共查询到20条相似文献,搜索用时 31 毫秒
1.
H. Arabi H. Vandewalle P. Pitor J. de Lattre H. Monod 《European journal of applied physiology and occupational physiology》1997,76(2):122-127
The present experiment was designed to study the importance of strength and muscle mass as factors limiting maximal oxygen
uptake (V˙O2
max
) in wheelchair subjects. Thirteen paraplegic subjects [mean age 29.8 (8.7) years] were studied during continuous incremental
exercises until exhaustion on an arm-cranking ergometer (AC), a wheelchair ergometer (WE) and motor-driven treadmill (TM).
Lean arm volume (LAV) was estimated using an anthropometric method based upon the measurement of various circumferences of
the arm and forearm. Maximal strength (MVF) was measured while pushing on the rim of the wheelchair for three positions of
the hand on the rim (−30°, 0° and +30°). The results indicate that paraplegic subjects reached a similar V˙O2
max
[1.23 (0.34) l · min−1, 1.25 (0.38) l · min−1, 1.22 (0.18) l · min−1 for AC, TM and WE, respectively] and V˙O2
max
/body mass [19.7 (5.2) ml · min−1 · kg−1, 19.5 (6.14) ml · min−1 · kg−1, 19.18 (4.27) ml · min−1 · kg−1 for AC, TM and WE, respectively on the three ergometers. Maximal heart rate f
c
max
during the last minute of AC (173 (17) beats · min−1], TM [168 (14) beats · min−1], and WE [165 (16) beats · min−1], were correlated, but f
c
max
was significantly higher for AC than for TM (P<0.03). There were significant correlations between MVF and LAV (P<0.001) and between the MVF data obtained at different angles of the hand on the rim [311.9 (90.1) N, 313.2 (81.2) N, 257.1
(71) N, at −30°, 0° and +30°, respectively]. There was no correlation between V˙O2
max
and LAV or MVF. The relatively low values of f
c
max
suggest that V˙O2
max
was, at least in part, limited by local aerobic factors instead of central cardiovascular factors. On the other hand, the
lack of a significant correlation between V˙O2
max
and MVF or muscle mass was not in favour of muscle strength being the main factor limiting V˙O2
max
in our subjects.
Accepted: 31 January 1997 相似文献
2.
Jerzy A. Zoladz Krzysztof Duda Joanna Majerczak 《European journal of applied physiology and occupational physiology》1998,77(5):445-451
A group of 12 healthy non-smoking men [mean age 22.3 (SD 1.1) years], performed an incremental exercise test. The test started
at 30 W, followed by increases in power output (P) of 30 W every 3 min, until exhaustion. Blood samples were taken from an antecubital vein for determination of plasma concentration
lactate [La−]pl and acid-base balance variables. Below the lactate threshold (LT) defined in this study as the highest P above which a sustained increase in [La−]pl was observed (at least 0.5 mmol · l−1 within 3 min), the pulmonary oxygen uptake (V˙O2) measured breath-by-breath, showed a linear relationship with P. However, at P above LT [in this study 135 (SD 30) W] there was an additional accumulating increase in V˙O2 above that expected from the increase in P alone. The magnitude of this effect was illustrated by the difference in the final P observed at maximal oxygen uptake (V˙O2max) during the incremental exercise test (P
max,obs at V˙O2max) and the expected power output at V˙O2max(P
max,exp at V˙O2max) predicted from the linear V˙O2-P relationship derived from the data collected below LT. The P
max,obs at V˙O2max amounting to 270 (SD 19) W was 65.1 (SD 35) W (19%) lower (P<0.01) than the P
max,exp at V˙O2max
. The mean value of V˙O2max reached at P
max,obs amounted to 3555 (SD 226) ml · min−1 which was 572 (SD 269) ml · min−1 higher (P<0.01) than the V˙O2 expected at this P, calculated from the linear relationship between V˙O2 and P derived from the data collected below LT. This fall in locomotory efficiency expressed by the additional increase in V˙O2, amounting to 572 (SD 269) ml O2 · min−1, was accompanied by a significant increase in [La−]pl amounting to 7.04 (SD 2.2) mmol · l−1, a significant increase in blood hydrogen ion concentration ([H+]b) to 7.4 (SD 3) nmol · l−1 and a significant fall in blood bicarbonate concentration to 5.78 (SD 1.7) mmol · l−1, in relation to the values measured at the P of the LT. We also correlated the individual values of the additional V˙O2 with the increases (Δ) in variables [La−]pl and Δ[H+]b. The Δ values for [La−]pl and Δ[H+]b were expressed as the differences between values reached at the P
max,obs at V˙O2max and the values at LT. No significant correlations between the additional V˙O2 and Δ[La−]pl on [H+]b were found. In conclusion, when performing an incremental exercise test, exceeding P corresponding to LT was accompanied by a significant additional increase in V˙O2 above that expected from the linear relationship between V˙O2 and P occurring at lower P. However, the magnitude of the additional increase in V˙O2 did not correlate with the magnitude of the increases in [La−]pl and [H+]b reached in the final stages of the incremental test.
