scholarly journals Non-Invasive Assessment of Inspiratory Ribcage Muscle Fatigue and Recovery During Two Endurance Tests in Healthy Individuals

2021 ◽  
Author(s):  
Thiago Bezerra Wanderley e Lima ◽  
Antonio Sarmento ◽  
Rayane Grayce Silva Vieira ◽  
Esmívany Lhara Freitas Castro ◽  
Francesca Pennati ◽  
...  
Keyword(s):  
Tissue Oxygenation ◽  
Linear Increase ◽  
Inspiratory Pressure ◽  
Median Frequency ◽  
Endurance Test ◽  
Shortening Velocity ◽  
Non Invasive ◽  
Optoelectronic Plethysmography ◽  
Pressure Threshold ◽  
Endurance Tests

Abstract Introduction: Fatigue is defined as a loss in the capacity for developing force and/or velocity of a muscle which is reversible by rest. The aim was to evaluate non-invasively the fatigue and recovery of the inspiratory ribcage muscles during two endurance tests in healthy subjects. Methods: 22 subjects were evaluated before, during and after performing a respiratory endurance test with normocapnic hyperpnea (NH) and inspiratory pressure threshold load (IPTL). Simultaneous measurements of muscle activity (electromyography), tissue oxygenation (NIRS), pressure (nasal inspiratory pressure), and volume (optoelectronic plethysmography) were performed. Results: There was a decrease in the maximum relaxation rate (MRR) and increase in the time constant (τ) after the IPTL test (p <0.05) and a decrease in the peak pressure generated in SNIP after both protocols (p <0.05). Additionally, there was a decrease in shortening velocity and mechanical power only after the IPTL test (p <0.05). The inspiratory ribcage muscles showed a linear drop in the median frequency in the IPTL test and an exponential drop in the NH test, which was not significant for the development of fatigue and there was a linear increase in the NIRS variables in both protocols. Conclusion: It was concluded that the inspiratory ribcage muscles undergo changes after performing an endurance test with NH and IPTL. Additionally, the development of fatigue in these muscles and their consequent changes are more evident in the protocol with IPTL.

scholarly journals Changes in electromyographic activity, mechanical power, and relaxation rates following inspiratory ribcage muscle fatigue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antonio Sarmento ◽  
Guilherme Fregonezi ◽  
Maria Lira ◽  
Layana Marques ◽  
Francesca Pennati ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Low Frequency ◽  
Mechanical Power ◽  
Electromyographic Activity ◽  
Median Frequency ◽  
Relaxation Rates ◽  
Shortening Velocity ◽  
Inspiratory Muscles ◽  
Underlying Mechanisms

AbstractMuscle fatigue is a complex phenomenon enclosing various mechanisms. Despite technological advances, these mechanisms are still not fully understood in vivo. Here, simultaneous measurements of pressure, volume, and ribcage inspiratory muscle activity were performed non-invasively during fatigue (inspiratory threshold valve set at 70% of maximal inspiratory pressure) and recovery to verify if inspiratory ribcage muscle fatigue (1) leads to slowing of contraction and relaxation properties of ribcage muscles and (2) alters median frequency and high-to-low frequency ratio (H/L). During the fatigue protocol, sternocleidomastoid showed the fastest decrease in median frequency and slowest decrease in H/L. Fatigue was also characterized by a reduction in the relative power of the high-frequency and increase of the low-frequency. During recovery, changes in mechanical power were due to changes in shortening velocity with long-lasting reduction in pressure generation, and slowing of relaxation [i.e., tau (τ), half-relaxation time (½RT), and maximum relaxation rate (MRR)] was observed with no significant changes in contractile properties. Recovery of median frequency was faster than H/L, and relaxation rates correlated with shortening velocity and mechanical power of inspiratory ribcage muscles; however, with different time courses. Time constant of the inspiratory ribcage muscles during fatigue and recovery is not uniform (i.e., different inspiratory muscles may have different underlying mechanisms of fatigue), and MRR, ½RT, and τ are not only useful predictors of inspiratory ribcage muscle recovery but may also share common underlying mechanisms with shortening velocity.

