共查询到20条相似文献,搜索用时 31 毫秒
1.
Thomas C Bernard O Enea C Jalab C Hanon C 《European journal of applied physiology》2012,112(2):667-675
This study aimed to determine metabolic and respiratory adaptations during intense exercise and improvement of long-sprint
performance following six sessions of long-sprint training. Nine subjects performed before and after training (1) a 300-m
test, (2) an incremental exercise up to exhaustion to determine the velocity associated with maximal oxygen uptake (v-VO2max), (3) a 70-s constant exercise at intensity halfway between the v-VO2max and the velocity performed during the 300-m test, followed by a 60-min passive recovery to determine an individual blood
lactate recovery curve fitted to the bi-exponential time function:
\textLa( t ) = \textLa( 0 ) + A 1 ( 1- \texte - g 1 t ) + A 2 ( 1- \texte - g 2 t ) {\text{La}}\left( t \right) = {\text{La}}\left( 0 \right) + A_{ 1} ( 1- {\text{e}}^{{ - \gamma_{{ 1 } }}^{{t}}} ) +\; A_{ 2} ( 1- {\text{e}}^{{ - \gamma_{{ 2 }} }^{{t}}} ) , and blood metabolic and gas exchange responses. The training program consisted of 3–6 repetitions of 150–250 m interspersed
with rest periods with a duration ratio superior or equal to 1:10, 3 days a week, for 2 weeks. After sprint training, reduced
metabolic disturbances, characterized by a lower peak expired ventilation and carbon dioxide output, in addition to a reduced
peak lactate (P < 0.05), was observed. Training also induced significant decrease in the net amount of lactate released at the beginning
of recovery (P < 0.05), and significant decrease in the net lactate release rate (NLRR) (P < 0.05). Lastly, a significant improvement of the 300-m performance was observed after training. These results suggest that
long-sprint training of short durations was effective to rapidly prevent metabolic disturbances, with alterations in lactate
accumulation and gas exchange, and improvement of the NLRR. Furthermore, only six long-sprint training sessions allow long-sprint
performance improvement in active subjects. 相似文献
2.
We studied the effect of Cl− (10–75 mM) and
\textHCO3- {\text{HCO}}_3^{-} ions (10–25 mM) on the ATP-dependent GABAA receptor-coupled Cl− channel (Cl−-ATPase) in rat brain plasma membranes. The total enzyme activity was detected in the presence of both anions at a Cl−/
\textHCO3- {\text{HCO}}_3^{-} ratio of 5:1 (Cl−,
\textHCO3- {\text{HCO}}_3^{-} -ATPase). Specific inhibitors of P-type transport ATPases (N-ethylmaleimide, ovanadate, and oligomycin) suppressed Cl−,
\textHCO3- {\text{HCO}}_3^{-} -ATPase, while the Cl−- and
\textHCO3- {\text{HCO}}_3^{-} -ATPase activities were low sensitive to these ligands. Bicuculline abolished the activating effect of Cl− and
\textHCO3- {\text{HCO}}_3^{-} ions on the enzyme.
\textHCO3- {\text{HCO}}_3^{-} ions had no effect on the ATP-dependent Cl− transport into proteoliposomes (with the involvement of reconstituted ATPase). In experiment with Cl−-preloaded liposomes, addition of
\textHCO3- {\text{HCO}}_3^{-} ions to the incubation medium caused the reversion of Cl− transport (ion efflux from liposomes). Our results suggest that
\textHCO3- {\text{HCO}}_3^{-} ions play an important role in the modification of properties of the ATP-dependent GABAA receptor-coupled Cl− channel and GABAA receptor-induced Cl−/
\textHCO3- {\text{HCO}}_3^{-} exchange. These ions are probably involved in GABAA receptor-induced Cl−/
\textHCO3- {\text{HCO}}_3^{-} exchange in neuronal membranes. 相似文献
3.
Christine Hanon Pierre-Marie Lepretre David Bishop Claire Thomas 《European journal of applied physiology》2010,109(2):233-240
This study aimed to investigate the oxygen uptake and metabolic responses during a 400-m run reproducing the pacing strategy
used in competition. A portable gas analyser was used to measure the oxygen uptake
( [(V)\dot]\textO 2 ) \left( {\dot{V}{{{\text{O}}_{ 2} }} } \right) of ten specifically trained runners racing on an outdoor track. The tests included (1) an incremental test to determine maximal
[(V)\dot]\textO 2 ( [(V)\dot]\textO 2 \textmax ) \dot{V}{{{\text{O}}_{ 2} }} \,\left( {\dot{V}{{{\text{O}}_{{ 2 {\text{max}}}} }} } \right) and the velocity associated with
[(V)\dot]\textO 2 \textmax ( \textv-[(V)\dot]\textO 2 \textmax ), \dot{V}{{{\text{O}}_{{ 2 {\text{max}}}} }} \left( {{\text{v}}-\dot{V}{{{\text{O}}_{{ 2 {\text{max}}}} }} } \right), (2) a maximal 400-m (400T) and 3) a 300-m running test (300T) reproducing the exact pacing pattern of the 400T. Blood lactate,
bicarbonate concentrations
[ \textHCO 3 - ], \left[ {{\text{HCO}}_{ 3}^{ - } } \right], pH and arterial oxygen saturation were analysed at rest and 1, 4, 7, 10 min after the end of the 400 and 300T. The peak
[(V)\dot]\textO 2 \dot{V}{{{\text{O}}_{ 2} }} recorded during the 400T corresponded to 93.9 ± 3.9% of
[(V)\dot]\textO2max \dot{V}{{{\text{O}}_{2\max } }} and was reached at 24.4 ± 3.2 s (192 ± 22 m). A significant decrease in
[(V)\dot]\textO 2 \dot{V}{{{\text{O}}_{ 2} }} (P < 0.05) was observed in all subjects during the last 100 m, although the velocity did not decrease below
\textv-[(V)\dot]\textO 2 \textmax . {\text{v}}-\dot{V}_{{{\text{O}}_{{ 2 {\text{max}}}} }} . The
[(V)\dot]\textO 2 \dot{V}{{{\text{O}}_{ 2} }} in the last 5 s was correlated with the pH (r = 0.86, P < 0.0005) and
[ \textHCO 3 - ] \left[ {{\text{HCO}}_{ 3}^{ - } } \right] (r = 0.70, P < 0.05) measured at the end of 300T. Additionally, the velocity decrease observed in the last 100 m was inversely correlated
with
[ \textHCO 3 - ] \left[ {{\text{HCO}}_{ 3}^{ - } } \right] and pH at 300T (r = −0.83, P < 0.001, r = −0.69, P < 0.05, respectively). These track running data demonstrate that acidosis at 300 m was related to both the
[(V)\dot]\textO 2 \dot{V}{{{\text{O}}_{ 2} }} response and the velocity decrease during the final 100 m of a 400-m run. 相似文献
4.
