Maximal physiological responses between aquatic and land exercise in overweight women

PURPOSE: To investigate the maximal physiological responses between aquatic and land-based graded exercise tests in overweight women. METHODS: Twenty healthy, overweight (body mass index (BMI) > or = 25 kg.m(-2)), Caucasian women (mean +/- SD; age 48 +/- 7 yr, BMI 30 +/- 4 kg.m(-2)) completed a deep water running (DWR) and treadmill walking (TMW) graded exercise test. Maximal responses during the DWR and TMW graded exercise tests were compared using paired t-tests. Comparisons were made in the incidence of achievement of maximal oxygen consumption (VO2max) criteria between DWR and TMW protocols. Criteria were a plateau in VO2 (change < 2.1 mL.kg.min(-1)), heart rate (HR) equal to or above the age-adjusted maximum, and respiratory exchange ratio (RER) > or = 1.15. RESULTS: Maximal responses for VO2max (22.5 +/- 4.86 vs 27.7 +/- 4.73 mL.kg.min(-1)), HRmax (159 +/- 16 vs 170 +/- 12 bpm), and RER (1.03 +/- 0.06 vs 1.10 +/- 0.06) were significantly lower (P < 0.01) for the DWR test compared with the TMW test, respectively. Achievement of various VO2max criteria was demonstrated more consistently during the TMW test than the DWR test. CONCLUSION: Maximal physiological responses of overweight women to DWR and TMW are significantly different but are comparable with other populations. As the maximal responses for DWR compared with TMW differ, the use of land-based criteria for VO2max is not recommended for a graded DWR exercise test.     

Cardiac and metabolic demands of in place shallow water running in trained and untrained men

AIM: The aim of this study was to assess maximal cardiac and metabolic demand imposed by in place shallow water running (SWR) and to compare such responses with those obtained during treadmill running (TMR). METHODS: Twelve males, 6 trained (T) pentathletes (age: 19+/-1 years) and 6 untrained (UT) controls (age: 22+/-1 years), performed one maximal TMR test and one SWR maximal test. Heart rate (HR) and oxygen consumption (VO(2)) were continuously measured in both test conditions. RESULTS: In both groups, resting HR decreased immediately after water immersion (UT group: from 81.8+/-6.2 b x min(-1) to 69.2+/-6 b min(-1); T group: from 71.7+/-2.1 b x min(-1) to 61.7+/-7.7 b x min(-1)). In UT subjects SWR metabolic demand was comparable to that obtained during treadmill (VO(2tmr)=47.9 ml min(-1)+/-3.6; VO(2tmr)=45.2 ml x min(-1) +/- 6.8). In contrast, during shallow SWR, T subjects obtained lower V.O(2max) values with respect to TMR (V.O(2tmr)=68.9 mL x min(-1) +/-5.1; VO(2TMR)=57.2 mL x min(-1)+/-3.9; P<0.05). In the T group maximal HR was lower during SWR (from 191+/-8.1 to 177+/-7.1). At a given stride frequency, SWR was less demanding than treadmill in terms of V.O(2) and HR responses. During SWR the metabolic adjustments were depressed more than the cardiac adjustments. CONCLUSION: These findings suggest that in place SWR may be a useful exercise to reduce the effects of detraining.     

Reliability of treadmill measures and criteria to determine VO2max in prepubertal girls