Accepted: 30 October 1997 相似文献
3.
Jerzy A. Zoladz Zbigniew Szkutnik Joanna Majerczak Krzysztof Duda 《European journal of applied physiology and occupational physiology》1998,78(4):369-377
The purpose of this study was to develop a method to determine the power output at which oxygen uptake (V˙O2) during an incremental exercise test begins to rise non-linearly. A group of 26 healthy non-smoking men [mean age 22.1 (SD
1.4) years, body mass 73.6 (SD 7.4) kg, height 179.4 (SD 7.5) cm, maximal oxygen uptake (V˙O2max) 3.726 (SD 0.363) l · min−1], experienced in laboratory tests, were the subjects in this study. They performed an incremental exercise test on a cycle
ergometer at a pedalling rate of 70 rev · min−1. The test started at a power output of 30 W, followed by increases amounting to 30 W every 3 min. At 5 min prior to the first
exercise intensity, at the end of each stage of exercise protocol, blood samples (1 ml each) were taken from an antecubital
vein. The samples were analysed for plasma lactate concentration [La]pl, partial pressure of O2 and CO2 and hydrogen ion concentration [H+]b. The lactate threshold (LT) in this study was defined as the highest power output above which [La−]pl showed a sustained increase of more than 0.5 mmol · l−1 · step−1. The V˙O2 was measured breath-by-breath. In the analysis of the change point (CP) of V˙O2 during the incremental exercise test, a two-phase model was assumed for the 3rd-min-data of each step of the test: X
i
=at
i
+b+ɛ
i
for i=1,2,…,T, and E(X
i
)>at
i
+b for i =T+1,…,n, where X
1, … , X
n
are independent and ɛ
i
∼N(0,σ2). In the first phase, a linear relationship between V˙O2 and power output was assumed, whereas in the second phase an additional increase in V˙O2 above the values expected from the linear model was allowed. The power output at which the first phase ended was called the
change point in oxygen uptake (CP-V˙O2). The identification of the model consisted of two steps: testing for the existence of CP and estimating its location. Both
procedures were based on suitably normalised recursive residuals. We showed that in 25 out of 26 subjects it was possible
to determine the CP-O2 as described in our model. The power output at CP-V˙O2 amounted to 136.8 (SD 31.3) W. It was only 11 W – non significantly – higher than the power output corresponding to LT. The
V˙O2 at CP-V˙O2 amounted to 1.828 (SD 0.356) l · min−1 was [48.9 (SD 7.9)% V˙O2
max
]. The [La−]pl at CP-V˙O2, amounting to 2.57 (SD 0.69) mmol · l−1 was significantly elevated (P<0.01) above the resting level [1.85 (SD 0.46) mmol · l−1], however the [H+]b at CP-V˙O2 amounting to 45.1 (SD 3.0) nmol · l−1, was not significantly different from the values at rest which amounted to 44.14 (SD 2.79) nmol · l−1. An increase of power output of 30 W above CP-V˙O2 was accompanied by a significant increase in [H+]b above the resting level (P=0.03).
Accepted: 25 March 1998 相似文献
4.
Greg J. Wilson Andrew D. Walshe Mark R. Fisher 《European journal of applied physiology and occupational physiology》1997,75(5):455-461
The aims of the present study were: (1) to assess aerobic metabolism in paraplegic (P) athletes (spinal lesion level, T4–L3)
by means of peak oxygen uptake (V˙O2peak) and ventilatory threshold (VT), and (2) to determine the nature of exercise limitation in these athletes by means of cardioventilatory
responses at peak exercise. Eight P athletes underwent conventional spirographic measurements and then performed an incremental
wheelchair exercise on an adapted treadmill. Ventilatory data were collected every minute using an automated metabolic system:
ventilation (l · min−1), oxygen uptake (V˙O2, l · min−1, ml · min−1 · kg−1), carbon dioxide production (V˙CO2, ml · min−1), respiratory exchange ratio, breathing frequency and tidal volume. Heart rate (HR, beats · min−1) was collected with the aid of a standard electrocardiogram. V˙O2peak was determined using conventional criteria. VT was determined by the breakpoint in the V˙CO2−V˙O2 relationship, and is expressed as the absolute VT (V˙O2, ml · min−1 · kg−1) and relative VT (percentage of V˙O2peak). Spirometric values and cardioventilatory responses at rest and at peak exercise allowed the measurement of ventilatory
reserve (VR), heart rate reserve (HRr), heart rate response (HRR), and O2 pulse (O2 P). Results showed a V˙O2peak value of 40.6 (2.5) ml · min−1 · kg−1, an absolute VT detected at 23.1 (1.5) ml · min−1 · kg−1
V˙O2 and a relative VT at 56.4 (2.2)% V˙O2peak. HRr [15.8 (3.2) beats · min−1], HRR [48.6 (4.3) beat · l−1], and O2 P [0.23 (0.02) ml · kg−1 · beat−1] were normal, whereas VR at peak exercise [42.7 (2.4)%] was increased. As wheelchair exercise excluded the use of an able-bodied
(AB) control group, we compared our V˙O2peak and VT results with those for other P subjects and AB controls reported in the literature, and we compared our cardioventilatory
responses with those for respiratory and cardiac patients. The low V˙O2peak values obtained compared with subject values obtained during an arm-crank exercise may be due to a reduced active muscle
mass. Absolute VT was somewhat comparable to that of AB subjects, mainly due to the similar muscle mass involved in wheelchair
and arm-crank exercise by P and AB subjects, respectively. The increased VR, as reported in patients with chronic heart failure,
suggested that P athletes exhibited cardiac limitation at peak exercise, and this contributed to the lower V˙O2peak measured in these subjects.
