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Relationship between training status and maximal fat oxidation rate.

Introduction

Fat and carbohydrate (CHO) are the main substrates for energy production during exercise. It has been well characterized that absolute carbohydrate oxidation increases linearly as the exercise intensity increases, while fat oxidation increases progressively from rest to approximately 60% of maximal oxygen uptake (V[O.sub.2]max) and then decreases gradually until it reaches the V[O.sub.2]max (Achten and Jeukendrup, 2004; van Loon et al., 2001; Venables et al., 2005). Achten et al. (2002) examined the fat oxidation over a wide range of exercise intensities and found a maximal level of fat oxidation rate ([Fat.sub.max]) to be around 63% of V[O.sub.2]max, suggesting the existence of an optimal intensity for the fat oxidation.

Endurance training provides several metabolic adaptations in exercising muscle related to the capacity to oxidize fat during exercise (Friedlander et al., 2007). However, the magnitude at which the aerobic training status could influence the [Fat.sub.max] has not been fully established. For example, Nordby et al. (2006) found that trained subjects had a higher [Fat.sub.max] that occurred at a higher intensity than in untrained subjects, whilst Stisen et al. (2006) did not find any differences between trained and untrained women in analyzing this same parameter.

These contradictory results might be explained by the criteria used for determination of the aerobic training status. In these studies (Nordby et al., 2006; Stisen et al., 2006), subjects with high and low V[O.sub.2]max values were compared, assuming that the higher V[O.sub.2]max values represented the more trained subjects. However, even if the V[O.sub.2]max is used frequently as a physiological parameter to discriminate the aerobic fitness (Costill et al., 1973; Wyndham et al., 1969), there are some studies that have indicated it may have limited power in predicting the endurance performance (Morgan et al., 1989; Noakes et al., 1990). This limited predictive power could be due to a complex interplay between other physiological factors beyond the V[O.sub.2]max and the endurance performance (Weston et al. 1999). Therefore, the relationship between [Fat.sub.max] and performance needs to be fully explored.

It is likely that the criteria for determination of the aerobic training status can influence the magnitude of differences on the [Fat.sub.max]. As a result, we hypothesized that the [Fat.sub.max] parameters should be greater for the best runners and that the sharper differences on the [Fat.sub.max] parameters are dependent on the criteria used to determine the training status. Thus, the objective of the present study was to analyze the impact of training status on the [Fat.sub.max] and exercise intensity that elicits the [Fat.sub.max], employing performance as different comprehensive criteria for categorizing the subjects.

Methods

Subjects

Eighteen athletes took part in this study, which was approved by an Institutional Review Board for use of human subjects. Each volunteer gave a written informed consent after experimental procedures, possible risks and benefits had been explained. All subjects were amateur competitors in regional or national 10,000 races in track and field championships, with a training background between 3 and 10 years. The subjects were included only if they had performed at least ten 10-km running races in the two years before the study and if they trained continuously for the last three years. The characteristics of the subjects are shown in Table 1.

Incremental test

In the first visit, anthropometric variables were measured, followed by a treadmill incremental test for individual estimation of fat oxidation rates over a range of speeds. The test started with 6 km x [h.sup.-1] and was increased by 1.2 km x [h.sup.-1] at 3-min intervals until exhaustion (Heck et al., 1985). According to Achten et al. (2002), 3-min increases provide similar [Fat.sub.max] results when compared to a continuous prolonged protocol. Therefore, this protocol with shorter stage duration (3-min) was chosen for practical reasons. Respiratory gases were analyzed and recorded breath by breath continuously throughout the test using an online integrated indirect calorimetry system (K4[b.sup.2], Cosmed, Italy) calibrated prior to each test according to manufacturer specifications. V[O.sub.2]max was calculated as the greatest mean V[O.sub.2] value obtained over the last 30 s of the test.

Determination of fat oxidation rate

Means of V[O.sub.2] and VC[O.sub.2] were calculated over the last 45 s for every stage of the incremental test. The fat oxidation rate was calculated using the following stoichiometric equation (Frayn, 1983), assuming that the urinary nitrogen excretion rate was negligible:

Fat oxidation = 1.67 V[O.sub.2]--1.67 VC[O.sub.2]

where V[O.sub.2] and VC[O.sub.2] are reported as l x [min.sup.-1] and oxidation rate as g x [min.sup.-1].