PURPOSE: The main objective of this study was to determine the reliability of measuring treadmill exercise economy (VO2submax) and the maximal oxygen uptake (VO2max) in prepubertal girls tested twice, 6 wk apart. We also wanted to examine the percentage of young girls who were able to reach the criteria for achieving VO2max and to describe methods that would allow a high proportion of young children to achieve criteria for reaching a true VO2max. METHODS: We studied 61 normal-weight, prepubertal girls with a mean (+/- SD) age 7.3+/-1.3 yr (range 4.8 to 10.3 yr). VO2submax was determined while walking for 4 min at 2.5 mph with 0% grade. VO2max was measured during a progressive, all-out, continuous treadmill test using standardized procedures and criteria. Heart rate (HR) was measured using a Polar monitor. Respiratory rate (RR), respiratory exchange ratio (RER), ventilation (V), and VO2 were measured using a Sensormedics metabolic monitor. RESULTS: There were no significant differences between visits I and 2 in mean HR, RR, RER, V, VO2submax (421 vs 422 mL x min(-1), respectively), and VO2max (1036 vs 1049 mL x min(-1), respectively). Intra-individual coefficients of variation (CV) between visits 1 and 2 for submaximal tests were: HR = 5.1%, RR = 12.4%, RER = 7.2%, V = 12.5%, and VO2 = 12.4%. Intra-individual CVs for the maximum tests were: HRmax = 2.1%, RRmax = 10.8%, RERmax = 5.3%, Vmax = 11.7%, and VO2max = 7.5%. A high proportion of the girls reached criteria for VO2max [RER> 1.00, HR>85% of age predicted maximum, and plateauing of VO2max] in both visits: 99% reached one of three criteria, 92% reached two of three criteria, and 70% reached all three criteria. Twenty girls [mean age 7.2+/-1.2 yr] reached at least two criteria in both visits, whereas 32 girls [mean (+/- SD) age 8.6+/-1.0 yr] reached three criteria in both visits. CONCLUSION: Exercise measurements using treadmill testing were reliable in healthy, normal-weight, prepubertal girls. Older girls when compared to the younger girls were able to reach criteria for VO2max more often. Thus, we recommend that one testing should give researchers an accurate measure of walking economy and aerobic capacity, and that two criteria are enough for determining VO2max.     

Physiologic responses to maximal treadmill and deep water running in men and women.

Maximal physiologic responses to treadmill running and deep water running using a flotation device were compared in 12 trained men and 12 trained women. Although the men had significantly higher ventilation volumes, VO2max (liters of oxygen per minute and milliliters of oxygen per kilogram per minute), there were no significant differences in maximal heart rates or respiratory exchange ratios between the sexes. Significantly lower ventilation volumes, VO2max (LO2.min-1 and mlO2.kg-1.min-1), and heart rates were obtained in response to maximal water running compared to treadmill running, regardless of gender. Neither the men's nor women's maximal respiratory exchange ratios were significantly different between modes. The analysis of variance indicated that there were no significant interactions for any of the maximal responses to the tests between the sexes. The magnitude of these differences is similar to that found between treadmill running and cycling ergometry and should not preclude deep water running as a training technique. Caution, however, is advised if the training intensity is to be prescribed on the basis of land-determined heart rates.     

Accuracy of polar S410 heart rate monitor to estimate energy cost of exercise

PURPOSE: The purpose of this study was to examine the accuracy of the Polar S410 for estimating gross energy expenditure (EE) during exercise when using both predicted and measured VO2max and HRmax versus indirect calorimetry (IC). METHODS: Ten males and 10 females initially had their VO2max and HRmax predicted by the S410, and then performed a maximal treadmill test to determine their actual values. The participants then performed three submaximal exercise tests at RPE of 3, 5, and 7 on a treadmill, cycle, and rowing ergometer for a total of nine submaximal bouts. For all submaximal testing, the participant had two S410 heart rate monitors simultaneously collecting data: one heart rate monitor (PHRM) utilized their predicted VO2max and HRmax, and one heart rate monitor (AHRM) used their actual values. Simultaneously, EE was measured by IC. RESULTS: In males, there were no differences in EE among the mean values for the AHRM, PHRM, and IC for any exercise mode (P > 0.05). In females, the PHRM significantly overestimated mean EE on the treadmill (by 2.4 kcal x min(-1)), cycle (by 2.9 kcal x min(-1)), and rower (by 1.9 kcal x min(-1)) (all P < 0.05). The AHRM for females significantly improved the estimation of mean EE for all exercise modes, but it still overestimated mean EE on the treadmill (by 0.6 kcal x min(-1)) and cycle (by 1.2 kcal x min(-1)) (P < 0.05). CONCLUSION: When the predicted values of VO2max and HRmax are used, the Polar S410 HRM provides a rough estimate of EE during running, rowing, and cycling. Using the actual values for VO2max and HRmax reduced the individual error scores for both genders, but in females the mean EE was still overestimated by 12%.     

