Binh Quach - Academia.edu (original) (raw)
Papers by Binh Quach
Journal of exercise science and fitness (JESF)
This study was designed to validate the Tanita (TBF_401) leg-to-leg bio-impedance analysis (BIA) ... more This study was designed to validate the Tanita (TBF_401) leg-to-leg bio-impedance analysis (BIA) system by comparing with dual-energy X-ray absorptiometry (DXA) in assessing the body composition in Chinese obese children. Free fat mass (FFM), fat mass (FM) and percentage body fat (%BF) were measured with BIA and DXA in 64 children (44 males, 20 females) with group mean BMI of 29.9 ±5.0 kg/m 2 . In all subjects, estimates of FFM, FM and %BF were highly correlated (r =0.85-0.95, P <0.001) between the two methods and the correlations were not gender dependent. However, a Bland-Altman comparison showed wide limits of agreement between the methods and the results of the comparisons were also not gender dependent. The mean difference in FFM, FM and %BF between BIA and DXA was -0.82 kg, -0.52 kg and -0.34% while the limits of agreement were -8.64 to 6.99 kg, -8.47 to 7.43 kg and -11.19 to 10.50%, respectively. Moreover, positive correlation was found between the mean and differences (BI...
We compared the optimal workload of Wingate test (WAnT), which was assigned according to total bo... more We compared the optimal workload of Wingate test (WAnT), which was assigned according to total body mass (TBM), between two groups of eight young male adults. The leg anaerobic power and fat free mass of these two groups were comparable while their percent body fat was either within (NOR) or above normal range (OF). The optimal WAnT workload was derived individually from the polynomial regression of power-workload against of 75, 100, 110, 125 and 140 g.kg -1 TBM. It was found that the maximum power elicited from the various workloads in the WAnT was not different (P>0.05) between NOR and OF groups. Further, there was no difference in the optimal workload between the two groups (NOR: 120.7 ±13.6; OF: 114.0 ±7.2 g.kg -1 TBM, P>0.05). The findings suggest that the counting of fat mass in workload assignment in the WAnT may not affect the maximum power output in minor overfat adults.
It was wondered if the counting of fat mass (FM) in the workload of Wingate test (WAnT) of 75 g.k... more It was wondered if the counting of fat mass (FM) in the workload of Wingate test (WAnT) of 75 g.kg−1 total body mass (TBM) would invalidate the test on evaluating leg anaerobic power in minor overfat young adults. This study examined the hypothesis that the neglect of FM in the WAnT workload assignment would improve the peak power (PP), mean power (MP) and fatigue index (FI) in minor overfat subjects. In this study, we found in 16 male and female young adults with normal percent body fat (%BF) that the WAnT workloads of 86 g.kg−1 and 95 g.kg−1 fat free mass, respectively, could develop the PP, MP and FI equivalent to those obtained from the original workload of 75 g.kg−1 TBM. When these new workloads were applied to 18 male and 15 female subjects with a little above-normal %BF, the PP and MP, but not the FI, were declined from the original values (p < 0.05). The declines were positively correlated to their %BF (p < 0.05). Such findings do not support our hypothesis. The findin...
This study aims in investigating the effects of simulating obesity-related restrictive ventilator... more This study aims in investigating the effects of simulating obesity-related restrictive ventilatory load (RVL) with external thoracic restriction (ETR) on sustaining moderate exercise and on associated cardio-respiratory responses, perceived breathlessness sensation and ventilatory muscle fatigue in nonobese men. Seven male adults with body fat 15% performed two identical exhaustive constant-load moderate cycle exercises with their resting total respiratory elastance either increased twofold by the ETR, with concomitant reduction in functional residual capacity in the RVL trial, or not manipulated in the control trial. In RVL condition, the ETR induced inspiratory muscle fatigue (as indicated by the reduction in post-exercise static maximum mouth pressure) and shortened the exercise time to exhaustion in all subjects ( p0.05). At exhaustion, hyperventi- lation composed of rapid and shallow breathing pattern and decreased end-tidal CO2 tension occurred, while arterial O2 saturation an...