Jérémy B. J. Coquart Roger G. Eston Jean-Marie Grosbois Christine Lemaire Alain-Eric Dubart David-Pol Luttenbacher Murielle Garcin 《European journal of applied physiology》2010,110(3):645-649
The purpose of this study was to develop a simple, convenient and indirect method for predicting peak oxygen uptake (
[(V)\dot]\textO2\textpeak \dot{V}{\text{O}}_{{2{\text{peak}}}} ) from a sub-maximal graded exercise test (GXT), in obese women. Thirty obese women performed GXT to volitional exhaustion.
During GXT, oxygen uptake and the power at RPE 15 (
P\textRPE 15 P_{{{\text{RPE}}\;15}} ) were measured, and
[(V)\dot]\textO2\textpeak \dot{V}{\text{O}}_{{2{\text{peak}}}} was determined. Following assessment of the relationships between
[(V)\dot]\textO2\textpeak \dot{V}{\text{O}}_{{2{\text{peak}}}} and
P\textRPE 15 P_{{{\text{RPE}}\;15}} , age, height and mass were made available in a stepwise multiple regression analysis with
[(V)\dot]\textO2\textpeak \dot{V}{\text{O}}_{{2{\text{peak}}}} as the dependent variable. The equation to predict
[(V)\dot]\textO2\textpeak \dot{V}{\text{O}}_{{2{\text{peak}}}} was:
[(V)\dot]\textO 2 \textpeak (\textl min -1) = 1.355 - 9.920\texte - 3 ×\textage + 8 . 4 9 7 \texte - 3 ×P\textRPE 15 \dot{V}{\text{O}}_{{ 2 {\text{peak}}}} ({\text{l}}\,{\hbox{min}}^{ -1}) = 1.355 - 9.920{\text{e}}^{ - 3} \times {\text{age + 8}} . 4 9 7 {\text{e}}^{ - 3} \times P_{{{\text{RPE}}\;15}} 相似文献
5.
Hideyo Yoshida Chikao Shimamoto Shigenori Ito Eriko Daikoku Takashi Nakahari 《The journal of physiological sciences : JPS》2010,60(4):273-282
Ionomycin (IM, 5 μM), which exchanges 1 Ca2+ for 1 H+, changed intracellular pH (pHi) with Ca2+ entry into rat submandibular acinar cells. IM-induced changes in pHi consisted of two components: the first is an HCO3
−-dependent transient pHi decrease, and the second is an HCO3
−-independent gradual pHi increase. IM (1 μM), which activates store-operated Ca2+ channels, induced an HCO3
−-dependent and transient pHi decrease without any HCO3
−-independent pHi increase. Thus, a gradual pHi increase was induced by the Ca2+/H+ exchange. The HCO3
−-dependent and transient pHi decrease induced by IM was abolished by acetazolamide, but not by methyl isobutyl amiloride (MIA) or diisothiocyanatostilbene
disulfonate (DIDS), suggesting that the Na+/H+ exchange, the Cl−/HCO3
− exchange, or the Na+-HCO3
− cotransport induces no transient pHi decrease. Thapsigargin induced no transient pHi decrease. Thus, IM, not Ca2+ entry, reduced pHi transiently. IM reacts with Ca2+ to produce H+ in the presence of
\textCO 2 /\textHCO 3 - : [ \textH - \textIM ] - + \text Ca 2+ + \textCO 2 \rightleftarrows [ \textH-\textCa - \textIM ] + ·\textHCO 3 - + \textH + {\text{CO}}_{ 2} /{\text{HCO}}_{ 3}{^{ - }} : \, \left[ {{\text{H}} - {\text{IM}}} \right]^{ - } + {\text{ Ca}}^{ 2+ } \,+ {\text{CO}}_{ 2} \rightleftarrows \left[ {{\text{H}}-{\text{Ca}} - {\text{IM}}} \right]^{ + } \cdot {\text{HCO}}_{ 3}{^{ - } }+ {\text{H}}^{ + } . In this reaction, a monoprotonated IM reacts with Ca2+ and CO2 to produce an electroneutral IM complex and H+, and then H+ is removed from the cells via CO2 production. Thus, IM transiently decreased pHi. In conclusion, in rat submandibular acinar cells IM (5 μM) transiently reduces pHi because of its chemical characteristics, with HCO3
− dependence, and increases pHi by exchanging Ca2+ for H+, which is independent of HCO3
−. 相似文献
6.
Buchheit M Abbiss CR Peiffer JJ Laursen PB 《European journal of applied physiology》2012,112(2):767-779
The purpose of this study was to examine the cardiorespiratory and muscle oxygenation responses to a sprint interval training
(SIT) session, and to assess their relationships with maximal pulmonary O2 uptake
([(V)\dot]\textO 2 \textp \textmax) (\dot{V}{\text{O}}_{{ 2 {\text{p}}}} {\text{max)}} , on- and off-
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} kinetics and muscle reoxygenation rate (Reoxy rate). Ten male cyclists performed two 6-min moderate-intensity exercises (≈90–95%
of lactate threshold power output, Mod), followed 10 min later by a SIT session consisting of 6 × 30-s all out cycling sprints
interspersed with 2 min of passive recovery.