The fat oxidation rate was plotted as a function of exercise intensity, expressed as percentage of V[O.sub.2]max. The following variables were identified on individual fat oxidation curves: [Fat.sub.max] (highest fat oxidation rate expressed as g x [min.sup.-1]); %V[O.sub.2]max that elicited [Fat.sub.max] (%V[O.sub.2]max at which the highest fat oxidation was observed); and, V[O.sub.2] and respiratory exchange ratio (RER) at the [Fat.sub.max]. The intensity of the [Fat.sub.max] was also expressed as speed (km x [h.sup.-1]) and percentage of maximal heart rate (%H[R.sub.max]).

10,000-m running performance

Approximately 14 days after the incremental test, all subjects performed a 10,000-m run on a 400-m track. The subjects were instructed to complete the run as quickly as possible, as they would in a competitive event. Verbal encouragement was used to achieve the fastest possible times. The time per 400 m was recorded and the average speed and the percentage of V[O.sub.2]max (%V[O.sub.2]max) used during the run were calculated.

Group sharing

Analysis of whole group (pooled data) showed an average time to cover the 10,000 m of 37.8 min. The subjects were split in two groups according to their 10,000-m time. Times above 37.8 min were classified as low performance and times below 37.8 min as moderate performance. The term "moderate performance" was chosen instead of "high performance" as previous studies have shown that elite runners are able to run 10,000 m within a range of 28 to 33 min (Coetzer et al., 1993; Weston et al., 1999). Additionally, the subjects had similar 10-km race experience before the study. There was no difference between the moderate and low performance groups (12 [+ or -] 1 vs 11 [+ or -] 1) in the number of 10-km running races performed in the last two years before the study.

The V[O.sub.2]max average for the whole group (pooled data) was 62.4 ml x [kg.sup.-1] x [min.sup.-1]. The subjects were also split in a group with V[O.sub.2]max below (low [??]O.sub.2]max group) and above 62.4 ml x [kg.sup.-1] x [min.sup.-1] (high [??][O.sub.2]max group). The use of average of V[O.sub.2]max values as a criterion for group allocation has been previously described (Achten and Jeukendrup, 2003).

Statistical analysis

Values are expressed as mean and standard deviation. An unpaired t-test was used to compare the variables between low and moderate performance groups or between high and low V[O.sub.2]max groups. Pearson's correlation coefficient was calculated to determine possible associations between 10,000-m performance and substrate oxidation parameters. A level of significance of 5% (p < 0.05) was adopted in all analyses.

Results

Whole group

The [Fat.sub.max] average was 0.36 [+ or -] 0.15 g x [min.sup.-1] and was observed at an exercise intensity of 9.7 [+ or -] 2.3 km x [h.sup.-1], corresponding to 63.3 [+ or -] 14.7 %V[O.sub.2]max or 71.1 [+ or -] 12.1 %H[R.sub.max]. The 10,000 m run was completed with a mean speed of 16.0 [+ or -] 1.4 km x [h.sup.-1], corresponding to 94.5 [+ or -] 5.1 %V[O.sub.2]max.

Differences between low and moderate performance groups

The time to complete the 10,000 m was significantly different (p < 0.0001) between groups, 41.3 [+ or -] 2.2 min for the low performance group (n = 7) and 35.5 [+ or -] 1.7 min for the moderate performance group (n = 11) (Table 2). V[O.sub.2]max did not differ between moderate and low performance groups (Table 2). There were no differences in age, body weight, height or H[R.sub.max] between groups. No difference in the [Fat.sub.max] values was observed between moderate and low performance groups, although this parameter tended toward higher values (p = 0.06) in moderate performance group (Table 2). The V[O.sub.2] at the [Fat.sub.max] was not significantly different between groups, but RER at the [Fat.sub.max] was higher in the moderate than in the low performance group. The intensity that elicited [Fat.sub.max] did not differ between groups and was located around 59.9 [+ or -] 16.5 and 68.7 [+ or -] 10.3 %V[O.sub.2]max in moderate and low performance groups, respectively (Table 2). The moderate performance group covered the 10,000 m with a higher %V[O.sub.2]max (p < 0.01) than the low performance group (Table 2). There was no observed correlation between [Fat.sub.max], %V[O.sub.2]max or speed elicited from the [Fat.sub.max] measures and the 10,000-m times (Table 3). However, the fraction of V[O.sub.2]max used during the run was significantly associated with 10,000-m time (p < 0.01).

