Maximal power output during incremental cycling test is dependent on the curvature constant of the power-time relationship

The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.

Exercise tolerance can be enhanced through a change in work rate within the severe intensity domain: work above critical power is not constant

The characterization of the hyperbolic power-time (P-tlim) relationship using a two-parameter model implies that exercise tolerance above the asymptote (Critical Power; CP), i.e. within the severe intensity domain, is determined by the curvature (W') of the relationship. The purposes of this study were (1) to test whether the amount of work above CP (W>CP) remains constant for varied work rate experiments of high volatility change and (2) to ascertain whether W' determines exercise tolerance within the severe intensity domain. Following estimation of CP (208 ± 19 W) and W' (21.4 ± 4.2 kJ), 14 male participants (age: 26 ± 3; peak [Formula: see text]: 3708 ± 389 ml.min-1) performed two experimental trials where the work rate was initially set to exhaust 70% of W' in 3 ('THREE') or 10 minutes ('TEN') before being subsequently dropped to CP plus 10 W. W>CP for TEN (104 ± 22% W') and W' were not significantly different (P>0.05) but lower than W>CP for THREE (119 ± 17% W', P<0.05). For both THREE (r = 0.71, P<0.01) and TEN (r = 0.64, P<0.01), a significant bivariate correlation was found between W' and tlim. W>CP and tlim can be greater than predicted by the P-tlim relationship when a decrement in the work rate of high-volatility is applied. Exercise tolerance can be enhanced through a change in work rate within the severe intensity domain. W>CP is not constant.

Acute mucociliary clearance response to aerobic exercise in smokers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of community-based physical exercise interventions carried out in primary helath care on plasma inflammatory biomarkers and cardiorespiratory fitness

Pós-graduação em Ciências da Motricidade - IBRC

Colombian results of the interlaboratory quality control exercise 2009 2010

Colombian Reference National Laboratory, GENES LTDA, have organized and coordinated for the past two years (2009 and 2010) the Quality Control Exercise for laboratories undertaking paternity, maternity and forensic tests with DNA markers. Twenty-two laboratories have participated in 2009, increasing the number to 27 in 2010. Laboratories in Colombia, Brazil, Ecuador, Peru, Dominican Republic and Panama have participated in these exercises. There have been some similarities in the two controls: A practical exercise, three blood samples on FTA cards were sent to each participating laboratory to be genotyped for DNA markers using the routine methodologies in their laboratories; theoretical exercises including optional and obligatory cases. For the theoretical exercises, the participating laboratories should calculate the partial and final PI or BRI (Biological Relationship Index or Paternity Index). Forty-nine and 52 markers were under consensus for 2009 and 2010, respectively, distributed in autosomal, Y and X chromosomes STR. With respect to 2008, 12 and 15 additional markers were under consensus for 2009 and 2010, respectively. The rate of reporting error was 2.9% in 2009 while in 2010, 4.7% error was reported. The Proficiency Test conducted through the Colombian National Reference Laboratory has become a useful tool for quality assurance of all Colombian laboratories and some of Latin America that do DNA testing to establish biological relationships and an excellent opportunity for ongoing training of experts from the region.

Long-term multimodal exercise program enhances mobility of patients with Parkinson's disease

Objective. This study aimed to evaluate the effect of a long-period multimodal exercise program on balance, mobility and clinical status of patients with Parkinson’s disease (PD). Methods. Thirty-three PD patients were assigned into two groups: a training group (TG—n = 22; aged 67.23 ± 8.39 years) and a control group (CG—n = 9; aged 71.56 ± 8.50 years). The TG patients were enrolled in a 6-month multimodal exercise program. This program was designed to improve physical capacity components and to reduce PD impairments. Balance and mobility were assessed immediately before and after the training protocol using the Berg Balance Scale (BBS), the “Timed up and go” (TUG), and the Posture Locomotion Test (PLM). Also, clinical variables were assessed (disease stage and impairments). Results. The TG showed an improvement in the TUG (P = 0.006) while CG were not influenced by the 6-months period. Both groups showed no differences for BBS and PLM and for their disease impairments—assessed through the Unified Parkinson’s disease Scale. Conclusions. Long-term multimodal exercise programs are able to improve mobility of patients with Parkinson’s disease and therefore should be used on clinical day life.

Do muscle strengthening exercises improve performance in the 6-minute walk test in postmenopausal women?

