Guilherme Borges Pereira

Effects of resistance training on resistin, leptin, cytokines, and muscle force in elderly post-menopausal women

Abstract It may be that resistance exercise can be used to prevent the degenerative processes and inflammation associated with ageing. Thus, the aim of the present study was to evaluate the effects of resistance training on cytokines, leptin, resistin, and muscle strength in post-menopausal women. Thirty-five sedentary women (mean age 63.18 years, s = 4.8; height 1.64 m, s = 0.07; body mass 57.84 kg, s = 7.70) were recruited. The 16 weeks of periodized resistance training consisted of two weekly sessions of three sets of 6–14 repetition maximum. Maximal strength was tested in bench press, 45° leg press, and arm curl. Plasma tumour necrosis factor-α, interleukin-6, interleukin-15, leptin, and resistin were determined by enzyme-linked immunosorbent assay. Maximal strength on all measures was increased after 16 weeks. There were minor or no modifications in tumour necrosis factor-α and interleukin-15. Interleukin-6 was decreased 48 h after compared with baseline and declined after 16 weeks. Leptin decreased 24 h after compared with baseline and was reduced at baseline and 48 h after compared with pre-training. There was a decrease in resistin after 24 and 48 h compared with baseline and a decline in baseline and immediately after levels compared with pre-training. A possible explanation of the results of the present study is a lower production of pro-inflammatory cytokines by the innate immune system. Periodized resistance training seems to be an important intervention to reduce systemic inflammation in this population.

Effects of ovariectomy and resistance training on lipid content in skeletal muscle, liver, and heart; fat depots; and lipid profile

The aim of the present study was to investigate the effects of resistance training on skeletal muscle lipid content, liver lipid content, heart lipid content, fat depots, and lipid profile in ovariectomized rats. Wistar adult female rats were divided into 4 groups (n = 10 per group): sedentary (Sed-Intact), sedentary ovariectomized (Sed-Ovx), strength trained (ChronicEx-intact), and strength trained ovariectomized (ChronicEx-Ovx). A 12-week strength-training period was used, during which the animals climbed a 1.1-m vertical ladder with weights attached to their tails. The sessions were performed once every 3 days, with 4-9 climbs and 8-12 dynamic movements per climb. Ovariectomy increased liver lipid content and fat depots, and heart and muscle lipid content. There was an increase in the atherogenic index and a negative change in lipid profile because of the ovariectomy. Resistance training decreased lipid content in the liver, soleus, and tibialis anterior, decreased fat depots (mesenteric and retroperitoneal), and changed the lipid profile, independently of ovarian hormone status. These results indicate the potential benefits of resistance training as an alternative strategy to control the effects of ovariectomy on fat depot, lipid profile, and tissue lipid content.

The measurement of lactate threshold in resistance exercise: a comparison of methods.

Resistance incremental tests (IT) make it possible to determine critical metabolic and cardiovascular changes, such as the lactate threshold (LT). Different methods are frequently used to improve the exactness of LT identification. The objective of the study was to identify LT by four different methods (visual inspection, log–log, algorithmic adjustment and QLac) during resistance exercise and to evaluate which methods present more precision. Twelve men performed a maximal IT on the leg press at relative intensities of 10%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80% and 90% of 1RM with 1‐min stages. During the 2‐min interval between stages, capillary blood was collected for blood lactate analysis. LT was detected using each of the four methods. The intensity of LT by visual inspection method was 26·9 (5·2)% of 1RM, adjustment algorithmic method was 27·8 (3·6)% of 1RM, log–log method was 23·3 (3·5)% of 1RM and QLac method was 31·6 (9·8)% of 1RM, with significant difference only between log–log and QLac methods. Bland and Altman analysis shows better concordance for visual inspection versus adjustment algorithmic methods. The visual inspection, algorithmic and log–log methods detected the LT at the same intensity. The mathematical models, specially the algorithmic method, provide more precision.

Effects of resistance training on matrix metalloproteinase‐2 activity and biomechanical and physical properties of bone in ovariectomized and intact rats