Journal of Strength and Conditioning Research, 2010
Tong, TK, Fu, FH, Eston, R, Chung, P-K, Quach, B, and Lu, K. Chronic and acute inspiratory muscle... more Tong, TK, Fu, FH, Eston, R, Chung, P-K, Quach, B, and Lu, K. Chronic and acute inspiratory muscle loading augment the effect of a 6-week interval program on tolerance of highintensity intermittent bouts of running. J Strength Cond Res 24(11): 3041-3048, 2010-This study examined the hypothesis that chronic (training) and acute (warm-up) loaded ventilatory activities applied to the inspiratory muscles (IM) in an integrated manner would augment the training volume of an interval running program. This in turn would result in additional improvement in the maximum performance of the Yo-Yo intermittent recovery test in comparison with interval training alone. Eighteen male nonprofessional athletes were allocated to either an inspiratory muscle loading (IML) group or control group. Both groups participated in a 6-week interval running program consisting of 3-4 workouts (1-3 sets of various repetitions of selected distance [100-2,400 m] per workout) per week. For the IML group, 4-week IM training (30 inspiratory efforts at 50% maximal static inspiratory pressure [P 0 ] per set, 2 setsÁd 21 , 6 dÁwk 21 ) was applied before the interval program. Specific IM warm-up (2 sets of 30 inspiratory efforts at 40% P 0 ) was performed before each workout of the program. For the control group, neither IML was applied. In comparison with the control group, the interval training volume as indicated by the repeatability of running bouts at high intensity was approximately 27% greater in the IML group. Greater increase in the maximum performance of the Yo-Yo test (control: 16.9 6 5.5%; IML: 30.7 6 4.7% baseline value) was also observed after training. The enhanced exercise performance was partly attributable to the greater reductions in the sensation of breathlessness and whole-body metabolic stress during the Yo-Yo test. These findings show that the combination of chronic and acute IML into a high-intensity interval running program is a beneficial training strategy for enhancing the tolerance to high-intensity intermittent bouts of running.
European Journal of Applied Physiology, 2004
To identify the effect of normal breathlessness sensation elicited during intense intermittent ex... more To identify the effect of normal breathlessness sensation elicited during intense intermittent exercise at exhaustion on limitation of exercise maintenance (Ex), the contribution of the flow-resistive unloading effect of normoxic helium-oxygen breathing on the breathlessness sensation to the change in the Ex was examined. Seven men repeatedly performed 12-s exercise at 160% maximal aerobic power output followed by passive recovery for 18-s under normal (CON) and unloaded (UL) breathing conditions until exhaustion. In UL, Ex was enhanced [mean (SD) 127.2 (11.8)% CON] concomitantly with reduction in averaged peak inhaled mouth pressure (PPm i ) of recorded breathing cycles that reflected approximate true inspiratory muscle force output. At the iso-time point of CON exhaustion, the reduction in PPm i to [75.7(10.2)% CON] in UL was concomitant with the reductions in the rating of perceived breathlessness (RPB) [87.5 (13.1)% CON] and in the slope of time course for RPB (RPB/2-min period) [82.1 (17.2)% CON]. It was also concomitant with increases in ventilation and total oxygen consumption. However, the augmented oxygen consumption did not result in lowering of subjects' metabolic stress that was indicated by accumulations of blood lactate and plasma ammonia and uric acid. Nevertheless, the reductions in the RPB and RPB/2-min period, which reflected the breathlessness intensity, were correlated to the CON Ex enhancement in UL (RPB r=-0.57, RPB/2-min period r=-0.83; P<0.05). These findings implied that the normal noxious breathlessness sensation elicited during intense intermittent exercise at exhaustion might contribute to the limitation of subjects' exercise maintenance.
European Journal of Applied Physiology, 2003
To identify the reserve of an individual&amp;#39;s tolerance of the sensation of breathle... more To identify the reserve of an individual&amp;#39;s tolerance of the sensation of breathlessness and metabolic stress in maintaining intense intermittent exercise at exhaustion under conditions of normal breathing, the contribution of the effect of modest inspiratory load on these two responses to the change in the exercise sustainability (Ex(sus)) were examined. Seven men repeatedly performed 12 s exercise at 160% maximal aerobic power output followed by passive recovery for 18 s under normal and ventilatory muscle loaded (VML) breathing conditions until exhaustion. In the VML trial, ventilatory muscle work at exhaustion was double that of the normal control. The control Ex(sus) was reduced [mean (SEM)] [31.7 (6.6)%] while the slope of the time course for the rating of the perceived magnitude of breathing effort (RPMBE/Time), which reflected the intensity of breathlessness, was increased [164.8 (32.2)%] from control and the RPMBE at exhaustion was higher than corresponding control value [144.4 (21.8)%]. Moreover, increases in plasma ammonia and uric acid concentrations, which indicated metabolic stress, were increased [168.1 (28.0)% and 251.7 (57.4)%, respectively], with no change in total oxygen uptake from control when the control exercise was repeated with an identical duration of VML exercise. It was found that the reduction in Ex(sus) in the VML trial was correlated to the increase in their sensations of the intensity of breathlessness (RPMBE/Time: r=0.81; RPMBE at exhaustion: r=0.97, P&amp;lt;0.05). The reduction in Ex(sus), however, was not correlated to the increase in metabolite concentrations. These findings implied that there was no substantial reserve of tolerance of the sensation of breathlessness relative to that of metabolic stress in subjects maintaining intense intermittent exercise at exhaustion under normal conditions of breathing.
