Abdou Temfemo

Cardiorespiratory fitness and functional capacity assessed by the 20-meter shuttle walking test in patients with coronary artery disease.

OBJECTIVE To validate the 20-meter shuttle walking test (20MST) in the assessment of maximal oxygen consumption (VO(2)max) and maximal speed in patients with coronary artery disease (CAD). DESIGN Single-sample validity study. SETTING Cardiac rehabilitation service in France. PARTICIPANTS Seventeen men with CAD. INTERVENTIONS Subjects underwent a symptom-limited treadmill test (SLTT) in a laboratory, with a speed starting at 2.5km/h and increasing by 0.5km/h every minute, and performed an adapted 20MST in a corridor, with a speed starting at 3km/h and increasing by 1km/h every minute until exhaustion. MAIN OUTCOME MEASURES VO(2) measured during the 20MST with the Cosmed K2 telemetric gas analyzer (K2 VO(2)), estimated VO(2) calculated by the Léger equation (Léger VO(2)) from the maximal speed obtained during the 20MST, and VO(2) measured during the SLTT (SLTT VO(2)). Maximal speeds attained on the treadmill and on the 20MST were also compared. RESULTS A significant (P<.0001) difference was observed between the Léger estimate of VO(2) and those of K2 VO(2) and SLTT VO(2) (mean +/- standard deviation, 12.28+/-5.90mL. min(-1).kg(-1) vs 23.04+/-7.17 and 22.56+/-6.29mL.min(-1).kg(-1)). No difference was found between the treadmill and the 20MST maximal speeds (6.73+/-0.91km/h, 6.78+/-1.23km/h, respectively). Measured with the Cosmed K2, a significant relationship existed between VO(2) and each speed level (r=.95, P<.0001; VO(2)=4.24x speed-7.37, standard estimation error=2.29mL.min(-1).kg(-1)). CONCLUSION Maximal VO(2) and maximal speed measured on the treadmill did not differ significantly from those obtained on the 20MST. The current 20MST equation (Léger equation) was not valid to estimate VO(2) in CAD patients. A modified prediction equation of VO(2) was given and would need a larger number of patients to be generalized.

Effect of Recovery Mode on Exercise Time to Exhaustion, Cardiorespiratory Responses, and Blood Lactate After Prior, Intermittent Supramaximal Exercise

Miladi, I, Temfemo, A, Mandengué, SH, and Ahmaidi, S. Effect of recovery mode on exercise time to exhaustion, cardiorespiratory responses, and blood lactate after prior, intermittent supramaximal exercise. J Strength Cond Res 25(1): 205-210, 2011-This study aimed to determine the effect of 3 different recovery modes (passive [PR], active [AR], and dynamic stretching [SR]) on exercise time to exhaustion (Tlim) and cardiorespiratory and blood lactate responses during supramaximal exercise. Exercise sessions consisted of 2 series of 4 repeated, intermittent supramaximal cycling exercise interspersed in random order with PR, AR, or SR before the supramaximal continuous cycling time limit (Tlim) exercise test performed at 120% of maximal aerobic power. Ten healthy volunteer soccer athletes aged 25.7 ± 2.4 years participated in this study. During each exercise session, heart rate (HR), oxygen consumption (&OV0312;o2), blood lactate concentration, and Tlim exercise performance were recorded. Higher values were obtained in HR (p < 0.01) and in &OV0312;o2 (p < 0.001) with SR and AR compared with PR. Moreover, lower blood lactate concentration (p < 0.01) was observed with SR and AR compared with PR. A greater Tlim exercise duration was obtained for SR compared with AR (p < 0.05) and PR (p < 0.01). Dynamic stretching appeared as the best recovery mode to enhance performance and cardiorespiratory and lactate responses during intermittent supramaximal cycling exercise.

Is there a beneficial effect difference between age, gender, and different cardiac pathology groups of exercise training at ventilatory threshold in cardiac patients?

BACKGROUND Research on cardiac rehabilitation has raised interesting methods and effects without however establishing the share of the profits according to age, sex and cardiac pathology. Yet today, this disease with various pathologies strikes people of all ages and both sexes, and the recommended rehabilitation exercise intensity is often the ventilatory threshold. The aim of this study was to compare benefits of a training program at ventilatory threshold according to age, gender and cardiac pathology. METHODS One hundred and eighty eight cardiac patients, of whom 62 had coronary artery bypass surgery, 22 artery angioplasty, 54 myocardial infarction and 50 valve replacements, aged 31-82 years, performed spirometric and cardiopulmonary exercise tests before and after a training program. This program consisted of exercise on a cycloergometer for three sessions of 45 min per week for eight weeks at heart rates attenuated at ventilatory threshold (V(Th)) obtained during a cardiopulmonary exercise test conducted before the training period. RESULTS Peak heart rate, peak aerobic power, and peak oxygen uptake determined at V(Th) increased during the training period in all groups of subjects. Men and adult groups had higher absolute values compared to women and elderly groups. No difference was observed in cardiac pathology groups. Similar improvements of aerobic capacities were observed in age, gender and cardiac pathology groups. CONCLUSIONS A training program conducted at personalised V(Th) significantly improves the aerobic physical capacities of all cardiac patients, and inducessimilar benefits whatever the age, gender or cardiac pathology.

