A single bout of downhill running transiently increases HOMA-IR without altering adipokine response in healthy adult women.

PURPOSE: Eccentric exercise-induced muscle damage may cause marked alterations in insulin sensitivity. However, it is not entirely known whether such alterations are also related to changes in adipokine levels. The aim of this study was to investigate the effects of muscle damage due to downhill running on inflammation, insulin sensitivity and selected adipokines related to insulin regulation (adiponectin, visfatin, resistin). METHODS: Data were collected from 12 healthy adult women. Each subject participated in two trials, 4 weeks apart. The first trial was reserved for resting measurements only (control trial), while the second trial involved a 45-min exercise (-15 % slope, ~60 % of VO2max) intervention (exercise trial). Insulin sensitivity (HOMA), creatine kinase activity (CK), delayed onset muscle soreness (DOMS), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), glucose, insulin, adiponectin, resistin, and visfatin were assessed pre-exercise and 1, 2, 3, and 4 days post-exercise and during the same time points in the control trial. RESULTS: Analyses revealed that CK, DOMS, TNF-α, IL-6, insulin and HOMA significantly increased (p < 0.05) throughout recovery (days 1-4). Adiponectin and visfatin remained unchanged, while resistin significantly increased (p < 0.05) only 2 days post-exercise. Visfatin was negatively correlated with HOMA at days 1 and 4 of recovery. CONCLUSION: Although muscle damage due to downhill running caused a decline of insulin sensitivity, this response was not associated with the changes in adipokine levels.

Short-term high-intensity interval exercise training attenuates oxidative stress responses and improves antioxidant status in healthy humans.

This study investigated the changes in oxidative stress biomarkers and antioxidant status indices caused by a 3-week high-intensity interval training (HIT) regimen. Eight physically active males performed three HIT sessions/week over 3 weeks. Each session included four to six 30-s bouts of high-intensity cycling separated by 4 min of recovery. Before training, acute exercise elevated protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC) and creatine kinase (CK), which peaked 24h post-exercise (252 ± 30%, 135 ± 17%, 10 ± 2%, 85 ± 14% and 36 ± 13%, above baseline, respectively; p<0.01), while catalase activity (CAT) peaked 30 min post-exercise (56 ± 18% above baseline; p<0.01). Training attenuated the exercise-induced increase in oxidative stress markers (PC by 13.3 ± 3.7%; TBARS by 7.2 ± 2.7%, p<0.01) and CK activity, despite the fact that total work done was 10.9 ± 3.6% greater in the post- compared with the pre-training exercise test. Training also induced a marked elevation of antioxidant status indices (TAC by 38.4 ± 7.2%; CAT by 26.2 ± 10.1%; GPX by 3.0 ± 0.6%, p<0.01). Short-term HIT attenuates oxidative stress and up-regulates antioxidant activity after only nine training sessions totaling 22 min of high intensity exercise, further supporting its positive effect not only on physical conditioning but also on health promotion.

No adverse effects of statins on muscle function and health-related parameters in the elderly: an exercise study.

The aim of the present study was to investigate the effects of a repeated bout of eccentric exercise on health-related parameters and muscle performance on subjects undergoing atorvastatin therapy. Twenty-eight elderly men participated in the investigation and were assigned either in a control (n = 14) or in a statin therapy group (n = 14). All participants performed two isokinetic eccentric exercise bouts separated by 3 weeks. Muscle damage indices, resting energy expenditure, substrate metabolism, lipid and lipoprotein profile, as well as insulin sensitivity, were evaluated before and after eccentric. No differences in muscle function were observed between the two groups either at rest or after exercise. Eccentric exercise increased resting energy expenditure, increased fat oxidation, improved lipid profile, and increased insulin resistance 2 days after both eccentric exercise bouts. However, these changes appeared to lesser extent after the second bout. No differences were observed in the responses in the health-related parameters in the control and in the statin therapy group. Eccentric exercise affected similarly the control and the atorvastatin-treated individuals. The present results indicate that atorvastatin-treated elderly individuals may participate in various physical activities, even high-intensity muscle-damaging activities, without negative impact on muscle function and adaptation.