Applied Physiology, Nutrition, and Metabolism, 2007
The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered... more The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered in a subsequent incremental badminton-footwork test (FW max ) were examined. Ten male badminton players were recruited to perform identical tests in three different trials in a random order. The control trial did not involve an IM warm-up, whereas the placebo and experimental trials did involve an IM warm-up consisting of two sets of 30-breath manoeuvres with an inspiratory pressure-threshold load equivalent to 15% (PLA) and 40% (IMW) maximum inspiratory mouth pressure, respectively. In the IMW trial, IM function was improved with 7.8% ± 4.0% and 6.9% ± 3.5% increases from control found in maximal inspiratory pressure at zero flow (P 0 ) and maximal rate of P 0 development (MRPD), respectively (p < 0.05). FW max was enhanced 6.8% ± 3.7%, whereas the slope of the linear relationship of the increase in the rating of perceived breathlessness for every minute (RPB/min) was reduced (p < 0.05). Reduction in blood lactate ([La -]b) accumulation was observed when the test duration was identical to that of the control trial (P < 0.05). In the PLA trial, no parameter was changed from control. For the changes (Á) in parameters in IMW (n = 10), negative correlations were found between ÁP 0 and ÁRPB/min (r 2 = 0.58), ÁMRPD and ÁRPB/min (r 2 = 0.48), ÁRPB/min, and ÁFW max (r 2 = 0.55), but not between Á[La -] b accumulation and ÁFW max . Such findings suggest that the IM-specific warm-up improved footwork performance in the subsequent maximum incremental badminton-footwork test. The improved footwork was partly attributable to the reduced breathless sensation resulting from the enhanced IM function, whereas the contribution of the concomitant reduction in [La -] b accumulation was relatively minor.
The Open Sports Sciences Journal, 2008
Abstract: Regular physical activity is widely accepted as playing a crucial role in cardiovascula... more Abstract: Regular physical activity is widely accepted as playing a crucial role in cardiovascular disease (CVD) prevention. However, despite extensive research in this field there are crucial gaps in our knowledge. This paper discusses future research directions including population subgroup-specific exercise doses, research in under represented populations, the role of cardiorespiratory fitness in predicting CVD risk, and novel biological mechanisms that might mediate the inverse association between physical activity and ...
Applied Physiology, Nutrition, and Metabolism, 2008
The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) duri... more The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) during Yo-Yo intermittent recovery test and on the physiological and perceptual responses to the running test were examined. Thirty men were randomly allocated to 1 of 3 groups. The experimental group underwent a 6 week pressure threshold IM training program by performing 30 inspiratory efforts twice daily, 6 d/week, against a load equivalent to 50% maximal static inspiratory pressure. The placebo group performed the same training procedure but with a minimal inspiratory load. The control group received no training. In post-intervention assessments, IM function was enhanced by >30% in the experimental group. The Ex was improved by 16.3% ± 3.9%, while the rate of increase in intensity of breathlessness (RPB/4i) was reduced by 11.0% ± 6.2%. Further, the whole-body metabolic stress reflected by the accumulations of plasma ammonia, uric acid, and blood lactate during the Yo-Yo test at the same absolute intensity was attenuated. For the control and placebo groups, no significant change in these variables was observed. In comparison with previous observations that the reduced RPB/4i resulting from IM warm-up was the major reason for improved Ex, the reduced RPB/4i resulting from the IM training program was lower despite the greater enhancement of IM function, whereas improvement in Ex was similar. Such findings suggest that although both IM training and warm-up improve the tolerance of intense intermittent exercise, the underlying mechanisms may be different.
