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  • Author: Miguel A. Rivera x
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Anita M. Rivera-Brown, Miguel A. Rivera and Walter R. Frontera

This study examined the effects of three testing protocols on the frequency of achievement of V̇O2max criteria in 13 male adolescent long-distance runners. All subjects completed the modified Taylor (T), Bruce (B), and Taylor intermittent (TI) running protocols on a treadmill to volitional fatigue. The criteria for V̇O2max were (a) respiratory exchange ratio (R) > 1.0, (b) heart rate (HR) >95% predicted max, and (c) increase in V̇O2 < 2.1 ml·kg−1·min−1 with an increase in workload. A plateau was identified in 54%, 39%, and 85% of the subjects during the T, B, and TI protocols, respectively (p < .05). V̇O2 at exhaustion was similar during all protocols (T = 70.8 ± 4.1, B = 71.4 ± 3.5, TI = 69.6 ± 5.0 ml·kg−1-min−1; p > .05). The data suggest that the characteristics of a protocol can determine the frequency of a plateau achievement but have no effect on the attainment of the R or HR criteria. V̇O2 during running exercise to volitional fatigue is independent of testing protocol.

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Anita M. Rivera-Brown, Miguel A. Rivera and Walter R. Frontera

This study examined the test-retest reliability of V̇O2max in adolescent V̇O2 plateau achievers and nonachievers. Nineteen male long-distance runners completed a modified Taylor running protocol to volitional fatigue twice within a one-week period. Results showed that 10 subjects did not achieve a plateau in either test (No P), and 9 achieved a plateau in at least one of the tests (P). The V̇O2max differed (p < .05) between tests (Test 1 and Test 2) for the entire sample (Test 1 = 70.4 ± 6.0, Test 2 = 71.7 ± 6.3) but not within the groups (No P, Test 1 = 72.1 ± 4.4, Test 2 = 73.2 ± 4.2; P, Test 1 = 68.5 ± 7.3, Test 2 = 70.1 ± 7.9). V̇O2max was similar for plateau achievers and nonachievers in both Test 1 and Test 2 (p > .05). Interclass correlation coefficients for V̇O2max were high for both the No P (R = .87) and P (R = .97) groups. A high test-retest reliability coefficient for V̇O2max can be obtained even when a plateau in V̇O2 is not achieved.

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Anita M. Rivera-Brown, Miguel A. Rivera and Walter R. Frontera

This study examined the applicability of criteria for maximal oxygen consumption (V̇O2max) in adolescents. Active females (n=38) and males (n=196) who were students at a sports-technical junior high school performed a treadmill Bruce protocol to volitional fatigue. The criteria for V̇O2max were R ≥1.0, HR ≥95% of predicted maximal for age, and an increase in V̇O2 ≤2.1 ml·kg−1·min−1 with an increase in workload. The first criterion was met by 97% of the females and 93% of the males, while 81% of the females and 75% of the males met the second criterion. Only 8% of the females and 13% of the males met the third criterion. Those who achieved a plateau showed higher HR at peak exercise compared to those who did not (204 ±7.0 vs. 200.6 ±7.2, P≤0.05). Our data indicate that a high proportion of adolescents exhibit subjective and objective indicators of maximal performance without showing a plateau in V̇O2. Age-specific criteria for V̇O2max should be developed.

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JesÚs Rico-Sanz, Walter R. Frontera, Paul A. Molé, Miguel A. Rivera, Anita Rivera-Brown and Carol N. Meredith

This study examined the nutritional and performance status of elite soccer players during intense training. Eight male players (age 17 ± 2 years) of the Puerto Rican Olympic Team recorded daily activities and food intake over 12 days. Daily energy expenditure was 3,833 ± 571 (SD) kcal, and energy intake was 3,952 ± 1,071 kcal, of which 53.2 ± 6.2% (8.3 g ⋅ kg BW−1) was from carbohydrates (CHO), 32.4 ± 4.0% from fat, and 14.4 ± 2.3% from protein. With the exception of calcium, all micronutrients examined were in accordance with dietary guidelines. Body fat was 7.6 ± 1.1% of body weight. Time to completion of three runs of the soccer-specific test was 37.65 ± 0.62 s, and peak torques of the knee flexors and extensors at 60° ⋅ s−1 were 139 ± 6 and 225 ± 9 N ⋅ m, respectively. Players' absolute amounts of CHO seemed to be above the minimum recommended intake to maximize glycogen storage, but calcium intakes were below recommended. Their body fat was unremarkable, and they had a comparatively good capacity to endure repeated bouts of intense soccer-specific exercise and to exert force with their knee extensors and flexors.