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} kinetics at Mod onset (
[(V)\dot]\textO 2 \textp t\texton \dot{V}{\text{O}}_{{ 2 {\text{p}}}} \tau_{\text{on}} ) and cessation (
[(V)\dot]\textO 2 \textp t\textoff \dot{V}{\text{O}}_{{ 2 {\text{p}}}} \tau_{\text{off}} ) were calculated. Cardiorespiratory variables, blood lactate ([La]b) and muscle oxygenation level of the vastus lateralis (tissue oxygenation index, TOI) were recorded during SIT. Percentage
of the decline in power output (%Dec), time spent above 90% of
[(V)\dot]\textO 2 \textp max \dot{V}{\text{O}}_{{ 2 {\text{p}}}} { \max } (t > 90%
[(V)\dot]\textO 2 \textp max \dot{V}{\text{O}}_{{ 2 {\text{p}}}} { \max } ) and Reoxy rate after each sprint were also recorded. Despite a low mean
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} (48.0 ± 4.1% of
[(V)\dot]\textO 2 \textp max \dot{V}{\text{O}}_{{ 2 {\text{p}}}} { \max } ), SIT performance was associated with high peak
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} (90.4 ± 2.8% of
[(V)\dot]\textO 2 \textp max \dot{V}{\text{O}}_{{ 2 {\text{p}}}} { \max } ), muscle deoxygenation (sprint ΔTOI = −27%) and [La]b (15.3 ± 0.7 mmol l−1) levels. Muscle deoxygenation and Reoxy rate increased throughout sprint repetitions (P < 0.001 for both). Except for t > 90%
[(V)\dot]\textO 2 \textp max \dot{V}{\text{O}}_{{ 2 {\text{p}}}} { \max } versus
[(V)\dot]\textO 2 \textp t\textoff \dot{V}{\text{O}}_{{ 2 {\text{p}}}} \tau_{\text{off}} [r = 0.68 (90% CL, 0.20; 0.90); P = 0.03], there were no significant correlations between any index of aerobic function and either SIT performance or physiological
responses [e.g., %Dec vs.
[(V)\dot]\textO 2 \textp t\textoff \dot{V}{\text{O}}_{{ 2 {\text{p}}}} \tau_{\text{off}} : r = −0.41 (−0.78; 0.18); P = 0.24]. Present results show that SIT elicits a greater muscle O2 extraction with successive sprint repetitions, despite the decrease in external power production (%Dec = 21%). Further, our
findings obtained in a small and homogenous group indicate that performance and physiological responses to SIT are only slightly
influenced by aerobic fitness level in this population. 相似文献
7.
Nipu Modak Dinabandhu Kejriwal Krishanu Nandy Amitava Datta Ranjan Ganguly 《Biomedical microdevices》2010,12(1):23-34
Magnetophoretic isolation of biochemical and organic entities in a microfluidic environment is a popular tool for a wide range
of bioMEMS applications, including biosensors. An experimental and numerical analysis of magnetophoretic capture of magnetic
microspheres in a microfluidic channel under the influence of an external field is investigated. For a given microfluidic
geometry, the operating conditions for marginal capture is found to be interrelated in such a manner that a unique critical
capture parameter
P\textcrit = ( I\textcrit \texta )2 \mathord | / | \vphantom ( I\textcrit \texta )2 \textQh \textQh \Pi _{{{\text{crit}}}} = {{\left( {I_{{{\text{crit}}}} {\text{a}}} \right)}^{2} } \mathord{\left/ {\vphantom {{{\left( {I_{{{\text{crit}}}} {\text{a}}} \right)}^{2} } {{\text{Q}}\eta }}} \right. \kern-\nulldelimiterspace} {{\text{Q}}\eta } , that is proportional to the ratio of the magnetic force to viscous force, can be identified. Influences of the flow rate, magnetic field and other parameters on the particle trajectories in the microfluidic channel are investigated both numerically and through bright-field imaging under a microscope. Like the event of critical capture, particle trajectories are also found to be guided by a similar parameter, π. Magnetophoretic capture efficiency of the device is also evaluated as a function of a nondimensional number P* = c\textP2 \texta2 \mathord | / |
\vphantom c\textP2 \texta2 ( \textU0 h\texth5 ) ( \textU0 h\texth5 ) \Pi ^{*} = {\chi {\text{P}}^{2} {\text{a}}^{2} } \mathord{\left/ {\vphantom {{\chi {\text{P}}^{2} {\text{a}}^{2} } {{\left( {{\text{U}}_{0} \eta {\text{h}}^{5} } \right)}}}} \right. \kern-\nulldelimiterspace} {{\left( {{\text{U}}_{0} \eta {\text{h}}^{5} } \right)}} , when both numerical and experimental results are found to agree reasonably well. Results of this investigation can be applied
for the selection of the operating parameters and for prediction of device performance of practical microfluidic separators. 相似文献
8.
