Stability of psychometric questionnaires

In 1999, Wilson and Batterham proposed a new approach to assessing the test–retest stability of psychometric questionnaires. They recommended assessing the proportion of agreement – that is, the proportion of participants that record the same response to an item – using a test–retest design. They went on to use a bootstrapping technique to estimate the uncertainty of the proportion of agreement. The aims of this short communication are (1) to demonstrate that the sampling distribution of the proportion of agreement is well known (the binomial distribution), making the technique of ‘bootstrapping’ redundant, and (2) to suggest a much simpler, more sensitive method of assessing the stability of a psychometric questionnaire, based on the test–retest differences (within-individuals) for each item. Adopting methods similar to Wilson and Batterham, 97 sport students completed the Social Physique Anxiety Scale on two occasions. Test–retest differences were calculated for each item. Our results show that the proportion of agreement ignores the nature of disagreement. Items 4 and 11 showed similar agreement (44.3% and 43.3% respectively), but 89 of the participants (91.8%) differed by just - 1 point when responding to item 4, indicating a relatively stable item. In contrast, only 78 of the participants (80.4%) recorded a difference within - 1 point when responding to item 11, suggesting quite contrasting stability for the two items. We recommend that, when assessing the stability of self-report questionnaires using a 5-point scale, most participants (90%) should record test–retest differences within a reference value of - 1.     

Test-retest stability of the Task and Ego Orientation Questionnaire

Establishing stability, defined as observing minimal measurement error in a test-retest assessment, is vital to validating psychometric tools. Correlational methods, such as Pearson product-moment, intraclass, and kappa are tests of association or consistency, whereas stability or reproducibility (regarded here as synonymous) assesses the agreement between test-retest scores. Indexes of reproducibility using the Task and Ego Orientation in Sport Questionnaire (TEOSQ; Duda & Nicholls, 1992) were investigated using correlational (Pearson product-moment, intraclass, and kappa) methods, repeated measures multivariate analysis of variance, and calculating the proportion of agreement within a referent value of +/-1 as suggested by Nevill, Lane, Kilgour, Bowes, and Whyte (2001). Two hundred thirteen soccer players completed the TEOSQ on two occasions, 1 week apart. Correlation analyses indicated a stronger test-retest correlation for the Ego subscale than the Task subscale. Multivariate analysis of variance indicated stability for ego items but with significant increases in four task items. The proportion of test-retest agreement scores indicated that all ego items reported relatively poor stability statistics with test-retest scores within a range of +/-1, ranging from 82.7-86.9%. By contrast, all task items showed test-retest difference scores ranging from 92.5-99%, although further analysis indicated that four task subscale items increased significantly. Findings illustrated that correlational methods (Pearson product-moment, intraclass, and kappa) are influenced by the range in scores, and calculating the proportion of agreement of test-retest differences with a referent value of +/-1 could provide additional insight into the stability of the questionnaire. It is suggested that the item-by-item proportion of agreement method proposed by Nevill et al. (2001) should be used to supplement existing methods and could be especially helpful in identifying rogue items in the initial stages of psychometric questionnaire validation.     

Test-Retest Stability of the Task and Ego Orientation Questionnaire

Abstract

Establishing stability, defined as observing minimal measurement error in a test-retest assessment, is vital to validating psychometric tools. Correlational methods, such as Pearson product-moment, intraclass, and kappa are tests of association or consistency, whereas stability or reproducibility (regarded here as synonymous) assesses the agreement between test-retest scores. Indexes of reproducibility using the Task and Ego Orientation in Sport Questionnaire (TEOSQ; Duda & Nicholls, 1992) were investigated using correlational (Pearson product-moment, intraclass, and kappa) methods, repeated measures multivariate analysis of variance, and calculating the proportion of agreement within a referent value of +1 as suggested by Nevill, Lane, Kilgour, Bowes, and Whyte (2001). Two hundred thirteen soccer players completed the TEOSQ on two occasions, 1 week apart. Correlation analyses indicated a stronger test-retest correlation for the Ego subscale than the Task subscale. Multivariate analysis of variance indicated stability for ego items but with significant increases in four task items. The proportion of test-retest agreement scores indicated that all ego items reported relatively poor stability statistics with test-retest scores within a range of +1, ranging from 82.7–86.9%. By contrast, all task items showed test-retest difference scores ranging from 92.5–99%, although further analysis indicated that four task subscale items increased significantly. Findings illustrated that correlational methods (Pearson product-moment, intraclass, and kappa) are influenced by the range in scores, and calculating the proportion of agreement of test-retest differences with a referent value of +1 could provide additional insight into the stability of the questionnaire. It is suggested that the item-by-item proportion of agreement method proposed by Nevill et al. (2001) should be used to supplement existing methods and could be especially helpful in identifying rogue items in the initial stages of psychometric questionnaire validation.     