Metabolic responses to prolonged work during treadmill and water immersion running

The primary aim of this study was to compare the physiological responses to prolonged treadmill (TM) and water immersion to the neck (WI) running at threshold intensity. Ten endurance runners performed TM and WI running VO2max tests. Subjects completed submaximal performance tests at ventilatory threshold (Tvent) intensities under TM and WI conditions and responses at 15 and 42 minutes examined. VO2 was lower in WI (p<0.05) at maximal effort and Tvent. The Tvent VO2 intensities interpolated from the TM and WI VO2max tests were performed in both TM (i.e., TM@TM(tvent),TM@WI(tvent), corresponding to 77.6 and 71.3% respectively of TM VO2max) and WI conditions (i.e., WI@TM(tvent), WI@WI(tvent), corresponding to 85.5% and 78.2% respectively of WI VO2max). Each of the dependent variables was analyzed using a 3-way repeated measures ANOVA (2 conditions X 2 exercise intensities X 7 time points during exercise). VO2max values were significantly lower in the WI (52.4(5.1) ml.kg(-1) min(-1)) versus TM (59.7(6.5) ml.kg(-1) min(-1)) condition. VO2 during submaximal tests were similar during the TM and WI conditions. HR and [BLa] responses to exercise at and above WI(tvent) were similar during short-term exercise, but values tended to be lower during prolonged exercise in the WI condition. There were no statistical differences in VE responses in the 2 conditions, however as with HR and [BLa] an upward trend was noted with TM exercise over the 42 minute duration of the tests. RPE at WI(tvent) was similar for TM and WI exercise sessions, however, RPE at TM(tvent) was higher during WI compared to TM running. Cardiovascular drift was observed during prolonged TM but not WI running. Results suggest differences in metabolic responses to prolonged submaximal exercise in WI, however it can be used effectively for cross training.     

Metabolic and cardiorespiratory responses to the performance of Wing Chun and T'ai Chi Chuan exercise

The primary purpose of this study was to examine the metabolic and cardiorespiratory responses to the continuous performance of Wing Chun and T'ai Chi Chuan exercise. No significant differences in VO2max or HRmax obtained during treadmill exercise were found between the practitioners of the two styles. Average values for oxygen uptake (VO2) were 23.3 +/- 7.5 ml.kg-1.min-1 (6.6 METS) and 16.0 +/- 3.9 ml.kg-1.min-1 (4.6 METS) for Wing Chun and T'ai Chi Chuan exercise, respectively. Mean heart rates obtained during exercise were 137 +/- 25 beats.min-1 for Wing Chun and 116 +/- 22 beats.min-1 for T'ai Chi Chuan exercise. These exercise values corresponded to 52.4% of VO2max and 70.5% of HRmax for Wing Chun and only 36.4% of VO2max and 59.8% of HRmax for T'ai Chi Chuan exercise. Thus, only the continuous performance of Wing Chun exercise elicited VO2 and HR responses that would be expected to bring about a cardiorespiratory training effect in subjects with a relatively low initial VO2max. The ventilatory equivalent for oxygen (VE/VO2) obtained during T'ai Chi Chuan exercise (21.7) was significantly lower than for Wing Chun exercise (24.2), suggesting that T'ai Chi practitioners utilize efficient breathing patterns during exercise. Both Wing Chun and T'ai Chi Chuan styles may have a small static component that produces a slightly elevated heart rate relative to metabolic load when compared to traditional aerobic activities. However, the effect was not severe and these forms of exercise should not be considered dangerous for individuals at high risk for cardiovascular disease.     

Running on land and in water: comparative exercise physiology.

