Self-paced cycling performance and recovery under a hot and highly humid environment after cooling.

AIM: This study investigated the effects of pre- and post-cooling on self-paced time-trial cycling performance and recovery of cyclists exercising under a hot and highly humid environment (29.92 °C-78.52% RH). METHODS: Ten male cyclists performed a self-paced 20-min time trial test (TT20) on a cyclo-ergometer while being cooled by a cooling vest and a refrigerating headband during the warm-up and the recovery period. Heart rate, power output, perceived exertion, thermal comfort, skin and rectal temperatures were recorded. RESULTS: Compared to control condition (222.78 ± 47 W), a significant increase (P<0.05) in the mean power output during the TT20 (239.07 ± 45 W; +7.31%) was recorded with a significant (P<0.05) decrease in skin temperature without affecting perceived exertion, heart rate, or rectal temperature at the end of the TT20. However, pace changes occurred independently of skin or rectal temperatures variations but a significant difference (P<0.05) in the body's heat storage was observed between both conditions. This result suggests that a central programmer using body's heat storage as an input may influence self-paced time-trial performance. During the recovery period, post-cooling significantly decreased heart rate, skin and rectal temperatures, and improved significantly (P<0.05) thermal comfort. CONCLUSION: Therefore, in hot and humid environments, wearing a cooling vest and a refrigerating headband during warm-up improves self-paced performance, and appears to be an effective mean of reaching skin rest temperatures more rapidly during recovery.

Self-regulated running using perceived exertion in children.

AIM: The aim of this study was to examine the ability of 5- to 7-year-old female (n=16) and male (n=16) children to use perceived exertion in order to self-regulate their running intensity. An estimation-production paradigm was used to determine if 1) self-regulation of exercise using OMNI Scale could be administered in young children, 2) children were able to distinguish 3 different intermittent exercise intensities and 3) gender would differentiate the use of perceived exertion. METHODS: Children underwent 1) 1 estimation trial and 2) 3 production trials. During the estimation trial, perceived exertion was estimated at the end of each stage of an incremental running field test. Then, during the production test, the children were requested to run in random order 300 m bouts on an outdoor track at an exercise intensity based on their interpretation of levels 2, 6 and 10 of the OMNI Scale. Heart rate was continuously recorded during both trials. RESULTS: Heart rate did not differ significantly between estimation and production trials at the level 2 (124.1 SD 6 vs 125.3 SD 4 bpm), 6 (164.9 SD 5 vs 166.2 SD 6 bpm) and 10 (200.9 SD 8 vs 203.1 SD 8) of the OMNI scale. Furthermore, HR responses at OMNI 6 were significantly (p<0.05) higher than OMNI 2, and OMNI 10 were significantly (p<0.05) higher that OMNI 6. No significant difference was found between female and male children. CONCLUSIONS: The present investigation supports the view that the young female and male children tested in this study were able to use perceived exertion to self-regulate during intermittent running exercises.

Modelling the relationships between training, anxiety, and fatigue in elite athletes.

This study investigated the effects of 40-week training on anxiety and perceived fatigue in four elite triathletes. Anxiety and perceived fatigue were self-reported by the subjects twice a week by the way of a specific questionnaire and were linked by a mathematical model to the training loads calculated from the exercise heart rate. A significant relationship (r=0.32; p<0.001) between the training loads and anxiety was identified using a two-component model: a first, negative (i.e., anxiety decreased) short-term (tau (1)=23 days) function and a second, positive long-term (tau (2)=59 days) function. The relationship between the training loads and perceived fatigue was significant (r=0.30; p<0.001), with one negative function (tau (1)=4 days). This mathematical model can potentially describe the relationships between training loads and anxiety or perceived fatigue and may improve both the adjustment of the duration of tapering and the early detection of staleness.

A perceptive individual time trial performed by triathletes to estimate the anaerobic threshold. A preliminary study.

