Markers Of Exercise Intensity Research Articles

Determination of the lactate threshold by means of salivary biomarkers: chromogranin A as novel marker of exercise intensity

This study examined intra-individual variations in salivary lactate (sLac), alpha-amylase (sAA) and chromogranin A (sCgA) with reference to the accumulation of blood lactate (bLac) during incremental maximal exercise in swimmers. Samples of blood and saliva were collected simultaneously from 12 male professional athletes during an incremental test that consisted of eight series of 100 m in front crawl with increasing velocity (0.03 m s(-1) each) and 70-s intervals. The concentration of blood and salivary lactate was determined by an electro-enzymatic assay, whereas sAA and CgA were analysed by Western blotting. Inflection points in the concentration of bLAc, sLac, sAA and CgA were found in all subjects. The accumulation of lactate in saliva followed the same pattern observed in blood with a high correlation between the two (r = 0.91). Similar results were observed between the dynamics of sAA (r = 0.81) and sCgA (r = 0.82) in relation to bLac. These findings support the usefulness of saliva for the determination of the lactate threshold and provide the first demonstration of sCgA as a novel marker of exercise intensity in well-trained men.

Relationship Between Perceived Exertion and Physiologic Markers During Arm Exercise With Able-Bodied Participants and Participants With Poliomyelitis

Al-Rahamneh HQ, Faulkner JA, Byrne C, Eston RG. Relationship between perceived exertion and physiologic markers during arm exercise with able-bodied participants and participants with poliomyelitis. Objective To investigate the strength of the relationship between ratings of perceived exertion (RPE) and oxygen uptake (V̇ o 2), heart rate, ventilation (V̇ e) and power output (PO) during an arm-crank ramped exercise test to volitional exhaustion in men and women who differed in physical status. Design Each participant completed an arm-crank ramp exercise test to volitional exhaustion. PO was increased by 15W·min −1 and 6W·min −1 for men and women able-bodied participants, respectively; for the poliomyelitis participants, 9W·min −1 and 6W·min −1 increments were used for men and women, respectively. Setting Laboratory facilities at a university. Participants Able-bodied participants (n=16; 9 men, 7 women) and participants with poliomyelitis (n=15, 8 men, 7 women) volunteered for the study. Main Outcome Measures Strength of the relationship ( R 2 values) between RPE and V̇ o 2, heart rate, V̇ e and PO. Results There were significantly higher values for maximum V̇ o 2 and maximum PO for able-bodied men compared with their counterparts with poliomyelitis ( P<.05). However, when the data were controlled for age, there were no significant differences in these values ( P>.05). Similar results were observed for the women who were able-bodied as well as for the women who had poliomyelitis ( P>.05). The relationships between heart rate and RPE and V̇ e and RPE for able-bodied patients and patients with poliomyelitis were similar ( R 2 >.87). The relationship between V̇ o 2 and RPE was stronger in the able-bodied participants compared wih the participants with poliomyelitis, regardless of sex ( P<.05). However, when the data were controlled for age, there was no significant difference in the strength of this relationship between able-bodied participants and those with poliomyelitis, regardless of sex ( P>.05). Conclusions RPE is strongly related to physiologic markers of exercise intensity during arm exercise, irrespective of sex or participant's poliomyelitis status.

Inflammatory responses to three modes of intense exercise in Standardbred mares – a pilot study

The objective of this study was to compare exercise-induced inflammatory responses in horses undergoing three different treadmill exercise tests. Mares completed a graded exercise test (GXT), an interval exercise test (IET) and a repeated sprint exercise test (RSET). Blood and synovial fluid samples were taken 24 h before (PRE) exercise, 20–30 min, 2 and 24 h following exercise (REC). Blood was analysed for total protein, haematocrit and total nitrite concentration. Pro-inflammatory and anti-inflammatory cytokine transcripts were measured in whole blood using quantitative real-time polymerase chain reaction. Synovial fluid was analysed for total nitrite. Mares spent more time at greater than 90% of their maximum heart rate during the RSET than they did for either the GXT or IET. There was an effect of exercise test (P < 0.0001) and exercise test by sample interaction (P = 0.010) for plasma total nitrite. Pro-inflammatory cytokine transcripts and plasma total protein were elevated (P < 0.05) after exercise and there was a higher (P < 0.0001) nitrite concentration in tibiotarsal joints compared with radiocarpal joints. As hypothesised, the higher-intensity exercise test (RSET) resulted in greater nitric oxide responses as well as markers of exercise intensity compared with less intense exercise tests (IET, GXT).

