Comparison of marker models for the analysis of the volume variation and thoracoabdominal motion pattern in untrained and trained participants.

Respiratory assessment and the biomechanical analysis of chest and abdomen motion during breathing can be carried out using motion capture systems. An advantage of this methodology is that it allows analysis of compartmental breathing volumes, thoraco-abdominal patterns, percentage contribution of each compartment and the coordination between compartments. In the literature, mainly, two marker models are reported, a full marker model of 89 markers placed on the trunk and a reduced marker model with 32 markers. However, in practice, positioning and post-process a large number of markers on the trunk can be time-consuming. In this study, the full marker model was compared against the one that uses a reduced number of markers, in order to evaluate (i) their capability to obtain respiratory parameters (breath-by-breath tidal volumes) and thoracoabdominal motion pattern (compartmental percentage contributions, and coordination between compartments) during quiet breathing, and (ii) their response in different groups such as trained and untrained, male and female. Although tests revealed strong correlations of the tidal volume values in all the groups (R2 > 0.93), the reduced model underestimated the trunk volume compared with the 89 marker model. The highest underestimation was found in trained males (bias of 0.43 L). The three-way ANOVA test showed that the model did not influence the evaluation of compartmental contributions and the 32 marker model was adequate to distinguish thoracoabdominal breathing pattern in the studied groups. Our findings showed that the reduced marker model could be used to analyse the thoracoabdominal motion in both trained and untrained populations but performs poorly in estimating tidal volume.

Environmental influence on the prevalence and pattern of airway dysfunction in elite athletes.

BACKGROUND AND OBJECTIVE: Elite swimming and boxing require athletes to achieve relatively high minute ventilation. The combination of a sustained high ventilation and provocative training environment may impact the susceptibility of athletes to exercise-induced bronchoconstriction (EIB). The purpose of this study was to evaluate the prevalence of EIB in elite Great British (GB) boxers and swimmers. METHODS: Boxers (n = 38, mean age: 22.1 ± 3.1 years) and swimmers (n = 44, mean age: 21.1 ± 2.6 years) volunteered for the study. Athletes completed an exercise-induced respiratory symptom questionnaire, baseline assessment of fraction of exhaled nitric oxide (FeNO), maximal spirometry manoeuvres and a eucapnic voluntary hyperpnoea (EVH) challenge. EIB was confirmed if forced expiratory volume in 1 s (FEV1 ) reduced by ≥10% from baseline at two time points post-EVH challenge. RESULTS: The prevalence of EIB was greater in elite swimmers (30 of 44; 68%) than in boxers (3 of 38; 8%) (P < 0.001). Twenty-two out of the 33 (67%) EVH-positive athletes had no prior diagnosis of asthma/EIB. Moreover, 12% (6 of 49) of the EVH-negative athletes had a previous diagnosis of asthma/EIB. We found a correlation between FeNO and FEV1 change in lung function post-EVH challenge in swimmers (r = 0.32; P = 0.04) but not in boxers (r = 0.24; P = 0.15). CONCLUSION: The prevalence of EIB was ninefold greater in swimmers when compared with boxers. Athletes who train and compete in provocative environments at sustained high ventilation may have an increased susceptibility to EIB. It is not entirely clear whether increased susceptibility to EIB affects elite sporting performance and long-term airway health in elite athletes.