The slope of the diastatic pressure–volume relationship (D-PVR) defines passive left ventricular (LV) stiffness K. \mathcal{K}. Although K \mathcal{K} is a relative measure, cardiac catheterization, which is an absolute measurement method, is used to obtain the former. Echocardiography,
including transmitral flow velocity (Doppler E-wave) analysis, is the preferred quantitative diastolic function (DF) assessment
method. However, E-wave analysis can provide only relative, rather than absolute pressure information. We hypothesized that
physiologic mechanism-based modeling of E-waves allows derivation of the D-PVRE-wave whose slope,
K\textE-\textwave \mathcal{K}_{{\text{E-}}{\text{wave}}} , provides E-wave-derived diastatic, passive chamber stiffness. Our kinematic model of filling and Bernoulli’s equation were
used to derive expressions for diastatic pressure and volume on a beat-by-beat basis, thereby generating D-PVRE-wave, and
K\textE-\textwave \mathcal{K}_{{\text{E-}}{\text{wave}}} . For validation, simultaneous (conductance catheter) P–V and echocardiographic E-wave data from 30 subjects (444 total cardiac cycles) having normal LV ejection fraction (LVEF) were
analyzed. For each subject (15 beats average) model-predicted
K\textE-\textwave \mathcal{K}_{{\text{E-}}{\text{wave}}} was compared to experimentally measured
K\textCATH \mathcal{K}_{\text{CATH}}
via linear regression yielding as follows:
K\textE-\textwave = aK\textCATH + b (R2 = 0.92), \mathcal{K}_{{\text{E-}}{\text{wave}}} = \alpha {\mathcal{K}}_{\text{CATH}} + b\;(R^{2} = 0.92), where, α = 0.995 and b = 0.02. We conclude that echocardiographically determined diastatic passive chamber stiffness,
K\textE-\textwave \mathcal{K}_{{\text{E-}}{\text{wave}}} , provides an excellent estimate of simultaneous, gold standard (P–V)-defined diastatic stiffness,
K\textCATH \mathcal{K}_{\text{CATH}} . Hence, in chambers at diastasis, passive LV stiffness can be accurately determined by means of suitable analysis of Doppler
E-waves (transmitral flow). 相似文献
9.
Miyamoto T Inagaki M Takaki H Kawada T Shishido T Kamiya A Sugimachi M 《European journal of applied physiology》2012,112(1):237-251
We have reported that minute ventilation [
[(V)\dot]\textE \dot{V}_{\text{E}} ] and end-tidal CO2 tension [
P\textETCO 2 P_{{{\text{ETCO}}_{ 2} }} ] are determined by the interaction between central controller and peripheral plant properties. During exercise, the controller
curve shifts upward with unchanged central chemoreflex threshold to compensate for the plant curve shift accompanying increased
metabolism. This effectively stabilizes
P\textETCO 2 P_{{{\text{ETCO}}_{ 2} }} within the normal range at the expense of exercise hyperpnea. In the present study, we investigated how endurance-trained
athletes reduce this exercise hyperpnea. Nine exercise-trained and seven untrained healthy males were studied. To characterize
the controller, we induced hypercapnia by changing the inspiratory CO2 fraction with a background of hyperoxia and measured the linear
P\textETCO 2 - [(V)\dot]\textE P_{{{\text{ETCO}}_{ 2} }} - \dot{V}_{\text{E}} relation [
[(V)\dot]\textE = S (P\textETCO2 - B) \dot{V}_{\text{E}} = S\, (P_{{{\text{ETCO}}_{2} }} - {\rm B}) ]. To characterize the plant, we instructed the subjects to alter
[(V)\dot]\textE \dot{V}_{\text{E}} voluntarily and measured the hyperbolic
[(V)\dot]\textE - P\textETCO 2 \dot{V}_{\text{E}} - P_{{{\text{ETCO}}_{ 2} }} relation (
P\textETCO 2 = A/[(V)\dot]\textE + C P_{{{\text{ETCO}}_{ 2} }} = A/\dot{V}_{\text{E}} + C ). We characterized these relations both at rest and during light exercise. Regular exercise training did not affect the characteristics
of either controller or plant at rest. Exercise stimulus increased the controller gain (S) both in untrained and trained subjects.
On the other hand, the
P\textETCO 2 P_{{{\text{ETCO}}_{ 2} }} -intercept (B) during exercise was greater in trained than in untrained subjects, indicating that exercise-induced upward shift of the
controller property was less in trained than in untrained subjects. The results suggest that the additive exercise drive to
breathe was less in trained subjects, without necessarily a change in central chemoreflex threshold. The hyperbolic plant
property shifted rightward and upward during exercise as predicted by increased metabolism, with little difference between
two groups. The
[(V)\dot]\textE \dot{V}_{\text{E}} during exercise in trained subjects was 21% lower than that in untrained subjects (P < 0.01). These results indicate that an adaptation of the controller, but not that of plant, contributes to the attenuation
of exercise hyperpnea at an iso-metabolic rate in trained subjects. However, whether training induces changes in neural drive
originating from the central nervous system, afferents from the working limbs, or afferents from the heart, which is additive
to the chemoreflex drive to breathe, cannot be determined from these results. 相似文献
10.
Marbella Quiñonez Fernando González Consuelo Morgado-Valle Marino DiFranco 《Journal of muscle research and cell motility》2010,31(1):13-33
Repetitive activation of skeletal muscle fibers leads to a reduced transmembrane K+ gradient. The resulting membrane depolarization has been proposed to play a major role in the onset of muscle fatigue. Nevertheless,
raising the extracellular K+ (
\textK\texto + {\text{K}}_{\text{o}}^{ + } ) concentration (
[ \textK + ]\texto [ {\text{K}}^{ + } ]_{\text{o}} ) to 10 mM potentiates twitch force of rested amphibian and mammalian fibers. We used a double Vaseline gap method to simultaneously
record action potentials (AP) and Ca2+ transients from rested frog fibers activated by single and tetanic stimulation (10 pulses, 100 Hz) at various
[ \textK + ]\texto [ {\text{K}}^{ + } ]_{\text{o}} and membrane potentials. Depolarization resulting from current injection or raised
[ \textK + ]\texto [ {\text{K}}^{ + } ]_{\text{o}} produced an increase in the resting [Ca2+]. Ca2+ transients elicited by single stimulation were potentiated by depolarization from −80 to −60 mV but markedly depressed by
further depolarization. Potentiation was inversely correlated with a reduction in the amplitude, overshoot and duration of
APs. Similar effects were found for the Ca2+ transients elicited by the first pulse of 100 Hz trains. Depression or block of Ca2+ transient in response to the 2nd to 10th pulses of 100 Hz trains was observed at smaller depolarizations as compared to that
seen when using single stimulation. Changes in Ca2+ transients along the trains were associated with impaired or abortive APs. Raising
[ \textK + ]\texto [ {\text{K}}^{ + } ]_{\text{o}} to 10 mM potentiated Ca2+ transients elicited by single and tetanic stimulation, while raising
[ \textK + ]\texto [ {\text{K}}^{ + } ]_{\text{o}} to 15 mM markedly depressed both responses. The effects of 10 mM
\textK\texto + {\text{K}}_{\text{o}}^{ + } on Ca2+ transients, but not those of 15 mM
\textK\texto + {\text{K}}_{\text{o}}^{ + } , could be fully reversed by hyperpolarization. The results suggests that the force potentiating effects of 10 mM
\textK\texto + {\text{K}}_{\text{o}}^{ + } might be mediated by depolarization dependent changes in resting [Ca2+] and Ca2+ release, and that additional mechanisms might be involved in the effects of 15 mM
\textK\texto + {\text{K}}_{\text{o}}^{ + } on force generation. 相似文献
11.
