Pak-Kwong Chung

The effect of inspiratory muscle training on high-intensity, intermittent running performance to exhaustion.

The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) during Yo-Yo intermittent recovery test and on the physiological and perceptual responses to the running test were examined. Thirty men were randomly allocated to 1 of 3 groups. The experimental group underwent a 6 week pressure threshold IM training program by performing 30 inspiratory efforts twice daily, 6 d/week, against a load equivalent to 50% maximal static inspiratory pressure. The placebo group performed the same training procedure but with a minimal inspiratory load. The control group received no training. In post-intervention assessments, IM function was enhanced by >30% in the experimental group. The Ex was improved by 16.3% +/- 3.9%, while the rate of increase in intensity of breathlessness (RPB/4i) was reduced by 11.0% +/- 6.2%. Further, the whole-body metabolic stress reflected by the accumulations of plasma ammonia, uric acid, and blood lactate during the Yo-Yo test at the same absolute intensity was attenuated. For the control and placebo groups, no significant change in these variables was observed. In comparison with previous observations that the reduced RPB/4i resulting from IM warm-up was the major reason for improved Ex, the reduced RPB/4i resulting from the IM training program was lower despite the greater enhancement of IM function, whereas improvement in Ex was similar. Such findings suggest that although both IM training and warm-up improve the tolerance of intense intermittent exercise, the underlying mechanisms may be different.

An assessment of the validity and reliability of two perceived exertion rating scales among Hong Kong children.

This study evaluated the validity and reliability of the Chinese-translated (Cantonese) versions of the Borg 6–20 Rating of Perceived Exertion (RPE) scale and the Childrens Effort Rating Table (CERT) during continuous incremental cycle ergometry with 10- to 11-yr.-old Hong Kong school children. A total of 69 children were randomly assigned, with the restriction of groups being approximately equal, to two groups using the two scales, CERT (n = 35) and RPE (n = 34). Both groups performed two trials of identical incremental continuous cycling exercise (Trials 1 and 2) 1 wk. apart for the reliability test. Objective measures of exercise intensity (heart rate, absolute power output, and relative oxygen consumption) and the two subjective measures of effort were obtained during the exercise. For both groups, significant Pearson correlations were found for perceived effort ratings correlated with heart rate (rs ≥ .69), power output (rs ≥ .75), and oxygen consumption (rs ≥ .69). In addition, correlations for CERT were consistently higher than those for RPE. High test-retest intraclass correlations were found for both the effort (R = .96) and perceived exertion (R = 89) groups, indicating that the scales were reliable. In conclusion, the CERT and RPE scales, when translated into Cantonese, are valid and reliable measures of exercise intensity during controlled exercise by children. The Effort rating may be better than the Perceived Exertion scale as a measure of perceived exertion that can be more validly and reliably used with Hong Kong children.

Psychometric Properties of the Acceptance and Action Questionnaire–II for Chinese College Students and Elite Chinese Athletes:

The purpose of the present study was to examine the psychometric properties of the Chinese version of the Acceptance and Action Questionnaire–II (AAQ-II) across two samples of Chinese college students (n = 183 and n = 366) and a sample of elite Chinese athletes (n = 330). Exploratory and confirmatory factor analyses supported the existence of a unidimensional AAQ-II. Adequate internal consistency reliability, test–retest reliability (one-month interval), factorial validity, and nomological validity with mindfulness, well-being, positive and negative affect/mood for both students and athletic samples were demonstrated. The AAQ-II also showed incremental validity in college students in explaining variances of well-being, positive and negative affect, anxiety, and depression, beyond the mindfulness measure. Most important, factorial invariance of the AAQ-II was demonstrated across male and female college students as well as across male and female athletes. Partial factorial invariance was also demonstrated across adolescent and adult athletes. Overall, results of this study suggest that the Chinese version of the AAQ-II may be a useful self-report measure of experiential avoidance in Chinese college students and elite Chinese athletes.