Stability of questionnaire items in sport and exercise psychology: bootstrap limits of agreement.

We describe an alternative method for assessing the stability of individual questionnaire items in sport and exercise psychology. To date, the Pearson product-moment correlation coefficient has been widely used in psychometrics. We propose an alternative non-parametric method based on proportion of agreement. Ninety-two male university students completed the revised 9-item Social Physique Anxiety Scale on two occasions, separated by a 2-week interval. Point estimates of the proportion of direct within-individual agreement between the two occasions were calculated separately for each item of the Social Physique Anxiety Scale. Estimates of uncertainty of the agreement were calculated using a bootstrapping resampling technique. For each item, 2000 bootstrap samples (each n = 92 pairs) were redrawn from the original sample. The sample statistic was calculated for each bootstrap sample to provide a bootstrap sampling distribution. The 95% confidence intervals (CI) were then calculated using the percentile method. The three most problematic items were items 7, 8 and 10 (as labelled in the original 12-item scale). These items demonstrated an agreement of 0.46 (95% CI= 0.36 0.56), 0.42 (95% CI = 0.33-0.52) and 0.41 (95% CI = 0.32-0.51) respectively. Our proposed method measures absolute agreement between test-retest responses, is free of normal assumptions, does not depend on high between-individuals variance, and can be applied successfully to individual items in the development of psychological tests.     

The Loughborough Intermittent Shuttle Test: a field test that simulates the activity pattern of soccer

The aims of this study were to describe and determine the test-retest reliability of an exercise protocol, the Loughborough Intermittent Shuttle Test (the LIST), which was designed to simulate the activity pattern characteristic of the game of soccer. The protocol consisted of two parts: Part A comprised a fixed period of variable-intensity shuttle running over 20 m; Part B consisted of continuous running, alternating every 20 m between 55% and 95% VO2max, until volitional fatigue. Seven trained games players (age 21.5+/-0.9 years, height 182+/-2 cm, body mass 80.1+/-3.6 kg, VO2max 59.0+/-1.9 ml x kg(-1) x min(-1); mean +/- s(x)) performed the test on two occasions (Trial 1 and Trial 2), at least 7 days apart, to determine the test-retest reliability of the sprint times and running capacity. The physiological and metabolic responses on both occasions were also monitored. The participants ingested water ad libitum during the first trial, and were then prescribed the same amount of water during the second trial. The 15 m sprint times during Trials 1 and 2 averaged 2.42+/-0.04 s and 2.43+/-0.04 s, respectively. Run time during Part B was 6.3+/-2.0 min for Trial 1 and 6.1+/-1.3 min for Trial 2. The 95% limits of agreement for sprint times and run times during Part B were -0.14 to 0.12 s and -3.19 to 2.16 min respectively. There were no differences between trials for heart rate, rating of perceived exertion, body mass change during exercise, or blood lactate and glucose concentrations during the test. Thus, we conclude that the sprint times and the Part B run times were reproducible within the limits previously stated. In addition, the activity pattern and the physiological and metabolic responses closely simulated the match demands of soccer.     

