, S.V. (2015). Comparison of maximum lactate between course navette test and hoff test in soccer players at 2600 meters above sea level. J. Hum. Sport Exerc., 10(1), pp.104-112. Introduction: Nowadays football (soccer) requires a high aerobic capacity and for its assessment the Test of Course Navette (TCN) has been widely used. However, other tests closer to the current conditions like the Test of Hoff (TH) have also been applied. The study assessed the maximum production of lactate using both tests in similar conditions. Materials and Methods: 17 male soccer players were evaluated twice. One time using the TCN and the other time using the TH. At both times lactate was assessed at rest and at the end of maximum heart rate and lactate. The differences were statistically evaluated by Wilcoxon T and its correlation via a linear regression. Results: The initial lactate values were: TCN 4.9 ± 2.1 mmol/L and TH 4.2 ± 2.4 mmol/L, (p=0.162) Final lactate values: 11.6 ± TCN 3.3 mmol / L and TH 12.4 ± 3.8 mmol/L, (p=0.325), maximum heart rate 193.8 ± 9.3 beats TCN and TH: 188.1 ± 7.6 beats (p <0.05), the maximum speed reached at the TCN compared to the distance achieved by the TH, has a R2=0.55. Conclusion: TH is a test given under conditions closer to those of the game, and it has a strong relation with the TCN in the assessment of the aerobic capacity, without significant differences in the results of maximal lactate.

Heart Rate Variability (HRV) in Frequency‐domain estimate the distribution into low‐frequency (LF: 0.04–0.15 Hz) and high‐frequency (HF 0.15–0.4 Hz) bands. On the other hand, when analyzing norepinephrine and acetylcholine cell signalling time kinetics, the summation of such times once converted to frequencies in Hertz, match the previously mentioned LF and HF values.Materials and MethodsGoogle Scholar databases and National Library of Medicine, were searched for articles published from 2000 to 2019 related to the time kinetics involved in cell signaling, with the following combination of terms: 1) “Title (TI) = (FRET) AND TI = (BRET) OR ‘Activation time B1 adrenergic’ OR ‘Activation time M2 muscarinic’ OR ‘Gs Protein Activation’ OR ‘Gi Protein Activation’ ‘Time Kinetics’ OR ‘Adenylate Cyclase’ ‘Activation HCN4’ OR ‘Nodal Pace Marker’ OR ‘In Vitro Model Cells')]”. The inclusion criteria for each study included the ligand‐receptor interaction and time related signalling cascade involved in the depolarization or hyperpolarization of cells. Both database searches yielded 7 studies matching the inclusion criteria. Once all the times of cell signalling cascade were found or estimated for all receptors, such times were summed, they were converted to Hertz using the inverse relationship between time and frequency.RESULTSDatabase searches yielded 7 studies matching the inclusion criteria. For B1‐Adrenergic Receptor cell signalling cascade the estimated times were: Ligand‐Receptor‐Activation (0.045 s), Receptor Gs protein interaction (0.044 s), Gs protein activation (0.369 s), Adenylate Cyclase activation (28.8s), cAMP mediated activation of HCN4 (0.461 s), for a total of 29.76 seconds, yielding 0.0336 Hz.For M2‐Cholinergic Receptor the estimated times were: Ligand‐Receptor activation (0.750 s), Receptor Gi protein interaction (12 ns**), Gi protein activation (1 s), and Gi mediated Adenylate Cyclase inactivation (3 s), for a total of 4.75 seconds, yielding 0.211 Hz.DISCUSSIONB1‐Adrenergic Receptor cell signaling summed 29.76 seconds, yielding 0.0336 Hertz, a very close value to the 0.04 Hz of LF band. On the other hand, M2 Cholinergic receptor cell signalling time was 4.75 s, yielding 0.211 Hz, a value within the HF band range of 0.15 to 0.4 Hz. Such results coincide with the possibility of direct correlation of biochemical cell signalling and HF and LF bands spectrums. However due to the scarcity of biochemical studies, it is important to mention that during the estimation process there was two issues worth mentioning. First, B1 Adrenergic Receptor Gs Adenylate cyclase activation was roughly estimated. Second, for M2 Cholinergic Gi mediated AC inhibition, a A2‐Adrenergic receptor model was used. Despite the previously mentioned limitations, the current study results suggest the possibility that LF and HF band spectrum could be refined into smaller range of Hertz segments, which might correspond to the summation of time kinetics involved in cell signalling cascade related to the different adrenergic or cholinergic receptor subtypes.Support or Funding InformationPROSEIMThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The paper presents a whole-body bio-energetic model of a cyclist which includes the mechanical dynamics of the bike. This model could be used to solve control-design problems for pedelec systems. The behavior of some physiological variables during cycling is reproduced by keeping an energy aware transfer flow. The modeling approach considers three main levels: i) physiological, ii) bio-mechanical and iii) pure-mechanical. Physical laws of energy/mass conservation were applied to simulate the ways in which energy is stored, transferred and dissipated at each level. A simulation example shows a scenario of a physiological test.

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El propósito de este trabajo es analizar el comportamiento autonómico mediado por la respuesta barorreceptora a una maniobra ortostática (MO) en sujetos hipertensos y no hipertensos. La frecuencia cardiaca (FC) fue obtenida en 65 sujetos (32 hipertensos y 33 no hipertensos) usando un monitor polar de frecuencia cardíaca, antes y después de una MO (al ponerse de pie súbitamente). Los intervalos R-R fueron transformados en series temporales (ST) de frecuencia cardíaca. Se aplicó interpolación debido a una falta de periodicidad en la ST de FC. Un muestreo de 10 Hz fue realizado, adicionalmente un filtro pasa banda seguida de un sub muestreo a 1 Hz. Los resultados mostraron un incremento en la actividad simpática del grupo hipertenso, lo cual no ocurrió en el grupo no hipertenso luego de la MO (Δ%=59.84%, P<0.01). En cuanto a los resultados parasimpáticos se observaron disminuciones solamente en el grupo hipertenso y no en el grupo no hipertenso luego de la intervención ortostática (Δ%= -43.4%, P<0.001). Se observaron incrementos en ambos grupos para el balance simpático vagal (hipertensos: Δ%= 45.63%, p= 0.004; no hipertensos: Δ%= 67.08%, p= 0.013). Los resultados mostraron un incremento en la actividad simpática en contraste con una disminución de la respuesta parasimpática en individuos hipertensos luego de una MO.