Biomedical subjects

Jean-Denis Rouillon

Publications and source records attributed to Jean-Denis Rouillon.

11 recordsLinked to original sources

PubMed2004

Short- and long-term effects of a single bout of exercise on heart rate variability: comparison between constant and interval training exercises.

Heart rate variability (HRV) was assessed during the short- (within 1 h) and long- (within 48 h) term recovery following a single bout of either constant (CST) or interval training (SWEET) exercise performed at the same total physical work [9.4 (0.3) kJ kg(-1)]. R-R intervals, systolic (SAP) and diastolic (DAP) arterial pressures were recorded in supine and upright positions before and 1, 24 and 48 h after the termination of the exercises in ten male subjects [mean (SEM), age 24.6 (0.6) years, height 177.2 (1.1) cm and body mass 68.5 (0.9) kg]. The parameters were also recorded in the supine position during the first 20 min following the end of the exercise. Spectral analysis parameters of HRV [total (TP), low- (LF), and high- (HF) frequency power, and LF/TP, HF/TP and LF/HF ratios] were determined over 5 min during each phase. Except for higher HF values in both supine and upright positions during the first hour following CST compared with SWEET, cardiovascular and HRV analysis responses were of the same magnitude after their termination. R-R intervals, TP, and HF/TP were significantly decreased while LF/TP and LF/HF were significantly increased during the early recovery, when compared with control values. This could be a response to the significant decrease in SAP and DAP at this time. Twenty-four and 48 h after the end of the exercise, HRV parameters were at the same levels as before exercises in the supine posture, but a persistent tachycardia continued to be observed in the upright posture, together with reduced TP values, showing that cardiovascular functions were still disturbed. The short-term HRV recovery seemed dependent on the type of exercise, contrary to the long-term recovery.

Adult↗

PubMed2004

Decrease in heart rate variability with overtraining: assessment by the Poincaré plot analysis.

Numerous symptoms have been associated with the overtraining syndrome (OT), including changes in autonomic function. Heart rate variability (HRV) provides non-invasive data about the autonomic regulation of heart rate in real-life conditions. The aims of the study were to: (i) characterize the HRV profile of seven athletes (OA) diagnosed as suffering of OT, compared with eight healthy sedentary (C) and eight trained (T) subjects during supine rest and 60 degrees upright, and (ii) compare the traditional time- and frequency-domain analysis assessment of HRV with the non-linear Poincaré plot analysis. In the latter each R-R interval is plotted as a function of the previous one, and the standard deviations of the instantaneous (SD1) and long-term R-R interval variability are calculated. Total power was higher in T than in C and OA both in supine (1158 +/- 1137, 6092 +/- 3554 and 2970 +/- 2947 ms2 for C, T and OA, respectively) and in upright (640 +/- 499, 1814 +/- 806 and 1092 +/- 712 ms2 for C, T and OA, respectively; P<0.05) positions. In supine position, indicators of parasympathetic activity to the sinus node were higher in T compared with C and OA (high-frequency power: 419.1 +/- 381.2, 1105.3 +/- 781.4 and 463.7 +/- 715.8 ms2 for C, T and OA, respectively; P<0.05; SD1: 29.5 +/- 18.5, 75.2 +/- 17.2 and 37.6 +/- 27.5 for C, T and OA, respectively; P<0.05). OA had a marked predominance of sympathetic activity regardless of the position (LF/HF were 0.47 +/- 0.35, 0.47 +/- 0.50 and 3.96 +/- 5.71 in supine position for C, T and OA, respectively, and 2.09 +/- 2.17, 7.22 +/- 6.82 and 12.04 +/- 10.36 in upright position for C, T and OA, respectively). The changes in HRV indexes induced by the upright posture were greater in T than in OA. The shape of the Poincaré plots allowed the distinction between the three groups, with wide and narrow shapes in T and OA, respectively, compared with C. As Poincaré plot parameters are easy to compute and associated with the 'width' of the scatter gram, they corroborate the traditional time- and frequency-domain analysis. We suggest that they could be used to indicate fatigue and/or prevent OT.