The purpose of this study was to investigate the influence of resistance training on the activity of matrix metalloproteinase (MMP)‐2 and bone biomechanical properties in ovariectomized and intact rats. Forty‐eight female rats were divided into two distinct groups, ovariectomized (OVX) and intact (Int), which were subdivided into three similar subgroups: sedentary, acute exercise and chronic exercise. Rats performed a resistance training for 12 weeks in which animals climbed a vertical ladder of 1.1 m with weights attached to their tails. Sessions were performed with an interval of 3, 4–9 and 8–12 days scaled dynamic movements of climbing. Biomechanical and physical analyses were performed using a universal testing machine, and MMP‐2 activity analysis by zymography. Bone density (BD), mineral density (MD), maximum load and fracture load was reduced in sedentary and acute exercise OVX groups compared with the sedentary intact group (P<0.05); in contrast, chronically trained groups (OVX and Int) showed a significant increase in BD, MD and fracture load compared with all the other groups. MMP‐2 activity in chronically trained groups also showed a significant increase, while the sedentary OVX group showed a decrease in MMP‐2 activity compared with the intact sedentary group (P<0.05). Our results suggest that the resistance training proposed in our work was efficient in reverting the deleterious effects of ovariectomy on bone tissue, and also produced modeling effects in intact rats. On the other hand, ovariectomy reduced the activity of MMP‐2 and produced deleterious effects on bone tissue, mimicking menopause intrinsically.

Acute effects of resistance exercise on 24-h blood pressure in middle aged overweight and obese women.

This investigation was designed to evaluate responses of blood pressure (BP) following an acute resistance exercise (RE) session. Middle-aged women (N=13) who were classified as overweight (N=8) or obese (N=5) according to body mass index (BMI) participated in the investigation. Participants were randomly submitted to a control session (30-min seated rest) and a exercise session (3 sets, 10 repetitions at 60% 1RM of exercises for the upper and lower body) with systolic (SBP), diastolic (DBP) and mean blood pressure (MBP) obtained at rest and 10, 20, 30, 40, 50, and 60-min following exercise, and through 24 h. Acute RE decreased SBP at 10, 30, and 40-min compared with pre-exercise and control (P<0.05). DBP decreased at 10 and 40-min post-exercise compared with the control trial (P<0.05). Both SBP and DBP decreased in the nighttime period (-4.2 mmHg and -4.1 mmHg, respectively) and in the overall 24 h period (-3.6 mmHg and -4.5 mmHg, respectively) following the acute RE session when compared with the control trial. These findings indicate important benefits of acute RE on BP circadian rhythm, particularly at night as well as in the morning, which are critical periods associated with increased risk for cardiovascular events.

Exercise order affects the total training volume and the ratings of perceived exertion in response to a super-set resistance training session

The super-set is a widely used resistance training method consisting of exercises for agonist and antagonist muscles with limited or no rest interval between them – for example, bench press followed by bent-over rows. In this sense, the aim of the present study was to compare the effects of different super-set exercise sequences on the total training volume. A secondary aim was to evaluate the ratings of perceived exertion and fatigue index in response to different exercise order. On separate testing days, twelve resistance-trained men, aged 23.0 ± 4.3 years, height 174.8 ± 6.75 cm, body mass 77.8 ± 13.27 kg, body fat 12.0% ± 4.7%, were submitted to a super-set method by using two different exercise orders: quadriceps (leg extension) + hamstrings (leg curl) (QH) or hamstrings (leg curl) + quadriceps (leg extension) (HQ). Sessions consisted of three sets with a ten-repetition maximum load with 90 seconds rest between sets. Results revealed that the total training volume was higher for the HQ exercise order (P = 0.02) with lower perceived exertion than the inverse order (P = 0.04). These results suggest that HQ exercise order involving lower limbs may benefit practitioners interested in reaching a higher total training volume with lower ratings of perceived exertion compared with the leg extension plus leg curl order.

Acute effects of resistance training on cytokines and osteoprotegerin in women with metabolic syndrome

Chronic inflammation has been identified as an important component of metabolic syndrome (MetS). Inhibition of the inflammatory mediator signals is a promising strategy against insulin resistance, atherosclerosis and other problems associated with MetS. Regular exercise decreases the components associated with MetS, including inflammatory cytokines. However, the relationship between an acute resistance training (RT) session, cytokine levels and MetS is unclear. Therefore, the aim was to evaluate the effects of a single bout of acute RT on tumour necrosis factor (TNF‐α), interleukins (IL) IL‐1a, IL‐1β, IL‐12, IL‐6, IL‐10 and osteoprotegerin (OPG) in women with MetS. Twenty‐four women were divided into 2 groups: metabolic syndrome (MetS) and non‐metabolic syndrome (Non‐MetS). After the familiarization and testing for 1 repetition maximum (1RM), participants completed 3 sets of 10 repetitions in the following exercises: machine leg press, leg extension, leg curl, chest press, lat front pull‐down and machine shoulder press with 60% of 1RM followed by 15 repetitions of abdominal crunches. A rest interval of 1 min was allowed between sets and exercises. Plasma TNF‐α, IL‐1a, IL‐1β, IL‐12, IL‐6, IL‐10 and OPG were measured before, immediately post and 60 min after RT. MetS group showed significantly higher concentrations of IL‐1β (P = 0·024) and IL‐6 (P = 0·049) and a trend for higher TNF‐α values (P = 0·092) compared with Non‐MetS. There was no group × time interactions after the RT session on the measured cytokines and osteoprotegerin. In conclusion, acute RT session induced no additional increase in pro‐inflammatory cytokines nor a decrease in anti‐inflammatory cytokines and OPG in women with MetS.