Background: Walking speed seems to be related to aerobic capacity, lower limb strength, and functional mobility, however it is not clear whether there is a direct relationship between improvement in muscle strength and gait performance in early postmenopausal women. Objective: To evaluate the effect of muscle strengthening exercises on the performance of the 6-minute walk test in women within 5 years of menopause. Methods: The women were randomized into control group (n=31), which performed no exercise, and exercise group (n=27), which performed muscle strengthening exercises. The exercises were performed twice a week for 3 months. The exercise protocol consisted of warm-up, stretching, and strengthening of the quadriceps, hamstring, calf, tibialis anterior, gluteus maximus, and abdominal muscles, followed by relaxation. Muscular strength training started with 60% of 1MR (2 series of 10-15 repetitions), reaching 85% until the end of the 3-month period (4 series of 6 repetitions each). Results: The between-group comparisons pre- and post-intervention did not show any difference in distance walked, heart rate or blood pressure (p>0.05), but showed differences in muscle strength post-intervention, with the exercise group showing greater strength (p<0.05). In the within-group comparison, there were differences in final heart rate and quadriceps and hamstring strength pre- and post-intervention in the exercise group (p<0.05). Conclusion: The results suggest that muscle strengthening of the lower limbs did not improve performance in the 6-minute walk test in this population of postmenopausal women. Trial registration ACTRN12609001053213.

Manipulation effects of prior exercise intensity feedback by the Borg scale during open-loop cycling

Objective To verify the effects of exercise intensity deception by the Borg scale on the ratings of perceived exertion (RPE), heart rate (HR) and performance responses during a constant power output open-loop exercise. Methods Eight healthy men underwent a maximal incremental test on a cycle ergometer to identify the peak power output (PPO) and heart rate deflection point (HRDP). Subsequently, they performed a constant power output trial to exhaustion set at the HRDP intensity, in deception (DEC) and informed (INF) conditions: DEC-subjects were told that they would be cycling at an intensity corresponding to two categories below the RPE quantified at the HRDP; INF-subjects were told that they would cycle at the exact intensity corresponding to the RPE quantified at the HRDP. Results The PPO and power output at the HRDP obtained in maximal incremental tests were 247.5 +/- 32.1 W and 208.1 +/- 27.1 W, respectively. No significant difference in the time to exhaustion was found between DEC (525 +/- 244 s) or INF (499 +/- 224 s) trials. The slope and the first and second measurements of the RPE and HR parameters showed no significant difference between trials. Conclusions Psychophysiological variables such as RPE and HR as well as performance were not affected when exercise intensity was deceptively manipulated via RPE scores. This may suggest that unaltered RPE during exercise is a regulator of performance in this open-loop exercise.

Effectiveness of an exercise program on postural control in frail older adults

Background: Exercise programs have proved to be helpful for frail older adults. This study aimed to investigate the effects of an exercise program with a focus on postural control exercises in frail older adults. Method: Twenty-six older adults (76.7 +/- 4.9 years) deemed clinically stable, chosen from the Falls Unit, University Hospital Mutua Terrassa, Barcelona, Spain, participated in this single-group study. Volunteers' postural control was evaluated using the Timed Up and Go test (TUG) and the Guralnik test battery, and their static and dynamic posturography were evaluated using the Synapsys Posturography System (R). These evaluations were performed before and after the intervention program, which included an educational session and two weekly 1-hour sessions over an 8-week period of stretching exercises, proprioception, balance, and motor coordination. Data were analyzed using the Student's t-test or the Wilcoxon test, with a significance level of 5%. Results: The TUG and Guralnik tests did not show significant differences. Concerning static posturography, there was improvement in the base of support (P = 0.006), anteroposterior displacement with eyes open (P = 0.02) and closed (P = 0.03), and the total amplitude of the center of pressure with eyes closed (P = 0.02). Regarding dynamic posturography, a decrease of the oscillation speed in the anteroposterior direction (P = 0.01) was observed in individuals with their eyes open. Conclusion: The program used in this study was safe and was able to promote some improvement in postural control, especially in the anteroposterior direction and in the base of support. However, it is noteworthy that further improvements could be obtained from a program of longer duration and greater frequency.

