This study evaluated the concurrent validity of the 300-yard and the 1.5-mile run with a group of mildly mentally retarded (MR) adults. The subjects, 15 healthy MR adults (M age = 29.5 + 5.6 yrs, M IQ = 60), underwent a maximal treadmill test utilizing a walking protocol, with heart rate and oxygen consumption data collected every minute. They also completed a 300-yard and a 1.5-mile run. The order of testing was counterbalanced. The results indicated that these subjects exhibited very poor cardiovascular fitness levels, with a mean V̇O2max of 28.1 ml•kg-1•min-1 and mean run times of 98.9 sec and 21.1 min for the 300-yard and the 1.5-mile runs, respectively. The correlation between V̇O2max and the 1.5-mile run was –.88, and the correlation for the 300-yard run and V̇O2max was –.71. However, partial correlations indicated that when the effect of height and weight were held constant, only the correlation between V̇O2max and the 1.5-mile run remained significant whereas that between V̇O2max and the 300-yard run dropped. Consequently, the 1.5-mile run appears to be a valid indicator of cardiovascular fitness for these adults with MR, but the 300 yard run is not.
Bo Fernhall and Garth T. Tymeson
Bo Fernhall and Kenneth H. Pitetti
This study evaluated the relationship between leg strength and endurance run performance, independent of aerobic capacity (V̇O2peak), body size, and gender, in children and adolescents with mild or moderate mental retardation. Twenty-six individuals (15 boys and 11 girls) volunteered and underwent tests of V̇O2peak, isokinetic leg strength, and endurance run performance (600-yard ran/walk and 20-m shuttle run). Results showed that leg strength was significantly related to both types of run performance; however, when controlling for V̇O2peak, body size, and gender, leg strength was a more significant contributor to the 600-yard run/walk than to 20-m shuttle run performance. Gender did not influence these relationships. These data suggest that leg strength has a significant influence on endurance run performance in children and adolescents with mild or moderate mental retardation.
Kenneth H. Pitetti and Bo Fernhall
The purpose of this study was to evaluate the relationship between aerobic capacity (VO2peak) and leg strength of male (n = 17) and female (n = 12) youths (age = 14.2 ± 2.1 years) with mild to moderate mental retardation. Aerobic capacity was determined by a treadmill test (GXT) and isokinetic knee flexion and extension strength (peak torque, peak force, average force) was determined by isokinetic dynamometry. Results indicate that significant positive relationships (p < .05) exist between VO2peak (ml · min−1 · kg−1) and isokinetic leg strength expressed relative to body weight. The results indicate that leg strength is a contributor to aerobic fitness in youths with mental retardation. Additionally, when considering the low levels of both strength and VO2peak, leg strength may be a limiting factor of VO2peak in these youths, or the relationship may be explained by the concept of metabolic nonspecialization.
Myriam Guerra, Maria Giné-Garriga, and Bo Fernhall
The Wingate anaerobic test (WAnT) has not been used to assess individuals with Down syndrome (DS) and it is unknown if it is reliable in this population. We investigated the reliability of the WAnT in 19 adolescents with DS (age = 14.8 yrs; weight = 52.7 kg; height = 146.3 cm). Participants completed, on separate days, two standards WAnT using a resistance of 0.7 Nm × body weight (kg) in individuals ≥ 14 years old, and 0.5 Nm × body weight (kg) in participants < 14 years of age. Data were analyzed using intraclass correlation coefficient (ICC), dependent t tests and Bland-Altman plots. There was a significant difference between days for peak power (210.37 W vs. 236.26 W; ICC = 0.93), but not for mean power (158.72 vs. 168.71 W; ICC = 0.86), time to peak power (6.67 vs. 6.28 s; ICC = 0.69), or the fatigue index (9.33 vs. 5.43 W/sec; ICC = 0.09). Adolescents with DS exhibit low WAnT performance compared with previously published data on adolescents without DS and the reliability of WAnT is questionable in this population.
Myriam Guerra, Kenneth H. Pitetti, and Bo Fernhall
The purpose of this study was to determine if the regression formula developed for the 20-m shuttle run test (20 MST) for children and adolescents with mild mental retardation (MR), used to predict cardiovascular fitness (V̇O2peak), is valid for adolescents with Down syndrome (DS). Twenty-six adolescents (mean age = 15.3 ± 2.7 yr) with DS (15 males, 11 females) completed a maximal treadmill protocol (measured V̇O2peak) and a 20 MST (predicted V̇O2peak). There was a significant difference (p < .01) between the means of the measured (25.5 ± 5.2 ml·kg-1-·min-1) and the predicted (33.5 ± 3.9 ml·kg-1·min-1) V̇O2peak, respectively. In addition, there was a low relationship between measured and predicted values (r = .54). The results of this study indicate that the regression formula developed for children and adolescents with MR to predict V̇O2peak was not valid in this sample of adolescents with DS.