Menopause: Highlighting the Effects of Resistance Training

The increase in lifespan and in the proportion of elderly women has increased the focus on menopause induced physiological alterations. These modifications are associated with the elevated risk of several pathologies such as cardiovascular disease, diabetes, obesity, hypertension, dyslipidemia, non-alcoholic fat liver disease, among others. Because of estrogen levels decline, many tissue and organs (muscular, bone, adipose tissue and liver) are affected. Additionally, body composition suffers important modifications. In this sense, there is a growing body of concern in understanding the physiological mechanisms involved and establishing strategies to prevent and reverse the effects of menopause. The hormone reposition therapy, diet and physical exercise have been recommended. Among the diverse exercise modalities, resistance training is not commonly used as a therapeutic intervention in the treatment of menopause. Thus, the aim of this review was to analyze the physiological alterations on several organs and systems induced by menopause and ovariectomy (experimental model to reproduce menopause), as well as, to study the effects of resistance training in preventing and reverting these modifications. In conclusion, resistance training promotes beneficial effects on several organs and systems, mainly, on muscular, bone and adipose tissue, allowing for a better quality of life in this population.

Effects of ovariectomy and resistance training on MMP-2 activity in skeletal muscle

Matrix metallopeptidases (MMPs) are crucial to the maintenance of healthy tissue. The aim of this study was to investigate MMP-2 activity in gastrocnemius, soleus, tibialis anterior (TA), and extensor digitorium longus (EDL) muscle after resistance training in ovariectomized rats. Wistar adult female rats were grouped into 7 groups (n = 10 per group): sedentary (Sed-Intact); ovariectomized sedentary (Sed-Ovx); pseudo-ovariectomized sedentary (Sed-Pseudo); acute exercise (AcuteEx-Intact); ovariectomized acute exercise (AcuteEx-Ovx); strength trained (ChronicEx-Intact); and ovariectomized strength trained (ChronicEx-Ovx). A 12-week resistance training period, during which the animals climbed a 1.1-m vertical ladder with weights secured to their tails, was used. The sessions were performed once every 3 days, with 4-9 climbs and 8-12 dynamic movements per climb. The MMP-2 activity was analyzed by zymography. There was higher MMP-2 activity in soleus muscle in the ChronicEx-Intact and ChronicEx-Ovx groups, and lower MMP-2 activity in the AcuteEx-Ovx group, compared with the Sed-Intact group (p < or =0.05). The Sed-Ovx and ChronicEx-Ovx groups presented lower MMP-2 activity than the Sed-Intact group in TA. There was higher MMP-2 activity in AcuteEx-Intact and the AcuteEx-Ovx compared with the Sed-Intact and Sed-Ovx in TA, respectively (p < or = 0.05). In TA and EDL, training increased MMP-2 activity in the Sed-Intact group. No statistically significant alterations were observed for gastrocnemius muscle. Strength training increases MMP-2 activity in soleus, TA, and EDL muscle, which may be important for muscle remodeling. Ovariectomy downregulates MMP-2 in TA and EDL, which may compromise muscle function.

Resistance Training and Glycogen Content in Ovariectomized Rats

The aim of the present study was to investigate the effects of resistance training on glycogen content and muscle cross-sectional area (CSA) in ovariectomized rats. Wistar rats were divided into: sedentary; ovariectomized sedentary; resistance trained; and ovariectomized resistance trained. In the 12-week resistance training, the animals climbed a 1.1 m vertical ladder, 3 days per week, with 4-8 climbs. Cardiac, liver and muscle glycogen content was determined. After the 12-week resistance training period there was a higher hepatic and muscle glycogen content in the resistance training group compared with the other groups (p<0.01). CSA was higher in soleus for the resistance trained, ovariectomized resistance trained and sedentary compared with ovariectomized sedentary (p<0.05). Ovariectomy attenuated the increase in liver and muscle glycogen content, while soleus muscle cross-sectional area increased with resistance training, even in ovariectomized rats. Resistance training could be an important exercise to increase muscle function in situations of reduced estrogen and progesterone.