The Loughborough Intermittent Shuttle Test: A field test that simulates the activity pattern of soccer

The aims of this study were to describe and determine the test-retest reliability of an exercise protocol, the Loughborough Intermittent Shuttle Test (the LIST), which was designed to simulate the activity pattern characteristic of the game of soccer. The protocol consisted of two parts: Part A comprised a fixed period of variable-intensity shuttle running over 20 m; Part B consisted of continuous running, alternating every 20 m between 55% and 95% VO 2max , until volitional fatigue. Seven trained games players (age 21.5 +/- 0.9 years, height 182 +/- 2 cm, body mass 80.1 +/- 3.6 kg, VO 2max 59.0 +/- 1.9 ml kg -1 min -1 ; mean s x ) performed the test on two occasions (Trial 1 and Trial 2), at least7 days apart, to determine the test-retest reliability of the sprint times and running capacity. The physiological and metabolic responses on both occasions were also monitored. The participants ingested water ad libitum during the first trial, and were then prescribed the same amount of water during the second trial. The 15 m sprint times during Trials 1 and 2 averaged 2.42 +/- 0.04 s and 2.43 +/- 0.04 s, respectively. Run time during Part B was 6.3 +/- 2.0 min for Trial 1 and 6.1 +/- 1.3 min for Trial 2. The 95% limits of agreement for sprint times and run times during Part B were -0.14 to 0.12 s and -3.19 to 2.16 min respectively. There were no differences between trials for heart rate, rating of perceived exertion, body mass change during exercise, or blood lactate and glucose concentrations during the test. Thus, we conclude that the sprint times and the Part B run times were reproducible within the limits previously stated. In addition, the activity pattern and the physiological and metabolic responses closely simulated the match demands of soccer.     

Validity and Reliability of Three Self-Report Instruments for Assessing Attainment of Physical Activity Guidelines in University Students

The purpose of this study was to compare the validity and reliability of three short physical activity self-report instruments to determine their potential for use with university student populations. The participants (N = 155; 44.5% male; 22.9 ± 5.13 years) wore an accelerometer for 9 consecutive days and completed a single-item measure, the a brief two item measure and the International Physical Activity Questionnaire—Short Form questionnaires on day 1 and 9. Correlations between self-reported and accelerometer derived moderate-to-vigorous physical activity levels were moderate for the International Physical Activity Questionnaire—Short Form, while poor for the single-item measure and the a brief two item measure. The agreement level was high with the International Physical Activity Questionnaire—Short Form (77.4%) and moderate for both the single-item measure (45.2 %) and a brief two item measure (44.5 %). The intraclass correlations between the two administrations were moderate to strong across all measures (0.52–0.70) in 133 participants. The International Physical Activity Questionnaire—Short Form is the most suitable of these three self-report instruments for use with this population due to higher correlations and levels of agreement with accelerometry.     

Are the Multidimensional Body Self-Relations Questionnaire Scales stable or transient?

Body image is an important concept when assessing mental health and, thus, a target for intervention work. The common approach to assess body image is via self-report and, consequently, it is important to assess stability and susceptibility of items to random change. Participants (N = 99, aged: 18–30 years) completed the 34-item Multidimensional Body Self-Relations Questionnaire-Appearance Scales (MBSRQ-AS) twice, separated by two weeks. Stability was quantified by calculating the test–retest differences for each item, with a stable item showing 90% of respondents’ differences within a criterion of ≤±1. This method was used in preference to correlation, which is a test of association rather than agreement. Analyses identified 29 stable items. Five items were found to be unstable including the entire “Appearance Evaluation” scale. One particular unstable question, Q9 = “Most people would consider me good-looking”, revealed strong associations with both gender and weight status. Forty-four per cent of “overweight” respondents changed their minds by more than ±1 compared with only 10% of “normal-weight” participants, suggesting that being overweight is associated with uncertainty and instability. We suggest that future research is needed to investigate why such factors as being overweight appear to be linked to instability in self-report measures of body image.     