Accepted: 22 April 1997 相似文献
5.
Fifteen young adult Singaporean male physical education students maximum oxygen consumption [(V˙O2max) = 56 (4.7) ml · kg−1 · min−1] performed three prolonged runs in a counterbalanced design. The running bouts varied in time (40 vs 60 min) and intensity
(70% vs 80% V˙O2
max
). Each prolonged run was separated by 7 days. The running economy (RE) at 10.8 km · h−1 during 10-min running bouts was measured before (RE1) and after (RE2) each prolonged run. A control study involved monitoring
RE at 10.8 km · h−1 before and after 60 min rest. There were no differences between RE1 and RE2 values during the control run. However, there
were differences between RE1 and RE2 values when separated by a prolonged run. For example, the mean (SD) changes in oxygen
consumption (ml · kg−1 · min−1) values were 38.2 (2.5) versus 40.1 (2.6) (40 min at 80% V˙O2
max
), 38.9 (2.8) versus 41.5 (2.6) (60 min at 70% V˙O2
max
), and 39.0 (3.1) versus 42.7 (2.9) (60 min at 80% V˙O2
max
; P < 0.01). The results of this investigation support the hypothesis that RE deteriorates during prolonged running, and that
the magnitude of the deterioration in RE increases with both increasing exercise intensity and duration.
Accepted: 14 July 1997 相似文献
6.
This study investigated the effects on running economy (RE) of ingesting either no fluid or an electrolyte solution with
or without 6% carbohydrate (counterbalanced design) during 60-min running bouts at 80% maximal oxygen consumption (V˙O2max). Tests were undertaken in either a thermoneutral (22–23°C; 56–62% relative humidity, RH) or a hot and humid natural environment
(Singapore: 25–35°C; 66–77% RH). The subjects were 15 young adult male Singaporeans [V˙O2max = 55.5 (4.4 SD) ml kg−1 min−1]. The RE was measured at 3 m s−1 [65 (6)% V˙O2max] before (RE1) and after each prolonged run (RE2). Fluids were administered every 2 min, at an individual rate determined
from prior tests, to maintain body mass (group mean = 17.4 ml min−1). The V˙O2 during RE2 was higher (P < 0.05) than that during the RE1 test for all treatments, with no differences between treatments (ANOVA). The mean increase
in V˙O2 from RE1 to RE2 ranged from 3.4 to 4.7 ml kg−1 min−1 across treatments. In conclusion, the deterioration in RE at 3 m s−1 (65% V˙O2max) after 60 min of running at 80% V˙O2max appears to occur independently of whether fluid is ingested and regardless of whether the fluid contains carbohydrates or
electrolytes, in both a thermoneutral and in a hot, humid environment.
Accepted: 30 October 1997 相似文献
7.
S. Grant W. Davidson T. Aitchison J. Wilson 《European journal of applied physiology and occupational physiology》1998,78(4):324-332
The aim of this study was to compare the exercise intensity and rating of perceived exertion (RPE) of a high-impact (HIP)
and a low-impact (LIP) university aerobic dance session. Ten women [mean (SD) age 22.9 (2.6) years] took part in the study.
An incremental treadmill test was performed by each subject to determine maximum oxygen consumption (V˙O2
max
) and maximum heart rate (HR
max
). The measured V˙O2
max
[mean (SD)] was 49.0 (7.5) ml · kg−1 · min−1. The subjects were randomly assigned to LIP and HIP sessions (i.e. five of the subjects participated in the HIP session first,
and the other five participated in the LIP session first). In a laboratory, heart rate, oxygen uptake and RPE were measured
throughout each session for each subject. Expired air was collected continuously throughout the sessions using Douglas bags
(ten bags over a 30-min period). The sessions consisted of 20 min of aerobic exercise (bags 1–7) followed by 5 min of local
muscular endurance exercise (bags 8 and 9) and 5 min of flexibility exercises (bag 10). The mean intensity of the aerobic
section of the LIP and HIP sessions was 51.6% and 64.7% V˙O2
max
, respectively. Ninety-five percent confidence intervals for the average difference between the HIP and LIP sessions demonstrate
that the %V˙O2
max
was between 12% and 14% higher for the HIP session. The mean %HR
max
for the LIP and HIP sessions was 71.4% and 76.7%, respectively, with the %HR
max
in the HIP session being between 5.4% and 7.2% higher on average than that of the LIP session. On average, the RPE for the
aerobic section of the HIP session (12.1) was consistently higher than that of the LIP session (11.1). HIP activity has the
potential to maintain/improve the aerobic fitness of its participants. According to the literature, the exercise intensity
elicited by LIP activity may have a limited training effect for the population utilised in this study, and for some individuals
may result in detraining. Conversely, LIP activities may be an appropriate mode of exercise for overweight and unfit individuals.
