Extended steep ramp test normative values for 19-24-year-old healthy active young adults.

PURPOSE: To extend currently available sex and age-specific normative values in children and adolescents for the peak work rate (WRpeak) attained at the steep ramp test (SRT) to healthy active young adults. METHODS: Healthy male and female participants aged between 19 and 24 years were recruited. After screening and anthropometric measurements, participants performed a SRT on a cycle ergometer (increments of 25 W/10 s), monitoring and recording SRT-WRpeak, heart rate (HR), and blood pressure (BP) at rest and directly after peak exercise. RESULTS: Fifty-seven participants (31 males and 26 females; median age of 21.3 years) volunteered and were tested. Anthropometrics, resting BP and lung function were all within normal ranges. Ninety-three percent of the participants attained a peak HR (HRpeak) > 80% of predicted (mean HRpeak 87 ± 5% of predicted). No differences were found in resting and peak exercise variables between females and males, except for absolute SRT-WRpeak (350 W [Q1: 306; Q3: 371] and 487 W [Q1: 450; Q3: 517], respectively) and SRT-WRpeak normalized for body mass (relative SRT-WRpeak; 5.4 ± 0.5 and 6.2 ± 0.6 W/kg, respectively). Low-to-moderate correlations (ρ [0.02-0.71]) were observed between SRT-WRpeak and anthropometric variables for females and males separately. Extended reference curves (8-24-year-old subjects) for SRT performance show different trends between male and female subjects when modelled against age, body height, and body mass. CONCLUSIONS: The present study provides sex-, age-, body height-, and body mass-related normative values (presented as reference centiles) for absolute and relative SRT performance throughout childhood and early adulthood.

Towards an individualized protocol for workload increments in cardiopulmonary exercise testing in children and adolescents with cystic fibrosis.

BACKGROUND: There is no single optimal exercise testing protocol for children and adolescents with cystic fibrosis (CF) that differs widely in age and disease status. The aim of this study was to develop a CF-specific, individualized approach to determine workload increments for a cycle ergometry testing protocol. METHODS: A total of 409 assessments consisting of maximal exercise data, anthropometric parameters, and lung function measures from 160 children and adolescents with CF were examined. 90% of the database was analyzed with backward linear regression with peak workload (W(peak)) as the dependent variable. Afterwards, we [1] used the remaining 10% of the database (model validation group) to validate the model's capacity to predict W(peak) and [2] validated the protocol's ability to provide a maximal effort within a 10±2 minute time frame in 14 adolescents with CF who were tested using this new protocol (protocol validation group). RESULTS: No significant differences were seen in W(peak) and predicted W(peak) in the model validation group or in the protocol validation group. Eight of 14 adolescents with CF in the protocol validation group performed a maximal effort, and seven of them terminated the test within the 10±2 minute time frame. Backward linear regression analysis resulted in the following equation: W(peak) (W)=-142.865+2.998×Age (years)-19.206×Sex (0=male; 1=female)+1.328×Height (cm)+23.362×FEV(1) (L) (R=.89; R(2)=.79; SEE=21). Bland-Altman analysis showed no systematic bias between the actual and predicted W(peak). CONCLUSION: We developed a CF-specific linear regression model to predict peak workload based on standard measures of anthropometry and FEV(1), which could be used to calculate individualized workload increments for a cycle ergometry testing protocol.

Is static hyperinflation a limiting factor during exercise in adolescents with cystic fibrosis?

Increased work of breathing is considered to be a limiting factor in patients with cystic fibrosis (CF) performing aerobic exercise. We hypothesized that adolescents with CF and with static hyperinflation are more prone to a ventilatorily limited exercise capacity than non-static hyperinflated adolescents with CF. Exercise data of 119 adolescents with CF [range 12-18 years], stratified for static hyperinflation, defined as ratio of residual volume to total lung capacity (RV/TLC) > 30%, were obtained during a progressive bicycle ergometer test with gas analysis and analyzed for ventilatory limitation. Static hyperinflation showed a significant, though weak association (Φ 0.38; P < 0.001) with a ventilatorily limited exercise capacity (breathing reserve index at maximal effort >0.70; FEV(1) < 80% predicted and reduced exercise capacity, defined as VO(2peak) < 85% predicted). Analysis of association for increasing degrees of hyperinflation showed an increase to Φ 0.49 (P < 0.001) for RV/TLC > 50%. In adolescents with static hyperinflation, peak work rate (W(peak) ; 3.1 ± 0.7 W/kg (75.1 ± 17.3% of predicted), peak oxygen uptake (VO(2peak) /kg (ml/min/kg); 39.2 ± 9.2 ml/min/kg (91.0 ± 20.3% of predicted), peak heart rate (HR(peak) ; 176 ± 19 beats/min) were significantly (P < 0.05) decreased when compared with non-static hyperinflated adolescents (W(peak) 3.5 ± 0.5 W/kg (81.4 ± 10.0% of predicted)); VO(2peak) /kg (ml/min/kg); 43.1 ± 7.5 ml/min/kg (98.0 ± 15.1% of predicted); and HR(peak) 185 ± 14 beats/min). Additionally, no difference was found in the degree of association of FEV(1) (%) and RV/TLC (%) with VO(2peak) /kg(pred) and W(peak) /kg(Pred) , but we found the RV/TLC (%) to be a slightly stronger predictor of VO(2peak) /kg(pred) and W(peak) /kg(Pred) than FEV(1) (%). These results indicate that the presence of static hyperinflation in adolescents with CF by itself does not strongly influence ventilatory constraints during exercise and that static hyperinflation is only a slightly stronger predictor of W(peak) /kg(Pred) and VO(2peak) /kg(Pred) than airflow obstruction (FEV(1) (%)).