Comparison of lactate measurements from earlobe and fingertip capillary blood using Biosen S-Line and lactate scout analyzers.

PURPOSE: This study aimed to compare variations between the earlobe and fingertip sampling sites in exercises dominated by upper body muscle exertion. It also sought to investigate capillary blood lactate differences between Lactate Scout 4 (LS4) and a bench-top analyzer (Biosen S-Line analyzer, BSL) during Double Poling. METHODS: Blood samples were collected from the earlobe and fingertip immediately before exercise, at the end of each of five stages, and at 1-, 3-, 5-, and 7-min post-exercise. Forty healthy university students participated as volunteers. During the study, they performed double poling on a ski ergometer with progressively increasing load. Lactate levels were measured using both the BSL and LS4 analyzers. RESULTS: Fingertip Bla values were significantly higher than earlobe values, with a mean bias of -0.66 mmol/L, reaching -0.86 mmol/L in the 4-8 mmol/L range. At the earlobe, the highest CCC between BSL and LS4-a was 0.84 (> 8 mmol/L), and for BSL and LS4-b, it was 0.85 (> 8 mmol/L). At the fingertip, the highest CCC between BSL and LS4-c was 0.68 (> 8 mmol/L), and for BSL and LS4-d, it was 0.52 (> 8 mmol/L). Comparing LS4-a and LS4-b at the earlobe, the highest CCC was 0.83 (0-4 mmol/L). At the fingertip, comparing LS4-c and LS4-d, the highest CCC was 0.68 (> 8 mmol/L). CONCLUSIONS: Blood lactate concentrations are higher at the fingertip than the earlobe during SkiErg double poling. The LS4 is less reliable, especially at the fingertip, so using the earlobe with the BSL analyzer is recommended for accurate measurements.

Acute physiological and perceptual responses to moderate intensity cycling with different levels of blood flow restriction.

The aim of this study was to compare: i) the physiological and perceptual responses of low-load exercise [(moderate intensity exercise (MI)] with different levels of blood flow restriction (BFR), and ii) MI with BFR on the bike with high intensity (HI) exercise without BFR. The protocol involved large muscle mass exercise at different levels of BFR, and this differentiates our study from others. Twenty-one moderately trained males (age: 24.6 ± 2.4 years; VO2peak: 47.2 ± 7.0 ml.kg-1.min-1, mean ± sd) performed one maximal graded exercise test and seven 5-min constant-load cycling bouts. Six bouts were at MI [40% peak power (Ppeak), 60%VO2peak], one without BFR and five with different levels of BFR (40%, 50%, 60%, 70%, 80% of estimated arterial occlusion pressure). The HI bout (70%Ppeak, 90%VO2peak) was without BFR. Oxygen uptake (VO2), heart rate (HR), blood lactate (BLa), rate of perceived exertion (RPE), and tissue oxygen saturation (TSI) were recorded. Regardless of pressure, HR, BLa and RPE during MI-BFR were higher compared to MI (p < 0.05, ES: moderate to very large), and TSI reduction was greater in MI-BFR than MI (p < 0.05, ES: moderate to large). The responses of VO2, HR, BLa, RPE and TSI induced by the different levels of BFR in MI-BFR were similar. Regardless of pressure, the responses of VO2, HR, BLa and RPE induced by MI-BFR were lower than HI (p < 0.05), except for TSI. TSI change was similar between MI-BFR and HI. It appears that BFR equal to 40% of arterial occlusion pressure is sufficient to reduce TSI when exercising with a large muscle mass.

[Analysis of the four parameter linear viscoelastic model on prosthetic nucleus and the influence of manufacture on parameters of this model].

The purpose of this study is to characterize the stress relax properties of PVA-H prosthetic nucleus via the four-parameter linear viscoelastic model and to analyze the influence of swelling ratio and initial PVA content upon the properties of dissipating compressive stress. The four-parameter linear viscoelastic model can simulate the viscoelastic property of prosthetic nucleus well (corr > 0.99) and be more effective than the three parameter linear viscoelastic model. From the parameters of this model we have obtained the following results: the prosthetic nucleus of higher water content can dissipate compressive stress more quickly than that of lower water content can do, but the quantity of stress relax can not be influenced by water content; the higher the initial PVA content,the slower and smaller the dissipation of compressive stress;the relax time of prosthetic nucleus is similar to that of human nucleus.

[Swelling characterization of poly (vinyl alcohol) hydrogel for prosthetic intervertebral disc nucleus].

In this study the poly(vinyl alcohol)(PVA) hydrogel elastomer was prepared by freezing-thawing method. The influences of percentage of poly (vinyl alcohol) in hydrogel, pH of solution and swelling temperature upon the swelling characteristic of PVA-hydrogel prosthetic nucleus material were studied. Its micropores were observed using SEM, and the swelling dynamics was further discussed. The experimental results showed that the poly (vinyl alcohol) hydrogel was a kind of network with a lot of micropores, the pore size was related with the PVA content. The maximum swelling ratio decreases when the percentage of PVA in hydrogel, the pH of solution and the swelling temperature were enhanced. The swelling process was described by the equation of swelling dynamics equation. The swelling rate was greatly influenced by the PVA content, the pH of solution and the dimension of hydrogel sample.

[Development of artificial disc nucleus materials (semicrystalline polyvinyl alcohol hydrogel elastomers)].

For the purpose of developing of disc nucleus replacement (semicrystalline PVA hydrogel elastomers) and explorating the possibility of clinical application, in this study,the aqueous PVA solution froze at -20 degrees C for 6-12 h, and then thawed at room temperature for 1-2 h. The same process was repeated 1-3 times. After the specimen was dehydrated in vacuum, a kind of artificial disc nucleus materials (semicrystalline PVA hydrogel elastomers ) was formed. DSC and mechanical tests were conducted to investigate the influence of aqueous PVA solution concentration, of dehydrating in vacuum, and of gamma-ray irradiating upon the degree of crystallity and mechanical properties of PVA hydrogel elastomers.