawley rats were randomly assigned to exercise (Ex; n = 8) or control (Con; n = 4) groups. Animals were operantly conditioned to press two levers, facilitating full extension and flexion of the hindlimbs (“squats”), while wearing an unweighted vest. After an 8-wk familiarization period, Ex animals performed 3 sessions/wk for 17–19 sessions with progressively increased amounts of weight applied to the vest. Con rats completed the same exercise protocol without applied resistance. No difference in cross-sectional, medullary, or cortical bone area was observed between Ex and Con rats in the tibial diaphysis. In contrast, the cancellous bone area in the proximal tibial metaphysis was significantly larger in trained rats. Trabecular number, trabecular thickness, and the percentage of cancellous bone covered by osteoid were significantly greater in the Ex animals compared with Con animals. In addition, steady-state mRNA levels for osteocalcin for the Ex group were 456% those expressed in the Con group. The data demonstrate that resistance training increases cancellous bone area in sexually mature male rats and suggest that it does so, in part, by stimulating bone formation.

2020 ◽  
Vol 9 (7) ◽  
pp. 2188 ◽  
Author(s):  
Andreas Mæchel Fritzen ◽  
Frank D. Thøgersen ◽  
Khaled Abdul Nasser Qadri ◽  
Thomas Krag ◽  
Marie-Louise Sveen ◽  
...  

Aging is related to an inevitable loss of muscle mass and strength. The mechanisms behind age-related loss of muscle tissue are not fully understood but may, among other things, be induced by age-related differences in myogenic regulatory factors. Resistance exercise training and deconditioning offers a model to investigate differences in myogenic regulatory factors that may be important for age-related loss of muscle mass and strength. Nine elderly (82 ± 7 years old) and nine young, healthy persons (22 ± 2 years old) participated in the study. Exercise consisted of six weeks of resistance training of the quadriceps muscle followed by eight weeks of deconditioning. Muscle biopsy samples before and after training and during the deconditioning period were analyzed for MyoD, myogenin, insulin-like growth-factor I receptor, activin receptor IIB, smad2, porin, and citrate synthase. Muscle strength improved with resistance training by 78% (95.0 ± 22.0 kg) in the elderly to a similar extent as in the young participants (83.5%; 178.2 ± 44.2 kg) and returned to baseline in both groups after eight weeks of deconditioning. No difference was seen in expression of muscle regulatory factors between elderly and young in response to exercise training and deconditioning. In conclusion, the capacity to gain muscle strength with resistance exercise training in elderly was not impaired, highlighting this as a potent tool to combat age-related loss of muscle function, possibly due to preserved regulation of myogenic factors in elderly compared with young muscle.


2011 ◽  
Vol 300 (3) ◽  
pp. R655-R662 ◽  
Author(s):  
Todd A. Trappe ◽  
Chad C. Carroll ◽  
Jared M. Dickinson ◽  
Jennifer K. LeMoine ◽  
Jacob M. Haus ◽  
...  

Evidence suggests that consumption of over-the-counter cyclooxygenase (COX) inhibitors may interfere with the positive effects that resistance exercise training has on reversing sarcopenia in older adults. This study examined the influence of acetaminophen or ibuprofen consumption on muscle mass and strength during 12 wk of knee extensor progressive resistance exercise training in older adults. Thirty-six individuals were randomly assigned to one of three groups and consumed the COX-inhibiting drugs in double-blind placebo-controlled fashion: placebo (67 ± 2 yr; n = 12), acetaminophen (64 ± 1 yr; n = 11; 4 g/day), and ibuprofen (64 ± 1 yr; n = 13; 1.2 g/day). Compliance with the resistance training program (100%) and drug consumption (via digital video observation, 94%), and resistance training intensity were similar ( P > 0.05) for all three groups. Drug consumption unexpectedly increased muscle volume (acetaminophen: 109 ± 14 cm3, 12.5%; ibuprofen: 84 ± 10 cm3, 10.9%) and muscle strength (acetaminophen: 19 ± 2 kg; ibuprofen: 19 ± 2 kg) to a greater extent ( P < 0.05) than placebo (muscle volume: 69 ± 12 cm3, 8.6%; muscle strength: 15 ± 2 kg), when controlling for initial muscle size and strength. Follow-up analysis of muscle biopsies taken from the vastus lateralis before and after training showed muscle protein content, muscle water content, and myosin heavy chain distribution were not influenced ( P > 0.05) by drug consumption. Similarly, muscle content of the two known enzymes potentially targeted by the drugs, COX-1 and -2, was not influenced ( P > 0.05) by drug consumption, although resistance training did result in a drug-independent increase in COX-1 (32 ± 8%; P < 0.05). Drug consumption did not influence the size of the nonresistance-trained hamstring muscles ( P > 0.05). Over-the-counter doses of acetaminophen or ibuprofen, when consumed in combination with resistance training, do not inhibit and appear to enhance muscle hypertrophy and strength gains in older adults. The present findings coupled with previous short-term exercise studies provide convincing evidence that the COX pathway(s) are involved in the regulation of muscle protein turnover and muscle mass in humans.


1995 ◽  
Vol 27 (Supplement) ◽  
pp. S221
Author(s):  
K C Westerlind ◽  
J D Fluckey ◽  
S E Gordon ◽  
W J Kraemer ◽  
R T Turner ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gabriela Alves Bronczek ◽  
Gabriela Moreira Soares ◽  
Jaqueline Fernandes de Barros ◽  
Jean Franciesco Vettorazzi ◽  
Mirian Ayumi Kurauti ◽  
...  