The effect of water immersion on cardiorespiratory and blood lactate responses during running was investigated. Wearing a buoyant vest, 10 trained runners (mean age 26 yr) ran in water at four different and specified submaximal loads (target heart rates 115, 130, 145, and 155-160 beats.min-1) and at maximal exercise intensity. Oxygen uptakes (VO2), heart rates, perceived exertion, and blood lactate concentrations were measured. Values were compared with levels obtained during treadmill running. For a given VO2, heart rate was 8-11 beats.min-1 lower during water running than during treadmill running, irrespective of exercise intensity. Both the maximal oxygen uptake (4.03 vs 4.60 1 x min-1) and heart rate (172 vs 188 beats.min-1) were lower during water running. Perceived exertion (legs and breathing) and the respiratory exchange ratio (RER) were higher during submaximal water running than during treadmill running, while ventilation (1 x min-1) was similar. The blood lactate concentrations were consistently higher in water than on the treadmill, both when related to VO2 and to %VO2max. Partly in conformity with earlier cycle ergometer studies, these data suggest that immersion induces acute cardiac adjustments that extend up to the maximal exercise level. Furthermore, both the external hydrostatic load and an altered running technique may add to an increased anaerobic metabolism during supported water running.     

Aerobic high-intensity intervals improve VO2max more than moderate training

PURPOSE: The present study compared the effects of aerobic endurance training at different intensities and with different methods matched for total work and frequency. Responses in maximal oxygen uptake (VO2max), stroke volume of the heart (SV), blood volume, lactate threshold (LT), and running economy (CR) were examined. METHODS: Forty healthy, nonsmoking, moderately trained male subjects were randomly assigned to one of four groups:1) long slow distance (70% maximal heart rate; HRmax); 2)lactate threshold (85% HRmax); 3) 15/15 interval running (15 s of running at 90-95% HRmax followed by 15 s of active resting at 70% HRmax); and 4) 4 x 4 min of interval running (4 min of running at 90-95% HRmax followed by 3 min of active resting at 70%HRmax). All four training protocols resulted in similar total oxygen consumption and were performed 3 d.wk for 8 wk. RESULTS: High-intensity aerobic interval training resulted in significantly increased VO2max compared with long slow distance and lactate-threshold training intensities (P<0.01). The percentage increases for the 15/15 and 4 x 4 min groups were 5.5 and 7.2%, respectively, reflecting increases in V O2max from 60.5 to 64.4 mL x kg(-1) x min(-1) and 55.5 to 60.4 mL x kg(-1) x min(-1). SV increased significantly by approximately 10% after interval training (P<0.05). CONCLUSIONS:: High-aerobic intensity endurance interval training is significantly more effective than performing the same total work at either lactate threshold or at 70% HRmax, in improving VO2max. The changes in VO2max correspond with changes in SV, indicating a close link between the two.     

Children's OMNI Scale of Perceived Exertion: walking/running evaluation

PURPOSE: The Children's OMNI-walk/run Scale of Perceived Exertion (category range, 0-10) was evaluated using male and female children (6-13 yr of age) during a treadmill graded exercise test. METHODS: A cross-sectional, perceptual estimation paradigm using a walking/running test protocol was administered. Oxygen uptake (VO(2), mL x min(-1)), %VO(2max), ventilation (VE, L x min(-1)), respiratory rate (RR, breaths x min(-1)), respiratory exchange ratio (RER), heart rate (HR, beats x min(-1)), V(E)/VO(2) ratio, and ratings of perceived exertion (RPE) measurements were made every minute throughout the test. RESULTS: Significant correlations were found between OMNI-walk/run Scale RPE responses and VO(2), %VO(2max), HR, V(E)/VO(2) ratio, and RR throughout the maximal treadmill exercise test. The strongest correlations were found between RPE and %VO(2max) (r = 0.41-0.60, P < 0.001) and HR (r = 0.26-0.52, P < 0.01). CONCLUSION: The psychophysiological responses provide validity evidence for use of the Children's OMNI-walk/run Scale over a wide range of exercise intensities during both walking and running.     