Journal of exercise science and fitness (JESF)
This study was designed to validate the Tanita (TBF_401) leg-to-leg bio-impedance analysis (BIA) ... more This study was designed to validate the Tanita (TBF_401) leg-to-leg bio-impedance analysis (BIA) system by comparing with dual-energy X-ray absorptiometry (DXA) in assessing the body composition in Chinese obese children. Free fat mass (FFM), fat mass (FM) and percentage body fat (%BF) were measured with BIA and DXA in 64 children (44 males, 20 females) with group mean BMI of 29.9 ±5.0 kg/m 2 . In all subjects, estimates of FFM, FM and %BF were highly correlated (r =0.85-0.95, P <0.001) between the two methods and the correlations were not gender dependent. However, a Bland-Altman comparison showed wide limits of agreement between the methods and the results of the comparisons were also not gender dependent. The mean difference in FFM, FM and %BF between BIA and DXA was -0.82 kg, -0.52 kg and -0.34% while the limits of agreement were -8.64 to 6.99 kg, -8.47 to 7.43 kg and -11.19 to 10.50%, respectively. Moreover, positive correlation was found between the mean and differences (BI...
We compared the optimal workload of Wingate test (WAnT), which was assigned according to total bo... more We compared the optimal workload of Wingate test (WAnT), which was assigned according to total body mass (TBM), between two groups of eight young male adults. The leg anaerobic power and fat free mass of these two groups were comparable while their percent body fat was either within (NOR) or above normal range (OF). The optimal WAnT workload was derived individually from the polynomial regression of power-workload against of 75, 100, 110, 125 and 140 g.kg -1 TBM. It was found that the maximum power elicited from the various workloads in the WAnT was not different (P>0.05) between NOR and OF groups. Further, there was no difference in the optimal workload between the two groups (NOR: 120.7 ±13.6; OF: 114.0 ±7.2 g.kg -1 TBM, P>0.05). The findings suggest that the counting of fat mass in workload assignment in the WAnT may not affect the maximum power output in minor overfat adults.
It was wondered if the counting of fat mass (FM) in the workload of Wingate test (WAnT) of 75 g.k... more It was wondered if the counting of fat mass (FM) in the workload of Wingate test (WAnT) of 75 g.kg−1 total body mass (TBM) would invalidate the test on evaluating leg anaerobic power in minor overfat young adults. This study examined the hypothesis that the neglect of FM in the WAnT workload assignment would improve the peak power (PP), mean power (MP) and fatigue index (FI) in minor overfat subjects. In this study, we found in 16 male and female young adults with normal percent body fat (%BF) that the WAnT workloads of 86 g.kg−1 and 95 g.kg−1 fat free mass, respectively, could develop the PP, MP and FI equivalent to those obtained from the original workload of 75 g.kg−1 TBM. When these new workloads were applied to 18 male and 15 female subjects with a little above-normal %BF, the PP and MP, but not the FI, were declined from the original values (p < 0.05). The declines were positively correlated to their %BF (p < 0.05). Such findings do not support our hypothesis. The findin...
This study aims in investigating the effects of simulating obesity-related restrictive ventilator... more This study aims in investigating the effects of simulating obesity-related restrictive ventilatory load (RVL) with external thoracic restriction (ETR) on sustaining moderate exercise and on associated cardio-respiratory responses, perceived breathlessness sensation and ventilatory muscle fatigue in nonobese men. Seven male adults with body fat 15% performed two identical exhaustive constant-load moderate cycle exercises with their resting total respiratory elastance either increased twofold by the ETR, with concomitant reduction in functional residual capacity in the RVL trial, or not manipulated in the control trial. In RVL condition, the ETR induced inspiratory muscle fatigue (as indicated by the reduction in post-exercise static maximum mouth pressure) and shortened the exercise time to exhaustion in all subjects ( p0.05). At exhaustion, hyperventi- lation composed of rapid and shallow breathing pattern and decreased end-tidal CO2 tension occurred, while arterial O2 saturation an...