Accepted: 5 January 1998 相似文献
8.
Carlo Capelli Dave R. Pendergast B. Termin 《European journal of applied physiology and occupational physiology》1998,78(5):385-393
The energy cost per unit of distance (C
s, kilojoules per metre) of the front-crawl, back, breast and butterfly strokes was assessed in 20 elite swimmers. At sub-maximal
speeds (v), C
s was measured dividing steady-state oxygen consumption (V˙O2) by the speed (v, metres per second). At supra-maximal v, C
s was calculated by dividing the total metabolic energy (E, kilojoules) spent in covering 45.7, 91.4 and 182.9 m by the distance. E was obtained as: E = E
an+V˙O2max
t
p−V˙O2max(1−e−(
t
p/)), where E
an was the amount of energy (kilojoules) derived from anaerobic sources, V˙O2max litres per second was the maximal oxygen uptake, α (=20.9 kJ · l O2
−1) was the energy equivalent of O2, τ (24 s) was the time constant assumed for the attainment of V˙O2max at muscle level at the onset of exercise, and t
p (seconds) was the performance time. The lactic acid component was assumed to increase exponentially with t
p to an asymptotic value of 0.418 kJ · kg−1 of body mass for t
p ≥ 120 s. The lactic acid component of E
an was obtained from the net increase of lactate concentration after exercise (Δ[La]b) assuming that, when Δ[La]b = 1 mmol · l−1 the net amount of metabolic energy released by lactate formation was 0.069 kJ · kg−1. Over the entire range of v, front crawl was the least costly stroke. For example at 1 m · s−1, C
s amounted, on average, to 0.70, 0.84, 0.82 and 0.124 kJ · m−1 in front crawl, backstroke, butterfly and breaststroke, respectively; at 1.5 m · s−1, C
s was 1.23, 1.47, 1.55 and 1.87 kJ · m−1 in the four strokes, respectively. The C
s was a continuous function of the speed in all of the four strokes. It increased exponentially in crawl and backstroke, whereas
in butterfly C
s attained a minimum at the two lowest v to increase exponentially at higher v. The C
s in breaststroke was a linear function of the v, probably because of the considerable amount of energy spent in this stroke for accelerating the body during the pushing
phase so as to compensate for the loss of v occurring in the non-propulsive phase.
Accepted: 14 April 1998 相似文献
9.
M. Sandsund M. Sue-Chu J. Helgerud R. E. Reinertsen L. Bjermer 《European journal of applied physiology and occupational physiology》1998,77(4):297-304
The effects of whole-body exposure to ambient temperatures of −15°C and 23°C on selected performance-related physiological
variables were investigated in elite nonasthmatic cross-country skiers. At an ambient temperature of −15°C we also studied
the effects of the selective β2-adrenergic agonist Salbutamol (0.4 mg × 3) which was administered 10 min before the exercise test. Eight male cross-country
skiers with known maximal oxygen uptakes (V˙O2
max
) of more than 70 ml · kg−1 · min−1 participated in the study. Oxygen uptake (V˙O2), heart rate (f
c), blood lactate concentration ([La−]b) and time to exhaustion were measured during controlled submaximal and maximal running on a treadmill in a climatic chamber.
Lung function measured as forced expiratory volume in 1 s (FEV1) was recorded immediately before the warm-up period and at the conclusion of the exercise protocol. Submaximal V˙O2 and [La−]b at the two highest submaximal exercise intensities were significantly higher at −15°C than at 23°C. Time to exhaustion was
significantly shorter in the cold environment. However, no differences in V˙O2
max
or f
c were observed. Our results would suggest that exercise stress is higher at submaximal exercise intensities in a cold environment
and support the contention that aerobic capacity is not altered by cold exposure. Furthermore, we found that after Salbutamol
inhalation FEV1 was significantly higher than after placebo administration. However, the inhaled β2-agonist Salbutamol did not influence submaximal and maximal V˙O2, f
c, [La−]b or time to exhaustion in the elite, nonasthmatic cross-country skiers we studied. Thus, these results did not demonstrate
any ergogenic effect of the β2-agonist used.
Accepted: 18 August 1997 相似文献
10.