The effect of experiential anchoring on the reproducibility of exercise regulation in adolescent children

In this study, we examined whether a preparatory perceptual 'anchoring' technique would enhance the reproducibility (test-retest reliability) of adolescent children in their ability to self-regulate their exercise output on the basis of their effort perceptions. Forty-one adolescents aged 12.6 +/- 0.7 years (mean +/- s), randomly assigned to either an anchor or non-anchor group, undertook two identical production trials (three 3-min cycle ergometer bouts at levels 3, 6 and 8 of the Children's Effort Rating Table) over 8 days. Before each trial, the anchor group received an experiential (exercise) trial intended to provide a frame of reference for their perceived exertions. The test-retest reproducibility of the heart rates and power outputs produced during the production trials was assessed using intraclass correlation coefficients and 95% limits of agreement analysis. For the anchor group, the intraclass correlation coefficients ranged from 0.68 to 0.81 for heart rate and from 0.39 to 0.86 for power output. For the non-anchor group, they were generally higher: 0.86 to 0.93 and 0.81 to 0.95 for heart rate and power output, respectively. The 95% limits of agreement indicated no marked differences between the two groups in the amount of bias and within-subject error. The results suggest that among these adolescents, the implementation of an experiential anchoring protocol had no positive effect on the reproducibility of their exercise regulation during prescribed cycling.     

Translation,cross-cultural adaptation,validity, reliability and stability of the Dutch Injury - Psychological Readiness to Return to Sport (I-PRRS-NL) scale

The Injury Psychological Readiness to Return to Sport (I-PRRS) scale measures the psychological readiness of injured athletes to resume sports participation. The aim of this study was to translate and culturally adapt the I-PRRS scale into Dutch (I-PRRS-NL) and assess its validity, reliability, and stability in patients after anterior cruciate ligament reconstruction (ACLR). The original I-PRRS was translated and culturally adapted from English into Dutch, and tested for clinimetric quality. To assess concurrent validity, 150 patients completed the I-PRRS-NL scale and five questionnaires measuring related constructs 3–16 months after ACLR. All predefined hypotheses regarding correlations between the I-PRRS-NL scale and these questionnaires were confirmed, indicating good concurrent validity. For test-retest reliability, 107 patients completed the I-PRRS-NL scale again two weeks later. The I-PRRS-NL scale showed good internal consistency (Cronbach’s alpha 0.94) and test-retest reliability (ICC 0.89). Standard error of measurement was 4.2 and smallest detectable change was 11.6. No systematic bias between test and retest was found. As the scale appears unstable at item level, only the total score should be used. Overall, the I-PRRS-NL scale showed sufficient validity and reliability to assess the psychological readiness to resume sports among Dutch-speaking patients after ACLR.     

Measurement error in short-term power testing in young people

The aim of this study was to examine the consistency or reproducibility of measuring cycling peak power in children and adults. Twenty-seven pre-pubertal girls and boys and 27 female and male physical education students (age 9.8 +/- 0.5 and 24.4 +/- 4.3 years, respectively; mean +/- s) participated in the study. All participants performed five tests over 15 days and underwent a habituation session before the study. Each test included four sprints against four different braking forces. We found that braking forces of 7.5% of body weight in children and 10% of body weight in adults were too high for most of the participants to elicit maximal cycling power. Unlike the children, the physical education students improved their performance between session 1 and session 2 (1025 +/- 219 vs 1069 +/- 243 W; P < 0.001). Therefore, to obtain reproducible measures of cycling peak power, a habituation session including a complete test protocol (i.e. warm-up plus three sprints) is highly recommended. When the protocol included three sprints in children and at least two sprints in adults, measurement of cycling peak power was found to be highly reliable (test-retest coefficient of variation approximately 3%). Finally, to avoid performance fluctuations, especially over several consecutive evaluations (e.g. longitudinal studies), it is necessary to maintain high motivation in children.     

The development and initial validation of the Exercise Causality Orientations Scale.