AIM: The aim of the study was to test the ability to estimate the power output (PO) and heart rate (HR) associated with ''anaerobic threshold'' levels for triathletes by means of a 30-min perceptive individual time trial (PITT30). METHODS: Thirteen triathletes (8 males and 5 females) performed an incremental exercise test to estimate maximal parameters such as oxygen uptake, power output and heart rate. From this incremental exercise test, the individual anaerobic threshold (IAT) and ventilatory threshold (VT) for all subjects were estimated. Then, the subjects completed a PITT30 at self-selected work intensity on a stationary ergometer equipped with the SRM Training System. Mean values of PO, HR, and pedalling cadence were recorded continuously between the 5th and the 30th min of the test. RESULTS: Significant correlations were observed between the mean PO recorded during PITT30 and PO measured at IAT (r=0.88; p<0.0001) and at VT (r=0.89; p<0.0001). Furthermore, bias and limits of agreement confirm the degree of association between the 3 METHODS: However, PITT30 over-estimated HR values compared to the values obtained at IAT and VT. CONCLUSION: It was concluded that, for triathletes, mean PO measured with PITT30 allows a partial valid estimation of PO associated with 2 known methods of ''anaerobic threshold'' determination. The application of PITT30 may offer a useful tool for athletes and coaches to estimate the ''anaerobic threshold'' in order to control accurately the training effects.

Physiological and metabolic responses of triathletes to a simulated 30-min time-trial in cycling at self-selected intensity.

The aim of this study was to investigate the metabolic and physiological responses to a laboratory-based simulated 30-min individual time-trial (ITT 30 ) in cycling at a self-selected intensity. Twelve experienced triathletes (n = 4 women) performed a progressive incremental exercise test on a cycle ergometer to determine .VO2max (52 +/- 5 ml x min -1 x kg -1), maximum power output (300 +/- 12 W), and the second ventilatory threshold. Then, the subjects completed an ITT30 at self-selected work intensity on a stationary ergometer equipped with the SRM Training System. In all subjects, during the ITT30, heart rate and minute ventilation increased (p < 0.05) progressively whereas oxygen consumption and power output remained unchanged. Triathletes rode at consistent pacing corresponding to their highest steady state of blood lactate concentration that increased by no more than 1.0 mmol x l -1 during the final 20-min of ITT30. The self-selected intensity of triathletes during ITT30 represented 88 +/- 5 % (mean +/- SD) of .VO2max and was not significantly different to the energy demand corresponding to the second ventilatory threshold (84 +/- 5 % of .VO2max). Our data suggest that ITT 30 at a self-selected intensity is a good predictor of individual endurance capacity and may be used to estimate racing pace for training purposes. This performance test for the identification of the exercise intensity that demarcate "steady state" is less troublesome than some of the traditional methods, limiting testing to a single session.

Perceived exertion and rehabilitation with wheelchair ergometer: comparison between patients with spinal cord injury and healthy subjects.

OBJECTIVES: The purpose of this study was to compare the effects of a rehabilitation program on the perceived exertion (PE) and the cardioventilatory responses during exercise in healthy people and paraplegics. METHODS: A group of seven healthy persons (age 26.6 SD 6.2 years) and one of seven paraplegics (age 42 SD 15.9 years) participated in a rehabilitation program composed of Square Wave Exercise Tests (SWEET) during six weeks. The maximal oxygen uptake, the power output (PO), heart rate (HR) and measures of PE using the Borg CR 10 scale were investigated during a maximal graded test performed before and after the rehabilitation program. During the first SWEET session (SWEET 1) measures of PE and HR (base and peak) were also investigated and compared to the last session (SWEET 2) of the same absolute workload after the 6 weeks. RESULTS: Statistical analysis revealed no significant difference in both groups for PE between the two maximal graded tests. However, a significant decrease in the PE values (P<0.01) was observed in both groups during the SWEET 2. There was no significant difference in maximal HR between the two graded tests, but a significant decrease in HR (P<0.0001 for base HR and P<0.001 for peak HR) was observed in SWEET 2 compared to 1. The maximal tolerated power (MTP) and the peak oxygen uptake increased significantly in both healthy and paraplegic groups (P<0.0001 and P<0.05 respectively) after the 6 weeks of rehabilitation exercise. CONCLUSION: The results of the present study suggest that PE could be used to control the exercise intensity during a rehabilitation training program for paraplegics, similar to healthy subjects. The increase in the peak oxygen uptake and MTP demonstrates the positive effects of the rehabilitation program on the physical fitness of the subjects.

Influence of the age on self regulation of static grip forces from perceived exertion values.