Differences between low and high V[O.sub.2]max groups

V[O.sub.2]max was 58.6 [+ or -] 5.4 ml x [kg.sup.-1] x [min.sup.-1] in the low V[O.sub.2]max group (n = 11) and 68.4 [+ or -] 4.5 ml x [kg.sup.-1] x [min.sup.-1] in the high V[O.sub.2]max group (n = 7) (p < 0.05). No differences in age, body weight, height or H[R.sub.max] were observed between groups. The [Fat.sub.max] was significantly lower in the low V[O.sub.2]max group than in the high V[O.sub.2]max group (Table 4; p < 0.05). Nevertheless, V[O.sub.2] and RER at the [Fat.sub.max] were not significantly different between groups. The intensity that elicited the [Fat.sub.max] did not differ between groups and was located around 64.4 [+ or -] 14.9 and 61.6 [+ or -] 15.4% V[O.sub.2]max in the low and high V[O.sub.2]max groups, respectively (p > 0.05). There was also no difference in 10,000-m running performance between groups [low V[O.sub.2]max: 38.7 [+ or -] 3.5 min, high V[O.sub.2]max: 36.4 [+ or -] 3.1 min, p > 0.05].

Discussion

The main finding of the present study was the lack of difference in the [Fat.sub.max] between the moderate and low performance groups, even though the [Fat.sub.max] tended to be higher in the moderate group. However, when V[O.sub.2]max was used as a criterion for sharing the groups, the [Fat.sub.max] values were significantly higher in high V[O.sub.2]max group. Another important finding was the lack of significant association between fat oxidation parameters and 10,000-m running performance.

The [Fat.sub.max] average obtained for both groups (0.36 g x [min.sup.-1]) was slightly lower than that reported in previous studies (Achten et al., 2002; 2003; Gonzalez-Haro et al., 2007). These studies employed a cycle ergometer protocol, whereas, a treadmill incremental protocol was employed in the present investigation. To our knowledge, only one study compared the [Fat.sub.max] during treadmill exercise with cycle ergometer exercise (Achten et al., 2003). The fat oxidation rate was significantly higher during treadmill exercise compared to cycling exercise over a wide intensity range. Unfortunately, the subjects in Achten's et al. study (2003) performed an uphill walk instead of treadmill running, which could exclude comparisons with the results from our study. Nevertheless, it could be speculated that the energy expenditure is higher during running compared to walking or cycling, resulting in a greater contribution of carbohydrate oxidation and a lower fat oxidation. In the present study RER values at the [Fat.sub.max] exceeded 0.85 units in all subjects, suggesting that carbohydrate oxidation was the major fuel at [Fat.sub.max] intensity. When analyzed by groups, RER values showed a higher carbohydrate oxidation in the [Fat.sub.max] intensity in moderate performance group.

A higher fat oxidation rate during submaximal exercise in trained individuals has been observed (Nordby et al., 2006; Stisen et al., 2006). However, the training effects on the [Fat.sub.max] and intensity that elicits the [Fat.sub.max] is not evident (Achten and Jeukendrup, 2003; Nordby et al., 2006; Stisen et al., 2006). For instance, Nordby et al. (2006) found that the [Fat.sub.max] occurred at higher relative workloads in trained subjects compared with untrained subjects, while Stisen et al. (2006) observed no differences in the [Fat.sub.max] or intensity that elicits the [Fat.sub.max] between trained and untrained women. Achten and Jeukendrup (2003) also found no differences in the [Fat.sub.max] intensity between individuals with high or low V[O.sub.2]max. In the present study, we found a higher [Fat.sub.max] in high V[O.sub.2]max group when V[O.sub.2]max was used to determine the aerobic training status. However, the intensity that elicited the [Fat.sub.max] was not different between groups. On the other hand, we observed no difference in the [Fat.sub.max] or [Fat.sub.max] intensity between moderate and low performance groups. It is worthy of note that there was a larger intra-individual variation in intensity that elicited [Fat.sub.max], as demonstrated by elevated standard deviation for both the groups. Nevertheless, the criterion used to determine the aerobic training status can affect the magnitude of differences on the [Fat.sub.max]. Consequently, performance parameters should be cautiously employed when the training effects on the [Fat.sub.max] are studied through data from transversal investigations.