Kenneth H. Pitetti, Bart Jongmans, and Bo Fernhall
The purpose of this study was to examine the validity and reliability of a treadmill (TM) test for adolescents with multiple disabilities, as defined by PL 105-17. Participants were 16 males and 2 females, ages 11 to 21 (M 14.9 ± 3.2), identified by teachers as potentially able to perform a TM test. Data were collected two times, separated by 2 to 3 weeks. Of the 18 adolescents, 5 could not perform the protocol, and 4 could not complete the test. Intraclass (test–retest) reliability coefficients for HRpeak, V̇Epeak, RERpeak, and V̇O2peak were .90, .90, .88, and .77, respectively, for the remaining 9 participants. Although none of these participants were able to meet the criteria commonly associated for a valid TM maximaltest (V̇O2max), they did meet the criteria for a valid TM maximum test (V̇O2peak) (Wasserman, Hansen, Sue, Whipp, & Casaburi, 1994). Further study of the feasibility of treadmill testing for this population is recommended.
Kenneth H. Pitetti, Bo Fernhall, and Steve Figoni
Two regression equations were developed to predict cardiovascular fitness (CVF) based on the 20-m shuttle run test (20-MST) for nondisabled youth and for youth with mild mental retardation (MR). The purpose of this study was to compare the validity of both regression formulas to predict CVF in nondisabled, healthy youths (ages 8 to 15 yrs; 38 females and 13 males). Participants performed two modified Bruce protocol treadmill (TM) tests and two 20-MSTs on separate days. CVF (V̇O2peak, ml • kg−1 • min−1) was measured during the TM tests and computed for the 20-MST using both regression equations. Results indicate that test-retest correlations for the 20-MST (# of laps; r = 0.89) and TM test (V̇O2peak, ml • kg−1 • min−1; r = 0.86) were high. Predicted V̇O2peak values were moderately significant (nondisabled youth: r = 0.55, p < .01; youth with MR: r = 0.66, p < .01) when compared with TM V̇O2peak. Correlation between the two regression equations was significant (r = 0.78, p < .01).
Sae Young Jae, Kevin Heffernan, Bo Fernhall, and Yoon-Ho Choi
We tested the hypothesis that higher levels of cardiorespiratory fitness are inversely associated with carotid artery intima media thickness in 746 (age 53 ± 7 yrs) men with type 2 diabetes.
We measured common carotid intima media thickness and defined carotid atherosclerosis as a carotid intima media thickness > 1.0 mm. Cardiorespiratory fitness was directly measured by peak oxygen uptake using expired gases analysis during a standard treadmill test.
Cardiorespiratory fitness was independently associated with common carotid intima media thickness in multivariable regression (β = –0.15, P < .05). After adjusting for established risk factors, high and moderate cardiorespiratory fitness were associated with lower odds ratios for having carotid atherosclerosis—0.49 (95% CI, 0.30–0.81), and 0.59 (95% CI, 0.38–0.92), respectively—as compared with low cardiorespiratory fitness. Each 1 metabolic equivalent increment higher cardiorespiratory fitness was associated with 27% (OR = 0.73; 95% CI, 0.61–0.87) lower prevalence of carotid atherosclerosis.
These results suggest that high cardiorespiratory fitness is inversely associated with common carotid intima media thickness in men with type 2 diabetes.
Jacob J. Sosnoff, Sae Young Jae, Kevin Heffernan, and Bo Fernhall
The purpose of the current investigation was to examine the relation between cardioballistic impulse and the fluctuations in continuous isometric force production. Subjects produced isometric force via index finger flexion to constant force targets (0.5, 1 and 2 N) with and without visual feedback while beat to beat blood pressure of their middle finger was recorded. Force fluctuations were quantified using distributional statistics. The association between blood pressure oscillations and fluctuations in force output were quantified with coherence analysis. Overall, it was found that force variability (i.e., SD) increased with force level and removal of visual feedback. Coherence values between blood pressure oscillations and force fluctuations were significant and the greatest in the 8–12 Hz bandwidth. There was no effect of force magnitude on the coupling strength between blood pressure oscillations and force production. This coupling was greater in the visual condition. These data suggest that peripheral alterations in blood pressure are related to fluctuations in isometric force production independent of force level and that this interaction is influenced by visual feedback.
Kenneth H. Pitetti, Daniel A. Yarmer, and Bo Fernhall
The purpose of this study was to compare the aerobic fitness and body mass index (BMI) of children and adolescents (8-18 yr) with and without mild mental retardation (MR). Sample size of participants with MR but without Down syndrome was 169 males and 99 females. Sample size of participants without MR was 289 males and 317 females. Analysis was made by gender and age: children (8-10 yr); early adolescents (11-14 yr); and late adolescents (15-18 yr). The 20-m shuttle run test (20 MST) was used to assess field test performance and predicted aerobic fitness. For all age groups, females and males without MR ran significantly more laps and had a significantly higher predicted aerobic fitness (V̇O2peak: ml $$ kg-1 $$ min-1) than their peers with MR. Additionally, participants with MR tended to have higher BMI than their peers without MR. The results of this study indicate that children and adolescents with MR have lower exercise capacity, lower aerobic fitness, and higher BMIs than their peers without MR.