Measurement of Peripheral Venous Oxygen Saturation in the Leg Using Near-Infrared Spectroscopy

1997 ◽  
Vol 12 (3) ◽  
pp. 96-99 ◽  
Author(s):  
D. Wertheim ◽  
R. Salaman ◽  
J. Melhuish ◽  
R. Williams ◽  
I. Lane ◽  
...  
Keyword(s):  
Near Infrared ◽  
Tissue Oxygenation ◽  
Venous Occlusion ◽  
Lower Leg ◽  
Non Invasive ◽  
Short Period ◽  
Venous Oxygen Saturation ◽  
Invasive Method ◽  
Healing Of Wounds ◽  
Total Haemoglobin

Background: It has been suggested that poor healing of wounds may be associated with reduced tissue oxygenation. A non-invasive method of assessing peripheral venous oxygenation has been investigated. Method: Changes in oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb), oxidized cytochrome aa3 (cyt aa3) and total haemoglobin (tHb) were monitored in the left lower leg of seven healthy volunteers. A short period of venous occlusion was achieved by rapidly inflating a sphygmomanometer cuff placed around the leg to 60 mmHg. The changes in O2Hb and tHb, with respect to the baseline readings, were evaluated. PSvO2 was calculated from (ΔO2Hb/ΔtHb) × 100%. Results: From 17 sets of readings on the seven volunteers the median PSvO2 calculated was 64% (range 50–86%). Conclusion: This method appears to be a simple means of evaluating PSvO2. A change in cyt aa3 was often seen associated with the venous occlusion.

An individually adjusted endurance test reveals differences in physical fitness between young and old Beagles

2021 ◽  
Vol 49 (03) ◽  
pp. 165-172
Author(s):  
Maray Willen ◽  
Malin Lorke ◽  
Patrick Wefstaedt ◽  
Karin Lucas ◽  
Ingo Nolte
Keyword(s):  
Heart Rate ◽  
Physical Fitness ◽  
Individual Performance ◽  
Carbon Dioxide Partial Pressure ◽  
Ground Reaction Forces ◽  
Endurance Test ◽  
Endurance Tests ◽  
Reaction Forces ◽  
Performance Development ◽  
The Individual

Abstract Objective Aim was to establish an individually adapted endurance test for dogs on a treadmill, which takes the individual‘s physical condition into account. To check the applicability of the test, two age groups of clinically healthy beagles were examined. Methods A total of 10 clinically healthy Beagles were enrolled and divided in a younger (1–3 years, n = 5) and older group (> 8 years, n = 5). The individual comfort gait speed of each dog was determined on a treadmill with integrated force plates. A maximal time of 20 minutes at trot was set for the endurance test. The test was terminated prematurely if the dog showed signs of fatigue (massive panting, unwillingness to move further). Blood samples were taken at general examination (G), prior to (B) and post exercise (P) for determination of lactate level (LL), oxygen and carbon dioxide partial pressure (pO2, pCO2), bicarbonate (HCO3 –), base excess (BE) and pH. On each occasion (G, B, P) heart rate (HR) and respiratory rate (RR) were recorded. Additionally, vertical ground reaction forces (Fz) were analysed. Results The older dogs (age: 10.4 ± 0.89 years) completed the test with less speed and duration compared to the younger dogs (age: 2.4 ± 0.89 years), which managed to complete the maximum time. Lactate levels in the older dogs were higher than in the younger dogs at all timepoints of examination. Contrary to the younger dogs, there was no significant increase in the heart rate of the older dogs. Ground reaction forces were not significantly different between the groups. Conclusion and clinical relevance Whereas standardised endurance tests allow for the comparison of fitness levels between dogs, an individually adjusted endurance test aims at objectively determining the physical fitness of the single dog taking into account its individual performance. Such a test allows to examine the individual performance development over time and to evaluate medicinal therapies or dietary measures, e. g. in aging dogs. HR, RR, LL, blood gases (pCO2, pO2) and acid-base metabolism (HCO3 –, BE, pH) were found to be appropriate parameters for determining the physical capacity of the dogs during endurance tests as these parameters change under physical stress and are indicative for the onset of fatigue.

Specific inspiratory muscle warm-up enhances badminton footwork performance

2007 ◽  
Vol 32 (6) ◽  
pp. 1082-1088 ◽  
Author(s):  
Hua Lin ◽  
Tom Kwokkeung Tong ◽  
Chuanye Huang ◽  
Jinlei Nie ◽  
Kui Lu ◽  
...  
Keyword(s):  
Random Order ◽  
Inspiratory Muscle ◽  
Inspiratory Pressure ◽  
Test Duration ◽  
Warm Up ◽  
Pressure Threshold ◽  
Mouth Pressure ◽  
Concomitant Reduction ◽  
Experimental Trials ◽  
Relationship Of

