Statistical analysis After sphericity assumption was verified with the Mauchly test, a repeated measures analysis of variance was performed to detect the exercise and intensity effects in RPE and its interaction. Linear regressions were used to investigate the precision of EC prediction as a function of RPE. The standard error of the regression (Sy.x) was used a measure Nutlin 3a of the goodness of the fit. Data analysis was performed with the SPSS 16.0 (SPSS Science, Chicago, USA) and the graphics designed with Sigma Plot 10.0 (SPSS Science, Chicago, USA). Data are presented as means and standard deviations. A minimum level of significance of P �� 0.05 was adopted. Results The loads that were used in each exercise and the duration of each bout are presented in Table 1.
When assessing the variations in RPE (see values also in Table 1) according to the four exercises and to the different loads, a general effect was identified for both independent variables. The RPE increased significantly with the exercise intensity (P=0,000; ��2=0.83) with an exception of the comparison between the first two bouts (12% vs. 16%). There were no significant differences between RPE in half squat and in bench press. The RPE during triceps extension was significantly higher compared to every other exercise and the RPE during Lat pull down was significantly lower when compared with every other exercise. Simple linear regressions were established to estimate the EC using RPE (Figure 2).Significant (p< 0,05) regression equations were noted for the bench press, triceps extension and lat pull down.
The linear regression that was obtained for the Half squat was not significant Figure 2 Simple regression analysis between energy cost (EC) and rate of perceived exertion (RPE): Lat Pull down (A), Bench Press (B) and Triceps Extension (C). Discussion The aim of the present study was to assess the accuracy of equations based on RPE obtained using the OMNI-RES to predict energy cost (EC) during low intensity resistance exercise (RE).The main finding of the present study was that EC can be accurately predicted from RPE during low intensity lat pull down, bench press and triceps extension in recreational body builders. Our results suggest that the accuracy of the prediction model based upon the half squat is not acceptable.
Generally, the RPE tended to be higher during triceps extension as compared with the remaining three exercises that were used in the present study. These results suggest that single-joint exercises result higher RPE than multiple joint exercises. This finding is consistent with Lagally et al. (2002b) who assessed RPE at intensities of 30 and 90% of 1RM in seven different exercises (both single-joint and multi-joint). Smolander et al. (1998), reported Anacetrapib similar differences in RPE in both young and old subjects performing single and multiple joint exercises. According to Hetzler et al.
The subjects were fitted with a chest HR transmitter and wrist monitor recorder. HR was recorded, from the beginning of the session, using individual Polar RS400 (Polar? Vantage selleck chemical MEK162 NV, Polar Electro Oy, Finland), and subsequently exported and analyzed using the Polar Pro-Trainer? software program (Polar Electro Oy, Finland). The subjects could not see their HR measurements during the experimental trial, because it could influence their perceived effort on the Borg and OMNI RPE scales. For this reason, a sticker was placed on each HR monitor. The experimental trial was divided into four stages: a warm-up (10 minutes in a seated position, with a cadence of 90�C100 RPM (revolutions per minute)), a main phase (35 minutes, where the subjects alternated between normal seated positions and seated and standing climb cycling, between 60�C80 RPM in climb techniques and between 80 �C 110 RPM in normal seated cycling).
Then, a cool down (5 minutes, with a cadence of 80�C100 RPM) in a seated position and, finally, stretching exercises, of the principal muscles used in the session off cycling. During the experimental trial, HR was recorded every 5 s. The participants were instructed to follow the directions of a qualified indoor cycling instructor, which included recommended frequencies of pedalling (RPM) in each phase of the session and recommended cycle resistance. The instructor provided feedback to help the subjects to regulate their intensity. Although the resistance of the cycle could be freely changed by the participants during the session, the study subjects had to follow the instructions about the resistance and the RPM indicated by the instructor.
The Borg 6�C20 RPE and the OMNI 0�C10 scales were used to assess perceived exertion. The RPE is a 15-point single-item scale ranging from 6 to 20, with anchors ranging from 6 ��No exertion�� to 20 ��Maximum exertion��. The OMNI 0�C10 scale has a category rating format that contains both pictorial and verbal descriptors positioned along a comparatively narrow numerical response range, 0�C10. Each pictorial descriptor is consistent with its corresponding verbal descriptor, from 0 ��Extremely easy�� to 10 ��Extremely hard��. Both RPE scales were positioned within sight in the indoor cycling room. The subjects were instructed to give an overall perception about how hard the exercise felt according to both RPE scales every five minutes, from the start to the end of the indoor cycling session.
These values were written on a record sheet which the subjects had on their handlebars. Before the measurements, subjects were asked to read instructions on how to use these scales. A familiarization period of two weeks (and a minimum of 3 sessions per week) prior Carfilzomib to the experimental trial was carried out to accustom the participants with the Borg and the OMNI RPE scales. The first session consisted of familiarization to the RPE scales.