Adolescent↗

PubMed2004

A specific arm-interval exercise program could improve the health status and walking ability of elderly patients after total hip arthroplasty: a pilot study.

OBJECTIVE: To investigate the influence of an arm-interval exercise program for the upper limbs on health status and walking ability in elderly patients after total hip arthroplasty. DESIGN: A randomized controlled investigation. After surgery, a control group started a general rehabilitation program, and a training group combined it with an arm-interval exercise program. SUBJECTS: Fourteen patients (age 75.1 +/- 4.8 years) were randomly assigned to the control group (n = 7) and the training group (n = 7). METHODS: A Western Ontario and MacMaster University (WOMAC) Osteoarthritis Index was completed and an incremental exercise test on an arm crank ergometer was also performed 1 month before (T(-1)) and 2 months after surgery (T2). Moreover, a 6-minute walk test was performed at T2. RESULTS: Both groups significantly improved all dimensions of WOMAC, except in WOMAC physical function subscale in the control group. The training group covered a significantly longer distance in the walking test than the control group and also presented significantly higher VO2 peak value at T2. Correlation analyses indicate that VO2 peak value and the distance covered in the 6-minute walking test were significantly associated with functional status. After calculating the ratio distance covered/score at WOMAC physical function, we observed a significantly higher ratio value in the training group than in the control group. CONCLUSION: Preliminary results indicate that the improvement in physical fitness and functional status of the training group seems to be associated with better health status.

Aged↗

PubMed2004

Evaluation of a theoretical model to quantify the sources of metabolic cost in walking.

OBJECTIVE: To evaluate the validity of a theoretical model of walking in which the oxygen uptake (V(O2)) is described as a function of speed by an equation in the form y = ax + b, with constant a representing the metabolic cost for performing the walking movement, and constant b representing the sum of the metabolic costs for basal metabolism and maintaining balance and posture. DESIGN: Repeated-measures analysis of variance was used to analyze our theoretical model. In a human exercise research laboratory, 12 healthy male subjects walked on a level treadmill at speeds of 0.39-1.83 m/sec under a control condition, while wearing "instability" shoes with peripheral vision obstructed, and with 2-kg weights around each wrist. Total transported mass was the same under each condition through the carriage of 4 kg in a back pack during the control and instability conditions. Outcome was determined by equations describing (V(O2)) as a function of speed and by kinematics of the center of mass. RESULTS: The constant b was higher (P < 0.01) for the instability condition than the other conditions, but constant a did not differ among the conditions. However, external work was greatest (P < 0.05) for the instability condition. CONCLUSIONS: Because the kinematic data demonstrate that the instability condition increased the metabolic cost for performing the walking movement compared with the control condition, and there was no difference among conditions in constant a, the theoretical model seems invalid.

Adult↗

PubMed2004

Perceived exertion and rehabilitation with arm crank in elderly patients after total hip arthroplasty: a preliminary study.

This preliminary study examined, in a restricted randomized trial, the effects of a 6-week arm-crank rehabilitation training program in elderly osteoarthrosis patients after total hip arthroplasty, first on physiological and perceptual responses and second on physical function. Two groups of patients were studied: a training group (N = 7, mean age = 74.9 yr, standard deviation [SD] = 5.0 yr) who followed a training program in addition to traditional rehabilitation, and a control group who followed traditional rehabilitation only (N = 7 mean age = 75.4 yr, SD = 5.1 yr). At the beginning of the training program, the heart rate and the perceived exertion were not significantly correlated during the exercise session. However, at the end of the training program, five patients had a significant heart rate/perceived exertion relationship (p < 0.05). Furthermore, positive effects of the arm-crank rehabilitation training program were observed on cardioventilatory and functional responses in the training group compared with the control group. These results suggest that after an habituation period, most of our elderly osteoarthrosis patients experienced physical sensations that were connected to physiological responses. Therefore, perceived exertion could be useful in these patients to regulate exercise intensity, especially at the end of and after the rehabilitation period.