Gerald S. Zavorsky David L. Montgomery David J. Pearsall 《European journal of applied physiology and occupational physiology》1998,77(3):224-230
The purposes of this study were to determine whether running economy (RE) is adversely affected following intense interval
bouts of 10 × 400-m running, and whether there is an interaction effect between RE and recovery duration during the workouts.
Twelve highly trained male endurance athletes [maximal oxygen consumption; V˙O2
max
=72.5 (4.3) ml·kg−1·min−1; mean (SD)] performed three interval running workouts of 10 × 400 m with a minimum of 4 days between runs. Recovery duration
between the repetitions was randomly assigned at 60, 120 or 180 s. The velocity for each 400-m run was determined from a treadmill
V˙O2
max
test. The average running velocity was 357.9 (9.0) m · min−1. Following the workout, the rating of perceived exertion (RPE) increased significantly (P < 0.01) as recovery duration between the 400-m repetitions decreased (14.4, 16.1, and 17.7 at 180s, 120s, and 60 s recovery,
respectively). Prior to and following each workout, RE was measured at speeds of 200 and 268 m · min−1. Changes in RE from pre- to post-workout, as well as heart rate (HR) and respiratory exchange ratio (R) were similar for the three recovery conditions. When averaged across conditions, oxygen consumption (V˙O2) increased significantly (P < 0.01) from pre- to post-test (from 38.5 to 40.5 ml · kg−1 · min−1 at 200 m · min−1, and from 53.1 to 54.5 ml · kg−1 · min−1 at 268 m · min−1, respectively). HR increased (from 124 to 138, and from 151 to 157 beats · min−1 respectively) and R decreased (from 0.90 to 0.78, and from 0.93 to 0.89, respectively) at 200 and 268 m · min−1, respectively (P < 0.01). This study showed that RE can be perturbed after a high-intensity interval workout and that the changes in V˙O2, HR and R were independent of the recovery duration between the repetitions.
Accepted: 23 June 1997 相似文献
11.
Hiroshi Takaki Kenji Sunagawa Masaru Sugimachi Yasushi Hara Toru Kawada Takashi Kurita Yoichi Goto 《European journal of applied physiology and occupational physiology》1998,78(4):333-339
The transient response of oxygen uptake (V˙O2) to submaximal exercise, known to be abnormal in patients with cardiovascular disorders, can be useful in assessing the functional
status of the cardiocirculatory system, however, a method for evaluating it accurately has not yet been established. As an
alternative approach to the conventional test at constant exercise intensity, we applied a random stimulus technique that
has been shown to provide relatively noise immune responses of system being investigated. In 27 patients with heart failure
and 24 age-matched control subjects, we imposed cycle exercise at 50 W intermittently according to a pseudo-random binary
(exercise-rest) sequence, while measuring breath-by-breath V˙O2. After determining the transfer function relating exercise intensity (W˙) to V˙O2 and attenuating the high frequency ranges (>6 exercise-rest cycles · min−1), we computed the high resolution band-limited (0–6 cycles · min−1) V˙O2 response (0–120 s) to a hypothetical step exercise. The V˙O2 response showed a longer time constant in the patients than in the control subjects [47 (SD 37) and 31 (SD 8) s, respectively,
P < 0.05]. Furthermore, the amplitude of the V˙O2 response after the initial response was shown to be significantly smaller in the patients than in the control subjects [176
(SD 50) and 267 (SD 54) ml · min−1 at 120 s]. The average amplitude over 120 s correlated well with peak V˙O2 (r = 0.73) and ΔV˙O2/ΔW˙ (r = 0.70), both of which are well-established indexes of exercise tolerance. The data indicated that our band-limited V˙O2
step response using random exercise was more markedly attenuated and delayed in the patients with heart failure than in the normal controls
and that it could be useful in quantifying the overall functional status of the cardiocirculatory system.
Accepted: 6 January 1998 相似文献
12.
M. Faina V. Billat R. Squadrone M. De Angelis J. P. Koralsztein A. Dal Monte 《European journal of applied physiology and occupational physiology》1997,76(1):13-20
Using 23 elite male athletes (8 cyclists, 7 kayakists, and 8 swimmers), the contribution of the anaerobic energy system to
the time to exhaustion (t
lim) at the minimal exercise intensity (speed or power) at which maximal oxygen uptake (V˙O2
max) occurs (I
V˙O2
max) was assessed by analysing the relationship between the t
lim and the accumulated oxygen deficit (AOD). After 10-min warming up at 60% of V˙O2
max, the exercise intensity was increased so that each subject reached his I
V˙O2max
in 30 s and then continued at that level until he was exhausted. Pre-tests included a continuous incremental test with 2 min
steps for determining the I
V˙O2max
and a series of 5-min submaximal intensities to collect the data that would allow the estimation of the energy expenditure
at I
V˙O2max
. The AOD for the t
lim exercise was calculated as the difference between the above estimation and the accumulated oxygen uptake. The mean percentage
value of energy expenditure covered by anaerobic metabolism was 15.2 [(SD 6)%, range 8.9–24.1] with significant differences
between swimmers and kayakists (16.8% vs 11.5%, P≤0.05) and cyclists and kayakists (16.4% vs 11.5%, P≤0.05). Absolute AOD values ranged from 26.4 ml · kg−1 to 83.6 ml · kg−1 with a mean value of 45.9 (SD 18) ml · kg−1. Considering all the subjects, the t
lim was found to have a positive and significant correlation with AOD (r = 0.62, P≤0.05), and a negative and significant correlation with V˙O2
max (r = −0.46, P≤0.05). The data would suggest that the contribution of anaerobic processes during exercise performed at I
V˙O2max
should not be ignored when t
lim is used as a supplementary parameter to evaluate specific adaptation of athletes.