Danielle M. Lambrick James A. Faulkner Ann V. Rowlands Roger G. Eston 《European journal of applied physiology》2009,107(1):1-9
This study assessed the utility of a single, continuous exercise protocol in facilitating accurate estimates of maximal oxygen
uptake (
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max) from submaximal heart rate (HR) and the ratings of perceived exertion (RPE) in healthy, low-fit women, during cycle ergometry.
Eleven women estimated their RPE during a continuous test (1 W 4 s−1) to volitional exhaustion (measured
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max). Individual gaseous exchange thresholds (GETs) were determined retrospectively. The RPE and HR values prior to and including
an RPE 13 and GET were extrapolated against corresponding oxygen uptake to a theoretical maximal RPE (20) and peak RPE (19),
and age-predicted HRmax, respectively, to predict
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max. There were no significant differences (P > 0.05) between measured (30.9 ± 6.5 ml kg−1 min−1) and predicted
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max from all six methods. Limits of agreement were narrowest and intraclass correlations were highest for predictions of
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max from an RPE 13 to peak RPE (19). Prediction of
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max from a regression equation using submaximal HR and work rate at an RPE 13 was also not significantly different to actual
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max (R
2
= 0.78, SEE = 3.42 ml kg−1 min−1, P > 0.05). Accurate predictions of
[(V)\dot] \textO 2 \dot{V} {\text{O}}_{ 2} max may be obtained from a single, continuous, estimation exercise test to a moderate intensity (RPE 13) in low-fit women,
particularly when extrapolated to peak terminal RPE (RPE19). The RPE is a valuable tool that can be easily employed as an adjunct to HR, and provides supplementary clinical information
that is superior to using HR alone. 相似文献
12.
Michael Morris Kevin L. Lamb John Hayton David Cotterrell John Buckley 《European journal of applied physiology》2010,109(5):983-988
The purpose of this study was to determine for the first time whether
[(V)\dot]\textO 2max {\dot{V}}{\text{O}}_{ 2\hbox{max}} could be predicted accurately and reliably from a treadmill-based perceptually regulated exercise test (PRET) incorporating
a safer and more practical upper limit of RPE 15 (“Hard”) than used in previous investigations. Eighteen volunteers (21.7 ± 2.8 years)
completed three treadmill PRETs (each separated by 48 h) and one maximal graded exercise test. Participants self-regulated
their exercise at RPE levels 9, 11, 13 and 15 in a continuous and incremental fashion. Oxygen uptake
( [(V)\dot]\textO 2 ) \left( {{\dot{V}}{\text{O}}_{ 2} } \right) was recorded continuously during each 3 min bout.
[(V)\dot]\textO2 {\dot{V}}{\text{O}}_{2} values for the RPE range 9–15 were extrapolated to RPE19 and RPE20 using regression analysis to predict individual
[(V)\dot]\textO2max {\dot{V}}{\text{O}}_{2\hbox{max}} scores. The optimal limits of agreement (LoA) between actual (48.0 ± 6.2 ml kg−1 min−1) and predicted scores were −0.6 ± 7.1 and −2.5 ± 9.4 ml.kg−1 min−1 for the RPE20 and RPE19 models, respectively. Reliability analysis for the
[(V)\dot]\textO2max {\dot{V}}{\text{O}}_{2\hbox{max}} predictions yielded LoAs of 1.6 ± 8.5 (RPE20) and 2.7 ± 9.4 (RPE19) ml kg−1 min−1 between trials 2 and 3. These findings demonstrate that (with practice) a novel treadmill-based PRET can yield predictions
of
[(V)\dot]\textO2max {\dot{V}}{\text{O}}_{2\hbox{max}} that are acceptably reliable and valid amongst young, healthy, and active adults. 相似文献
13.
Physiological determinants of Yo-Yo intermittent recovery tests in male soccer players 总被引:1,自引:0,他引:1
Ermanno Rampinini Aldo Sassi Andrea Azzalin Carlo Castagna Paolo Menaspà Domenico Carlomagno Franco M. Impellizzeri 《European journal of applied physiology》2010,108(2):401-409
The physiological determinants of performance in two Yo-Yo intermittent recovery tests (Yo-YoIR1 and Yo-YoIR2) were examined
in 25 professional (n = 13) and amateur (n = 12) soccer players. The aims of the study were (1) to examine the differences in physiological responses to Yo-YoIR1 and
Yo-YoIR2, (2) to determine the relationship between the aerobic and physiological responses to standardized high-intensity
intermittent exercise (HIT) and Yo-Yo performance, and (3) to investigate the differences between professional and amateur
players in performance and responses to these tests. All players performed six tests: two versions of the Yo-Yo tests, a test
for the determination of maximum oxygen uptake (
[(\textV)\dot]\textO2 max {\dot{\text{V}}}{\text{O}}_{{2\,{ \max }}} ), a double test to determine
[(\textV)\dot]\textO2 {\dot{\text{V}}}{\text{O}}_{2} kinetics and a HIT evaluation during which several physiological responses were measured. The anaerobic contribution was
greatest during Yo-YoIR2.
