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Age, Sex, and Training Specific Effects on Cross-Education Training

Aymen Ben Othman, Saman Hadjizadeh Anvar, José Carlos Aragão-Santos, Anis Chaouachi, and David G. Behm

Cross-education refers to the transfer of training effects (ie, motor control, strength, endurance, skill, and acceleration) following a period of unilateral exercise training of a trained limb to a homologous untrained limb ( 17 , 19 , 20 , 25 , 32 ) and has been identified in various populations

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The Relationship Between Self-Regulatory Efficacy and Physical Activity in Adolescents With a Caveat: A Cross-Lag Design Examining Weather

Kathleen S. Wilson and Kevin S. Spink

persist at a particular behavior in the face of obstacles or challenges ( 3 ). While experimental designs provide the best evidence for establishing directionality, most studies in the physical activity setting have used correlational designs, including both cross-sectional ( 6 , 28 ) and longitudinal

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Physiologic Comparison of Adolescent Female and Male Cross-Country Runners

Lee N. Cunningham

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.

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Cross-Validation of Aerobic Capacity Prediction Models in Adolescents

Ryan D. Burns, James C. Hannon, Timothy A. Brusseau, Patricia A. Eisenman, Pedro F. Saint-Maurice, Greg J. Welk, and Matthew T. Mahar

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 VO2 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 VO2 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 VO2 Peak. Multiple correlations among various models with measured VO2 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 VO2 Peak, fair prediction error, and fair-to-good criterion referenced agreement with measured VO2 Peak into FITNESSGRAM’s Healthy Fitness Zones.

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Body Composition of Elite, Eumenorrheic and Amenorrheic, Adolescent Cross-Country Runners

Marc Bonis, Mark Loftin, Richard Speaker, and Anthony Kontos

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.

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Strength, Power, and Aerobic Exercise Correlates of 5-km Cross-Country Running Performance in Adolescent Runners

Andrew S. Cole, Megan E. Woodruff, Mary P. Horn, and Anthony D. Mahon

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.

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The Wisconsin Wrestling Minimal Weight Project: Cross-Validation of Prediction Equations

R. Randall Clark, Jacqueline M. Kuta, and Robert A. Oppliger

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.

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Cross-Validation of Two Accelerometers for Assessment of Physical Activity and Sedentary Time in Preschool Children

Sofiya Alhassan, John R. Sirard, Laura B. F. Kurdziel, Samantha Merrigan, Cory Greever, and Rebecca M. C. Spencer

Purpose:

The purpose of this study was to cross-validate previously developed Actiwatch (AW; Ekblom et al. 2012) and AcitGraph (AG; Sirard et al. 2005; AG-P, Pate et al. 2006) cut-point equations to categorize free-living physical activity (PA) of preschoolers using direct observation (DO) as the criterion measure. A secondary aim was to compare output from the AW and the AG from previously developed equations.

Methods:

Participants’ (n = 33; age = 4.4 ± 0.8 yrs; females, n=12) PA was directly observed for three 10-min periods during the preschool-day while wearing the AW (nondominant wrist) and AG (waist). Device specific cut-points were used to reduce the AW-E (Ekblom et al. 2012) and AG (AG-S, Sirard et al. 2005; AG-P, Pate et al. 2006) data into intensity categories. Spearman correlations (rsp) and agreement statistics were used to assess associations between the DO intensity categories and device data. Mixed model regression was used to identify differences in times spent in activity intensity categories.

Results:

There was a significant correlation between AW and AG output across all data (rsp = 0.41, p < .0001) and both were associated with the DO intensity categories (AW: rsp = 0.47, AG: rsp = 0.47; p < .001). At the individual level, all devices demonstrated relatively low sensitivity but higher specificity. At the group level, AW-E and AG-P provided similar estimates of time spent in moderate-to-vigorous PA (MVPA, AW-E: 4.7 ± 4.1, AG-P: 4.4 ± 3.3), compared with DO (5.1 ± 3.5). Conclusion: The AW-E and AG-P estimated times spent in MVPA were similar to DO, but the weak agreement statistics indicate that neither device cut-point equations provided accurate estimates at the individual level.

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Relationship between the Lactate Threshold and Cross-Country Run Performance in High School Male and Female Runners

Bo Fernhall, Wendy Kohrt, Lee N. Burkett, and Steven Walters

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.

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A Cross-Sectional Survey Assessing Physical Fitness of 9- to 19-Year-Old Girls and Boys in Switzerland

Michel Cauderay, Françoise Narring, and Pierre-André Michaud

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.