The warm-up procedures (dry and in-water) consisted of their typical Paclitaxel microtubule warm-up frequently performed before a competitive swimming event (total volume: 1000 m). After 10 min rest, the tethered swimming protocol was implemented. One day after, the same protocol was repeated, but without warming up. The swimmers were wearing a belt attached to a steel cable (negligible elasticity). As the force vector in the tethered system presented a small angle to the horizontal, computing the horizontal component of force, data was corrected. A load-cell system connected to the cable was used as a measuring device, recording at 100 Hz with a measure capacity of 5000 N. The data obtained was transferred by a Globus Ergometer data acquisition system (Globus, Italy) that exported the data in ASCII format to a computer.
Individual force to time F (t) curves were assessed and registered to obtain maximum force (Fmax, the highest value of force produced in first 10 s) absolute and relative values and; mean force (Fmean �C average force values during the 30s test) absolute and relative values. The test started after an acoustic signal, with the swimmers in a horizontal position, with the cable fully extended. The data collection started after the first stroke cycle to avoid the inertial effect of the cable extension after the first propulsion. The swimmers swam as natural as possible during 30 s, at maximum intensity. Additionally, capillary blood samples were collected from the fingertip before and after each tethered swimming (at the 1st and 3rd min of recovery) to access the higher values of blood lactate concentration ([La-]) (Accutrend Lactate?Roche, Germany).
The values of [La-]net were determined by the difference between [La-] after the test and the resting values. The Borg (1998) ratings of perceived exertion (RPE) scale was used to quantify exercise level of exertion after each test. Statistics Standard statistical methods were used for calculation of means and standard deviations. Normality was determined by Shapiro-Wilk test. Since, the very low value of the N (i.e., N < 30) and the rejection of the null hypothesis (H0) in the normality assessment, non-parametric procedures were adopted. In order to compare the data obtained with and without warm-up, non-parametric Wilcoxon signed rank test was used. Differences were considered significant for p �� 0.05.
Results Table 1 presents the mean �� SD values for the tethered absolute variables, namely the maximum force and mean force. Significant differences were evident for the data obtained on tethered front crawl swimming test after warm-up and without warm-up. The warm-up condition presented higher values. GSK-3 Table 1 Mean �� SD values of maximum (Fmax) and mean forces (Fmean) exerted during the tethered swimming test. P-values are presented Figure 1 presents relative values of the maximum and mean forces in both conditions.
COP-AV is assumed to decrease with Imatinib supplier improved balance ability (Winter, 1990). The children completed the PAQ-C (Crocker et al., 1997), a physical activity (PA) level questionnaire designed to quantify their daily activity level, which is a guided self-administered 7-day recall measure for children. It provides a summary PA score derived from nine items, each scored on a 5-point scale. A score of 5 indicates high PA level, whereas a score of 1 indicates low PA. The PAQ-C has been suggested as one of the most reliable and valid self-administered recall instruments (Crocker et al., 1997). Data are described as means ��SD. An independent sample t-test was used to examine the gender difference in postural stability parameters, whereas one-way ANOVA was used to examine the differences between conditions.
Effect sizes (Cohen��s d) were calculated to determine the practical difference between girls and boys. Effect size values of 0�C0.19, 0.20�C0.49, 0.50�C0.79 and 0.8 and above were considered to represent trivial, small, medium and large differences, respectively (Cohen, 1988). Pearson product moment correlation coefficient was used to assess the relationship between COP parameters and other variables. The magnitude of the correlations was determined using the modified scale by Hopkins (2000): trivial: r < 0.1; low: 0.1�C0.3; moderate: 0.3�C0.5; high: 0.5�C0.7; very high: 0.7�C0.9; nearly perfect > 0.9; and perfect: 1. Significance level was defined as p < 0.05. Results Significant gender differences (p < 0.05) were observed in COP-PV, COP-RD and COP-AV when the three conditions were pooled (Table 1).
Specifically, boys had significantly higher COPPV (p < 0.05, medium effect), longer COP-RD (p < 0.05, medium effect), and higher COP-AV (p < 0.05, medium effect), as compared to girls. Furthermore, COP-RD (p < 0.05, large effect) and COP-AV (p < 0.05, large effect) were significantly different between genders in CONTROL condition (Table 1), indicating the sensitivity of these two parameters in differentiating postural stability between genders in this age group. Table 1 Gender difference in postural stability performance and percentage change from CONTROL in postural stability performance for girls and boys with effect sizes, effect size magnitudes and 95% confidence intervals The data in Table 1 include the analysis of the percentage change from the CONTROL condition and these data are presented in Figure 1.
While there were no significant gender differences in the percentage change in COP-PV for either ECHB or EOCS, there was a significant gender difference (p > 0.05) in COP-RD for the ECHB condition with a medium gender effect for EOCS. There were medium gender effects in COP-AV Batimastat in both ECHB and EOCS conditions. Figure 1 Percentage change (with reference to CONTROL) in postural stability performance for boys and girls (* indicate significant gender difference: p<0.