Journal of Strength and Conditioning Research, 2010
Tong, TK, Fu, FH, Eston, R, Chung, P-K, Quach, B, and Lu, K. Chronic and acute inspiratory muscle... more Tong, TK, Fu, FH, Eston, R, Chung, P-K, Quach, B, and Lu, K. Chronic and acute inspiratory muscle loading augment the effect of a 6-week interval program on tolerance of highintensity intermittent bouts of running. J Strength Cond Res 24(11): 3041-3048, 2010-This study examined the hypothesis that chronic (training) and acute (warm-up) loaded ventilatory activities applied to the inspiratory muscles (IM) in an integrated manner would augment the training volume of an interval running program. This in turn would result in additional improvement in the maximum performance of the Yo-Yo intermittent recovery test in comparison with interval training alone. Eighteen male nonprofessional athletes were allocated to either an inspiratory muscle loading (IML) group or control group. Both groups participated in a 6-week interval running program consisting of 3-4 workouts (1-3 sets of various repetitions of selected distance [100-2,400 m] per workout) per week. For the IML group, 4-week IM training (30 inspiratory efforts at 50% maximal static inspiratory pressure [P 0 ] per set, 2 setsÁd 21 , 6 dÁwk 21 ) was applied before the interval program. Specific IM warm-up (2 sets of 30 inspiratory efforts at 40% P 0 ) was performed before each workout of the program. For the control group, neither IML was applied. In comparison with the control group, the interval training volume as indicated by the repeatability of running bouts at high intensity was approximately 27% greater in the IML group. Greater increase in the maximum performance of the Yo-Yo test (control: 16.9 6 5.5%; IML: 30.7 6 4.7% baseline value) was also observed after training. The enhanced exercise performance was partly attributable to the greater reductions in the sensation of breathlessness and whole-body metabolic stress during the Yo-Yo test. These findings show that the combination of chronic and acute IML into a high-intensity interval running program is a beneficial training strategy for enhancing the tolerance to high-intensity intermittent bouts of running.
European Journal of Applied Physiology, 2004
To identify the effect of normal breathlessness sensation elicited during intense intermittent ex... more To identify the effect of normal breathlessness sensation elicited during intense intermittent exercise at exhaustion on limitation of exercise maintenance (Ex), the contribution of the flow-resistive unloading effect of normoxic helium-oxygen breathing on the breathlessness sensation to the change in the Ex was examined. Seven men repeatedly performed 12-s exercise at 160% maximal aerobic power output followed by passive recovery for 18-s under normal (CON) and unloaded (UL) breathing conditions until exhaustion. In UL, Ex was enhanced [mean (SD) 127.2 (11.8)% CON] concomitantly with reduction in averaged peak inhaled mouth pressure (PPm i ) of recorded breathing cycles that reflected approximate true inspiratory muscle force output. At the iso-time point of CON exhaustion, the reduction in PPm i to [75.7(10.2)% CON] in UL was concomitant with the reductions in the rating of perceived breathlessness (RPB) [87.5 (13.1)% CON] and in the slope of time course for RPB (RPB/2-min period) [82.1 (17.2)% CON]. It was also concomitant with increases in ventilation and total oxygen consumption. However, the augmented oxygen consumption did not result in lowering of subjects' metabolic stress that was indicated by accumulations of blood lactate and plasma ammonia and uric acid. Nevertheless, the reductions in the RPB and RPB/2-min period, which reflected the breathlessness intensity, were correlated to the CON Ex enhancement in UL (RPB r=-0.57, RPB/2-min period r=-0.83; P<0.05). These findings implied that the normal noxious breathlessness sensation elicited during intense intermittent exercise at exhaustion might contribute to the limitation of subjects' exercise maintenance.
European Journal of Applied Physiology, 2003
To identify the reserve of an individual&amp;#39;s tolerance of the sensation of breathle... more To identify the reserve of an individual&amp;#39;s tolerance of the sensation of breathlessness and metabolic stress in maintaining intense intermittent exercise at exhaustion under conditions of normal breathing, the contribution of the effect of modest inspiratory load on these two responses to the change in the exercise sustainability (Ex(sus)) were examined. Seven men repeatedly performed 12 s exercise at 160% maximal aerobic power output followed by passive recovery for 18 s under normal and ventilatory muscle loaded (VML) breathing conditions until exhaustion. In the VML trial, ventilatory muscle work at exhaustion was double that of the normal control. The control Ex(sus) was reduced [mean (SEM)] [31.7 (6.6)%] while the slope of the time course for the rating of the perceived magnitude of breathing effort (RPMBE/Time), which reflected the intensity of breathlessness, was increased [164.8 (32.2)%] from control and the RPMBE at exhaustion was higher than corresponding control value [144.4 (21.8)%]. Moreover, increases in plasma ammonia and uric acid concentrations, which indicated metabolic stress, were increased [168.1 (28.0)% and 251.7 (57.4)%, respectively], with no change in total oxygen uptake from control when the control exercise was repeated with an identical duration of VML exercise. It was found that the reduction in Ex(sus) in the VML trial was correlated to the increase in their sensations of the intensity of breathlessness (RPMBE/Time: r=0.81; RPMBE at exhaustion: r=0.97, P&amp;lt;0.05). The reduction in Ex(sus), however, was not correlated to the increase in metabolite concentrations. These findings implied that there was no substantial reserve of tolerance of the sensation of breathlessness relative to that of metabolic stress in subjects maintaining intense intermittent exercise at exhaustion under normal conditions of breathing.
