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To compare the physiologic differences between adolescent male and female cross-country runners, 12 male and 12 female high school nonelite distance runners who had competed successfully at the All State 5-km championship cross-country meet were tested in the laboratory. Data were analyzed in relation to maximal oxygen consumption (VO₂max), ventilatory threshold (VT), and running economy (RE). Male runners were taller, heavier, had less body fat, and ran faster by 2 minutes and 18 seconds than female runners. Running economy was similar between gender. VO₂ at a 215 m•min⁻¹ pace was 46.7 ml•kg⁻¹•min⁻¹ for male runners and 47.8 ml•kg⁻¹•min⁻¹ for female runners. At the VT, males demonstrated a higher VO₂ and treadmill velocity than females. Heart rate, percent HR max, and percent VO₂ max at the VT were not different between gender. Males demonstrated a higher VO₂ max of 74.6 versus 66.1 ml•kg⁻¹•min⁻¹ than female runners. The fractional utilization of VO₂ at race pace was not different between males (90%) and females (91%). In conclusion, the primary physiologic determinant for performance differences between nonelite, competitive male and female adolescent distance runners is associated with VO₂ max.

Cardiorespiratory endurance is a component of health-related fitness. FITNESSGRAM recommends the Progressive Aerobic Cardiovascular Endurance Run (PACER) or One mile Run/Walk (1MRW) to assess cardiorespiratory endurance by estimating VO_{2 Peak}. No research has cross-validated prediction models from both PACER and 1MRW, including the New PACER Model and PACER-Mile Equivalent (PACER-MEQ) using current standards. The purpose of this study was to cross-validate prediction models from PACER and 1MRW against measured VO_{2 Peak} in adolescents. Cardiorespiratory endurance data were collected on 90 adolescents aged 13–16 years (Mean = 14.7 ± 1.3 years; 32 girls, 52 boys) who completed the PACER and 1MRW in addition to a laboratory maximal treadmill test to measure VO_{2 Peak}. Multiple correlations among various models with measured VO_{2 Peak} were considered moderately strong (R = .74–0.78), and prediction error (RMSE) ranged from 5.95 ml·kg^-1, min^-1 to 8.27 ml·kg^-1.min^-1. Criterion-referenced agreement into FITNESSGRAM’s Healthy Fitness Zones was considered fair-to-good among models (Kappa = 0.31–0.62; Agreement = 75.5–89.9%; F = 0.08–0.65). In conclusion, prediction models demonstrated moderately strong linear relationships with measured VO_{2 Peak}, fair prediction error, and fair-to-good criterion referenced agreement with measured VO_{2 Peak} into FITNESSGRAM’s Healthy Fitness Zones.

The purpose of the study was to investigate the seasonal relationship of athletic amenorrhea and body composition in elite, adolescent, cross-country runners. The participants consisted of 28 female adolescent cross-country runners (mean age ± SD = 15.4 ± 1.5 years); 17 eumenorrheics and 11 amenorrheics. The participants’ body composition was measured pre- and postseason using dual-energy X-ray Absorptiometer (DXA). The eumenorrheics’ postseason BMD was significantly greater than the amenorrheics’ postseason BMD (F(1,54) = 16.22, p < .05, partial η ² = .231). The eumenorrheics’ postseason bodyweight (F(1,54) = 7.65, p < .05, partial η ² = .124), BF (F(1,54) = 8.56, p < .05, partial η ² = .137), and BMC (F(1,54) = 8.52, p < .05, partial η ² = .136) were significantly greater than the amenorrheic subgroup. There was also a significant seasonal increase in BMD (t(27) = –4.01, p < .05) for the overall group and the eumenorrheic subgroup (t(16) = –3.90, p < .05). Bodyweight best predicted BMD (F(1,26) = 46.434, p < .05, R² = .641). In the study, athletic amenorrhea was highly associated with lower levels of BMD in the participants, and crosscountry running was highly associated with increased BMD.

Relationships between physiological parameters and 5-km running performance were examined in 15 male runners (17.3 ± 0.9 years). Running economy (RE) and blood lactate concentration ([BLa]) at 241.2 m/min, VO₂max, velocity at VO₂max (vVO₂max), vertical jump height and muscle power, and isokinetic knee extension strength at 60°/sec and 240°/sec were measured. The participants’ best 5-km race time over the last month of the cross-country season (16.98 ± 0.76 min) was used in the analysis. The data were analyzed using Pearson correlation coefficients. Significant relationships to run time were observed for VO₂max (r = -.53), RE (r = .55), and vVO₂max (r = -.66), but not [BLa], isokinetic muscle torque, or vertical jump. Identifying the unique strength and power characteristics related to running performance in this age group is warranted.

Wisconsin has mandated minimal weight (MW) testing for high school wrestlers. In preparation, six MW predictions were cross-validated on 69 Wisconsin wrestlers (age 15.7±1.1 yrs, height 169.2±6.3 cm, weight 63.3±8.1 kg, percent fat 11.2±4.7%, and MW 58.9±6.9 kg). Minimal weight, defined as fat-free body/.93, determined by hydrostatic weighing (HW) and residual volume using 0₂ dilution, served as the criterion. Analyzed using repeated-measures ANOVA, statistically significant but clinically small (<1.3 kg) differences were shown in four of six predictions. Lohman 1, Lohman2, and Katch equations appear more appropriate with smaller mean differences, smaller total error, and higher correlations.

This study evaluated the relationship between run performance, lactate threshold (LT), VO₂max, and running economy in adolescent boys (n = 11) and girls (n = 10). Subjects completed laboratory tests to establish VO₂max, LT, and running economy. The race performance was the finish time from a cross-country meet. The boys exhibited higher VO₂max (67.7 vs. 54.6 ml · kg⁻¹ · min⁻¹) and VO₂ at LT (61.7 vs. 48.4 ml · kg⁻¹ · min⁻¹) compared with the girls (p < .05), but there was no difference in running economy, peak lactate, or the %VO₂max at LT (p > .05). VO₂max (r = −.70) and VO₂ at LT (r = −.74) were significantly correlated to performance for the boys, but running economy was not (r = .10). For the girls, VO₂max (r = −.90), VO₂ at LT (r = −.77), and running economy (r = −.86) were all significantly related to performance. LT was important for cross-country run performance. However, VO₂max was an equally strong or better predictor than either LT or running economy.

Biometric status, cardiovascular endurance, strength, speed, flexibility, and coordination were assessed in a cross-sectional survey involving 3,540 Swiss boys and girls, aged 9 to 19. Strength and endurance were better among boys, whereas girls displayed better flexibility. Most of the performances among girls did not change from 14 years onwards, while boys exhibited better performances after 15–16 years. The coefficients of correlation between the tests varied from as low as .16 (NS) to .63 (p < .01). Multiple regression analyses showed that height, weight, and chronological and biological age altogether were independently related to the performance on most of the tests. Fitness is a multidimensional concept that not only evolves with chronological age but also depends on biometrical characteristics such as pubertal stage, height, and weight.