Psychometric properties of the Brunel Mood Scale in Chinese adolescents and adults

Abstract Building on the work of Terry and colleagues (Terry, P. C., Lane, A. M., Lane, H. J., & Keohane, L. (1999). Development and validation of a mood measure for adolescents. Journal of Sports Sciences, 17, 861–872; Terry, P. C., Lane, A. M., & Fogarty, G. J. (2003). Construct validity of the Profile of Mood States-Adolescents for use with adults. Psychology of Sport & Exercise, 4, 125–139.), the present study examined the validity and internal consistency reliability of the Chinese version of the Brunel Mood Scale (BRUMS-C) among 2,548 participants, comprising adolescent athletes (n = 520), adult athletes (n = 434), adolescent students (n = 673), and adult students (n = 921). Both adolescent and adult athletes completed the BRUMS-C before, during, or after regular training and both adolescent and adult students completed the BRUMS-C in a classroom setting. Confirmatory factor analyses (CFAs) provided support for the factorial validity of a 23-item six-factor model, with one item removed from the hypothesised measurement model. Internal consistency reliabilities were satisfactory for all subscales across each of the four samples. Criterion validity was supported with strong relationships between the BRUMS-C, abbreviated POMS, and Chinese Affect Scale consistent with theoretical predictions. Multi-sample CFAs showed the BRUMS-C to be invariant at the configural, metric, strong, and structural levels for all samples. Furthermore, latent mean difference analyses showed that athletes reported significantly higher levels of fatigue than students while maintaining almost the same levels of vigour, and adolescent students reported significantly higher levels of depressed mood than the other three samples.

CHRONIC AND ACUTE INSPIRATORY MUSCLE LOADING AUGMENT THE EFFECT OF A 6-WEEK INTERVAL PROGRAM ON TOLERANCE OF HIGH-INTENSITY INTERMITTENT BOUTS OF RUNNING

Tong, TK, Fu, FH, Eston, R, Chung, P-K, Quach, B, and Lu, K. Chronic and acute inspiratory muscle loading augment the effect of a 6-week interval program on tolerance of high-intensity intermittent bouts of running. J Strength Cond Res 24(11): 3041-3048, 2010-This study examined the hypothesis that chronic (training) and acute (warm-up) loaded ventilatory activities applied to the inspiratory muscles (IM) in an integrated manner would augment the training volume of an interval running program. This in turn would result in additional improvement in the maximum performance of the Yo-Yo intermittent recovery test in comparison with interval training alone. Eighteen male nonprofessional athletes were allocated to either an inspiratory muscle loading (IML) group or control group. Both groups participated in a 6-week interval running program consisting of 3-4 workouts (1-3 sets of various repetitions of selected distance [100-2,400 m] per workout) per week. For the IML group, 4-week IM training (30 inspiratory efforts at 50% maximal static inspiratory pressure [P0] per set, 2 sets·d−1, 6 d·wk−1) was applied before the interval program. Specific IM warm-up (2 sets of 30 inspiratory efforts at 40% P0) was performed before each workout of the program. For the control group, neither IML was applied. In comparison with the control group, the interval training volume as indicated by the repeatability of running bouts at high intensity was approximately 27% greater in the IML group. Greater increase in the maximum performance of the Yo-Yo test (control: 16.9 ± 5.5%; IML: 30.7 ± 4.7% baseline value) was also observed after training. The enhanced exercise performance was partly attributable to the greater reductions in the sensation of breathlessness and whole-body metabolic stress during the Yo-Yo test. These findings show that the combination of chronic and acute IML into a high-intensity interval running program is a beneficial training strategy for enhancing the tolerance to high-intensity intermittent bouts of running.

Evaluation of an Internet-Short Message Service-Based Intervention for Promoting Physical Activity in Hong Kong Chinese Adolescent School Children: A Pilot Study

Evaluation of acceptability and preliminary efficacy of an Internet and short message service (SMS) intervention for promoting physical activity (PA) in Hong Kong Chinese school children. An 8-week quasi-experimental study non-randomly assigned 78 school children (mean age=12.8 years) to (a) an intervention group that received a stage-matched, Internet PA program two times a week and tailored SMS messages daily; or (b) a no-treatment control. Data were collected from September 2008 until June 2009. Acceptability measures included exposure rate and participants satisfaction. Efficacy measures were changes in stage of motivational readiness (SMR) and self-reported PA level. Intervention participants demonstrated significant pre-post increments in SMR (Z=-2.558, p=0.011) and self-reported PA level [F(1, 76)=4.50, p=0.04]. There was a non-significant trend between groups in both SMR (p=0.24) and PA (p=0.13). Despite the similar ratings of satisfaction between Internet (M=3.12±0.74) and SMS (M=3.12±0.84), participants displayed distinct patterns of exposure with 66% exhibiting a weekly login rate of 0.5 times/person and an average of 3.75 minutes/visit/person. In contrast, 79% of participants read an average of 1.3 SMS/person/week and 47% voluntarily replied to ∼3.8 SMS/person. These findings demonstrate the acceptability and preliminary efficacy of an Internet-SMS-based intervention for promoting PA in Hong Kong school children. The divergent exposure rates between the Internet and SMS may be a unique pattern for adolescents in early SMR. Future research should be cognizant of the importance of SMR since it may influence utilization and/or adherence.