Applied Physiology, Nutrition, and Metabolism, 2007
The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered... more The effects of inspiratory muscle (IM) warm-up on IM function and on the maximum distance covered in a subsequent incremental badminton-footwork test (FW max ) were examined. Ten male badminton players were recruited to perform identical tests in three different trials in a random order. The control trial did not involve an IM warm-up, whereas the placebo and experimental trials did involve an IM warm-up consisting of two sets of 30-breath manoeuvres with an inspiratory pressure-threshold load equivalent to 15% (PLA) and 40% (IMW) maximum inspiratory mouth pressure, respectively. In the IMW trial, IM function was improved with 7.8% ± 4.0% and 6.9% ± 3.5% increases from control found in maximal inspiratory pressure at zero flow (P 0 ) and maximal rate of P 0 development (MRPD), respectively (p < 0.05). FW max was enhanced 6.8% ± 3.7%, whereas the slope of the linear relationship of the increase in the rating of perceived breathlessness for every minute (RPB/min) was reduced (p < 0.05). Reduction in blood lactate ([La -]b) accumulation was observed when the test duration was identical to that of the control trial (P < 0.05). In the PLA trial, no parameter was changed from control. For the changes (Á) in parameters in IMW (n = 10), negative correlations were found between ÁP 0 and ÁRPB/min (r 2 = 0.58), ÁMRPD and ÁRPB/min (r 2 = 0.48), ÁRPB/min, and ÁFW max (r 2 = 0.55), but not between Á[La -] b accumulation and ÁFW max . Such findings suggest that the IM-specific warm-up improved footwork performance in the subsequent maximum incremental badminton-footwork test. The improved footwork was partly attributable to the reduced breathless sensation resulting from the enhanced IM function, whereas the contribution of the concomitant reduction in [La -] b accumulation was relatively minor.
The Open Sports Sciences Journal, 2008
Abstract: Regular physical activity is widely accepted as playing a crucial role in cardiovascula... more Abstract: Regular physical activity is widely accepted as playing a crucial role in cardiovascular disease (CVD) prevention. However, despite extensive research in this field there are crucial gaps in our knowledge. This paper discusses future research directions including population subgroup-specific exercise doses, research in under represented populations, the role of cardiorespiratory fitness in predicting CVD risk, and novel biological mechanisms that might mediate the inverse association between physical activity and ...
Applied Physiology, Nutrition, and Metabolism, 2008
The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) duri... more The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) during Yo-Yo intermittent recovery test and on the physiological and perceptual responses to the running test were examined. Thirty men were randomly allocated to 1 of 3 groups. The experimental group underwent a 6 week pressure threshold IM training program by performing 30 inspiratory efforts twice daily, 6 d/week, against a load equivalent to 50% maximal static inspiratory pressure. The placebo group performed the same training procedure but with a minimal inspiratory load. The control group received no training. In post-intervention assessments, IM function was enhanced by >30% in the experimental group. The Ex was improved by 16.3% ± 3.9%, while the rate of increase in intensity of breathlessness (RPB/4i) was reduced by 11.0% ± 6.2%. Further, the whole-body metabolic stress reflected by the accumulations of plasma ammonia, uric acid, and blood lactate during the Yo-Yo test at the same absolute intensity was attenuated. For the control and placebo groups, no significant change in these variables was observed. In comparison with previous observations that the reduced RPB/4i resulting from IM warm-up was the major reason for improved Ex, the reduced RPB/4i resulting from the IM training program was lower despite the greater enhancement of IM function, whereas improvement in Ex was similar. Such findings suggest that although both IM training and warm-up improve the tolerance of intense intermittent exercise, the underlying mechanisms may be different.