Accepted: 17 December 1996 相似文献
13.
J. Hall I. A. Macdonald P. J. Maddison J. P. O''Hare 《European journal of applied physiology and occupational physiology》1998,77(3):278-284
This study compared the cardiorespiratory responses of eight healthy women (mean age 30.25 years) to submaximal exercise
on land (LTm) and water treadmills (WTm) in chest-deep water (Aquaciser). In addition, the effects of two different water
temperatures were examined (28 and 36°C). Each exercise test consisted of three consecutive 5-min bouts at 3.5, 4.5 and 5.5 km · h−1. Oxygen consumption (V˙O2) and heart rate (HR), measured using open-circuit spirometry and telemetry, respectively, increased linearly with increasing
speed both in water and on land. At 3.5 km · h−1
V˙O2 was similar across procedures [χ = 0.6 (0.05) l · min−1]. At 4.5 and 5.5 km · h−1
V˙O2 was significantly higher in water than on land, but there was no temperature effect (WTm: 0.9 and 1.4, respectively; LTm:
0.8 and 0.9 l · min−1, respectively). HR was significantly higher in WTm at 36°C compared to WTm at 28°C at all speeds, and compared to LTm at
4.5 and 5.5 km · h−1 (P ≤ 0.003). The HR-V˙O2 relationship showed that at a V˙O2 of 0.9 l · min−1, HR was higher in water at 36°C (115 beats · min−1) than either on land (100 beats · min−1) or in water at 28°C (99 beats · min−1). The Borg scale of perceived exertion showed that walking in water at 4.5 and 5.5 km · h−1 was significantly harder than on land (WTm: 11.4 and 14, respectively; LTm: 9.9 and 11, respectively; P ≤ 0.001). These cardiorespiratory changes occurred despite a slower cadence in water (the mean difference at all speeds was
27 steps/min). Thus, walking in chest-deep water yields higher energy costs than walking at similar speeds on land. This data
has implications for therapists working in hydrotherapy pools.
Accepted: 3 September 1997 相似文献
14.
Stephen S. Cheung Tom M. McLellan 《European journal of applied physiology and occupational physiology》1998,78(1):50-58
The purpose of the present study was to determine the separate and combined effects of a short-term aerobic training program
and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in
the heat (40°C, 30% relative humidity). Males of moderate fitness [<50 ml · kg−1 · min−1 maximal O2 consumption (V˙O2
max
)] were tested while euhydrated or hypohydrated by ≈2% of body weight through exercise and fluid restriction the day preceding
the trials. Tests were conducted before and after either a 2-week program of daily aerobic training (1 h treadmill exercise
at 65% V˙O2
max
for 12 days; n = 8) or a control period (n = 7), which had no effect on any measured variable. The training increased V˙O2
max
by 6.5%, while heart rate (f
c) and the rectal temperature (T
re) rise decreased during exercise in a thermoneutral environment. In the heat, training resulted in a decreased skin temperature
and increased sweat rate, but did not affect f
c, T
re or tolerance time (TT). In both training and control groups, hypohydration significantly increased T
re and f
c and decreased the TT. It was concluded that the short-term aerobic training program had no benefit on exercise-heat tolerance
in this uncompensable heat stress environment.
Accepted: 12 November 1997 相似文献
15.
D. L. Thompson K. M. Townsend R. Boughey K. Patterson D. R. Bassett Jr 《European journal of applied physiology and occupational physiology》1998,78(1):43-49
Substrate utilization during and after low- and moderate-intensity exercise of similar caloric expenditure was compared.
Ten active males [age: 26.9 (4.8) years; height: 181.1 (4.8) cm; Mass: 75.7 (8.8) kg; maximum O2 consumption (V˙O2
max
): 51.2 (4.8) ml · kg−1 · min−1] cycled at 33% and 66% V˙O2
max
on separate days for 90 and 45 min, respectively. After exercise, subjects rested in a recumbent position for 6 h. Two h
post-exercise, subjects ate a standard meal of 66% carbohydrate (CHO), 11% protein, and 23% fat. Near-continuous indirect
calorimetry and measurement of urinary nitrogen excretion were used to determine substrate utilization. Total caloric expenditure
was similar for the two trials; however, significantly (P<0.05) more fat [42.4 (3.6) g versus 24.0 (12.2) g] and less CHO [142.5 (28.5) g versus 188.8 (45.2) g] was utilized as a
substrate during the low-intensity compared to the moderate-intensity trial. Protein utilization was similar for the two trials.