The Motor-Proficiency-Test for children between 4 and 6 years of age (MOT 4-6): an investigation of its suitability in Greece.

Given the negative influence of motor difficulties on people's quality of life their early identification seems to be crucial and consequently the information provided by a sound assessment tool is of great importance. The aim of this study was to examine the suitability of the MOT 4-6 (Zimmer & Volkamer, 1987) for use with preschoolers in Greece. Seven hundred and seventy-eight Greek children aged 48-71 months participated in the study. The two-way ANOVA used on total MOT performance revealed significant differences among the age groups formed in preschool age within Greeks, while boys' and girls' scores were quite similar. From the comparisons of Greeks' scores with the German standardization sample's ones, statistically significant differences were found in two age groups. However according to the Cohen's d effect size they were not of great importance. The distribution of Greeks' scores according to the test cut-offs, revealed that the MOT can differentiate all levels of performance, although a slight deviation from the distribution of Germans' scores was noticed. Finally, both the test-retest reliability and internal consistency of the test were found to be excellent. The MOT 4-6 seems to be a valuable motor assessment tool for Greek preschoolers. Regarding its norms, despite the minor differences that were noticed between the motor development of Greek and German preschoolers, their adjustment was thought to be unnecessary. Instead of lowering the norms, efforts for preventing the motor performance decline should be enhanced.

Validity and reliability of the single-trial line drill test of anaerobic power in basketball players.

AIM: This study evaluated the validity, reliability, and sensitivity of the single-trial line drill test (SLDT) for anaerobic power assessment. METHODS: Twenty-four volunteers were assigned to either a control (C, N.=12) or an experimental (BP, N.=12 basketball players) group. SLDT's (time-to-complete) concurrent validity was evaluated against the Wingate testing (WAnT: mean [MP] and peak power [PP]) and a 30-sec vertical jump testing test (VJT: mean height and MP). Blood lactate concentration was measured at rest and immediately post-test. SLDT's reliability [test-retest intraclass correlation coefficients (ICC), coefficient of variation (CV), Bland-Altman plots] and sensitivity were determined (one-way ANOVA). RESULTS: Kendall's tau correlation analysis revealed correlations (P<0.05) between SLDT time and WAnT's PP (=0.78) and MP (=0.56) and VJT's MP (=0.85) and height (=0.90). SLDT lactate concentration was moderately (P<0.05) correlated with the respective lactate values of WAnT (=0.40) and VJT (=0.66). SLDT time in BP correlated (P<0.05) with VJT's MP (=0.80) and height (=0.90) but not with WAnT performance variables. SLDT lactate responses in BP were moderately (P<0.05) correlated with WAnT's PP (=0.54) and VJT MP (=0.68), height (=0.65), and lactate concentration (=0.65). ICCs for time and lactate were 0.92 and 0.93, respectively (P<0.05) although Bland-Altman plots and CV indicate that SLDT time demonstrated greater reliability than lactate responses. In all tests, BP demonstrated higher (P<0.05) performance levels compared to C indicating an adequate sensitivity for SLDT. CONCLUSION: Results suggest that the SLDT appears to be a valid, reliable, and sensitive field test of anaerobic capacity for basketball players.

Effect of rhythmic gymnastics on volumetric bone mineral density and bone geometry in premenarcheal female athletes and controls.