[(\textV)\dot]\textO2 max {\dot{\text{V}}}{\text{O}}_{{2\,{ \max }}} was strongly correlated with Yo-YoIR1 (r = 0.74) but only moderately related to Yo-YoIR2 (r = 0.47). The time constant (τ) of
[(\textV)\dot]\textO2 {\dot{\text{V}}}{\text{O}}_{2} kinetics was largely related to both Yo-Yo tests (Yo-YoIR1: r = 0.60 and Yo-YoIR2: r = 0.65). The relationships between physiological variables measured during HIT (blood La−, H+, HCO3
− and the rate of La− accumulation) and Yo-Yo performance (in both versions) were very large (r > 0.70). The physiological responses to HIT and the τ of the
[(\textV)\dot]\textO2 {\dot{\text{V}}}{\text{O}}_{2} kinetics were significantly different between professional and amateur soccer players, whilst
[(\textV)\dot]\textO2 max {\dot{\text{V}}}{\text{O}}_{{2\,{ \max }}} was not significantly different between the two groups. In conclusion,
[(\textV)\dot]\textO2 max {\dot{\text{V}}}{\text{O}}_{{2\,{ \max }}} is more important for Yo-YoIR1 performance, whilst τ of the
[(\textV)\dot]\textO2 {\dot{\text{V}}}{\text{O}}_{2} kinetics and the ability to maintain acid–base balance are important physiological factors for both Yo-Yo tests. 相似文献
14.
Yasuda Y Ito T Miyamura M Niwayama M 《The journal of physiological sciences : JPS》2011,61(4):279-286
The effect of exercise on the increase of exhaled CO in smokers compared to non-smokers has not been clarified yet. In this
study we compared the dynamics of exhaled CO before, during and after exercise between smokers and non-smokers. A group of
8 smokers and a group of 8 non-smokers underwent a bicycle exercise in a ramp fashion to near maximum intensity. Ventilation
and gas exchange, and CO exhalation were continuously measured every 30-s before, during and after the exercise. The fraction
of CO (F
CO) in the exhaled air decreased gradually, but the total amount of exhaled CO
([(V)\dot]\textCO ) (\dot{V}_{{{\text{CO}}}} ) increased in a linear manner during the ramp exercise, and F
CO and
[(V)\dot]\textCO \dot{V}_{\text{CO}} returned to the pre-exercise level within several minutes after exercise in all subjects. A linear relationship was observed
between
[(V)\dot]\textO 2 \dot{V}_{{{\text{O}}_{ 2} }} and
[(V)\dot]\textCO , \dot{V}_{\text{CO}} , and between
[(V)\dot]\textE \dot{V}_{\text{E}} and
[(V)\dot]\textCO \dot{V}_{\text{CO}} in both the whole period of measurement and during the ramp exercise period in all subjects. However, the
[(V)\dot]\textCO \dot{V}_{\text{CO}} at 0 W, the peak
[(V)\dot]\textCO \dot{V}_{\text{CO}} and the slope coefficients in the regression equation between
[(V)\dot]\textCO \dot{V}_{\text{CO}} and
[(V)\dot]\textO 2 , \dot{V}_{{{\text{O}}_{ 2} }} , and between
[(V)\dot]\textCO \dot{V}_{\text{CO}} and
[(V)\dot]\textE \dot{V}_{\text{E}} in the ramp exercise as well as the entire periods of measurement were significantly higher in smokers compared with those
in non-smokers, and these were correlated with the number of cigarettes smoked per day. It was concluded that CO exhalation
increases linearly with the increase of
[(V)\dot]\textO 2 \dot{V}_{{{\text{O}}_{ 2} }} and
[(V)\dot]\textE \dot{V}_{\text{E}} during exercise, and habitual smoking shifts these relationships upward depending on the number of cigarettes smoked daily. 相似文献
15.
Marwood S Roche D Garrard M Unnithan VB 《European journal of applied physiology》2011,111(11):2775-2784
Previous studies have demonstrated faster pulmonary oxygen uptake (
[(V)\dot]\textO2 \dot{V}{\text{O}}_{2} ) kinetics in the trained state during the transition to and from moderate-intensity exercise in adults. Whilst a similar
effect of training status has previously been observed during the on-transition in adolescents, whether this is also observed
during recovery from exercise is presently unknown. The aim of the present study was therefore to examine
[(V)\dot]\textO2 \dot{V}{\text{O}}_{2} kinetics in trained and untrained male adolescents during recovery from moderate-intensity exercise. 15 trained (15 ± 0.8 years,
[(V)\dot]\textO2max \dot{V}{\text{O}}_{2\max} 54.9 ± 6.4 mL kg−1 min−1) and 8 untrained (15 ± 0.5 years,
[(V)\dot]\textO2max \dot{V}{\text{O}}_{2\max } 44.0 ± 4.6 mL kg−1 min−1) male adolescents performed two 6-min exercise off-transitions to 10 W from a preceding “baseline” of exercise at a workload
equivalent to 80% lactate threshold;
[(V)\dot]\textO2 \dot{V}{\text{O}}_{2} (breath-by-breath) and muscle deoxyhaemoglobin (near-infrared spectroscopy) were measured continuously. The time constant
of the fundamental phase of
[(V)\dot]\textO2 \dot{V}{\text{O}}_{2} off-kinetics was not different between trained and untrained (trained 27.8 ± 5.9 s vs. untrained 28.9 ± 7.6 s, P = 0.71). However, the time constant (trained 17.0 ± 7.5 s vs. untrained 32 ± 11 s, P < 0.01) and mean response time (trained 24.2 ± 9.2 s vs. untrained 34 ± 13 s, P = 0.05) of muscle deoxyhaemoglobin off-kinetics was faster in the trained subjects compared to the untrained subjects.