Frequency of the VO2max plateau phenomenon in world-class cyclists

We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test of 1-min workloads until exhaustion. Power output was increased from a starting value of 25 W (cyclists) or 20 W (controls) at the rate of 25 W.min(-1) (cyclists) or 20 W.min(-1) (controls) until volitional exhaustion. We measured gas-exchange and heart rate (HR) throughout the test. Blood concentrations of lactate (BLa) were measured at end-exercise in both groups. We defined maximal exercise exertion as the attainment of a respiratory exchange rate (RER) >or= 1.1; HR > 95 % age-predicted maximum; and BLa > 8 mmo.l(-1). The VO2max plateau phenomenon was defined as an increase in two or more consecutive 1-min mean VO2 values of less than 1.5 ml.kg(-1).min(-1). Most cyclists met our criteria for maximal exercise effort (RER > 1.1, 100 %; 95 % predicted maximal HR [HRmax], 82 %; BLa > 8 mmol.l(-1), 84 %). However, the proportion of cyclists attaining a V.O (2max) plateau was considerably lower, i.e., 47 %. The majority of controls met the criteria for maximal exercise effort (RER > 1.1, 100 %; predicted HRmax, 68 %; BLa > 8 mmol. l(-1), 73 %), but the proportion of these subjects with a VO2max plateau was only 24 % (significantly lower proportion than in cyclists [p < 0.05]). Scientists should consider 1) if typical criteria of attainment of maximal effort are sufficiently stringent, especially in elite endurance athletes; and 2) whether those humans exhibiting the VO2max plateau phenomenon are those who perform an absolute maximum effort or there are additional distinctive features associated with this phenomenon.     

Cardiovascular and metabolic responses during 30 minutes of treadmill exercise shortly after consuming a small, high-carbohydrate meal.

Fourteen male endurance runners (VO2peak = 64.8 +/- 8.7 ml x kg(-1) x min(-1)) participated in this study to determine the cardiovascular and metabolic responses during 30 minutes of treadmill running at a moderate intensity soon after consuming a small, high-carbohydrate meal (CHO-M). In randomized order on separate days, subjects either consumed the CHO-M (2088 kJ; 77% carbohydrate) 15 minutes prior to running or they fasted (FAST). Data were collected for 5 minutes beginning at 5, 15, and 25 minutes of the 30-minute run. Heart rate (HR) was determined, a metabolic measurement cart was used to determine VO2 and respiratory exchange ratio (RER), and the CO2 rebreathing procedure (Collier plateau method) was used to determine cardiac output (Q). Statistical analyses indicated that the CHO-M did not affect HR, stroke volume, Q, VO2, or RER compared to FAST. However, all grouped CHO-M and FAST variables, except VO2, changed significantly across the 30-minute exercise session. These data suggest that a small, high-carbohydrate meal does not alter cardiovascular and metabolic function during moderate-intensity exercise in endurance-trained subjects.     

Interaction of test protocol and inclined run training on maximal oxygen uptake

Twenty-two men, 17 to 27 years of age, volunteered to participate in an inclined terrain running program. Men were randomly assigned to a control (N = 10) or an experimental (N = 12) group. The experimental group ran on inclined terrain 4 times/wk for 35 min a session at an intensity of 65 to 85% of maximal aerobic power for 12 wk. The purpose of this study was to analyze the interaction between a subject's VO2max on an inclined protocol (IP) vs a horizontal protocol (HP) before and after training on incline terrain. VO2max, HRmax, VEmax, Rmax, and maximum treadmill time were evaluated on both treadmill protocols (IP and HP). Prior to training, results indicated no difference in VO2max values between protocols. Following training, VEmax, maximum treadmill time, and VO2max increased 8.7, 9.1, and 8.5%, respectively, on the IP and 5.8, 6.8, and 5.3% on the HP respectively. All increases were statistically significant at the 0.05 level. The post-training VO2max on the IP was significantly greater than the value on the HP. These results support the concept of specificity of training and indicate the importance of careful selection of both the test protocol as well as the test mode.     

Measurement of maximal oxygen uptake from two different laboratory protocols in runners and squash players.