It should be noted that athletes selected for the present study cannot be considered as elite runners (Coetzer et al., 1993; Weston et al., 1999). In fact, Coetzer et al. (1993) and Weston et al. (1999) suggested that elite runners are able to run 10,000 m below 33 min. The faster group in the present study covered 10,000-m in 35.5 [+ or -]1.7 min. Therefore, we preferred to use the term "moderate performance" instead of "high performance" in order to characterize the faster group. However, the differences between the moderate and low performance groups, with regard to the time to cover 10,000-m, was about 6 min (p = 0.00001). This suggests that even though the moderate group was classified as better runners and had a better performance level than their counterparts in the low performance group they did not have a difference in [Fat.sub.max]. The higher proportion of V[O.sub.2]max used during the run, not the fat oxidation parameters, was associated with 10,000-m running performance. These results could suggest that the performance during a 10,000-m run might depend on capacity to oxidize carbohydrates rapidly, since higher exercise intensities requires energy derived from carbohydrate fuel (Brooks and Mercier, 1994; Brooks and Trimmer, 1996). Previously, Bergman and Brooks (1999) demonstrated that trained subjects were able to maintain a greater workload and energy expenditure at intensities around 59 and 75% V[O.sub.2]max and this greater mechanical power output was covered by an in creased carbohydrate oxidation rate. Friedlander et al. (2007) showed that carbohydrates are the main fuel used by working muscle during exercise in moderate and high intensities, although endurance training increases the oxidation capacity for all substrates. However, as we did not measure carbohydrate oxidation during the run, this assumption remains unclear and questions arising from this require further investigation. Nevertheless, if athletes used more energy at an equal fat oxidation, it could suggest a greater carbohydrate oxidation.

Conclusion

In conclusion, the results show that the criteria used for categorizing aerobic training status of the subjects can influence the magnitude of differences in the [Fat.sub.max] or exercise intensity that elicits the [Fat.sub.max]. When the performance during a simulated event was used to determine performance status, we did not find significant training effects on the [Fat.sub.max] or intensity that elicits the [Fat.sub.max]. In addition, it is possible that 10,000-m running performance is associated with an increased ability for carbohydrate oxidation. However, further studies that address this question are necessary.

Key points

* The results of the present study suggest that the criteria used to categorize aerobic training status of subjects can influence the magnitude of differences in [Fat.sub.max].

* The [Fat.sub.max] is similar between groups with similar 10,000-m running performance.

* The 10,000-m running performance seems to be associated with an increased ability to oxidize carbohydrate.

Acknowledgments

We are grateful to Edson Degaki for the technical assistance. Flavio Pires is grateful to CAPES for his PhD scholarship.

Received: 25 June 2009 / Accepted: 25 November 2009 / Published (online): 01 March 2010

References

Achten, J., Gleeson, M. and Jeukendrup, A.E. (2002) Determination of the exercise intensity that elicits maximal fat oxidation. Medicine and Science in Sports and Exercise 34, 92-97.

Achten, J. and Jeukendrup, A.E. (2003) Maximal fat oxidation during exercise in trained men. International Journal of Sports Medicine 24, 603-608.

Achten, J. and Jeukendrup, A.E. (2004) Relation between plasma lactate concentration and fat oxidation rates over a wide range of exercise intensities. International Journal of Sports Medicine 25, 32-37.

Achten, J., Venables, M.C. and Jeukendrup, A.E. (2003) Fat oxidation rates are higher during running compared with cycling over a wide range of intensities. Metabolism 52, 747-752.

Bergman, B.C. and Brooks, G.A. (1999) Respiratory gas-exchange ratios during graded exercise in fed and fasted trained and untrained men. Journal of Applied Physiology 86, 479-487.

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Morgan, D.W., Baldini, F.D., Martin, P.E. and Kohrt, W.M. (1989) Ten kilometer performance and predicted velocity at V[O.sub.2]max among well-trained male runners. Medicine and Science in Sports and Exercise 21, 78-83.

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Nordby, P., Saltin, B. and Helge, J.W. (2006) Whole-body fat oxidation determined by graded exercise and indirect calorimetry: a role for muscle oxidative capacity? Scandinavian Journal of Medicine and Science in Sports 16, 209-214.