The investigation of self-regulation of grip force provides indirect cues about the developmental neurobiology of the subject. The aim of this study was to examine the ability of subjects of different ages to produce different forces based on their perceived exertion during a grip force task by using a test and a randomised re-test procedure. Eighteen young children (aged 6.5 years), 18 adolescents (13.5 years) and 18 adults (28.5 years) performed a graded hand grip strength test (GST) at four intensities. Perceived exertion (RPE-C) was recorded at the end of each load level. Then, subjects were scheduled for a randomised grip strength test performed in the same experimental conditions than GST. Statistical analysis revealed no significant effect in grip strength for test in the three groups. However, a significant main effect for intensities was obtained in the three groups (P < 0.0001). Significant correlations were observed between GST and RPE-C (r(2) = 0.62, P < 0.0001; r(2) = 0.53, P < 0.0001; r(2) = 0.51, P < 0.0001), in the children, adolescent and adult groups, respectively. However at low grip force intensities, it appears that children have some difficulties to rate their perceived exertion. The results of this study suggest that the neurodevelopmental level of 6-year-old children do not affect the ability to produce reliably moderate to intense forces from perceived exertion during a grip force task.

Does endurance or sprint training influence the perception of the optimal pedalling rate during submaximal cycling exercise?

The purpose of this study was to investigate the effects of endurance and sprint training on the perception of the optimal pedalling rate during a submaximal cycling exercise. Six subjects specialized in endurance activities and 6 subjects trained in sprinting activities used the model of bicycling at various pedalling rates with the same power output (150W) on a cycle ergometer. Individual 2nd order polynomial relationships were determined between oxygen consumption (VO(2)) and velocity and between rate of perceived exertion (RPE) and velocity. Optimal velocity, with respect to minimum of VO(2) (OV(VO2)) and to minimum of RPE (OV(RPE)), were calculated for all subjects, respectively. The close similarity found between the VO(2)-velocity and the RPE-velocity curves confirmed that the overall RPE was mainly influenced by the central factor. As OV(RPE) and OV(VO2) were not significantly correlated and as OV(RPE) was significantly higher than OV(VO2), other factors than central may also have influenced the RPE. The significant higher OV(RPE) values (p<0.05) observed in the sprint vs. endurance groups suggested that different training background may have influenced the RPE. These differences could also be explained by a significantly higher OV(VO2) in sprint than in endurance groups, the subjects being sensitive to the pedalling rate for which the energy expenditure is minimal.

Validation of a rating scale of perceived exertion in young children.

The aim of this study was to develop and validate a scale rating the perceived exertion of young children (RPE-C) who do not read. This scale presents seven pictures showing a man who becomes progressively fatigued. In order to evaluate this scale, we examined its reliability and sensitivity. Thirteen children (aged 5 to 6 years) completed two identical incremental maximal running trials during a period of one week. A group of 12 adolescents and a group of 12 adults also tested the RPE-C by performing one trial under the same experimental conditions as the child group. RPE-C was recorded at the end of each load level. Statistical analysis revealed significant effects for velocity (F = 23.98, p < 0.0001) with non-significant effects for the trials. Intraclass correlation coefficient (ICC) revealed an acceptable reliability of RPE-C at low and high exercise intensities but also showed a low reliability at intermediate load levels (0.17 < ICC < 0.77). A significant correlation between RPE-C and heart rate (r2 = 0.61, p < 0.0001) was observed in children. However, the r2 level was lower than that observed for the adolescent or adult groups. This finding demonstrates the sensitivity of RPE-C to discriminate the effects of age on perceived exertion. RPE-C seems to be a good tool which can be used in young children to monitor exercise performed at low and high intensities.

Validation of simple tests of biathlon shooting ability.

The aim of this study was to validate three simple tests of biathlon shooting abilities. Twelve expert biathletes performed visual reaction time tests adapted for the rifle in the standing (RT-S) and prone positions (RT-P), and a tremometer test adapted for the rifle in the standing position (TT-S). Six consecutive days' measurements showed an acceptable reproducibility for these tests (coefficient of variation = 1.2% for RT-S, 1.1% for RT-P and 6.5% for TT-S). A significant difference was observed between TT-S at rest and after roller skiing 2.1 km at 90 % of maximal heart rate. This finding demonstrates the sensitivity of TT-S to discriminate the effects of fatigue on postural control. Among 24 biathletes of regional to expert level, significant correlations were observed between resting RT-P and prone shooting performance after roller skiing (r2 = 0.23; p = 0.01) and between resting TT-S and shooting performance in the standing position after roller skiing (r2 = 0.68; p = 0.0001), demonstrating the specificity of these tests. From these results, we conclude that TT-S is a valid field test of biathlon shooting performance.