Relationship between Power Output, Lactate, Skin Temperature, and Muscle Activity During Brief Repeated Exercises With Increasing Intensity

Temfemo, A, Carling, C, and Ahmaidi, S. Relationship between power output, lactate, skin temperature and muscle activity during brief repeated exercises with increasing intensity. J Strength Cond Res 25(4): 915-921, 2011-The aim of this study was to assess the relationship between power output, lactate, skin temperature, and quadriceps muscle activity during brief repeated exercise with increasing intensity. Eighteen regional level soccer players (age 24.5 ± 3.8 years) were selected after a test of maximal exercise capacity to participate in 2 force velocity (Fv) exercise tests separated by 3 days. The tests were done to examine the reliability of variables measured in the selected subjects during this type of task. During each Fv exercise test, data on power output, heart rate (HR), skin temperature, blood lactate accumulation, the root mean square (RMS), and the mean power frequency (MPF) of the surface electromyography of the superficial quadriceps muscle were collected. Results showed a significant correlation between power output and HR, skin temperature, blood lactate accumulation, and RMS. However, no association was observed with MPF that informs on the level of fatigue and power output. Thus, the result of this study may suggest that the Fv exercise test is not a fatigability test.

Advanced Mechanical Ventilatory Constraints During Incremental Exercise in Class III Obese Male Subjects

BACKGROUND: We investigated the role of mechanical ventilatory constraints in obese class III subjects during incremental exercise. METHODS: We examined 14 control subjects (body mass index [BMI], 23.6 ± 3.2 kg/m2), 15 obese class II subjects (BMI, 37.2 ± 4.5 kg/m2), and 17 obese class III subjects (BMI, 53.4 ± 6.8 kg/m2). All subjects performed pulmonary function tests and maximal inspiratory pressure at rest, ventilatory parameters, flow-volume loops, and rated perceived exertion and breathlessness during exercise. RESULTS: All subjects had normal pulmonary function. Obesity resulted in increased minute ventilation for a given submaximal work rate, although minute ventilation during peak exercise was lowest in the obese class III subjects. End-expiratory lung volume was significantly lower in the obese subjects at rest and during exercise at the ventilatory threshold but not during peak exercise. During heavy-to-peak exercise, the obese subjects increased their end-expiratory lung volume, whereas the control group continued to decrease this parameter. Compared with controls, end-inspiratory lung volume was significantly lower in obese class II subjects and obese class III subjects at rest and at the ventilatory threshold but not during peak exercise. At maximal exercise, obese class III subjects had a greater end-inspiratory lung volume than obese class II subjects and controls. Obese class III subjects displayed a greater expiratory air flow limitation at rest, at the ventilatory threshold, and during peak exercise than both controls and obese class II subjects. CONCLUSIONS: Mechanical ventilatory constraints increase progressively with degrees of obesity, contributing to exercise limitation in obese subjects.

Burnout syndrome and associated factors among university teaching staff in Cameroon: Effect of the practice of sport and physical activities and leisures

OBJECTIVES This study aimed to evaluate the epidemiology of burnout syndrome among university teaching staff in Cameroon; and to establish if the practice of physical activities and leisures could have preventive effect. METHODS A cross-sectional study using a self-administered questionnaire on socio-demographic characteristics, socio-professional conditions, Maslach Burnout Inventory-Educator Survey (MBI-ES) to evaluate burnout syndrome, and Ricci-Gagnon metrics to assess level of physical activities practice among grades of teaching staff, in the various faculties of the University of Douala, Cameroon. RESULTS Three hundreds and three teaching staff members aged 43±7 years were included (69% males). The prevalence of burnout syndrome was 68%, distributed within the three dimensions as follows: emotional exhaustion (15.2%), depersonalization (32.1%) and loss of personal accomplishment (22.1%), with 57% low level, 38% moderate and 6% severe. Burnout affected respectively 55.4% lecturers, 38.3% senior lecturers and 6.3% professors. Burnout was significantly associated with poor working conditions (P=0.0001), unsatisfactory salary (P=0.0001), part time teaching in private university institutions (P=0.027), sensation of strenuous job (P=0.002), conflict with colleagues (P=0.028), sedentariness (P=0.007). Sport and physical activities showed significant protective effect against burnout (P=0.004), the same with leisures (P=0.016). CONCLUSION The prevalence burnout syndrome is high among university teaching staff in Cameroon. The practice of sport and physical activities and leisures has a protective effect against burnout syndrome.