PURPOSE: The aims of the study were to assess whether different test protocols used to elicit maximal oxygen uptake values (VO2max) attain similar results, whether different VO2max protocols were preferable for different athletic groups, and to assess whether the noninvasive criteria used to indicate the attainment of VO2max are achieved similarly in different VO2max testing protocols. METHODS: This study evaluated the attainment of either VO2max or peak VO2 (VO2peak) during two treadmill VO2max protocols: a progressive speed protocol (PSP) and a progressive incline protocol (PIP). Ten runners and 10 squash players were studied to assess whether achievement of VO2max criteria was either sport-specific or protocol-specific, or both. RESULTS: There were no significant differences in the VO2peak values reached in either PSP or PIP protocol (64.4 +/- 5.9 vs 66.5 +/- 6.0 mLO2 x kg(-1) x min(-1)). But HRmax (196 +/- 5 vs 189 +/- 5 beats x min(-1); PSP vs PIP; P < 0.01) and RER (1.14 +/- 0.05 vs 1.07 +/- 0.04; PSP vs PIP; P < 0.01) were significantly higher during the PSP test. Fifty percent of the subjects reached a plateau in either test, and of these subjects, 90% satisfied the three noninvasive criteria for VO2max in the PSP group, compared with 10% in the PIP group. CONCLUSIONS: The indirect criteria used to assess the attainment of VO2max may be limited, as the VO2peak values were higher in the PIP protocol compared with the PSP protocol, although not significantly different, whereas the HR and RER values were significantly lower in the PIP than PSP protocol. Furthermore, only 50% of subjects demonstrated the plateau phenomenon in oxygen uptake with either protocol. It may be concluded that the measured physiological variables coinciding with VO2peak may differ when different protocols are used to elicit VO2max.     

Exercise metabolism in runners.

The purpose of this study was to re-examine the commonly accepted association between high maximum oxygen uptake (VO2 max) values and the characteristics of metabolic adaptation to endurance training. The metabolic responses of 9 active males and 8 endurance trained females were observed during one hour of treadmill running at two speeds. One speed was common to both groups (3.58 m s-1. Test 1) whereas the second speed represented approximately 62% VO2 max for each individual (Test 2). The VO2 max values of the males were significantly (p less than 0.01) higher than those of the females but observations of the respiratory exchange ratio and of the changes in the concentrations of metabolites were indicative of greater fat metabolism in the well-trained female group in both Tests. Thus the results of this study suggest that the benefits of endurance training are independent of the absolute values of VO2 max.     

A longitudinal assessment of change in VO2max and maximal heart rate in master athletes

PURPOSE: The purpose of this study was to determine the longitudinal change in VO2max and HRmax in male and female master endurance runners and to compare these changes based upon gender, age, and change in training volume. METHODS: Eighty-six male (53.9 +/- 1.1 yr) and 49 female (49.1 +/- 1.2 yr) master endurance runners were tested an average of 8.5 yr apart. Subjects were grouped by age at first visit, change in VO2max, and change in training volume. Measurements included body composition by hydrostatic weighing, maximal exercise testing on a treadmill, and training history by questionnaire. Data were analyzed by ANOVA and multiple regression. RESULTS: VO2max and HRmax declined significantly regardless of gender or age group (P < 0.05). The rate of change in VO2max by age group ranged from -1% to -4.6% per year for men and -0.5% to 2.4% per year for women. Men with the greatest loss in VO2max had the greatest loss in LBM (-2.8 +/- 0.7 kg), whereas women with the greatest loss in VO2max demonstrated the greatest change in training volume (-24.1 +/- 3.0 km.wk-1). Additionally, women with the greatest loss in VO2max (-9.6 +/- 2.6 mL.kg-1.min-1) did not replace estrogen after menopause independent of age. HRmax change did not differ by VO2max change or training volume change in either gender. CONCLUSIONS: In conclusion, these data suggest that VO2max declines in male and female master athletes at a rate similar to or greater than that expected in sedentary older adults. Additionally, these data suggest that maintenance of LBM and VO2max were associated in men, whereas in women, estrogen replacement and maintenance of training volume were associated with maintained VO2max.     