Deci and Ryan's causality orientations theory suggests that there are individual differences in motivational orientation towards initiating and regulating behaviour. They described three causality orientations: autonomy, control and impersonal. The aim of this paper is to describe the development and concurrent validity of the Exercise Causality Orientations Scale (ECOS), which was designed to measure the strength of these three orientations within exercise. Altogether, 592 working adults aged 35.0 +/- 11.4 years (mean +/- s) completed the ECOS and measures of self-determination, self-consciousness and social desirability. The analysis was conducted in two parts. First, the data were subjected to confirmatory factor analysis using a multi-trait, multi-method framework. The original model resulted in a poor fit to the data. On the basis of its modification indices, three scenarios with ambiguous items were removed successively, resulting in a scale with good psychometric properties. Secondly, Pearson's correlations were conducted between the subscales of the ECOS and those of the questionnaires used for validation. Most of the results supported a priori hypotheses. In conclusion, our results show the ECOS to have good psychometric properties and they provide some support for its concurrent validity.     

Improving the Memory Sections of the Standardized Assessment of Concussion Using Item Analysis

The purpose of the study was to improve the immediate and delayed memory sections of the Standardized Assessment of Concussion (SAC) by identifying a list of more psychometrically sound items (words). A total of 200 participants with no history of concussion in the previous six months (aged 19.60 ± 2.20 years; N?=?93 men, N?=?107 women) volunteered to participate in this study. An observation research design was used. Participants were tested once with a verbal interview that took approximately five minutes to complete. Classic item analysis including three parts: (1) Item difficulty, (2) item discrimination, and (3) item determination was used to assess the psychometric properties of the new items on the alternative word list for the SAC test. Overall, 80.0% of the items in the immediate memory section were acceptable. In the delayed memory section, 90.0% of the items were acceptable. The mean total SAC scores were 17.96 ± 2.45 (of a possible 30). The majority of new items have acceptable psychometric properties that would improve the validity of baseline SAC score for the assessment of the effects from concussions.     

Cushioning and lateral stability functions of cloth sport shoes

In this study, we evaluated the protective functions of cloth sport shoes, including cushioning and lateral stability. Twelve male students participated in the study (mean +/- s: age 12.7 +/- 0.4 years, mass 40.7 +/- 5.9kg, height 1.50 +/- 0.04m). Cloth sport shoes, running shoes, basketball shoes, crosstraining shoes, and barefoot conditions were investigated in random sequence. Human pendulum and cutting movement tests were used to assess cushioning performance and lateral stability, respectively. For cushioning, the running shoes (2.06 body weight, BW) performed the best, while the cross-training shoes (2.30 BW) and the basketball shoes (2.37 BW) both performed better than the cloth sport shoes (2.55 BW) and going barefoot (2.63 BW). For the lateral stability test, range of inversion--eversion was found to be from 3.6 to 4.9 degrees, which was far less than that for adult participants (> 20 degrees). No significant differences were found between conditions. All conditions showed prolonged durations from foot-strike to maximum inversion (66-95 ms), which was less vigorous than that for adult participants (< 40 ms) and was unlikely to evoke intrinsic stability failure. In conclusion, the cloth sport shoe showed inferior cushioning capability but the same lateral stability as the other sports shoes for children.     

Improving the Validity and Reliability of a Health Promotion Survey for Physical Therapists

Purpose

Physical therapists (PTs) have a unique opportunity to intervene in the area of health promotion. However, no instrument has been validated to measure PTs’ views on health promotion in physical therapy practice. The purpose of this study was to evaluate the content validity and test-retest reliability of a health promotion survey designed for PTs.

Methods

An expert panel of PTs assessed the content validity of “The Role of Health Promotion in Physical Therapy Survey” and provided suggestions for revision. Item content validity was assessed using the content validity ratio (CVR) as well as the modified kappa statistic. Therapists then participated in the test-retest reliability assessment of the revised health promotion survey, which was assessed using a weighted kappa statistic.

Results

Based on feedback from the expert panelists, significant revisions were made to the original survey. The expert panel reached at least a majority consensus agreement for all items in the revised survey and the survey-CVR improved from 0.44 to 0.66. Only one item on the revised survey had substantial test-retest agreement, with 55% of the items having moderate agreement and 43% poor agreement.