Comparing Three Experimental Protocols for the Determination of Blood Lactate Values

The measurement of blood lactate has long been used as marker of exercise intensity and training status. The abundance of methodologies for determination of blood lactate during exercise renders comparisons of lactate values between studies difficult, often resulting in confusion. PURPOSE: We used a unique combination of three methods to determine blood lactate levels. METHODS: We compared three commercially available products: two spectrophotometric methods, one using hydrogen peroxidase (HPO) and the other lactate dehydrogenase (LDH) as catalysts, and one lactate analyzer. We established the ideal combinations of sample volume, lysing agent, enzyme concentrations and total solution through a series of calibration curves over physiological range of lactate values (1-15 mmol/l). Capillary blood samples (25 ul) were analyzed from aerobically trained participants (n=5) who repeatedly performed a series of exercise bouts of varying intensities on a cycle ergometer, and the data were analyzed using an ANOVA (alpha=0.05). RESULTS: Calibration curves for all three methods had almost perfect correlations over the physiological range tested: HPO (R2 = 0.9958), LDH (R2 = 0.9873), and the lactate analyzer (R2 = 0.9983). Although all three experimental protocols yielded similarly-shaped lactate curves, the actual values for the HPO method was significantly different from the LDH and the lactate analyzer at every intensity level. For example, blood lactate levels at Maximum Lactate Steady State ranged from 4.32 mmol/l (HPO) to 3.62 mmol/l (analyzer), to 3.01 mmol/l (LDH). In addition, the LDH and analyzer methods demonstrated considerably smaller variability in within-subject comparisons than the HPO method. CONCLUSION: We were successful in comparing the three method of lactate determination, and we provide a quantification of the differences between them. We conclude that all three methods can provide useful within-subject curves, and that the LDH method and the analyzer provide more consistent results than the HPO method. Finally, based on the lower operating costs and greater ease of use, we recommend the use of the lactate analyzer for work with blood lactate.

Measures of Exercise Intensity During Soccer Training Drills With ProfessionalSoccer Players

Recent evidence supports the use of certain soccer drills for combined technical and physical training. Therefore, it is important to be able to accurately monitor training intensity during soccer drills intended for physical development to allow the optimization of training parameters. Twenty-eight professional soccer players were assessed for heart rate (HR) and rating of perceived exertion (RPE) responses to 5 commonly used soccer training drills (2v2 to 8v8 drills). The responses of both HR and RPE differed significantly (p < 0.05) between the drills, generally showing an elevated response to drills involving lower player numbers. However, the 2v2 drill showed a significantly (p < 0.05) lower HR response (mean +/- SD: 88.7 +/- 1.2% HRmax) than 3v3 (91.2 +/- 1.3% HRmax) and 4v4 drills (90.2 +/- 1.6% HRmax). There was no significant correlation between the HR and RPE responses to the various drills (r = 0.60, p = 0.200). This poor relationship is probably because during the 2v2 drill, RPE was higher than during any of the other 6 drills, whereas HR was only fourth highest of the 6 drills. This demonstrates that HR and RPE are only poorly related during the intense drills used in this study, and that HR underestimates the intensity of the 2v2 drill. Heart rate demonstrated lower intersubject variability (1.3-2.2%) than RPE (5.1-9.9%). However, unlike HR, Borg 15-point RPE appears to be a valid marker of exercise intensity over a wide range of soccer training drills by maintaining validity in all drills and demonstrating acceptable intersubject variability. A combination of both HR- and RPE-based training load calculations appears optimal for use in soccer training.

Determining the intensity and energy expenditure during commuter cycling

Objectives: To determine the intensity and energy expenditure during commuter cycling, and to investigate whether cycling to work at a self-chosen intensity corresponds to recommendations of the Centers for Disease...

Self-selected exercise intensity during household/garden activities and walking in 55 to 65-year-old females

This study determined whether some of the more vigorous household and garden tasks (sweeping, window cleaning, vacuuming and lawn mowing) were performed at a moderate intensity (3-6 METs or metabolic equivalents) by a representative sample of 50, 55 to 65-year-old women (X +/- SD; 59.3 +/- 3.1 years, 161.5 +/- 5.2 cm, 69.4 +/- 12.4 kg, 38.4 +/- 7.3% BF). Data collection was conducted in a standardised laboratory environment and in the subjects' homes. Energy expenditure during self-perceived moderate paced walking around a quadrangle was also used as a marker of exercise intensity. Energy expenditure measured via indirect calorimetry was also predicted from: HR, CSA accelerometer counts, Quetelet's index and the Borg rating of perceived exertion. Ninety-six percent of the subjects walked at an intensity of >or= 3.0 METs. Except for vacuuming in the laboratory (X = 2.9 METs; P = 0.19), the intensity of each of the other activities was significantly (P </or= 0.002) greater than 3.0 METs. Subjects swept (3.7 vs. 3.3 METs) and vacuumed (3.6 vs. 2.9 METs) at greater intensities in the home than in the laboratory, whereas the converse applied to window cleaning (3.3 vs. 3.6 METs) and lawn mowing (4.9 vs. 5.5 METs). Eighty-six percent (172 out of 200) of the VO2 measurements were >or= 3.0 METs when the four household/garden activities were performed in the subjects' homes. These activities therefore have the potential to contribute to the 30 min day(-1) of moderate intensity physical activity required to confer health benefits but there was much inter-individual variability in the intensity at which these tasks were performed. Random intercept regression analyses yielded prediction equations with 95% confidence intervals of +/- 0.80 and +/- 0.84 METs for the laboratory and home based equations, respectively. Considering the means for the five activities ranged from 2.9 to 5.5 METs, these 95% confidence intervals lack predictive precision at the individual level. Nevertheless, the laboratory and home-based equations predicted with correct classification rates of 89 and 90%, respectively, whether energy expenditure was < 3.0 or >or= 3.0 METs.