Aged↗

PubMed2003

Quantitative Poincaré plot analysis of heart rate variability: effect of endurance training.

The aim of the study was to evaluate the effectiveness of the Poincaré plot analysis of heart rate variability (HRV) in observing endurance training-induced changes. Four 10-min manoeuvres were performed (supine lying, standing, steady state exercising and subsequent recovery) by eight control subjects before and after a short-term endurance training and by eight subjects trained for at least 3 years. HRV was assessed by traditional time- and frequency-domain indexes, in parallel with the Poincaré plot analysis. In the latter each R-R interval is plotted as a function of the previous one, and the standard deviations of the instantaneous and long-term R-R interval variability are calculated. In our subjects, the Poincaré scatter grams became gradually narrower from supine to exercising, with progressive parasympathetic withdrawal. Short- and long-term endurance training led to higher aerobic power ( p<0.05) and ventilatory threshold shifted towards higher power output ( p<0.05). All HRV evaluation methods showed that HRV values were higher after training both during supine lying and standing ( p<0.05). The Poincaré scatter grams were wider in the trained state. Standard deviations of the Poincaré plot were significantly correlated with the main parameters of the time- and frequency-domain analyses, especially concerning the parasympathetic indicators. These results suggested that Poincaré plot parameters as well as the "width" of the scatter gram could be considered as surrogates of time- and frequency-domain analysis to assess training-induced changes in HRV.

Adult↗

PubMed2003

The effect of prolonged submaximal exercise on gas exchange kinetics and ventilation during heavy exercise in humans.

This study compared ventilation, gas exchange (oxygen uptake, VO(2)) and the surface electromyogram (EMG) activity of four major lower limb muscles during heavy exercise before (Pre-Ex) and after (Post-Ex) a sustained 90-min cycling exercise at 60% VO(2peak). The 90-min exercise was incorporated under the hypothesis that sustained exercise would alter substrate availability in the second exercise bout causing differences in fibre recruitment patterns, gas exchange and ventilation. Nine trained male subjects [VO(2peak)=60.2 (1.7) ml.kg(-1).min(-1)] completed two identical 6-min bouts of cycling performed at high intensity [approximately 90% VO(2peak); 307 (6) W, mean (SE)]. Ventilation and gas exchange were measured breath-by-breath and the EMG was recorded during the last 12 s of each minute of the two 6-min bouts. EMG signals were analysed to determine integrated EMG (iEMG) and mean power frequency (MPF). VO(2) at min 3 and min 6 in Post-Ex were significantly higher (i.e., +201 and 141 ml.min(-1), respectively, P<0.05) than in Pre-Ex but there was a approximately 25% decrease of the slow component, taken as the difference between min 6 and min 3 [187 (27) vs 249 (35) ml.min(-1), respectively, P<0.05]. The greater whole-body VO(2) after 3 min of exercise in Post-Ex was not accompanied by clear alterations in the iEMG and MPF of the examined leg muscles. Ventilation and heart rate were elevated (approximately 12-16 l.min(-1) and approximately 10 beats.min(-1), respectively, P<0.05) as were the ratios V(E)/O(2) and V(E)/VCO(2) in the Post-Ex tests. It was concluded that the VO(2) and ventilation responses to high-intensity exercise can be altered following prolonged moderate intensity exercise in terms of increased amplitude without associated major changes in either iEMG or MPF values among conditions.

Adult↗

PubMed2003

Force-velocity characteristics of upper limb extension during maximal wheelchair sprinting performed by healthy able-bodied females.

