Changes in irisin, inflammatory cytokines and aerobic capacity in response to three weeks of supervised sprint interval training in older men.

BACKGROUND: This study investigated the effects of supervised short-term sprint interval training (SIT) on circulating irisin, interleukin (IL)-6 and tumour necrosis factor (TNF)-α concentrations, and aerobic capacity and body composition values in healthy older men. METHODS: Eleven older men (63±8 years; 178.0±5.5 cm; 82.7±8.6 kg; 22.7±3.7% body fat) underwent SIT (6 repetitions of 30 s all-out cycling bouts with 4 min active recovery after each bout) three days a week for three consecutive weeks. Body composition measured by dual-energy X-ray absorptiometry, aerobic capacity assessed by direct peak oxygen consumption (VO2peak) test and morning fasting blood samples were obtained before and after a 3-week SIT intervention. RESULTS: Nine supervised SIT sessions moderately (effect size [ES] =0.65; P<0.05) increased irisin concentrations (from 135.40±28.73 to 154.20±47.09 ng.mL-1) together with moderate decreases (P<0.05) in IL-6 (ES=0.89; from 1.26±0.44 to 0.87±0.44 pg.mL-1) and TNF-α (ES=0.64; from 5.10±1.23 to 4.31±1.20 pg.mL-1) levels in older men. In addition, increase in VO2peak was significant but small (ES=0.25; P<0.05; from 36.0±7.1 to 37.8±6.7 mL.min.-1kg-1), while no changes (P>0.05) in body composition variables were observed after a short-term SIT period. CONCLUSIONS: A 3-week SIT intervention with only nine training sessions increased circulating irisin concentrations, improved inflammatory profile and aerobic capacity without changes in body composition in healthy older men. Accordingly, a short-term SIT programme is a time efficient alternative for traditional aerobic training to improve metabolic health and aerobic capacity in older adults.

Resistin concentration is inversely associated with objectively measured physical activity in healthy older women.

Regular physical activity (PA) has been associated with decreased risk of many chronic diseases and increased longevity among older adults. In addition, ageing has been associated with higher levels of different inflammatory biomarkers while the association between inflammatory biomarkers and PA has remained controversial. The aim of the current investigation was to examine the association between blood biomarkers and objectively assessed PA among a sample of healthy older women with different levels of PA engagement. A total of 81 healthy women were recruited. Study participants were allocated to three groups according to accelerometer-obtained PA data. Body composition was assessed with dual-energy X-ray absorptiometry. Fasting blood samples were collected for the measurement of resistin, leptin, tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP) concentrations. There were no significant differences between groups for resistin, leptin, TNFα and for CRP concentrations; however, higher moderate-to-vigorous physical activity (MVPA) groups tended to have lower level of blood biomarker concentrations. There was a significant negative relationship between resistin and steps per day. Inverse association between leptin and MVPA was significant after controlling for age. In multivariate stepwise linear regression analysis, steps per day were the strongest independent predictor for resistin, whereas for leptin, TNFα and CRP the strongest independent predictor was whole body fat mass. In conclusion, this study demonstrated negative association between resistin concentration and steps per day. Sedentary time and light PA had no relationship with resistin, leptin, TNFα or CRP concentrations.

Associations of distinct levels of physical activity with mobility in independent healthy older women.

BACKGROUND: Older adults have twice as many disabilities and four times as many physical limitations as people <60 years of age. Positive influence of physical activity to prevent these limitations has been presented in some studies. However, the indispensable combination of physical abilities and body composition parameters to maintain independence in later life and their relationship with physical activity has not been studied thoroughly. OBJECTIVE: The main aim of this study was to determine possible differences in body composition and mobility parameters among older women with various levels of engagement in physical activity. In addition, the relationships between mobility and distinct levels of physical activity were evaluated in healthy older women. METHODS: Eighty-one healthy older women aged from 65 to 91 years participated in this study and were allocated to three groups according to weekly moderate-to-vigorous physical activity (MVPA) time in 10 min bouts: highest MVPA (H-MVPA) (n = 27), middle MVPA (M-MVPA) (n = 40) and lowest MVPA (L-MVPA) (n = 14). Body composition (fat mass [FM] and fat free mass [FFM]) variables were assessed with dual-energy X-ray absorptiometry (DXA), objective physical activity data were collected with accelerometers and mobility tests were carried out to assess static and dynamic balance, lower limbs strength and aerobic capacity. RESULTS: No differences in body composition parameters were observed between studied groups (p > 0.0025). Women in L-MVPA covered significantly shorter distance during the six-minute walk test (6MWT) compared to H-MVPA (p = 0.000) and M-MVPA (p = 0.003) groups, performed timed-up-and-go (TUG) slower compared to H-MVPA group (p = 0.003) and five-times-sit-to-stand (FTSTS) test slower compared to H-MVPA (p = 0.006) and M-MVPA (p = 0.009) groups. There were no differences in body composition and mobility parameters between women in H-MVPA and M-MVPA groups. Regardless of bout duration, MVPA was correlated with mobility (TUG r = -0.47; FTSTS r = -0.37; 6MWT r = 0.53) parameters, whereas no relationships was observed with light physical activity (LPA). CONCLUSION: MVPA is associated with body composition and mobility parameters, while LPA is not related to any measured body composition nor mobility parameters. Accordingly, healthy older women could benefit from MVPA to maintain body composition and mobility parameters to preserve independence in later life.