Letter: Caution when using heart rate as a marker of exercise intensity

SA Sports Medicine Vol.15(3) 2003: 32

Measurement and prediction of energy expenditure in males during household and garden tasks.

Participation in at least 30 min of moderate intensity activity on most days is assumed to confer health benefits. This study accordingly determined whether the more vigorous household and garden tasks (sweeping, window cleaning, vacuuming and lawn mowing) are performed by middle-aged men at a moderate intensity of 3-6 metabolic equivalents (METs) in the laboratory and at home. Measured energy expenditure during self-perceived moderate-paced walking was used as a marker of exercise intensity. Energy expenditure was also predicted via indirect methods. Thirty-six males [ X (SD): 40.0 (3.3) years; 179.5 (6.9) cm; 83.4 (14.0) kg] were measured for resting metabolic rate (RMR) and oxygen consumption ( VO(2)) during the five activities using the Douglas bag method. Heart rate, respiratory frequency, CSA (Computer Science Applications) movement counts, Borg scale ratings of perceived exertion and Quetelet's index were also recorded as potential predictors of exercise intensity. Except for vacuuming in the laboratory, which was not significantly different from 3.0 METs ( P=0.98), the MET means in the laboratory and home were all significantly greater than 3.0 ( P</=0.006). The sweeping and vacuuming MET means were significantly higher ( P<0.001) at home than in the laboratory, whereas the converse applied for window cleaning and lawn mowing. Measured RMR was significantly lower ( P<0.001) than the 1-MET constant. Estimating METs by fitting random intercept regression models to the data resulted in standard deviations for the "leave-one-out" prediction errors (predicted-measured) of 0.4 and 0.5 METs for the laboratory and home equations, respectively. While the means indicate that all the activities were performed at a moderate intensity, there was great inter-individual variability in energy expenditure. The laboratory and home-based equations predicted with correct classification rates of 89% and 88%, respectively, whether energy expenditure was <3.0 or >/=3.0 METs.

RELIABILITY OF ENERGY EXPENDITURE MEASUREMENT FOR SELF-PACED HOUSEHOLD AND GARDEN TASKS IN WOMEN

National physical activity and health guidelines now recommend regular moderate intensity exercise (3.0–6.0 METs) to reduce the risk of several chronic diseases. The aim of this project was to determine the reliability and precision of energy expenditure (EE) measurement for self-paced household and garden chores. We therefore measured in duplicate EE at rest, whilst walking and performing four household activities in 12 female subjects ( ± SD; 39.9 ± 3.2 yr, 75.9 ± 16.4 kg, 163.8 ± 6.6 cm) via indirect calorimetry. Moderate-paced walking was used as a marker of exercise intensity for comparison with the household activities. The results are presented below: The intraclass correlation coefficients (ICCs) and technical errors of measurement (%TEM) show that the EE of these household and garden chores can be measured with a high degree of reliability and precision in our hands. These data challenge the convention of using 3.5 ml.kg−1.min−1 as an index of RMR, and hence the accuracy of tables of MET values for common activities. This research was supported by the National Health and Medical Research Council of Australia.Table

Submaximal markers of exercise intensity

Numerous approaches have been used to improve the science and art of exercise prescription, and particular challenges exist in the prescription of exercise intensity. Traditionally, work in the area has been the province of exercise physiologists interested in the improvement of training programmes for athletes, as opposed to the more widespread recent interest in health-related fitness and physical activity for all. The generalized approach to the provision of guidelines for exercise prescription has meant that individuals have, at best, prediction equations which provide a wide band of heart rate between which they can work to derive health benefits. This paper explores some of the commonly employed submaximal markers of exercise intensity and proposes a number of approaches for improvements beyond generalized equations.