The aim of this study was to determine the relationship between force and velocity parameters during a specific multi-articular upper limb movement--namely, hand rim propulsion on a wheelchair ergometer. Seventeen healthy able-bodied females performed nine maximal sprints of 8 s duration with friction torques varying from 0 to 4 N x m. The wheelchair ergometer system allows measurement of forces exerted on the wheels and linear velocity of the wheel at 100 Hz. These data were averaged for the duration of each arm cycle. Peak force and the corresponding maximal velocity were determined during three consecutive arm cycles for each sprint condition. Individual force-velocity relationships were established for peak force and velocity using data for the nine sprints. In line with the results of previous studies on leg cycling or arm cranking, the force-velocity relationship was linear in all participants (r = -0.798 to -0.983, P < 0.01). The maximal power output (mean 1.28 W x kg(-1)) and the corresponding optimal velocity (1.49 m x s(-1)) and optimal force (52.3 N) calculated from the individual force-velocity regression were comparable with values reported in the literature during 20 or 30 s wheelchair sprints, but lower than those obtained during maximal arm cranking. A positive linear relationship (r = 0.678, P < 0.01) was found between maximal power and optimal velocity. Our findings suggest that although absolute values of force, velocity and power depend on the type of movement, the force-velocity relationship obtained in multi-articular limb action is similar to that obtained in wheelchair locomotion, cycling and arm cranking.

Acceleration↗

PubMed2003

Recovery after total hip joint arthroplasty in elderly patients with osteoarthritis: positive effect of upper limb interval-training.

OBJECTIVE: To evaluate the influence of an interval training program for the upper limbs on cardiorespiratory fitness and walking ability in elderly patients after total hip joint arthroplasty. DESIGN: A randomized controlled trial. After surgery, control and training groups started general rehabilitation. Training group combined it with an arm-interval exercise program (3 sessions of 30 minutes per week, for 6 weeks). SUBJECTS: Patients were assigned randomly to control (n = 7) and training groups (n = 7). METHODS: Incremental exercise tests were carried out until exhaustion on an arm crank ergometer 1 month before and 2 months after surgery. A 6-minute walk test was also performed 2 months after surgery. RESULTS: VO2 peak increased significantly in the training group (p = 0.0424) and did not change in the control group. The difference in VO2 peak change between the groups was significant (p = 0.0362, +19.2% in the training group and -3.5% in the control group). In the walking test the training group covered a significantly longer distance than did the control group (p = 0.0055, 396.4 metres and 268.1 metres, respectively). CONCLUSION: These results stress the importance of physical training in a rehabilitation program after total hip joint arthroplasty and this should be considered for improving the current practices in rehabilitation.

Aged↗

PubMed2003

Does the mechanical work in running change during the VO2 slow component?

PURPOSE: The origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the VO2 slow component under the effect of fatigue. METHODS: Twelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak VO2 obtained during an incremental test. The VO2 response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (W(kin)), potential work (W(pot)), external work (W(ext)), and an index of internal work (W(int)) per unit of distance were quantified continuously. RESULTS: During the slow component of VO2, a significant increase in W (P< 0.01), no change in W, and a significant decrease in W and W index (P< 0.05, P< 0.001, respectively) were observed. CONCLUSION: The present study showed that the slow component of VO2 did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P< 0.001) and contact time (P< 0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

Adult↗

PubMed2003

Effects of exercise on perceptual estimation and short-term recall of shooting performance in a biathlon.

Little is known about the effects of exercise on cognitive function, but in a biathlon it is known that intense skiing exercise decreases shooting performance. So the present study was designed to assess the cognitive origin of this decrease by examining the influence of skiing exercise on perceptual estimation and short-term verbal recall of shooting performance in a biathlon. 10 elite biathletes (6 men, 4 women) performed five trials of five shots in standing position in two conditions, at rest and after a standardised skiing exercise. At the end of each trial, the shooting performance was investigated by measuring the actual shooting performance and the perceptual estimation of the shooting performance. A two-way analysis of variance and the effect size indicated a significant decrease in shooting performance after skiing, but none between the actual and estimated shooting performance. At rest .4% of the shots were not estimated (1 out of 250), whereas after exercise the biathletes were not able to estimate 4.8% of the shots (12 out of 250). Further, only .01% of the nonestimated shots after exercise missed the target, i.e., 3 out of 250. The results suggest that the perceptual estimation of the shooting is not significantly affected by skiing exercise and do not explain the decrease in shooting performance observed after intense exercise. However, intense exercise could increase the difficulty of recall shooting performance and may force biathletes to use their memory selectively.

Adult↗