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Stisen, A.B., Stougaard, O., Langfort, J., Helge, J.W., Sahlin, K. and Madsen, K. (2006) Maximal fat oxidation rates in endurance trained and untrained women. European Journal of Applied Physiology 98, 497-506.

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Venables, M.C., Achten, J. and Jeukendrup, A.E. (2005) Determinants of fat oxidation during exercise in healthy men and women: a cross-sectional study. Journal of Applied Physiology 98, 160-167.

Weston, A.R., Karamizrak, O., Smith, A., Noakes, T.D. and Myburgh, K.H. (1999) African runners exhibit greater fatigue resistance, lower lactate accumulation, and higher oxidative enzyme activity. Journal of Applied Physiology 86, 915-923.

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Adriano E. Lima-Silva (1,2) [mail], Romulo C. M. Bertuzzi (2), Flavio O. Pires (2), Joao F. L. Gagliardi (2), Ronaldo V. Barros (2), John Hammond (3) and Maria A. P. D. M. Kiss (2)

(1) Sports Science Research Group, Federal University of Alagoas, Brazil, (2) Department of Sport, School of Physical Education and Sport, Sao Paulo University, Brazil, (3) Department of Sport, Coaching and Exercise Science, University of Lincoln, UK.

[mail Adriano Eduardo Lima-Silva

Centro de Educacao--Universidade Federal de Alagoas, Avenida Lourival Melo Mota S/N--Campus A.C. Simoes, Brazil

Adriano E. LIMA-SILVA

Employment

Associate professor of Federal University of Alagoas, Maceio, Brazil

Degree

Dr

Research interests

Metabolism and quantification of energetic systems contribution during exercise.

E-mail: adrianosilva@usp.br

Romulo C. M. BERTUZZI

Employment

School of Physical Education and Sport, Sao Paulo University, Sao Paulo, Brazil.

Degree

PhD

Research interests

Metabolism and quantification of energetic systems contribution during exercise.

E-mail: bertuzzi@usp.br_

Flavio O. PIRES

Employment

PhD student, School of Physical Education and Sport, Sao Paulo University, Sao Paulo, Brazil.

Degree

MSc

Research interests

Metabolism and quantification of energetic systems contribution during exercise.

E-mail: piresfo@usp.br

Joao F. L. GAGLIARDI

Employment

Adjunct professor of University Fieo, Sao Paulo, Brazil.

Degree

PhD

Research interests

Morphologic and physiologic aspects of human performance.

E-mail: joaogagliardi@uol.com.br

Ronaldo V. BARROS

Employment

Researcher, School of Physical Education and Sport, Sao Paulo University, Sao Paulo, Brazil.

Degree

MSc

Research interests

Morphologic and physiologic aspects of human performance.

E-mail: ronaldob@usp.br

John HAMMOND

Employment

Prof., Head of the Department of Sport, Coaching and Exercise Science, University of Lincoln, UK.

Degree

PhD

Research interests

Scientific analysis of human performance.

E-mail: jhammond@lincoln.ac.uk

Maria A.P.D.M. KISS

Employment

Titular professor of School of Physical Education and Sport, Sao Paulo University, Sao Paulo, Brazil.

Degree

PhD, MD

Research interests

Metabolism and quantification of energetic systems contribution during exercise.

E-mail: mapedamk@usp.br
Table 1. Physical and physiological characteristics
of the subjects. Data are means ([+ or -] SD).

Age (years)                                       28.0 (4.9)
Height (m)                                        1.71 (0.07)
Body weight (kg)                                  65.7 (9.9)
V[O.sub.2]max (ml x [kg.sup.-1] x [min.sup.-1])   62.4 (6.9)
10-km running race numbers-last two years         12.0 (1.0)

V[O.sub.2]max: maximal oxygen uptake.

Table 2. Physiological parameters, fat metabolism parameters and
10,000-m running performance in the low and moderate performance
groups. Data are means ([+ or -] SD).