Body Composition, Neuromuscular Performance, and Mobility: Comparison Between Regularly Exercising and Inactive Older Women.

The purpose of this study was to evaluate the differences in body composition, neuromuscular performance, and mobility in healthy, regularly exercising and inactive older women, and examine the relationship between skeletal muscle indices and mobility. Overall, 32 healthy older women participated. They were divided into groups according to their physical activity history as regularly exercising (n = 22) and inactive (n = 10) women. Body composition, hand grip strength, leg extensor muscle strength, rapid force development, power output, and mobility indices were assessed. Regularly exercising women had lower fat mass and higher values for leg extensor muscle strength and muscle quality, and also for mobility. Leg extensor muscle strength and power output during vertical jumping and appendicular lean mass per unit of body mass were associated with mobility in healthy older women. It was concluded that long-term regular exercising may have beneficial effects on body composition and physical function in older women.

Upper Extremity and Cue Kinematics, and Shoulder Muscle Electromyographic Activity of Novus Players of Different Skill Levels.

Our aim with the current study was to compare upper extremity and cue kinematics, and electromyographic (EMG) activation of shoulder muscles during novus (a special form of billiards) shots of different difficulty levels. Ten proficient and 10 less-skilled novus players performed 3 types of novus shots (penalties, cuts, rebounds) 10 times each. During each shot, elbow flexion and cue-forearm angles (using a movement analysis system), and surface EMG activity of the trapezius, posterior, and lateral deltoid muscles of each subject's dominant side, were measured. Data were compared between more- and less-skilled players, and successful compared with unsuccessful shots. Elbow flexion angle among the more-skilled players was 24.5% larger (P < .001) during unsuccessful cut shots than successful ones. The more-skilled players performed successful penalty and rebound shots with 26.8% and 49.8% lower (P < .01 and P < .001, respectively) EMG activity of the trapezius muscle than unsuccessful ones. Less-skilled players' shots were characterized by higher EMG activity in the trapezius muscle. The obtained findings suggest that the more-skilled novus players had acquired a different muscle recruitment pattern than less-skilled players.

Quadriceps femoris muscle function prior and after total knee arthroplasty in women with knee osteoarthritis.

PURPOSE: The aim of the present study was to evaluate an isometric voluntary force generation and relaxation capacity of the quadriceps femoris (QF) muscle prior and after total knee arthroplasty (TKA). METHODS: Isometric maximal voluntary contraction force, rate of force development, voluntary activation, half-relaxation time, and latency of contraction of the QF muscle were recorded in 12 female patients (aged 49-68 years) with knee osteoarthritis one day before, 3 and 6 months following TKA in the operated and nonoperated leg. Knee pain intensity was assessed by visual analog scale, and Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire was used to assess knee problems during daily living. RESULTS: A significant decrease in knee pain and significant increase in KOOS were established after TKA. Maximal voluntary isometric force in the operated leg was lower (P < 0.05) before, 3 and 6 months after TKA as compared to the nonoperated leg. Rate of force development of the QF muscle in the operated leg compared to the nonoperated leg was significantly lower (P < 0.05) 3 and 6 months after TKA. Voluntary activation, latency of contraction, and half-relaxation time of the QF muscle did not differ significantly before, 3 and 6 months after TKA. CONCLUSIONS: The present study indicated reduced maximal and explosive strength of quadriceps femoris muscle in the operated leg 3 and 6 months after TKA with no significant changes in voluntary activation, and capacity for rapid contraction and relaxation. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Relationships between adiponectin, leptin, and blood lipids in physically active postmenopausal females.