The difference in substrate use can be attributed to the exercise period because over twice as much fat was utilized during
low-intensity [30.0 (11.0) g] compared to moderate-intensity exercise [13.6 (6.6) g]. Significantly more (P<0.05) CHO was utilized during the moderate-intensity [106.0 (27.8) g] compared to the low-intensity exercise [68.7 (20.0) g].
Substrate use during the recovery period was not significantly different. We conclude that low-intensity, long-duration exercise
results in a greater total fat oxidation than does moderate intensity exercise of similar caloric expenditure. Dietary-induced
thermogenesis was not different for the two trials.
Accepted: 3 November 1997 相似文献
16.
Savvas P. Tokmakidis Luc A. Léger Theophilos C. Pilianidis 《European journal of applied physiology and occupational physiology》1998,77(4):333-342
The purpose of this study was to compare various methods and criteria used to identify the anaerobic threshold (AT), and
to correlate the AT obtained with each other and with running performance. Furthermore, a number of additional points throughout
the entire range of lactate concentrations [La−] were obtained and correlated with performance. A group of 19 runners [mean age 33.7 (SD 9.6) years, height 173 (SD 6.3)
cm, body mass 68.3 (SD 5.4) kg, maximal O2 uptake (V˙O2
max
) 55.2 (SD 5.9) ml · kg−1 · min−1] performed a maximal multistage treadmill test (1 km · h−1 every 3.5 min) with blood sampling at the end of each stage while running. All AT points selected (visual [La−], 4 mmol · l−1 [La−], 1 mmol · l−1 above baseline, log-log breakpoint, and 45° tangent to the exponential regression) were highly correlated one with another
and with performance (r > 0.90) even when there were many differences among the AT (P < 0.05). The additional points (ranging from 3 to 8 mmol · l−1 [La−], 1 to 6 mmol · l−1 [La−] above the baseline, and 30 to 70° tangent to the exponential curve of [La−]) were also highly correlated with performance (r > 0.90). These results failed to demonstrate a distinct AT because many points of the curve provided similar information.
Intercorrelations and correlations between AT and performance were, however, reduced when AT were expressed as the percentage
of maximal treadmill speed obtained at AT or percentage of V˙O2
max
. This would indicate that different attributes of aerobic performance (i.e. maximal aerobic power, running economy and endurance)
are measured when manipulating units. Thus, coaches should be aware of these results when they prescribe an intensity for
training and concentrate more on the physiological consequences of a chosen [La−] rather than on a “threshold”.
Accepted: 22 October 1997 相似文献
17.
D. Habedank I. Reindl G. Vietzke U. Bauer A. Sperfeld S. Gl?ser K. D. Wernecke F. X. Kleber 《European journal of applied physiology and occupational physiology》1998,77(5):421-426
The ventilatory equivalent for CO2 defines ventilatory efficiency largely independent of metabolism. An impairment of ventilatory efficiency may be caused by
an increase in either anatomical or physiological dead space, the latter being the most important mechanism in the hyperpnoea
of heart failure, pulmonary embolism, pulmonary hypertension and the former in restrictive lung disease. However, normal values
for ventilatory efficiency have not yet been established. We investigated 101 (56 men) healthy volunteers, aged 16–75 years,
measuring ventilation and gas exchange at rest (n = 64) and on exercise (modified Naughton protocol, n = 101). Age and sex dependent normal values for ventilatory efficiency at rest defined as the ratio ventilation:carbon dioxide
output (V˙
E:V˙CO2), exercise ventilatory efficiency during exercise, defined as the slope of the linear relationship between ventilation and
carbon dioxide output (V˙
E vs V˙CO2 slope), oxygen uptake at the anaerobic threshold and at maximum (V˙O2AT,V˙O2max, respectively) and breathing reserve were established. Ventilatory efficiency at rest was largely independent of age, but
was smaller in the men than in the women [V˙
E:V˙CO2 50.5 (SD 8.8) vs 57.6 (SD 12.6) P<0.05]. Ventilatory efficiency during exercise declined significantly with age and was smaller in the men than in the women
(men: (V˙
E vs V˙CO2 slope = 0.13 × age + 19.9; women: V˙
E vs V˙CO2 slope = 0.12 × age + 24.4). The V˙O2AT and V˙O2max were 23 (SD 5) and 39 (SD 7) ml O2 · kg · min−1 in the men and 18 (SD 4) and 32 (SD 7) in the women, respectively, and declined significantly with age. The V˙O2AT was reached at 58 (SD 9)% V˙O2max. Breathing reserve at the end of exercise was 41% and was independent of sex and age. It was concluded from this study that
ventilatory efficiency as well as peak oxygen uptake are age and sex dependent in adults.
Accepted: 11 June 1997 相似文献
18.