Exercise training in juvenile dermatomyositis

Objective. To investigate the effects of a supervised exercise training program on health parameters, physical capacity, and health-related quality of life in patients with mild and chronic juvenile dermatomyositis (DM). Methods. This was a prospective longitudinal study following 10 children with mild and chronic juvenile DM (disease duration >1 year). The exercise program consisted of twice-a-week aerobic and resistance training. At baseline and after the 12-week intervention, we assessed muscle strength and function, aerobic conditioning, body composition, juvenile DM scores, and health-related quality of life. Results. Child self-report and parent proxy-report Pediatric Quality of Life Inventory scores were improved after the intervention (-40.3%; P = 0.001 and -48.2%; P = 0.049, respectively). Importantly, after exercise, the Disease Activity Score was reduced (-26.9%; P = 0.026) and the Childhood Muscle Assessment Scale was improved (+2.5%; P = 0.009), whereas the Manual Muscle Test presented a trend toward statistical significance (+2.2%; P = 0.081). The peak oxygen consumption and time-to-exhaustion were increased by 13.3% (P = 0.001) and 18.2% (P = 0.003), respectively, whereas resting heart rate was decreased by 14.7% (P = 0.006), indicating important cardiovascular adaptations to the exercise program. Upper and lower extremity muscle strength and muscle function were also significantly improved after the exercise training (P < 0.05). Both the whole-body and the lumbar spine bone mineral apparent density were significantly increased after training (1.44%; P = 0.044 and 2.85%; P = 0.008, respectively). Conclusion. We showed for the first time that a 12-week supervised exercise program is safe and can improve muscle strength and function, aerobic conditioning, bone mass, disease activity, and health-related quality of life in patients with active and nonactive mild and chronic juvenile DM with near normal physical function and quality of life.

Sleep desaturation and its relationship to lung function, exercise and quality of life in LAM

Background: Lymphangioleiomyomatosis (LAM) is characterised by progressive airway obstruction and hypoxaemia in young women. Although sleep may trigger hypoxaemia in patients with airway obstruction, it has not been previously investigated in patients with LAM. Methods: Consecutive women with lung biopsy proven LAM and absence of hypoxaemia while awake were evaluated with pulmonary function test, echocardiography, 6-min walk test, overnight full polysomnography, and Short Form 36 health-related quality-of-life questionnaire. Results: Twenty-five patients with (mean +/- SD) age 45 +/- 10 years, SpO(2) awake 95% +/- 2, forced expiratory volume in the first second (median-interquartile) FEV1 (% predicted) 77 (47-90) and carbonic monoxide diffusion capacity, DLCO (%) 55 (34-74) were evaluated. Six-minute walk test distance and minimum SpO(2) (median-interquartile) were, respectively, 447 m (411 -503) and 90% (82-94). Median interquartile apnoea-hypopnoea index was in the normal range 2 (1-5). Fourteen patients (56%) had nocturnal hypoxaemia (10% total sleep time with SpO(2) <90%), and the median sleep time spent with SpO(2) <90% was 136 (13-201) min. Sleep time spent with SpO(2) <90% correlated with the residual volume/total lung capacity ratio (r(s) = 0.5, p: 0.02), DLCO (r(s) = -0.7, p: 0.001), FEV1 (r(s) = -0.6, p: 0.002). Multivariate linear regression model showed that RV/TLC ratio was the most important functional variable related to sleep hypoxaemia. Conclusion: Significant hypoxaemia during sleep is common in LAM patients with normal SpO(2) while awake, especially among those with some degree of hyperinflation in lung function tests. (C) 2011 Published by Elsevier Ltd.

Reliability and construct validity of the karate-specific aerobic test

Chaabene, H, Hachana, Y, Franchini, E, Mkaouer, B, Montassar, M, and Chamari, K. Reliability and construct validity of the karate-specific aerobic test. J Strength Cond Res 26(12): 3454-3460, 2012-The aim of this study was to examine absolute and relative reliabilities and external responsiveness of the Karate-specific aerobic test (KSAT). This study comprised 43 male karatekas, 19 of them participated in the first study to establish test-retest reliability and 40, selected on the bases of their karate experience and level of practice, participated in the second study to identify external responsiveness of the KSAT. The latter group was divided into 2 categories: national-level group (G(n)) and regional-level group (Gr). Analysis showed excellent test-retest reliability of time to exhaustion (TE), with intraclass correlation coefficient ICC(3,1) >0.90, standard error of measurement (SEM) <5%: (3.2%) and mean difference (bias) +/- the 95% limits of agreement: -9.5 +/- 78.8 seconds. There was a significant difference between test-retest session in peak lactate concentration (Peak [La]) (9.12 +/- 2.59 vs. 8.05 +/- 2.67 mmol.L-1; p < 0.05) but not in peak heart rate (HRpeak) and rating of perceived exertion (RPE) (196 +/- 9 vs. 194 +/- 9 b.min(-1) and 7.6 +/- 0.93 vs. 7.8 +/- 1.15; p > 0.05), respectively. National-level karate athletes (1,032 +/- 101 seconds) were better than regional level (841 +/- 134 seconds) on TE performance during KSAT (p < 0.001). Thus, KSAT provided good external responsiveness. The area under the receiver operator characteristics curve was >0.70 (0.86; confidence interval 95%: 0.72-0.95). Significant difference was detected in Peak [La] between national- (6.09 +/- 1.78 mmol.L-1) and regional-level (8.48 +/- 2.63 mmol.L-1) groups, but not in HRpeak (194 +/- 8 vs. 195 +/- 8 b.min(-1)) and RPE (7.57 +/- 1.15 vs. 7.42 +/- 1.1), respectively. The result of this study indicates that KSAT provides excellent absolute and relative reliabilities. The KSAT can effectively distinguish karate athletes of different competitive levels. Thus, the KSAT may be suitable for field assessment of aerobic fitness of karate practitioners.