[(V)\dot]\textO2 \dot{V}{\text{O}}_{2} kinetics was unaffected by training status; the faster muscle deoxyhaemoglobin kinetics in the trained subjects thus indicates
slower blood flow kinetics during recovery from exercise compared to the untrained subjects. 相似文献
16.
Short-term exercise-heat acclimation enhances skin vasodilation but not hyperthermic hyperpnea in humans exercising in a hot environment 总被引:1,自引:0,他引:1
Fujii N Honda Y Ogawa T Tsuji B Kondo N Koga S Nishiyasu T 《European journal of applied physiology》2012,112(1):295-307
We tested the hypothesis that short-term exercise-heat acclimation (EHA) attenuates hyperthermia-induced hyperventilation
in humans exercising in a hot environment. Twenty-one male subjects were divided into the two groups: control (C, n = 11) and EHA (n = 10). Subjects in C performed exercise-heat tests [cycle exercise for ~75 min at 58%
[(V)\dot]\textO 2 \textpeak \dot{V}_{{{\text{O}}_{{ 2 {\text{peak}}}} }} (37°C, 50% relative humidity)] before and after a 6-day interval with no training, while subjects in EHA performed the tests
before and after exercise training in a hot environment (37°C). The training entailed four 20-min bouts of exercise at 50%
[(V)\dot]\textO 2 \textpeak \dot{V}_{{{\text{O}}_{{ 2 {\text{peak}}}} }} separated by 10 min of rest daily for 6 days. In C, comparison of the variables recorded before and after the no-training
period revealed no changes. In EHA, the training increased resting plasma volume, while it reduced esophageal temperature
(T
es), heart rate at rest and during exercise, and arterial blood pressure and oxygen uptake (
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} ) during exercise. The training lowered the T
es threshold for increasing forearm vascular conductance (FVC), while it increased the slope relating FVC to T
es and the peak FVC during exercise. It also lowered minute ventilation (
[(V)\dot]\textE \dot{V}_{\text{E}} ) during exercise, but this effect disappeared after removing the influence of
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} on
[(V)\dot]\textE \dot{V}_{\text{E}} . The training did not change the slope relating ventilatory variables to T
es. We conclude that short-term EHA lowers ventilation largely by reducing metabolism, but it does not affect the sensitivity
of hyperthermia-induced hyperventilation during submaximal, moderate-intensity exercise in humans. 相似文献
17.
Jamie S. McPhee Alun G. Williams Hans Degens David A. Jones 《European journal of applied physiology》2010,109(6):1111-1118
There is considerable inter-individual variability in adaptations to endurance training. We hypothesised that those individuals
with a low local leg-muscle peak aerobic capacity
([(V)\dot] \textO2\textpeak) (\dot{V} {\text{O}}_{{2{\text{peak}}}}) relative to their whole-body maximal aerobic capacity
( [(V)\dot] \textO2max) ( \dot{V} {\text{O}}_{2\max}) would experience greater muscle training adaptations compared to those with a relatively high
[(V)\dot] \textO2\textpeak \dot{V} {\text{O}}_{{2{\text{peak}}}} . 53 untrained young women completed one-leg cycling to measure
[(V)\dot] \textO2\textpeak \dot{V} {\text{O}}_{{2{\text{peak}}}} and two-leg cycling to measure
[(V)\dot] \textO2max \dot{V} {\text{O}}_{2\max} . The one-leg
[(V)\dot] \textO2\textpeak \dot{V} {\text{O}}_{{2{\text{peak}}}} was expressed as a ratio of the two-leg
[(V)\dot] \textO2max \dot{V} {\text{O}}_{2\max} (Ratio
1:2). Magnetic resonance imaging was used to indicate quadriceps muscle volume. Measurements were taken before and after completion
of 6 weeks of supervised endurance training. There was large inter-individual variability in the pre-training Ratio
1:2 and large variability in the magnitude of training adaptations. The pre-training Ratio
1:2 was not related to training-induced changes in
[(V)\dot] \textO2max \dot{V} {\text{O}}_{2\max} (P = 0.441) but was inversely correlated with changes in one-leg
[(V)\dot] \textO2\textpeak \dot{V} {\text{O}}_{{2{\text{peak}}}} and muscle volume (P < 0.05). No relationship was found between the training-induced changes in two-leg
[(V)\dot] \textO2max \dot{V} {\text{O}}_{2\max} and one-leg
[(V)\dot] \textO2\textpeak \dot{V} {\text{O}}_{{2{\text{peak}}}} (r = 0.21; P = 0.129). It is concluded that the local leg-muscle aerobic capacity and Ratio
1:2 vary from person to person and this influences the extent of muscle adaptations following standardised endurance training.
These results help to explain why muscle adaptations vary between people and suggest that setting the training stimulus at
a fixed percentage of
[(V)\dot] \textO2max \dot{V} {\text{O}}_{2\max} might not be a good way to standardise the training stimulus to the leg muscles of different people. 相似文献
18.
Lisa M. K. Chin George J. F. Heigenhauser Donald H. Paterson John M. Kowalchuk 《European journal of applied physiology》2010,108(5):913-925
The effect of hyperventilation-induced hypocapnic alkalosis (HYPO) and prior heavy-intensity exercise (HVY) on pulmonary O2 uptake
([(V)\dot]\textO 2 \textp) (\dot{V}{\text{O}}_{{ 2 {\text{p}}}}) kinetics were examined in young adults (n = 7) during moderate-intensity exercise (MOD). Subjects completed leg cycling exercise during (1) normal breathing (CON,
PETCO2 ~ 40 mmHg) and (2) controlled hyperventilation (HYPO, PETCO2 ~ 20 mmHg) throughout the protocol, with each condition repeated on four occasions. The protocol consisted of two MOD transitions
(MOD1, MOD2) to 80% estimated lactate threshold with MOD2 preceded by HVY (Δ50%); each transition lasted 6 min and was preceded
by 20 W cycling.