Conclusions

All items on the revised health promotion survey demonstrated at least fair validity, but few items had reasonable test-retest reliability. Further modifications should be made to strengthen the validity and improve the reliability of this survey.Key Words: health promotion, physical therapy, validity, reliability     

Relationship between maximal oxygen uptake and oxygen uptake attained during treadmill middle-distance running

Traditionally, it has been assumed that during middle-distance running oxygen uptake (VO2) reaches its maximal value (VO2max) providing the event is of a sufficient duration; however, this assumption is largely based on observations in individuals with a relatively low VO2max. The aim of this study was to determine whether VO2max is related to the VO2 attained (i.e. VO2peak) during middle-distance running on a treadmill. Fifteen well-trained male runners (age 23.3 +/- 3.8 years, height 1.80 +/- 0.10 m, body mass 76.9 +/- 10.6 kg) volunteered to participate in the study. The participants undertook two 800-m trials to examine the reproducibility of the VO2 response. These two trials, together with a progressive test to determine VO2max, were completed in a randomized order. Oxygen uptake was determined throughout each test using 15-s Douglas bag collections. Following the application of a 30-s rolling average, the highest VO2 during the progressive test (i.e. VO2max) was compared with the highest VO2 during the 800-m trials (i.e. VO2peak) to examine the relationship between VO2max and the VO2 attained in the 800-m trials. For the 15 runners, VO2max was 58.9 +/- 7.1 ml x kg(-1) x min(-1). Two groups were formed using a median split based on VO2max. For the high and low VO2max groups, VO2max was 65.7 +/- 3.0 and 52.4 +/- 1.8 ml x kg(-1) x min(-1) respectively. The limits of agreement (95%) for test-retest reproducibility for the VO2 attained during the 800-m trials were +/- 3.5 ml x kg(-1) x min(-1) for a VO2peak of 50.6 ml x kg(-1) x min(-1) (the mean VO2peak for the low VO2max group) and +/- 2.3 ml x kg(-1) x min(-1) for a VO2peak of 59.0 ml x kg(-1) x min(-1) (the mean VO2peak for the high VO2max group), with a bias in VO2peak between the 800-m runs (i.e. the mean difference) of 1.2 ml x kg(-1) x min(-1). The VO2peak for the 800-m runs was 54.8 +/- 4.9 ml x kg(-1) x min(-1) for all 15 runners. For the high and low VO2max groups, VO2peak was 59.0 +/- 3.3 ml x kg(-1) x min(-1) (i.e. 90% VO2max) and 50.6 +/- 2.0 ml x kg(-1) x min(-1) (i.e. 97% VO2max) respectively. The negative relationship (-0.77) between VO2max and % VO2max attained for all 15 runners was significant (P = 0.001). These results demonstrate that (i) reproducibility is good and (ii) that VO2max is related to the %VO2max achieved, with participants with a higher VO2max achieving a lower %VO2max in an 800-m trial on a treadmill.     

Validity and reliability of body composition assessed by the sulphur hexafluoride dilution method

The aims of this study were to assess the validity and reliability of body volume and percent body fat determined by sulphur hexafluoride dilution, using underwater weighing as the criterion method, and to determine the influence of the magnitude of body volume. Thirty-one healthy Japanese individuals aged 18-27 years (16 males: height 1.70 +/- 0.06 m, mass 64.8 +/- 7.7 kg; 15 females: height 1.60 +/- 0.05 m, mass 55.2 +/- 6.2 kg; mean +/- s) participated in the study. Sulphur hexafluoride dilution measures the concentration of sulphur hexafluoride gas in the chamber (BSF-200, Shimazu Corp.). Underwater weighing was performed five times using a weight scale (AD-6204, A&D) after residual volume had been determined (System9, Minato Medical Corp.). There were no significant differences in the mean between two trials for body volume, body density or percent body fat determined by sulphur hexafluoride dilution. The intra-class correlation coefficient of these variables ranged from 0.985 to 0.999. The results suggest that sulphur hexafluoride dilution is a reliable method for assessing body composition. There was no significant difference in body volume or percent body fat between sulphur hexafluoride dilution (males: 61.3 +/- 7.6 litres, 18.4 +/- 6.7%; females: 52.8 +/- 6.9 litres, 21.0 +/- 8.9%) and underwater weighing (males: 60.6 +/- 7.0 litres, 15.6 +/- 3.5%; females: 53.0 +/- 6.5 litres, 23.7 +/- 6.1%) and there was a high correlation between the two (r = 0.997, P < 0.05). A Bland-Altman plot of the difference between percent body fat estimated by underwater weighing and sulphur hexafluoride dilution versus average percent body fat by the two methods showed no systematic difference (mean difference = -0.12 +/- 6.6 kg). The upper and lower limits of agreement were 13.2% and -13.4%, respectively. Determination by sulphur hexafluoride dilution resulted in both over- and underestimations in body volume and the difference between the two body volumes (determined by underwater weighing and by sulphur hexafluoride dilution) was inversely proportional to the mean body volume by the two methods. This suggests that improvements need to be made to the device or to the technique to maintain a constant volume of sulphur hexafluoride in the chamber.     