Pre- and post-exercise electrocardiogram pattern modifications in apparently healthy school adolescents in Cameroon

Abstract Background Physical Education and Sport (PES) is compulsory in Cameroonian education system. Cardiac accidents and sudden cardiac deaths (SCD) have been reported during PES examinations. This study aimed to contribute in the prevention of these cardiac accidents by studying pre- and post-exercise electrocardiogram (ECG) pattern modifications in apparently healthy school adolescents. Methods One hundred school adolescents without apparent heart disease [aged 18 ± 2 years; body mass index (BMI): 21.9 ± 2.3] were included. Participants performed two intermittent sprint-endurance tests. The test consisted in walking 2000 m as warm-up, followed by sprint and endurance races. A 12-leads ECG was performed before and in 5 min after the tests. ECG patterns changes were studied with particular attention to abnormalities that could be associated with risk of SCD. Results At rest, ECG patterns variants consisted of bradycardia (30%), sinus arrhythmia (9%), posterior hemi post-block (2%), and early repolarization (3%). which disappeared after exercise in all participants. QTc (ms) and heart rate (HR) increased after exercise (p < 0.001); and RR (ms) decreased post-exercise (p < 0.001). Other changes includes the appearance of the T-waves reversed in precordial leads (V2–V4) (p < 0.001), ventricular (6%), atrial and other supraventricular premature beats (2%) in the post-exercise ECG. Left ventricular hypertrophy (2%), right auricular enlargement (2%), short PR (2%) appeared at the end of the tests. Conclusion This study suggests that an intermittent exercise can induce cardiac abnormalities able to provoke cardiac accidents and SCD in apparently healthy school adolescents.

Inspiratory muscle performance in endurance-trained elderly males during incremental exercise.

The aim of this study was to compare the inspiratory muscle performance during an incremental exercise of twelve fit old endurance-trained athletes (OT) with that of fit young athletes (YT) and healthy age-matched controls (OC). The tension-time index (TT0.1) was determined according to the equation TT0.1=P0.1/PImax×ti/ttot, where P0.1 is the mouth occlusion pressure, PImax the maximal inspiratory pressure and ti/ttot the duty cycle. For a given VCO2, OT group displayed P0.1, P0.1/PImax ratio, TT0.1 and effective impedance of the respiratory muscle values which were lower than OC group and higher than YT group. At maximal exercise, P0.1/PImax ratio and TT0.1 was still lower in the OT group than OC group and higher than YT group. This study showed lower inspiratory muscle performance attested by a higher (TT0.1) during exercise in the OT group than YT group, but appeared to be less marked in elderly men having performed lifelong endurance training compared with sedentary elderly subjects.

Analysis of the effects of self-selected warm-up on isometric contraction performance and on surface electromyogram of vastus lateralis

Background/objective: Self-selected warm-up also called reference warmup (RWU) was reported improving the performance endurance dynamic exercise. This study aimed to assess the effects of RWU on isometric endurance contraction. Methods: Ten university level athletes performed two endurance isometric exercises on a dynamometer, with no warm-up (I-NWU) and with a self-selected warm-up (I-RWU). Skin temperature (Tsk), heart rate (HR), oxygen consumption (VO2), blood lactate [La-], root mean square (RMS), mean frequency (MF) and time limit (Tlim) were measured to assess the effects of RWU. Results: Tsk, HR, (VO2) and [La-] were significantly raised (p < 0.01) after RWU compare to resting values, and remained significantly higher (p < 0.01) at the onset of I-RWU compare to I-NWU. Tlim significantly decreased after RWU (01:19 ± 00:25 for I-RWU vs. 01:49 ± 00:27 mm:ss for I-NWU) (p < 0.0005). RMS and MF showed no significant differences between I-NWU and I-RWU (p > 0.05). Conclusion: Self-selected warm-up impairs the performance of consecutive isometric exercise. Athletes appear less able to self-perceive an optimal warm-up for endurance isometric. Metabolic and electromyogram parameters changes did not thoroughly explained the decline of performance; this gives room for a possible anticipation of central fatigue regulation, which need further investigation.