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} was measured breath-by-breath and concentration changes in oxy- and deoxy-hemoglobin/myoglobin (Δ[HHb]) of the vastus lateralis
muscle were measured by near-infrared spectroscopy. Adjustment of
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} and Δ[HHb] were modeled using a mono-exponential equation by non-linear regression. During MOD1, the phase 2 time constant
(τ) for
[(V)\dot]\textO 2 \textp (t[(V)\dot]\textO 2 \textp ) \dot{V}{\text{O}}_{{ 2 {\text{p}}}} \,(\tau \dot{V}{\text{O}}_{{ 2 {\text{p}}}} ) was greater (P < 0.05) in HYPO (45 ± 24 s) than CON (28 ± 17 s). During MOD2,
t[(V)\dot]\textO 2 \textp \tau \dot{V}{\text{O}}_{{ 2 {\text{p}}}} was reduced (P < 0.05) in both conditions (HYPO: 24 ± 7 s, CON: 20 ± 8 s). The Δ[HbTOT] and Δ[O2Hb] were greater (P < 0.05) prior to and throughout MOD2. The Δ[HHb] mean response time was similar in MOD1 and MOD2, and between conditions,
however, the MOD1 Δ[HHb] amplitude was greater (P < 0.05) in HYPO compared to CON, with no differences between conditions in MOD2. These findings suggest that the speeding
of
[(V)\dot]\textO 2 \textp \dot{V}{\text{O}}_{{ 2 {\text{p}}}} kinetics after prior HVY in HYPO was related, in part, to an increase in microvascular perfusion. 相似文献
19.
Green HJ Duhamel TA Smith IC Rich SM Thomas MM Ouyang J Yau JE 《European journal of applied physiology》2011,111(5):827-837
A single session of prolonged work was employed to investigate changes in selected metabolic, transporter and enzymatic properties
in muscle. Ten active but untrained volunteers (weight = 73.9 ± 4.2 kg) with a peak aerobic power
( [(V)\dot]\textO2\textpeak ) \left( {\dot{V}{\text{O}}_{{2{\text{peak}}}} } \right) of 2.95 ± 0.27 l min−1, cycled for 2 h at 62 ± 1.3%
( [(V)\dot]\textO2\textpeak ) \left( {\dot{V}{\text{O}}_{{2{\text{peak}}}} } \right) Tissue extraction from the vastus lateralis occurred prior to (E1-Pre) and following (E1-Post) exercise and on 3 consecutive
days of recovery (R1, R2, R3). The exercise resulted in decreases (P < 0.05) in ATP (−9.3%) and creatine phosphate (−49%) and increases in lactate (+100%), calculated free ADP (+253%) and free
AMP (+1,207%), all of which recovered to E1-Pre by R1. Glycogen concentration, which was depressed (P < 0.05) by 75% at E1-Post, did not recover until R3. Compared to E1-Pre, the cycling also resulted in decreases (P < 0.05) in the activities of cytochrome c oxidase, phosphorylase, and hexokinase but not in citrate synthase (CS) or 3-hydroxy-CoA dehydrogenase at E1-Post. With the
exception of CS, which was elevated (P < 0.05) at R3, all enzyme activities were not different from E1-Pre during recovery. For the glucose (GLUT1, GLUT4) and monocarboxylate
(MCT1, MCT4) transporters, changes in expression levels (P < 0.05) were only observed for GLUT1 at R1 (+42%) and R3 (+33%). It is concluded that the metabolic stress produced by prolonged
exercise is reversed by 1 day of recovery. One day of exercise also resulted in a potential upregulation in the citric acid
cycle and glucose transport capabilities, adaptations which are expressed at variable recovery durations. 相似文献
20.
Christian Doria Arsenio Veicsteinas Eloisa Limonta Martina A. Maggioni Pierluigi Aschieri Fabrizio Eusebi Giorgio Fanò Tiziana Pietrangelo 《European journal of applied physiology》2009,107(5):603-610
Breath-by-breath O2 uptake (
[(V)\dot]\textO2 \dot{V}_{{{\text{O}}_{2} }} , L min−1) and blood lactate concentration were measured before, during exercise, and recovery in six kata and six kumite karate Word Champions performing a simulated competition.
[(V)\dot]\textO 2 \textmax , \dot{V}_{{{\text{O}}_{{ 2 {\text{max}}}} }} , maximal anaerobic alactic, and lactic power were also assessed. The total energy cost (
V\textO 2 \textTOT , V_{{{\text{O}}_{{ 2 {\text{TOT}}}} }} , mL kg−1 above resting) of each simulated competition was calculated and subdivided into aerobic, lactic, and alactic fractions. Results
showed that (a) no differences between kata and kumite groups in
[(V)\dot]\textO 2 \textmax , \dot{V}_{{{\text{O}}_{{ 2 {\text{max}}}} }} , height of vertical jump, and Wingate test were found; (b)
V\textO 2 \textTOT V_{{{\text{O}}_{{ 2 {\text{TOT}}}} }} were 87.8 ± 6.6 and 82.3 ± 12.3 mL kg−1 in kata male and female with a performance time of 138 ± 4 and 158 ± 14 s, respectively; 189.0 ± 14.6 mL kg−1 in kumite male and 155.8 ± 38.4 mL kg−1 in kumite female with a predetermined performance time of 240 ± 0 and 180 ± 0 s, respectively; (c) the metabolic power was significantly
higher in kumite than in kata athletes (p ≤ 0.05 in both gender); (d) aerobic and anaerobic alactic sources, in percentage of the total, were significantly different
between gender and disciplines (p < 0.05), while the lactic source was similar; (e) HR ranged between 174 and 187 b min−1 during simulated competition. In conclusion, kumite appears to require a much higher metabolic power than kata, being the energy source with the aerobic contribution predominant. 相似文献
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