6). Figure 6. B-line reproduction by hydration of gelatin samples using different controlled water PD 0332991 volumes. One 10 ��L drop (A) and two drops (B) spaced about 1 cm apart. Materials and Methods Materials All materials were purchased from Sigma-Aldrich. A 5% w/v gelatin solution was prepared by dissolving gelatin (Type A) in deionized water dH2O stirring the solution for 1 h at 50��C. A batch cross-linking solution of glutaraldehyde (GTA) in water was prepared with a concentration of 0.1 M and used for sequential dilution. A 40% v/v ethanol: dH2O solution was used to rinse samples. Preparation of porous gelatin matrices Gelatin sponges were prepared to evaluate the porosity and mechanical properties as functions of cross-linking conditions as well as to recreate B-lines in an in vitro model.
In particular, the preparation method was divided into two steps. In the first step gelatin was cross-linked using GTA with different concentration (nominated GC); then, in order to obtain a porous matrix, a freeze-drying process was used as described by Lien et al.17 Briefly GTA was added to a 5% w/v gelatin solution to obtain a final volume of 1 mL and 0.1, 1 and 10 mM GC scaffolds were fabricated. The scaffolds were kept in a plastic tube (internal diameter 12 mm) at 25��C for 12 h, until the cross-link reaction had occurred. Two cooling steps were used to freeze the samples; the first step in a refrigerator at 4��C for 6 h and then the second step in a -20��C freezer over-night. Finally samples were freeze-dried (-50��C, 150 mBar) until all water content was removed.
Measurement of swelling ratio The water absorption capability of porous gelatin structures was determined by immersing freeze-dried samples in water for 1, 24 and 48 h. The swelling ratio was calculated according the following equation (Eq. 1): In which Wd is the air-dried scaffold weight and Ww is the weight of the wet scaffold.10 Porosity evaluation The porosity was evaluated by imbibition method and was assumed as the gelatin volume fraction in the swollen samples (). Through the water saturation, pore volume was evaluated by weighing swollen and dried samples. The gelatin volume fraction was calculated according to Equation 2:18,19 in which W0 is the dry weight of the sample, W is the weight of the swollen sample, ��w is the density of the water at RT (room temperature), and �� is the density of the dry gelatin sample.
Pore dimension was evaluated through histological analysis. Samples were embedded and fixed in Tissue-Tek O.C.T. before cryo-sectioning. Horizontal sections of 10 ��m thickness were obtained from the cylindrical scaffolds and then observed with an optical microscope (Olympus IX81, Olympus Italia, 4X objective). Measurement of mechanical properties Compressive mechanical tests were Drug_discovery performed using a twin column testing machine Zwick-Roell Z005 Instron (Zwick Testing Machines, Ltd.).
So, all the temporal variables and the PP from the frequency variables show differences between genders. Considering the performance level, most the differences are not significant (p<0.05). However, in the gender and performance analysis there are only differences between male levels in RMS and PP (p<0.05). Also it is confirmed the existence of two types of frequency spectrums in the front crawl swimming. About the types of frequency spectrums of the acceleration The observation of the spectrum profiles allowed us to concentrate the swimmers into different groups, regarding the number of peaks shown, similar to that of Tella et al. (2008) and Madera et al. (2010) observed in their respective works.
In this study and with the intention of differentiating those spectrums that visually presented smaller variation (type 1), those spectrums with more than one relevant PP regarding the rest of the signal and those with a wide range of frequencies in the PP were considered as type 2. So the type 1 spectrums show only one PP associated to only one frequency. This work confirms that there are different types of frequency spectrums of the acceleration in front crawl swimming. Type 1 and 2 spectrums are common in both genders and performance levels. Regarding the percentage of type 1 spectrums in this study (43.1%) it should be noted the difference with the 27.85%, observed by Madera et al. (2010). The possible cause may be the two instead of three groups that were utilized in that work. The analysis of the spectrum profiles have been done by several authors with the aim of explaining them.
Holm��r(1979) identified the front crawl spectrum with a low SF (PPF<1Hz) and suggested that it represented the propulsive actions of the arms. Furthermore, this author identified several smaller peaks (between 1.5 and 10 Hz) and suggested that these may correspond to the movement of the legs. As it has been used in previous studies, the methodology in this work has reduced the registered accelerations (Madera et al., 2010: 1 to 10Hz; Tella et al., 2008: 1 to 20Hz) to frequencies lower than 1Hz by filtering the signal with a band-pass filter of 1�C10Hz, after considering that the accelerations below 1Hz would represent the global actions of a complete cycle (i.e. bodyroll). Also the accelerations with frequency higher than 10Hz have been reduced, because the spectrums that were found by Tella et al.
(2008) did not show important peaks in those frequencies. Then to preserve only those frequencies of interest for the study, the accelerations whose frequencies were lower Drug_discovery than 1Hz and were higher than 10Hz were reduced to achieve a representation of only the ones that could be related to intra-cycle accelerations. Thus the analyzed spectrums may represent the propulsive actions in front crawl swimming (i.e. arms and legs) with two different types that exist at both genders and performance levels.