CONTEXT AND OBJECTIVE: Weight-bearing exercise during growth exerts positive effects on the skeleton. Our objective was to test the hypothesis that long-term elite rhythmic gymnastics exerts positive effects on volumetric bone mineral density and geometry and to determine whether exercise-induced bone adaptation is associated with increased periosteal bone formation or medullary contraction using tibial peripheral quantitative computed tomography and bone turnover markers. DESIGN AND SETTING: We conducted a cross-sectional study at a tertiary center. SUBJECTS: We studied 26 elite premenarcheal female rhythmic gymnasts (RG) and 23 female controls, aged 9-13 yr. MAIN OUTCOME MEASURES: We measured bone age, volumetric bone mineral density, bone mineral content (BMC), cortical thickness, cortical and trabecular area, and polar stress strength index (SSIp) by peripheral quantitative computed tomography of the left tibia proximal to the distal metaphysis (trabecular) at 14, 38 (cortical), and 66% (muscle mass) from the distal end and bone turnover markers. RESULTS: The two groups were comparable according to height and chronological and bone age. After weight adjustment, cortical BMC, area, and thickness at 38% were significantly higher in RG (P < 0.005-0.001). Periosteal circumference, SSIp, and muscle area were higher in RG (P < 0.01-0.001). Muscle area was significantly associated with cortical BMC, area, and SSIp, whereas years of training showed positive association with cortical BMC, area, and thickness independent of chronological age. CONCLUSIONS: RG in premenarcheal girls may induce positive adaptations on the skeleton, especially in cortical bone. Increased duration of exercise is associated with a positive response of bone geometry.

Beneficial changes in energy expenditure and lipid profile after eccentric exercise in overweight and lean women.

The aim was to compare lean and overweight females in regard to the effects of eccentric exercise on muscle damage indices, resting energy expenditure (REE) and respiratory quotient (RQ) as well as blood lipid and lipoprotein profile. Lean and overweight females (deviated by their body mass index) performed an eccentric exercise session. Muscle damage, energy cost and lipid profile were assessed pre-exercise and up to 72 h post-exercise. After eccentric exercise (i) muscle damage indices were affected more in the overweight subjects compared with the lean subjects; (ii) the elevation of absolute and relative REE was larger and more prolonged in the overweight group compared with the lean group; (iii) after 24 h, RQ had significantly declined, with the overweight subjects exhibiting a larger reduction compared with the lean group; and (iv) the blood lipid profile was favorably modified, with the overweight group exhibiting more favorable responses compared with the lean group. The differences between the lean and the overweight subjects may be partly due to the fact that overweight individuals experienced greater muscle damage than lean individuals. Eccentric exercise may be a promising lifestyle factor to combat obesity and dyslipidemias.

The effects of acute exercise on serum adiponectin and resistin levels and their relation to insulin sensitivity in overweight males.

The purpose of this study was to investigate the effects of a submaximal aerobic exercise bout on adiponectin and resistin levels as well as insulin sensitivity, until 48 h post-exercise in healthy overweight males. Nine subjects performed an exercise bout at an intensity corresponding to approximately 65% of their maximal oxygen consumption for 45 min. Adiponectin, resistin, cortisol, insulin, glucose and insulin sensitivity were measured prior to exercise, immediately after exercise as well as 24 and 48 h after exercise. Data were analyzed using repeated measures ANOVA while Pearson's correlations were performed to identify possible relationship among the assessed variables. There were no significant differences for adiponectin (microg ml(-1)) [pre, 3.61(0.73); post, 3.15(0.43); 24 h, 3.15(0.81); 48 h, 3.37(0.76)] or resistin (ng ml(-1)) [pre, 0.19(0.03); post, 0.13(0.03); 24 h, 0.23(0.04); 48 h, 0.23(0.03)] across time. Insulin sensitivity increased and insulin concentration decreased significantly only immediately after exercise. Furthermore, no significant correlations were observed among the variables assessed except for the expected between insulin level and insulin sensitivity. These results indicate that a submaximal aerobic workout does not result in significant changes in adiponectin and resistin up to 48 h post-exercise. Furthermore, it appears that adiponectin or resistin is not associated with insulin sensitivity.

Strength training and detraining effects on muscular strength, anaerobic power, and mobility of inactive older men are intensity dependent.

