The rating of perceived exertion predicts intermittent vertical jump demand and performance

The aims of this study were (a) to assess the ability of the rating of perceived exertion (RPE) to predict performance (i.e. number of vertical jumps performed to a fixed jump height) of an intermittent vertical jump exercise, and (b) to determine the ability of RPE to describe the physiological demand of such exercise. Eight healthy men performed intermittent vertical jumps with rest periods of 4, 5, and 6s until fatigue. Heart rate and RPE were recorded every five jumps throughout the sessions. The number of vertical jumps performed was also recorded. Random coefficient growth curve analysis identified relationships between the number of vertical jumps and both RPE and heart rate for which there were similar slopes. In addition, there were no differences between individual slopes and the mean slope for either RPE or heart rate. Moreover, RPE and number of jumps were highly correlated throughout all sessions (r=0.97-0.99; P0.001), as were RPE and heart rate (r=0.93-0.97; P0.001). The findings suggest that RPE can both predict the performance of intermittent vertical jump exercise and describe the physiological demands of such exercise.

Evaluation of an Innovative Critical Power Model in Intermittent Vertical Jump

The aim of this study was to test if the critical power model can be used to determine the critical rest interval (CRI) between vertical jumps. Ten males performed intermittent countermovement jumps on a force platform with different resting periods (4.1 +/- 0.3 s, 5.0 +/- 0.4 s, 5.9 +/- 0.6 s). Jump trials were interrupted when participants could no longer maintain 95% of their maximal jump height. After interruption, number of jumps, total exercise duration and total external work were computed. Time to exhaustion (s) and total external work (J) were used to solve the equation Work = a + b . time. The CRI (corresponding to the shortest resting interval that allowed jump height to be maintained for a long time without fatigue) was determined dividing the average external work needed to jump at a fixed height (J) by b parameter (J/s). in the final session, participants jumped at their calculated CRI. A high coefficient of determination (0.995 +/- 0.007) and the CRI (7.5 +/- 1.6 s) were obtained. In addition, the longer the resting period, the greater the number of jumps (44 13, 71 28, 105 30, 169 53 jumps; p<0.0001), time to exhaustion (179 +/- 50, 351 +/- 120, 610 +/- 141, 1,282 +/- 417 s; p<0.0001) and total external work (28.0 +/- 8.3, 45.0 +/- 16.6, 67.6 +/- 17.8, 111.9 +/- 34.6 kJ; p<0.0001). Therefore, the critical power model may be an alternative approach to determine the CRI during intermittent vertical jumps.

Does muscle imbalance affect fatigue after soccer specific intermittent protocol?

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

Muscle protein metabolism in neonatal alloxan-administered rats: effects of continuous and intermittent swimming training

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

Fracture resistance of endodontically treated teeth with different heights of crown ferrule restored with prefabricated carbon fiber post and composite resin core by intermittent loading

This study evaluated the fracture resistance of endodontically treated teeth restored with prefabricated carbon fiber posts and varying quantities of coronal dentin. Sixty freshly extracted upper canines were randomly divided into groups of 10 teeth each. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis. Data were analyzed by 1-way analysis of variance and Tukey test (alpha = .05). Significant differences (P < .001) were found among the mean fracture forces of the test groups (positive control, 0 mm, 1 mm, 2 mm, 3 mm, and negative control groups: 1022.82 N, 1008.22 N, 1292.52 N, 1289.19 N, 1255.38 N, and 1582.11, respectively). These results suggested that the amount of coronal dentin did not significantly increase the fracture resistance of endodontically treated teeth restored with prefabricated carbon fiber post and composite resin core. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:e52-e57)

FUNCTIONAL AND ULTRASTRUCTURAL EVALUATION OF MYOCARDIAL PROTECTION PROVIDED BY INTERMITTENT CORONARY SINUS PERFUSION IN THE ISOLATED DOG HEART

1. The protection offered by intermittent perfusion of of cardioplegic solution through the coronary sinus was investigated in isovolumic blood-perfused dog heart preparations submitted to 60 min of ischemia and 45 min of reperfusion.2. The preparations were divided into three treatment groups: a) coronary sinus, consisting of preparations (N = 10) perfused through the coronary sinus under 40 cm water pressure; b) aortic, consisting of preparations (N = 10) perfused through the aortic stump under 100 mmHg pressure; c) control, consisting of hearts (N = 9) that were not perfused with cardioplegic solution.3. Properties of contractile capacity and relaxation were markedly impaired in the control group but were preserved to a comparable extent in the groups perfused with cardioplegic solution through the aorta and coronary sinus. Developed pressure decreased in the control group (before ischemia: 70 +/- 5.5 mmHg; after reperfusion: 35 +/- 12 mmHg; P < 0.05) and didn't vary in the aortic group (from 69 +/- 4 mmHg to 65 +/- 13 mmHg; P > 0.05) and coronary sinus group (from 69 +/- 4.6 mmHg to 60 +/- 10 mmHg; P > 0.05). Myocardial relaxation was evaluated by the +/- dp/dt ratio. In the control group there was impairment of myocardial relaxation as indicated by an increase of this index after reperfusion (from 1.05 +/- 0.05 to 1.46 +/- 0.23; P < 0.05), whereas in the aortic (from 1.10 +/- 0.13 to 1.15 +/- 0.20; P > 0.05) and the coronary sinus (from 1.03 +/- 0.14 to 1.08 +/- 0.16; P > 0.05) groups there was no variation. Ultrastructural changes in the myocardium were negligible in all three groups at the end of reperfusion.4. We conclude that intermittent perfusion of a hypothermic cardioplegic solution through the coronary sinus is effective for the protection of the myocardium during total ischemia.

