The impact of physical activity level, degree of dyspnoea and pulmonary function on the performance of healthy young adults during exercise

Kinematic evaluation of patients with chronic obstructive pulmonary disease during the 6-min walk test

BACKGROUND

A better understanding of gait kinematics during the 6-min walk test (6MWT) may facilitate the development of rehabilitation strategies for patients with chronic obstructive pulmonary disease (COPD).

AIM

To evaluate gait kinematics during the 6MWT in patients with COPD.

METHOD

Thirty-six patients with COPD and 19 healthy controls underwent a full-body kinematic analysis during the 6MWT. Data were collected using a system with four infrared cameras to capture the movement of a spherical marker covered with retroreflective tape attached to a helmet worn during the test.

RESULTS

The walking distances measured by the assessor and by kinematics analysis were lower in the group of patients (P = 0.036 and P = 0.013, respectively). Moreover, the walking distances measured by kinematics analysis were greater than those measured by the assessor for both groups (P < 0.001). In the kinematics analysis of the complete test, the mean and maximum speeds were higher for the controls than for the patients (P = 0.007 and P = 0.044, respectively). In the half-turn analysis, acceleration, speed, and deceleration peaks (maximal absolute values) were lower for the patients than for the controls (P = 0.002, P = 0.012 and P = 0.006, respectively).

CONCLUSIONS

Patients with COPD show worse functional capacity due to lower gait speed and acceleration-deceleration peaks after turnings as compared to healthy individuals during the 6MWT. Assessors can accurately predict the 6MWD measured by kinematics, though they underestimate this distance.

Validity and precision of the International Physical Activity Questionnaire for climacteric women using computational intelligence techniques

This study aimed to evaluate the validity and precision of the International Physical Activity Questionnaire (IPAQ) for climacteric women using computational intelligence techniques. The instrument was applied to 873 women aged between 40 and 65 years. Considering the proposal to regroup the set of data related to the level of physical activity of climacteric women using the IPAQ, we used 2 algorithms: Kohonen and k-means, and, to evaluate the validity of these clusters, 3 indexes were used: Silhouette, PBM and Dunn. The questionnaire was tested for validity (factor analysis) and precision (Cronbach's alpha). The Random Forests technique was used to assess the importance of the variables that make up the IPAQ. To classify these variables, we used 3 algorithms: Suport Vector Machine, Artificial Neural Network and Decision Tree. The results of the tests to evaluate the clusters suggested that what is recommended for IPAQ, when applied to climacteric women, is to categorize the results into two groups. The factor analysis resulted in three factors, with factor 1 being composed of variables 3 to 6; factor 2 for variables 7 and 8; and factor 3 for variables 1 and 2. Regarding the reliability estimate, the results of the standardized Cronbach's alpha test showed values between 0.63 to 0.85, being considered acceptable for the construction of the construct. In the test of importance of the variables that make up the instrument, the results showed that variables 1 and 8 presented a lesser degree of importance and by the analysis of Accuracy, Recall, Precision and area under the ROC curve, there was no variation when the results were analyzed with all IPAQ variables but variables 1 and 8. Through this analysis, we concluded that the IPAQ, short version, has adequate measurement properties for the investigated population.