The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered in a subsequent incremental badminton-footwork test (FWmax) were examined. Ten male badminton players were recruited to perform identical tests in three different trials in a random order. The control trial did not involve an IM warm-up, whereas the placebo and experimental trials did involve an IM warm-up consisting of two sets of 30-breath manoeuvres with an inspiratory pressure-threshold load equivalent to 15% (PLA) and 40% (IMW) maximum inspiratory mouth pressure, respectively. In the IMW trial, IM function was improved with 7.8% ± 4.0% and 6.9% ± 3.5% increases from control found in maximal inspiratory pressure at zero flow (P0) and maximal rate of P0 development (MRPD), respectively (p < 0.05). FWmax was enhanced 6.8% ± 3.7%, whereas the slope of the linear relationship of the increase in the rating of perceived breathlessness for every minute (RPB/min) was reduced (p < 0.05). Reduction in blood lactate ([La–]b) accumulation was observed when the test duration was identical to that of the control trial (P < 0.05). In the PLA trial, no parameter was changed from control. For the changes (Δ) in parameters in IMW (n = 10), negative correlations were found between ΔP0 and ΔRPB/min (r2 = 0.58), ΔMRPD and ΔRPB/min (r2 = 0.48), ΔRPB/min, and ΔFWmax (r2 = 0.55), but not between Δ[La–]b accumulation and ΔFWmax. Such findings suggest that the IM-specific warm-up improved footwork performance in the subsequent maximum incremental badminton-footwork test. The improved footwork was partly attributable to the reduced breathless sensation resulting from the enhanced IM function, whereas the contribution of the concomitant reduction in [La–]b accumulation was relatively minor.

scholarly journals Friction Behavior of Pre-Damaged Wet-Running Multi-Plate Clutches in an Endurance Test

Lubricants ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 68
Author(s):  
Thomas Schneider ◽  
Katharina Voelkel ◽  
Hermann Pflaum ◽  
Karsten Stahl
Keyword(s):  
Coefficient Of Friction ◽  
Later Life ◽  
Second Step ◽  
Experimental Investigations ◽  
Endurance Test ◽  
Friction Behavior ◽  
Speed Range ◽  
The Coefficient Of Friction ◽  
Endurance Tests

Wet-running multi-plate clutches should be prevented from failing due to the often safety-relevant functions they fulfill in the drive train. In addition to long-term damage, spontaneous damage is of particular relevance for failures. This paper focuses on the influence of spontaneous damage on frictional behavior in the later life cycle. The aim of the experimental investigations is to initially cause spontaneous damage in wet-running multi-plate clutches with sintered friction linings. For this purpose, three clutches are first pre-damaged in stage tests with different intensities, so that the first spontaneous damage (local discoloration, sinter transfer) occurs. In the second step, an endurance test is carried out with the pre-damaged clutch packs and a non-pre-damaged reference clutch. The friction behavior of the clutches during the endurance test is compared and evaluated. It shows that local discoloration and sinter transfer are no longer visible after the endurance tests. At the beginning of the endurance test, the values of coefficient of friction are higher over the entire speed range of the heavily pre-damaged clutches than with the slightly pre-damaged clutch and the non-pre-damaged reference clutch. At the end of the endurance test, it can be observed that the greater the pre-damage to the clutches is, the greater the coefficient of friction increases with decreasing sliding speed.

scholarly journals Electroencephalographic changes associated with non-invasive nociceptive stimulus in minimally anaesthetised dogs

2016 ◽  
Vol 19 (4) ◽  
pp. 675-683 ◽  
Author(s):  
U. Kaka ◽  
Y.M. Goh ◽  
L.W. Chean ◽  
H.C. Chen
Keyword(s):  
Peripheral Nerve ◽  
Analgesic Effect ◽  
Median Frequency ◽  
Nerve Stimulator ◽  
Peripheral Nerve Stimulator ◽  
Electric Stimulus ◽  
Non Invasive ◽  
Nociceptive Stimulus ◽  
Before And After ◽  
Electrical Stimuli

Abstract Electroencephalography (EEG) has been reported as an objective, non-invasive and stress free technique for nociceptive studies. Electrical stimuli can be used to evaluate the efficacy of centrally acting agents. Peripheral nerve stimulator can be a good and cheap source of electric stimulus for studies of nociception, and studies evaluating analgesic effect of drugs under EEG. In this study suitability of peripheral nerve stimulator, and milliamperage for nociceptive studies under electroencephalography were evaluated. Six dogs were subjected to electric stimulus of 20, 40, 60 and 80 milliamperes (mAs) before and after tramadol administration at 4 mg/kg IV. Electroencephalograph was recorded during electric stimulus prior tramadol (pre-tramadol) and during electric stimulus after tramadol (post-tramadol) under minimal anaesthesia. Anaesthesia was induced with propofol and maintained with halothane at a stable concentration between 0.85 and 0.95%. Pre-tramadol median frequency (MF) increased significantly (p<0.05) at 40, 60 and 80 mAs post-electric stimulus compared to baseline MF. No difference in pre-tramadol MF was observed between 60 and 80 mAs. Tramadol produced significant effect by depression of MF at all intensities. The effect was less evident at 80 mAs. The results revealed that tramadol produced evident effect between 20 and 60 mAs. Thus, it is concluded that nerve stimulator can be used with the current between 20 and 60 mAs for nociceptive studies.

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