BACKGROUND: Although strength training (ST) enhances physical function in the elderly, little is known about the effect of training intensity on training and detraining adaptations in musculoskeletal fitness. OBJECTIVE: To determine the effect of exercise intensity on strength, anaerobic power, and mobility of older men subjected to a 24 week ST protocol followed by prolonged detraining. METHODS: Fifty two healthy but inactive older men (mean (SD) age 71.2 (4.1) years) were assigned to a control (n = 14), low intensity training (LIST; n = 18; 55% 1RM), or high intensity training (HIST; n = 20; 82% 1RM) group. They carried out a 24 week, whole body (10 exercises, two to three sets/exercise) ST programme followed by a 48 week detraining period. Upper and lower body strength, anaerobic power (Wingate testing), and mobility (timed up and go, walking, climbing stairs) were measured at baseline and immediately after training and during detraining. RESULTS: Although low intensity training improved (p<0.05) strength (42-66%), anaerobic power (10%), and mobility (5-7%), high intensity training elicited greater (p<0.05) gains (63-91% in strength, 17-25% in anaerobic power, 9-14% in mobility). All training induced gains in the LIST group had been abolished after four to eight months of detraining, whereas in the HIST group strength and mobility gains were maintained throughout detraining. However, anaerobic power had returned to baseline levels after four months of detraining in both groups. CONCLUSIONS: Higher intensity training protocols induce greater gains in strength, anaerobic power, and whole body physical function of older men. Moreover, higher intensity training may maintain the gains for more prolonged periods after training ceases.

Leptin and adiponectin responses in overweight inactive elderly following resistance training and detraining are intensity related.

CONTEXT: Adiponectin and leptin are closely related to weight control and energy balance, whereas exercise affects elderly metabolic regulation and functional capacity. OBJECTIVE: The objective of this study was to investigate leptin and adiponectin responses in elderly males after exercise training and detraining. DESIGN: The study design was a 1-yr randomized controlled trial. SETTING: The study was performed at the Laboratory of Physical Education and Sport Science Department. PARTICIPANTS: Fifty inactive men [age, 65-78 yr; body mass index (BMI), 28.7-30.2 kg/m2] were recruited from a volunteer database by word of mouth and fliers sent to medical practitioners, physiotherapists, and nursing homes in the local community. INTERVENTION(S): Participants were randomly assigned to a control (n = 10), low-intensity (n = 14), moderate-intensity (n = 12), or high-intensity training (HI; n = 14) group. Resistance training (6 months, 3 d/wk, 10 exercises/three sets) was followed by 6 months of detraining. MAIN OUTCOME MEASURE(S): Strength, exercise energy cost, skinfold sum, body weight, maximal oxygen consumption, resting metabolic rate (RMR), and plasma leptin and adiponectin were determined at baseline and after training and detraining. RESULTS: Strength, maximal oxygen consumption, RMR, and exercise energy cost increased (P < 0.05) after training in an intensity-dependent manner. Skinfold sum and BMI were reduced by resistance training (P < 0.05), with HI being more effective (P < 0.05) than moderate-intensity/low-intensity training. Leptin was diminished (P < 0.05) by all treatments, whereas adiponectin increased (P < 0.05) only in HI. Detraining maintained training-induced changes only in HI. The percent leptin decrease was associated (P < 0.05) with the percent BMI decrease and the percent RMR increase, whereas the percent adiponectin increase was associated (P < 0.05) with the percent BMI decrease. CONCLUSIONS: Resistance training and detraining may alter leptin and adiponectin responses in an intensity-dependent manner. Leptin and adiponectin changes were strongly associated with RMR and anthropometric changes.

The effects of strength training, cardiovascular training and their combination on flexibility of inactive older adults.