The aim of this study was to investigate the possible relationships between adiponectin and leptin with blood lipids (CHOL, HDL-C, LDL-C, and TG) in physically active postmenopausal women. One hundred and thirty-four physically active practicing gymnastics (2-3 times per week) women between the ages of 51 to 85 years participated in this cross-sectional study. Body height, body mass, waist-to-hip circumference ratio (WHR), and BMI were used as anthropometrical parameters. Body composition parameters (fat%, fat mass, fat free mass) were measured by DXA. The fasting adiponectin, leptin, CHOL, HDL-C, LDL-C, and TG were measured. From the anthropometrical and body composition parameters, only WHR correlated significantly with adiponectin (r = -0.306). In addition, adiponectin correlated with TG (r = -0.277) and leptin (r = -0.381). Leptin was positively related to body mass (r = 0.261), and BMI (r = 0.274) from anthropometrical parameters and body fat% (r = 0.288) and fat mass (r = 0.298) from body composition variables. No relationships emerged between leptin and blood lipids. We found that there are some significant relationships between adiponectin, leptin and anthropometrical and body composition parameters in physically active postmenopausal females. From blood lipids, only TG correlated significantly with adiponectin.

Relationships between contraction properties of knee extensor muscles and fasting IGF-1 and adipocytokines in physically active postmenopausal women.

The aim of this cross-sectional study was to find possible relationships between insulin-like growth factor-1 (IGF-1), adipocytokines (leptin and adiponectin) and twitch contraction (TC) characteristics of the knee extensor (KE) muscles in healthy physically active postmenopausal women (n = 28, 64-78 years old). We hypothesized that IGF-1 is related at least to isometric TC peak torque (Pt) as the highest value of isometric torque production and maximal voluntary contraction (MVC) torque, and there will not be any relationships between TC characteristics and leptin and adiponectin. During the measurement of MVC torque and twitch contractile properties of KE muscles, the subjects sat in a custom-made dynamometric chair with the knee and hip angles equal to 90 degrees and 100 degrees, respectively. To assess the contractile properties of the KE muscles, electrically evoked isometric twitch was elicited by percutaneous electrical nerve stimulation. Serum leptin, adiponectin, IGF-1, insulin-like growth factor-binding protein-3 (IGFBP-3) and insulin were determined. There were a very few significant relationships between the measured muscle contractile parameters and fasting blood hormones. TC Pt correlated significantly with IGFBP-3 (r = 0.652, P = 0.001) and insulin (r = 0.495, P = 0.007). In conclusion, this study suggests that only TC peak torque correlated positively with serum fasting IGFBP-3 and insulin concentration. Adipocytokines leptin and adiponectin not correlated significantly with measured strength parameters in physically active postmenopausal women.

Plasma adiponectin concentration is associated with the average accelerometer daily steps counts in healthy elderly females.

This study is aimed to evaluate whether circulating adiponectin concentration is associated with physical activity (PA) level in healthy older females. To date, daily PA in older adults (> or = 65 years) has primarily relied on self-report. This study used accelerometry, which objectively measured minute-by-minute movement to assess PA volume and intensity performed by elderly females. In addition, body composition, leptin and insulin resistance values were measured to assess the influence of these parameters on the possible relationship between adiponectin and PA levels in this specific age group of older women. On 49 women (mean age: 73.6 +/- 4.2 years), adiponectin, leptin, insulin resistance, body composition and 7-day PA parameters were measured. Average daily accelerometer step counts and time spent in different PA levels were obtained from 7-day PA measurement. Average daily accelerometer step-count was 7,722 +/- 3,069 steps day(-1) and the recommended 150 min weekly of at least moderate/vigorous PA in bouts of at least 10 min was achieved by 71.4% (35/49) of the participants. Correlation analysis showed that plasma adiponectin concentration (16.0 +/- 6.1 microg ml(-1) ) was related (P < 0.001) to steps per day (r = 0.438) and leptin (r = -0.443) values. Multivariate regression analysis further revealed that only steps per day and leptin were independent predictors of circulating adiponectin concentration in healthy elderly females. In conclusion, these data support the hypothesis that being physically active is associated with better adiponectin concentration and a reduced risk of having metabolic disease risk in the specific group of healthy elderly females.

Plasma ghrelin concentration is a signal of decreased fat free mass in healthy elderly females.

