The influence of recovery duration between periods of exercise on the critical power function

It has been shown that when three periods of exercise at different intensities are performed to exhaustion, the linear regression of the work accomplished on the time taken defines the critical power (CP) function. The slope of this function is related to endurance ability, whereas the γ-intercept is considered to represent anaerobic work capacity (AWC). The purpose of this study was to determine whether two different recovery durations (3 and 24 h), separating three periods of exercise, would elicit differences in the linear CP function. Nine healthy, untrained female students [19.5 (SD 1.6) years] completed five sessions of cycle exercise to exhaustion in random order (familiarisation). Three of these five power outputs were then used in the main part of the study in which the subjects were randomly assigned to two groups. Group one first performed the three power outputs on the same day, with 3 h of passive recovery separating each session (3 on 1). Group two first performed the three power outputs on 3 consecutive days, with approximately 24 h between sessions (3 con). Following 1 day of rest, group one repeated their three power outputs on 3 consecutive days and group two completed their three tests on the same day. Repeated-measures ANOVA revealed no significant differences between the mean values of CP or AWC calculated from the 3 on 1 or 3 con conditions. Trial two estimates of CP were, however, 3.4% (P < 0.05) higher than trial one (familiarisation) estimates. The results of this study showed that reliable measurements of both CP and AWC can be determined from three tests separated by rest periods of 3 h, provided that the subjects are first familiarised with the tests. We found one series of we exercise sessions to be sufficient familiarisation to ensure similar subsequent estimates of CP

KmL: k-means for longitudinal data

Functional analysis, Longitudinal data, k-means, Cluster analysis, Non-parametric algorithm,

Beclomethasone dipropionate and formoterol fumarate synergistically interact in hyperresponsive medium bronchi and small airways

Background: Corticosteroids increase the expression of β2-adrenoceptors (β2-ARs) and protect them against down-regulation. Conversely, β2-AR agonists improve the anti-inflammatory action of corticosteroids. Nevertheless, it is still uncertain whether adding a long-acting β2-AR agonist (LABA) to an inhaled corticosteroid (ICS) results in an additive effect, or there is true synergy. Therefore, the aim of this study was to pharmacologically characterize the interaction between the ICS beclomethasone diproprionate (BDP) and the LABA formoterol fumarate (FF) in a validated human ex vivo model of bronchial asthma. Methods: Human medium and small airways were stimulated by histamine and treated with different concentrations of BDP and FF, administered alone and in combination at concentration-ratio reproducing ex vivo that of the currently available fixed-dose combination (FDC; BDP/FF 100:6 combination-ratio). Experiments were performed in non-sensitized (NS) and passively sensitized (PS) airways. The pharmacological interaction was assessed by using Bliss Independence and Unified Theory equations. Results: BDP/FF synergistically increased the overall bronchorelaxation in NS and PS airways (+15.15%±4.02%; P <0.05 vs. additive effect). At low-to-medium concentrations the synergistic interaction was greater in PS than in NS bronchioles (+16.68%±3.02% and+7.27%±3.05%, respectively). In PS small airways a very strong synergistic interaction (Combination Index: 0.08; +20.04%±2.18% vs. additive effect) was detected for the total concentrations of BDP/FF combination corresponding to 10.6 ng/ml. Conclusion: BDP/FF combination synergistically relaxed human bronchi; the extent of such an interaction was very strong at low-to-medium concentrations in PS small airways