Effects of recovery type after a judo combat on blood lactate removal and on performance in an intermittent anaerobic task

Aim. The objective of this study was to verify the effects of active (AR) and passive recovery (PR) after a judo match on blood lactate removal and on performance in an anaerobic intermittent task (4 bouts of upper body Wingate tests with 3-min interval between bouts; 4WT).Methods. The sample was constituted by 17 male judo players of different competitive levels: A) National (Brazil) and International medallists (n. 5). B) State (São Paulo) medallists (n. 7). Q City (São Paulo) medallists (n. 5). The subjects were submitted to: 1) a treadmill test for determination of VO2peak and velocity at anaerobic threshold (VAT); 2) body composition; 3) a 5-min judo combat, 15-min of AR or PR followed by 4WT.Results. The groups did not differ with respect to: body weight, VO2peak, VAT, body fat percentage, blood lactate after combats. No difference was observed in performance between AR and PR, despite a lower blood lactate after combat (10 and 15 min) during AR compared to PR. Groups A and B performed better in the high-intensity intermittent exercise compared to athletes with lower competitive level (C).Conclusion. The ability to maintain power output during intermittent anaerobic exercises can discriminate properly judo players of different levels. Lactate removal was improved with AR when compared to PR but AR did not improve performance in a subsequent intermittent anaerobic exercise.

Reversible intermittent flow-injection determination of mercury in sediments and vinasses by cold vapor atomic absorption spectrometry

A reversible intermittent pow-injection procedure is proposed for the automated determination of mercury in sediments and vinasses by cold vapor atomic absorption spectrometry, CVAAS. Solutions of sample and stannous chloride are carried by two air streams and sequentially injected into the generator/separator chamber in a segmented asynchronous merging zone configuration. The intermittent flow in the forward direction carries the mercury vapor through the flow cell, and in the backward direction, if aspirates the the remaining solution from the vessel to waste. We investigated composition and concentration of reagents, pow rates, commutation times, reactor configuration, and conditions for mercury release. The accuracy was checked by mercury determination in a certified sediment and spiked vinasses and river waters. The system handles about 100 samples per hour (0.50-5.00 mu g L-1), consuming ca. 2.5 mL of sample and 50 mg of SnCl2 per determination; Good recoveries (92-103%) were obtained with spiked samples. Results are precise (RSD <3% for 2.5 mu g Hg L-1, n = 12) and in agreement with values for certified reference material at 95% confidence level. (C) 1999 John Wiley & Sons, Inc.

Physicochemical properties of maize starch obtained from intermittent milling and dynamic steeping (IMDS) under various steeping conditions

Physicochemical properties of maize starch obtained under different steeping conditions by intermittent milling and dynamic steeping process (IMDS) were studied. Brazilian dent maize (hybrid XL 606) was milled using a 2x2x3 factorial experimental design with two lactic acid levels (0.0 and 0.55%, v/v), two SO2 levels (0.05 and 0.1%, w/v), and three temperatures (52, 60, and 68degreesC). Properties of starch obtained by conventional wet-milling process (36 hr at 52degreesC, 0.55% lactic acid, and 0.2% SO2) were used for comparison. Starch protein content and solubility increased with presence of lactic acid, while swelling power decreased. Higher SO2 concentration (0.1%) had the same effect as lactic acid on some properties. Steeping temperatures of 60 and 68degreesC increased solubility and most of the thermal properties but reduced swelling power, suggesting stronger starch annealing during IMDS at these temperatures. Some thermal changes on starch granules were visualized by scanning electron microscopy (SEM) at 60 and 68degreesC. Amylose content as well as pasting properties were affected by steeping factors and interactions. Starches from IMDS and conventional wet-milling processes were similar in most properties, indicating that IMDS provides starch with quality similar to that from conventional milling.

Serum Vitamins in Adult Patients With Short Bowel Syndrome Receiving Intermittent Parenteral Nutrition

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

MAXIMAL LACTATE STEADY-STATE INDEPENDENT of RECOVERY PERIOD DURING INTERMITTENT PROTOCOL

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

Stroking Parameters during Continuous and Intermittent Exercise in Regional-Level Competitive Swimmers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Is maximal lactate steady state during intermittent cycling different for active compared with passive recovery?

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

Maize germ recovery and quality using the intermittent milling and dynamic steeping process

The intermittent milling and dynamic steeping (IMDS) process is an alternative method developed for wet milling of maize. In this process, the steeping stage can be reduced to 5 h by soaking maize in water at 60°C for 2 h and cracking the kernels to remove solution components diffusional barriers with minimum germ damage. Maize was dynamically steeped in solutions with 0.0, 0.1, and 0.2% sulphur dioxide (SO2) and 0.00, 0.55% lactic acid. Germ recovery, germ damage, fibre in germ, oil content and uncracked kernels were determined. A conventional steeping procedure was also performed. Germ recovery was higher for all tests using both SO2 and lactic acid than for the others with best germ yield for concentrations of 0.2% SO2 and 0.55% lactic acid. Germ damage ranged from 7.4 to 18.2% for all tests. The presence of lactic acid in the steeping solution decreased the amount of fibre in germ fraction. Germ oil content ranged from 39.3% (0-0% SO2, 0.55% lactic acid) to 44.0% (0.2% SO2, 0.55% lactic acid) for all treatments using IMDS. The smallest difference was 5.5% between IMDS (0.2% SO2, 0.55% lactic acid) and the conventional 36 h steeping process. An average of 1.3% of kernels remained uncracked after IMDS process. © 2002 Silsoe Research Institute. Published by Elsevier Science Ltd. All rights reserved.