M. De Angelis G. Vinciguerra A. Gasbarri C. Pacitti 《European journal of applied physiology and occupational physiology》1998,78(2):121-127
The aim of this research was to investigate the physiological responses and, in particular, the participation of lactic acid
anaerobic metabolism in aerobic dance, which is claimed to be pure aerobic exercise. In contrast to previous studies, that
have put subjects in very unfamiliar situations, the parameters were monitored in the familiar context of gymnasium, practice
routine and habitual instructor. A group of 30 skilled fairly well-trained women performed their usual routine,␣a combination
of the two styles: low (LI) and high impact (HI), and were continuously monitored for heart rate (HR) and every 8 min for
blood lactate concentration ([La−]b). Of the group, 15 were tested to determine their maximal aerobic power (V˙O2max) using a cycleergometer. They were also monitored during the routine for oxygen uptake (V˙O2) by a light telemetric apparatus. The oxygen pulses of the routine and of the corresponding exercise intensity in the incremental
test were not statistically different. The mean values in the exercise session were: peak HR 92.8 (SD 7.8)% of the subject's
maximal theoretical value, peak V˙O2 99.5 (SD 12.4)% of V˙O2max, maximal [La−]b 6.1 (SD 1.7) mmol · l−l, and mean 4.8 (SD 1.3) mmol · l−l. Repeated measures ANOVA found statistically significant differences between the increasing [La−]b values (P < 0.001). In particular, the difference between the [La−]b values at the end of the mainly LI phase and those of the LI-HI combination phase, and the difference between the samples
during the combination LI-HI phase were both statistically significant (both P= 0.002 and P= 0.002). The similar oxygen pulses confirmed the validity of the present experiment design and the reliability of HR monitoring
in this activity. The HR, V˙O2 and, above all, the increase of [La−]b to quite high values, showing a non steady state, demonstrated the high metabolic demand made by this activity that involved
lactic acid metabolism at a much higher level than expected.
Accepted: 23 September 1997 相似文献
19.
Keisho Katayama Yasitake Sato Koji Ishida Shigeo Mori Miharu Miyamura 《European journal of applied physiology and occupational physiology》1998,78(3):189-194
The present study was performed to investigate the effects of a combination of intermittent exposure to hypoxia during exercise
training for short periods on ventilatory responses to hypoxia and hypercapnia (HVR and HCVR respectively) in humans. In a
hypobaric chamber at a simulated altitude of 4,500 m (barometric pressure 432 mmHg), seven subjects (training group) performed
exercise training for 6 consecutive days (30 min · day−1), while six subjects (control group) were inactive during the same period. The HVR, HCVR and maximal oxygen uptake (V˙O2 max) for each subject were measured at sea level before (pre) and after exposure to intermittent hypoxia. The post exposure test
was carried out twice, i.e. on the 1st day and 1 week post exposure. It was found that HVR, as an index of peripheral chemosensitivity
to hypoxia, was increased significantly (P < 0.05) in the control group after intermittent exposure to hypoxia. In contrast, there was no significant increase in HVR
in the training group after exposure. The HCVR in both groups was not changed by intermittent exposure to hypoxia, while V˙O2 max increased significantly in the training group. These results would suggest that endurance training during intermittent exposure
to hypoxia depresses the increment of chemosensitivity to hypoxia, and that intermittent exposure to hypoxia in the presence
or absence of exercise training does not induce an increase in the chemosensitivity to hypercapnia in humans.
Accepted: 18 March 1998 相似文献
20.
Michael J. Webster 《European journal of applied physiology and occupational physiology》1998,77(6):486-491
The purpose of this study was to investigate the physiological and performance responses to supplementation with allithiamin
and pantethine. On two separate occasions, six highly trained cyclists [maximum O2 consumption or V˙O2max 61.8 (2.1) ml · kg−1 · min−1] performed a 50-km steady-state ride on a cycle ergometer at a workload corresponding to ∼60% of V˙O2max followed by a 2000-m time trial. For 7 days prior to each ride, subjects daily ingested either a placebo (PL) or a combination
of 1 g of allithiamin and 1.8 g of a 55%/45% pantethine/pantothenic acid compound (AP). Treatments were administered using
a randomized, double-blind, counter-balanced design. During the 50-km ride, measures of heart rate, respiratory gas exchange
and ratings of perceived exertion were recorded at 5, 15, 25, 35 and 45 km. Blood samples were collected at 10, 20, 30, 40
and 50 km and analyzed for lactate, glucose and free fatty acids. Blood samples for the analysis of lactate were also collected
3 and 5 min after the completion of the 2000-m time trial. There were no significant differences in any of the measured parameters
between experimental conditions. Time to complete the 2000-m time trial was also not significantly different between experimental
conditions [PL 178.2 (8.4), AP 170.7 (10.2) s; P = 0.58]. These results suggest that, despite the reported enhanced absorption properties, supplementation with allithiamin
and pantethine does not alter exercise metabolism or exercise performance.
Accepted: 9 October 1997 相似文献