Development and Initial Validation of the Psychological Needs Satisfaction Scale in Physical Education

The current study presents the development process and initial validation of a measure designed for assessing psychological needs satisfaction in a secondary school physical education context (Psychological Needs Satisfaction Scale in Physical Education, PNSSPE). Junior secondary school (grades 7 to 9) students (N = 1,258) were invited to participate in three studies. In Study 1, item generation (34 items) and initial content validity of the PNSSPE were achieved. In Study 2, the factorial structure of the PNSSPE was tested using exploratory and confirmatory factor analyses. Internal consistency reliabilities of the subscales were also examined. In Study 3, the reliability and validity of the scores derived from the PNSSPE were further examined in an independent sample. Overall, the PNSSPE demonstrated good content, factorial, discriminant, and nomological validities. It also demonstrated acceptable internal consistency and test–retest reliability. The measurement model was proven invariant across gender and samples. Psychometric evidence from a series of studies suggests that the PNSSPE could be used as a reliable and valid measure to assess Hong Kong secondary school students’ satisfaction of psychological needs in physical education.

Validity and reliability of a Cantonese-translated rating of perceived exertion scale among Hong Kong adults.

This study assessed the validity and reliability of the Cantonese-translated version of the Borg 6–20 Rating of Perceived Exertion (RPE) scale during continuous incremental cycle ergometry by Hong Kong adults. A total of 54 participants (25 males and 29 females), ages 22.2 ± 4.7 yr., volunteered to participate. They performed two trials of identical continuous incremental cycling exercise 1 wk. apart for the reliability test. The objective measures of exercise intensity (heart rate, power output, and oxygen consumption) and the subjective measure of effort (RPE) were obtained during the incremental exercise. Significant (p<.01) Pearson correlations were found when RPE values were correlated with heart rate (rs ≥ .73), power output (rs ≥ .69), and oxygen consumption (rs ≥ .68). The overall test-retest intraclass correlation (R = .92) indicated that the scale was reliable. In conclusion, this Cantonese scale for rating of perceived exertion appears to be a valid and reliable psychophysiological tool to measure perceptions of exertion during controlled cycle ergometer exercise by Hong Kong adults.

Examination of the Psychometric Properties of the Chinese Translated Behavioral Regulation in Exercise Questionnaire-2

The present study was designed to examine the psychometric properties of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 (Markland & Tobin, 2004). A sample of Chinese university students (N = 555) was invited to take part in this study. Confirmatory factor analysis was employed to examine the factorial validity, and the results supported the 5-factor structure of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2. Examination of the 95% confidence interval of the inter-factor correlations suggested that the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 assesses related but distinct constructs, which provided support for the discriminant validity. Composite reliability values of subscales were all over .75, which suggested that internal consistency reliability of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 was acceptable. Examination of the pattern of inter-factor correlations between different regulations suggested that the simplex-like pattern was displayed, which provided evidence for the nomological validity of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2. Examination of the correlations of different regulations with affective and behavioral outcomes provided further support for the nomological validity. Multi-group confirmatory factor analysis was conducted to examine the gender invariance of Chinese-translated Behavioral Regulation in Exercise Questionnaire-2, and the results suggested that the factor loadings and factor variances and covariances of the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2 measurement model to be invariant across male and female participants. Overall, the study provided initial psychometric evidence for the Chinese-translated Behavioral Regulation in Exercise Questionnaire-2.

Construction and Validation of a Perceived Physical Literacy Instrument for Physical Education Teachers.

The purpose of this study was to construct and validate a “Perceived Physical Literacy Instrument” (PPLI) for physical education teachers. Based on literature review and focus group interviews, an 18-item instrument was developed for the initial tests. This self-report measure, using a 5-point Likert scale, formed the PPLI and was administered to 336 physical education teachers in Hong Kong. The sample was randomly split, and exploratory and confirmatory factor analyses resulted in a 9-item, 3-factor scale. Exploratory factor analysis (EFA) item loadings ranged from 0.69 to 0.87, and Cronbach’s alpha ranged from 0.73 to 0.76. Confirmatory factor analysis (CFA) showed that the construct demonstrated good fit to the model. The PPLI thus appeared to be reliable and valid to measure the perceived physical literacy of physical education teachers. It is argued that the instrument can be used for both research and applied purposes and potential uses for the instrument in physical education, medical and health settings are discussed.