Reliability and variability of running economy in elite distance runners

PURPOSE: To establish the typical error (TE) associated with equipment, testing, and biological variation of a running economy (RE) test in 11 elite male distance runners (VO2max 70.3 +/- 7.3 mL x min(-1) x kg(-1)), and measure the between-athlete variation of 70 highly trained runners (VO2max 69.7 +/- 6.0 mL x min(-1) x kg(-1)) to determine the magnitude of the smallest worthwhile change (SWC) required for RE. METHODS: Runners performed three 4-min bouts of submaximal treadmill running at speeds of 14, 16, and 18 km x h(-1) (0% grade), on two separate occasions within a 7-d period to determine reliability and once over a 3-yr period to measure the SWC. During all RE tests O2 consumption (VO2), ventilation (VE), respiratory exchange ratio (RER), heart rate (HR), stride rate (SR), and concentration of blood lactate (Lac) were determined. RESULTS: The TE for the pooled data of three running speeds (14, 16, and 18 km x h(-1)) was 2.4% for VO2, 7.3% for VE, 27% for Lac, and ranged between 1 and 4% for RER, HR, and SR. CONCLUSIONS: The results demonstrate that although the magnitude of the TE for a submaximal treadmill running protocol of three 4-min work efforts is small (2.4-7.3%) for measures associated with cardiorespiratory parameters, it is three- to fourfold higher for Lac. Given the small TE associated with RE, and a SWC of similar magnitude for this cohort of distance runners, the RE test is useful in detecting changes attributable to training interventions. Changes in RE greater than approximately 2.4% in this cohort of elite distance runners are likely to be "real" and "worthwhile," and not simply related to testing error and typical variation.     

Oxygen uptake and ventilation during rowing and running in females and males

This study evaluated if the ventilatory response to exercise is impaired by the cramp position of rowing. Maximal oxygen uptake (VO2max), maximal expiratory volume (VEmax), and maximal heart rate (HRmax) during rowing and running were compared in 55 males (age, mean +/- SD, 21 +/- 3 years; height 176 +/- 5 cm; body mass 72 +/- 6 kg) and 18 females (age 20 +/- 2 years; height 164 +/- 5 cm; body mass 61 +/- 4 kg). VEmax was larger during rowing than during running (males, 157 +/- 16 vs. 147 +/- 13 L min(-1); 114 +/- 9 vs. 105 +/- 11 L min(-1), P<0.01). Also VO2max was larger during rowing than during running (males, 4.5 +/- 0.5 vs. 4.3 +/- 0.4 L min(-1); females, 3.3 +/- 0.4 vs. 3.2 +/- 0.4 L min(-1), P<0.01). However, HRmax was lower during rowing than during running (males, 194 +/- 8 vs. 198 +/- 11 beats min(-1); females, 192 +/- 6 vs. 196 +/- 8 beats min(-1), P<0.05). VEmax was correlated to body mass and fat-free mass, as was VO2max. Thus, the oxygen pulse (VO2max/HRmax) was larger during rowing than during running, while the ventilatory equivalent for oxygen (VEmax/VO2max) was similar. We showed that bending the body during rowing does not seem to impair ventilation either in males or in females. The results indicate that VEmax and VO2max relate to body size and fat-free mass for both females and males. The findings indicate that the involvement of more muscles, the entrainment, and the body position during rowing facilitates ventilation and venous return and lowers maximal heart rate.     

Laboratory running test vs. field roller skiing test in cross-country skiers: a longitudinal study

Laboratory treadmill running tests are commonly used to assess the effect of training programs and to prescribe training intensity for cross-country skiers. The present study compared the physiological parameters during a treadmill running (R) test and a field roller skiing (RS) test both at the beginning (Beg) and at the end (End) of a 6-month specific training program in seven competitive cross-country skiers. Oxygen uptake (VO2) and blood lactate concentration ([La]) were assessed for exercise intensity corresponding to 70%, 80%, 90% of maximal heart rate (HRmax) and to HRmax.VO2 was lower for the RS test compared to the R test at any HR levels at Beg only (p<0.05). Maximal VO2 increased from Beg to End for the RS test only (+23.7+/-10.4; p<0.05). [La] was lower for the R test compared to the RS test during both testing periods at 90% HRmax (p<0.05), and no significant modification in [La] from Beg to End at any HR levels was observed (p>0.05). The [La]/V.O2 curve shifted toward the right from Beg to End to a greater extent for the RS test compared to the R test. The present study emphasised the importance of exercise specificity in order to assess the effect of specific training program in competitive cross-country skiers.