Effects of acute physical exercise on executive functions: a comparison between aerobic and strength exercise

The aim of this study was to compare the effects of acute aerobic and strength exercises on selected executive functions. A counterbalanced, crossover, randomized trial was performed. Forty-two healthy women were randomly submitted to three different conditions: (1) aerobic exercise, (2) strength exercise, and (3) control condition. Before and after each condition, executive functions were measured by the Stroop Test and the Trail Making Test. Following the aerobic and strength sessions, the time to complete the Stroop "non-color word" and "color word" condition was lower when compared with that of the control session. The performance in the Trail Making Test was unchanged. In conclusion, both acute aerobic and strength exercises improve the executive functions. Nevertheless, this positive effect seems to be task and executive function dependent.

Combined effect of AMPK/PPAR agonists and exercise training in mdx mice functional performance

The present investigation was undertaken to test whether exercise training (ET) associated with AMPK/PPAR agonists (EM) would improve skeletal muscle function in mdx mice. These drugs have the potential to improve oxidative metabolism. This is of particular interest because oxidative muscle fibers are less affected in the course of the disease than glycolitic counterparts. Therefore, a cohort of 34 male congenic C57Bl/10J mdx mice included in this study was randomly assigned into four groups: vehicle solution (V), EM [AICAR (AMPK agonist, 50 mg/Kg-1.day-1, ip) and GW 1516 (PPAR delta agonist, 2.5 mg/Kg-1.day-1, gavage)], ET (voluntary running on activity wheel) and EM+ET. Functional performance (grip meter and rotarod), aerobic capacity (running test), muscle histopathology, serum creatine kinase (CK), levels of ubiquitined proteins, oxidative metabolism protein expression (AMPK, PPAR, myoglobin and SCD) and intracellular calcium handling (DHPR, SERCA and NCX) protein expression were analyzed. Treatments started when the animals were two months old and were maintained for one month. A significant functional improvement (p<0.05) was observed in animals submitted to the combination of ET and EM. CK levels were decreased and the expression of proteins related to oxidative metabolism was increased in this group. There were no differences among the groups in the intracellular calcium handling protein expression. To our knowledge, this is the first study that tested the association of ET with EM in an experimental model of muscular dystrophy. Our results suggest that the association of ET and EM should be further tested as a potential therapeutic approach in muscular dystrophies.

AEROBIC OR RESISTANCE EXERCISE IMPROVES PERFORMANCE IN ACTIVITIES OF DAILY LIVING IN ELDERLY WOMEN

The purpose of this randomized non-controlled study was to determine the effect of an aerobic or resistance exercise protocol on performance of activities of daily living in elderly women. The sample was constituted of 41 apparently healthy elderly women aged 60 to 85 years (x: 65.1 +/- 7.9 years) randomly assigned in resistance exercise (n: 22) or aerobic groups (n: 19). The resistance exercise protocol consisted of three sets of eight to 12 repetitions at 60% of one repetition maximum test for the leg press 45 degrees. The aerobic exercise protocol consisted in cycling in a cycle ergometer during 40 minutes at 60% of reserve heart rate. Both protocols were performed three times per week during five weeks. Activities of daily living were estimated by velocity to stand from sitting to standing position (VSitting), velocity to move from supine to standing position (VSupine), velocity to climb stairs (VCS) and velocity to wear sneakers (VWS). Volunteers of aerobic exercise protocol improved significantly the time to perform VWS (19.1%), while the volunteers of resistance exercise protocol improved the capacity to perform VCS (4.3%) and VSupine (8.9%). These results let us conclude that aerobic as well as resistance exercise protocols induced positive effect on activities of daily living, suggesting that both protocols must be associated for an adequate exercise program to improve the functional capacity of elderly people.