The purpose of this study was to investigate the effects of aerobic training, strength training and their combination on joint range of motion of inactive older individuals. Thirty-two inactive older men (65 - 78 yr) were assigned to one of four groups (n = 8 per group): control (C), strength training (ST), cardiovascular training (CT), and combination of strength and aerobic training (SA). Subjects in the S, A, and SA trained three times a week for 16 weeks. ST included 10 resistance exercises for the major muscle groups at an intensity of 55 - 80% of 1-RM and CT included walking/jogging at 50 - 80 % of maximal heart rate. Body weight and height, physical activity level and maximal oxygen uptake (.VO(2)max) were measured before the training period. Isokinetic (60 and 180 deg x sec(-1)) and concentric strength (1-RM in bench and leg press) were assessed prior to and at the end of the training period. Hip flexion, extension, abduction, and adduction, shoulder extension, flexion, and adduction, knee flexion, elbow flexion and sit-and-reach score were determined before and at 8 and 16 weeks of training. There were no differences between groups in .VO(2)max, body weight, and height (p < 0.05). ST and SA but not CT and C increased isokinetic and concentric strength at the end of the training period (p < 0.05). ST and SA increased significantly (p < 0.05) sit-and-reach performance, elbow flexion, knee flexion, shoulder flexion and extension and hip flexion and extension both at mid- and post-training. CT increased (p < 0.05) only hip flexion and extension at post training. Results indicate that resistance training may be able to increase range of motion of a number of joints of inactive older individuals possibly due to an improvement in muscle strength.

Beta-endorphin infusion during exercise in rats does not alter hepatic or muscle glycogen.

The aim of this study was to determine whether beta-endorphin infusion influences liver or muscle glycogen concentration during exercise. Thirty-two rats (Harlan Co., IN, USA) with a body mass of 265-290 g were assigned at random to four groups, each of eight rats: (1) beta-endorphin infusion for 90 min at rest; (2) beta-endorphin infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade; (3) saline infusion (0.9% NaCl) for 90 min at rest; and (4) saline infusion for 90 min while running on a rodent treadmill at 22 m x min(-1) and 0% grade. Beta-endorphin infusion elevated plasma beta-endorphin concentration by 2.5-fold at rest compared with saline infusion at rest, and by two-fold after exercise compared with saline infusion after exercise. Beta-endorphin infusion attenuated exercise-induced glucose concentration but did not alter the fasting hepatic glycogen concentration at rest or after exercise compared with saline infusion. Fasting hepatic glycogen decreased significantly as a result of 90 min of exercise independent of treatment. Deep intermedius muscle glycogen concentration at rest was similar after 90 min of both beta-endorphin and saline infusion and decreased significantly as a result of 90 min of exercise independent of treatment. Our results suggest that liver and muscle glycogenolysis is not responsible for the differences in plasma glucose with beta-endorphin infusion during exercise.

Beta-endorphin infusion alters pancreatic hormone and glucose levels during exercise in rats.

beta-Endorphin (BE) infusion at rest can influence insulin and glucagon levels and thus may affect glucose availability during exercise. To clarify the effect of BE on levels of insulin, glucagon and glucose during exercise, 72 untrained male Sprague-Dawley rats were infused i.v. with either: (1) BE (bolus 0.05 mg.kg-1 + 0.05 mg.kg-1.h-1, n = 24); (2) naloxone (N, bolus 0.8 mg.kg-1 + 0.4 mg.kg-1, n = 24); or (3) volume-matched saline (S, n = 24). Six rats from each group were killed after 0, 60, 90 or 120 min of running at 22 m.min-1, at 0% gradient. BE infusion resulted in higher plasma glucose levels at 60 min [5.93 (0.32) mM] and 90 min [4,16 (0.29) mM] of exercise compared to S [4.62 (0.27) and 3.41 (0.26 mM] and N [4.97 (0.38) and 3.44 (0.25) mM]. Insulin levels decreased to a greater extent with BE [21.5 (0.9) and 18.3 (0.6) uIU.ml-1] at 60 and 90 min compared to S [24.5 (0.5) and 20.6 (0.6) uIU.ml-1] and N [24.5 (0.4) and 21.6 (0.7) uIU.ml-1] groups. Plasma C-peptide declined to a greater extent at 60 and 90 min of exercise with BE infusion compared to both S and N. BE infusion increased glucagon at all times during exercise compared to S and N. These data suggest that BE infusion during exercise influences plasma glucose by augmenting glucagon levels and attenuating insulin release.