                                                          Moderate
                                    Low performance     performance
                                         (n =7)           (n = 11)

V[O.sub.2]max (ml x [kg.sup.-1]
  x [min.sup.-1])                      59.4 (5.9)        64.3 (7.1)
Time to cover 10,000 m (min)           41.3 (2.2)       35.5 (1.7) *
Average speed during 10,000 m
  (km x [h.sup.-1])                    14.5 (.7)        16.9 (.8) *
%V[O.sub.2]max at 10,000 m             89.9 (4.6)       97.4 (2.8) *
[Fat.sub.max] (g x [min.sup.-1])       .27 (.12)         .41 (.16)
V[O.sub.2] at [Fat.sub.max]        38.2 [+ or -] 9.4)    41.0 (8.9)
RER at [Fat.sub.max]                   .89 (.05)        .94 (.03) *
% V[O.sub.2]max at [Fat.sub.max]      68.7 (10.3)       59.9 (16.5)
Speed at [Fat.sub.max]
  (km x [h.sup.-1])                    10.5 (1.9)        9.2 (2.4)

%V[O.sub.2]max at 10,000 m: percentage of maximal oxygen uptake
during a 10,000-m race; [Fat.sub.max]: maximal fat oxidation
rate; V[O.sub.2] at [Fat.sub.max]: oxygen uptake at intensity
correspondent at [Fat.sub.max]; RER at [Fat.sub.max]: respiratory
exchange ratio at intensity correspondent at [Fat.sub.max];
%V[O.sub.2]max at [Fat.sub.max]: percentage of maximal oxygen
uptake that elicited [Fat.sub.max]; speed at [Fat.sub.max]:
running speed that elicited [Fat.sub.max]. * Significant
difference between groups (p < 0.01).

Table 3. Correlation coefficients between physiological or
fat metabolism parameters and 10,000-m running performance.

                                           Time to cover 10,000 m

%V[O.sub.2]max at 10,000 m                         -74 **
[Fat.sub.max] (g x [min.sup.-1])                    -.23
%V[O.sub.2]max at [Fat.sub.max]                     .42
Speed at [Fat.sub.max] (km x [h.sup.-1])            .33

%V[O.sub.2]max at 10,000 m: percentage of maximal oxygen uptake
during a 10,000-m race; [Fat.sub.max]: maximal fat oxidation
rate; %V[O.sub.2]max at [Fat.sub.max]: percentage of maximal
oxygen uptake that elicited [Fat.sub.max]; speed at
[Fat.sub.max]: running speed that elicited [Fat.sub.max];

** p < 0.01.

Table 4. Physiological parameters, fat metabolism parameters and
10,000-m running performance in the low and high V[O.sub.2]max
groups. Data are means ([+ or -] SD).

                                               Low           High
                                           V[O.sub.2]     V[O.sub.2]
                                           max (n =11)    max (n =7)

V[O.sub.2]max
  (ml x [kg.sup.-1] x [min.sup.-1])        58.6 (5.4)    68.4 (4.5) *
Time to cover 10,000 m (min)               38.7 (3.5)     36.4 (3.1)
Average speed during 10,000 m
  (km x [h.sup.-1])                        15.6 (1.4)     16.6 (1.3)
%V[O.sub.2]max at 10,000 m                 93.7 (6.0)     95.9 (3.3)
[Fat.sub.max] (g x [min.sup.-1])            .29 (.10)    .47 (.17) *
V[O.sub.2] at [Fat.sub.max]                37.7 (8.8)     41.9 (9.5)
RER at [Fat.sub.max]                        .93 (.03)     .89 (.07)
% V[O.sub.2]max at [Fat.sub.max]           64.4 (14.9)   61.6 (15.4)
Speed at [Fat.sub.max] (km x [h.sup.-1])    9.6 (2.1)     9.8 (2.6)

%V[O.sub.2]max at 10,000 m: percentage of maximal oxygen uptake
during a 10,000-m race; [Fat.sub.max]: maximal fat oxidation
rate; V[O.sub.2] at [Fat.sub.max]: oxygen uptake at intensity
correspondent at [Fat.sub.max]; RER at [Fat.sub.max]: respiratory
exchange ratio at intensity correspondent at [Fat.sub.max];
%V[O.sub.2]max at [Fat.sub.max]: percentage of maximal oxygen
uptake that elicited [Fat.sub.max]; speed at [Fat.sub.max]:
running speed that elicited [Fat.sub.max]. * Significant
difference between groups (p < 0.05).
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Title Annotation:Research article
Author:Lima-Silva, Adriano E.; Bertuzzi, Romulo C.M.; Pires, Flavio O.; Gagliardi, Joao F.L.; Barros, Ronal
Publication:Journal of Sports Science and Medicine
Article Type:Clinical report
Geographic Code:3BRAZ
Date:Mar 1, 2010
Words:4742
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