This study aimed to evaluate whether circulating ghrelin is associated with changes in different body composition parameters over a 12-month prospective study period in healthy older females. On 41 postmenopausal women (mean age: 71.0 +/- 6.5 years), ghrelin, leptin, insulin resistance (IR), and body composition parameters were assessed before and after the study period. Trunk fat: leg fat ratio (+3.6%), fat free mass (FFM) (-4.1%), glucose (+5.8%), and IR (+7.0%) were significantly changed (P < 0.05), whereas no changes in height, body mass, body mass index, fat mass (FM), %FM, trunk fat, leptin, ghrelin, and insulin were observed as a result of study period. At baseline, ghrelin correlated negatively (r > -0.306; P < 0.05) with body mass, FM, %FM, trunk fat, FFM, leptin, insulin, and IR. Multivariate linear regression analysis demonstrated that baseline ghrelin concentration was significantly associated only with the mean change in FFM value over the 12-month study period. In conclusion, basal ghrelin concentration predicted the loss of FFM in healthy elderly females. In addition, these results suggest that circulating ghrelin concentration could be regarded as a signal of decreased FFM in healthy elderly females.

Adipocytokine and ghrelin levels in relation to bone mineral density in physically active older women: longitudinal associations.

PURPOSE: We investigated the relationship between the decrease in bone mineral mass (BMC) and bone mineral density (BMD) values with baseline adipocytokine and ghrelin concentrations in physically active postmenopausal women. METHODS: Leptin, adiponectin, ghrelin, BMC, BMD and different body composition values were measured in 35 women (age: 69.7+/-6.0 years) before and after a 12-month prospective study period. RESULTS: Significant (P<0.05) decreases in fat-free mass (FFM) (by 2.56%) and BMC (by 1.63%) and increases in adiponectin (by 14.8%) were seen in older females as a result of the study period. The independent variables that were associated with decreases in total BMC were baseline fat mass (FM) and adiponectin explaining 30.6% (R(2)x100) of the total variance. In another model, baseline FFM and leptin were the independent variables that explained 20.6% (P<0.05) of the total variance in the decreases in total BMD value. The variables that were associated with decreases in femoral neck BMD were FM and leptin (R(2)=0.102; P<0.05), while the independent variables were baseline trunk fat:leg fat ratio and adiponectin in the model with decreases in lumbar spine BMD as the dependent variable, and accounted for 13.1% (P<0.05) of the decreases in BMD variance. CONCLUSIONS: Initial adiponectin concentration together with specific body composition characteristics predicted loss in BMC and lumbar spine BMD values, while initial leptin concentration together with specific body composition parameters determined the loss in total and femoral neck BMD values in physically active older women.

The influence of ghrelin, adiponectin, and leptin on bone mineral density in healthy postmenopausal women.

The association of body fat mass (FM) with bone mineral mass (BMC) and bone mineral density (BMD) has been attributed to a mechanical load exerted on the skeleton by FM and by the effect of different hormones. The aim of the present study was to determine whether there is a relationship between ghrelin, adiponectin, and leptin with BMC and BMD in healthy postmenopausal women (n = 88; age, 68.9 +/- 6.8 years; body mass index, 27.4 +/- 3.6 kg/m(2)). Body composition, BMC, and BMD were derived by dual-energy X-ray absorptiometry. Waist-to-hip (WHR) and waist-to-thigh (WTR) ratios were also obtained. Ghrelin was associated with total BMC (beta = -0.945; P = 0.0001), total BMD (beta = -0.959; P = 0.0001), lumbar spine BMD (beta = -0.945; P = 0.0001), and femoral neck BMD (beta = -0.957; P = 0.0001), and remained associated (P < 0.041) in different analyses that controlled for measured body composition and hormonal and insulin resistance values. However, the associations between ghrelin and measured bone mineral values were no longer significant (P > 0.149) when adjusted for body fat distribution values (WHR, WTR). Adiponectin was significantly related to total BMC (beta = -0.931; P = 0.0001), total BMD (beta = -0.940; P = 0.0001), lumbar spine BMD (beta = -0.937; P = 0.0001), and femoral neck BMD (beta = -0.940; P = 0.0001) values, and these relationships remained significant (P < 0.019) after adjusting for measured body fat, hormonal, and insulin resistance values but not when adjusted for fat-free mass (FFM; P > 0.106). In addition, significant associations of leptin with total BMC (beta = 0.912; P = 0.0001), total BMD (beta = 0.907; P = 0.0001), lumbar spine BMD (beta = 0.899; P = 0.0001), and femoral neck BMD (beta = 0.906; P = 0.0001) were found. These associations remained significant (P < 0.010) in different analyses that controlled for hormonal and insulin resistance values, but the associations between leptin and bone mineral values were no longer significant (P > 0.145) when adjusted for specific body composition values (WHR, WTR, FM, and FFM). In conclusion, it appears that the influence of plasma ghrelin, adiponectin, and leptin levels on BMC and BMD values is mediated or confounded by the specific body composition parameters in healthy postmenopausal women.