AbstractResistance exercise exerts beneficial effects on glycemic control, which could be mediated by exercise-induced humoral factors released in the bloodstream. Here, we used C57Bl/6 healthy mice, submitted to resistance exercise training for 10 weeks. Trained mice presented higher muscle weight and maximum voluntary carrying capacity, combined with reduced body weight gain and fat deposition. Resistance training improved glucose tolerance and reduced glycemia, with no alterations in insulin sensitivity. In addition, trained mice displayed higher insulinemia in fed state, associated with increased glucose-stimulated insulin secretion. Islets from trained mice showed reduced expression of genes related to endoplasmic reticulum (ER) stress, associated with increased expression of Ins2. INS-1E beta-cells incubated with serum from trained mice displayed similar pattern of insulin secretion and gene expression than isolated islets from trained mice. When exposed to CPA (an ER stress inducer), the serum from trained mice partially preserved the secretory function of INS-1E cells, and prevented CPA-induced apoptosis. These data suggest that resistance training, in healthy mice, improves glucose homeostasis by enhancing insulin secretion, which could be driven, at least in part, by humoral factors.


2007 ◽  
Vol 293 (5) ◽  
pp. H3180-H3186 ◽  
Author(s):  
Kevin S. Heffernan ◽  
Christopher A. Fahs ◽  
Kevin K. Shinsako ◽  
Sae Young Jae ◽  
Bo Fernhall

The purpose of this study was to examine heart rate recovery (HRR) and linear/nonlinear heart rate variability (HRV) before and after resistance training. Fourteen young men (25.0 ± 1.1 yr of age) completed a crossover design consisting of a 4-wk time-control period, 6 wk of resistance training (3 days/wk), and 4 wk of detraining. Linear HRV was spectrally decomposed using an autoregressive approach. Nonlinear dynamics of heart rate complexity included sample entropy (SampEn) and Lempel-Ziv entropy (LZEn). HRR was calculated from a graded maximal exercise test as maximal heart rate attained during the test minus heart rate at 1 min after exercise (HRR). There was no change in SampEn, LZEn, or HRR after the time-control portion of the study ( P > 0.05). SampEn ( P < 0.05), LZEn ( P < 0.05), and HRR ( P < 0.05) increased after resistance training and returned to pretraining values after detraining. There was no change in spectral measures of HRV at any time point ( P > 0.05). These findings suggest that resistance exercise training increases heart rate complexity and HRR after exercise but has no effect on spectral measures of HRV in young healthy men. These autonomic changes regress shortly after cessation of training.


1999 ◽  
Vol 277 (1) ◽  
pp. E118-E125 ◽  
Author(s):  
Kevin E. Yarasheski ◽  
Jina Pak-Loduca ◽  
Debbie L. Hasten ◽  
Kathleen A. Obert ◽  
Mary Beth Brown ◽  
...  

Muscle atrophy (sarcopenia) in the elderly is associated with a reduced rate of muscle protein synthesis. The purpose of this study was to determine if weight-lifting exercise increases the rate of muscle protein synthesis in physically frail 76- to 92-yr-old women and men. Eight women and 4 men with mild to moderate physical frailty were enrolled in a 3-mo physical therapy program that was followed by 3 mo of supervised weight-lifting exercise. Supervised weight-lifting exercise was performed 3 days/wk at 65–100% of initial 1-repetition maximum on five upper and three lower body exercises. Compared with before resistance training, the in vivo incorporation rate of [13C]leucine into vastus lateralis muscle protein was increased after resistance training in women and men ( P < 0.01), although it was unchanged in five 82 ± 2-yr-old control subjects studied two times in 3 mo. Maximum voluntary knee extensor muscle torque production increased in the supervised resistance exercise group. These findings suggest that muscle contractile protein synthetic pathways in physically frail 76- to 92-yr-old women and men respond and adapt to the increased contractile activity associated with progressive resistance exercise training.


2021 ◽  
Vol 25 (2) ◽  
pp. 8-14
Author(s):  
Kevin Boldt ◽  
Stela Mattiello ◽  
Venus Joumaa ◽  
Jeannine Turnbull ◽  
Paul W.M. Fedak ◽  
...  

[Purpose] The purpose of this study was to investigate the effects of a high-fat high-sucrose (HFHS) diet on previously reported adaptations of cardiac morphological and contractile properties to resistance training.[Methods] Twelve-week-old rats participated in 12-weeks of resistance exercise training and consumed an HFHS diet. Echocardiography and skinned cardiac muscle fiber bundle testing were performed to determine the structural and mechanical adaptations.[Results] Compared to chow-fed sedentary animals, both HFHS- and chow-fed resistance-trained animals had thicker left ventricular walls. Isolated trabecular fiber bundles from chow-fed resistance-trained animals had greater force output, shortening velocities, and calcium sensitivities than those of chow-fed sedentary controls. However, trabeculae from the HFHS resistance-trained animals had greater force output but no change in unloaded shortening velocity or calcium sensitivity than those of the chow-fed sedentary group animals.[Conclusion] Resistance exercise training led to positive structural and mechanical adaptations of the heart, which were partly offset by the HFHS diet.


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