A modified incremental shuttle run test for the determination of peak shuttle running speed and the prediction of maximal oxygen uptake.

The aim of this study was to determine the incidence of subject drop-out on a multi-stage shuttle run test and a modified incremental shuttle run test in which speed was increased by 0.014 m x s(-1) every 20-m shuttle to avoid the need for verbal speed cues. Analysis of the multi-stage shuttle run test with 208 elite female netball players and 381 elite male lacrosse players found that 13 (+/-3) players stopped after the first shuttle of each new level, in comparison with 5 (+/-2) players on any other shuttle. No obvious drop-out pattern was observed on the incremental shuttle run test with 273 male and 79 female undergraduate students. The mean difference between a test-retest condition (n = 20) for peak shuttle running speed (-0.03+/-0.01 m x s(-1)) and maximal heart rate (0.4+/-0.1 beats x min(-1)) on the incremental test showed no bias (P > 0.05). The 95% absolute confidence limits of agreement were+/-0.11 m x s(-1) for peak shuttle running speed and+/-5 beats min(-1) for maximal heart rate. The relationship (n = 27) between peak shuttle running speed on the incremental shuttle run test (4.22+/-0.14 m x s(-1)) and VO2max (59.0+/-1.7 ml kg(-1) x min(-1)) was r= 0.91 (P< 0.01), with a standard error of prediction of +/-2.6 ml x kg(-1) x min(-1). These results suggest verbal cues during the multi-stage shuttle run test may influence subject drop-out. The incremental shuttle run test shows no obvious drop-out patten and provides a valid estimate of VO2max.     

专业运动员心理疲劳和心理耗竭的社会学成因分析

疲劳的生物心理社会模型提出,运动员所处的情景因素以及运动员对情景的认知评价是产生心理疲劳和心理耗竭的原因之一.运用运动员训练满意度量表和训练状态量表,通过典型相关分析对186专业运动员进行测试,结果表明:除了运动员对自身的信心投入,成长进步的满意程度是引起心理疲劳和心理耗竭的原因之外,运动员对教练的民主行为、个人关怀满意程度.对运动队的日常管理的满意程度是引起运动员心理疲劳和心理耗竭的主要社会原因.指出完善运动队的训练体系,实施科学化和人文化管理,同时提高广大教练员的执教效果,给予运动员更多的关怀是预防和消除运动性心理疲劳与心理耗竭的主要途径.     

Assessment of hydration status by urinary analysis of elite junior taekwon-do athletes in preparing for competition

The aim of this study was to assess over time the hydration status of taekwon-do athletes during a preparatory camp. Measures of urine osmolality, conductivity, specific gravity and colour were made on the first urine sample passed by the participants (n = 32) in the morning before breakfast. The urinary measurements were made on samples collected at the beginning of the camp, 5 days later and one day before competition. Body mass was also measured at the same instants. Body mass (mean +/- s) was essentially the same on each of the measurement days (62.6 +/- 12.2, 62.7 +/- 12.3 and 62.2 +/- 12.6 kg, respectively). Mean urine osmolality at the beginning of the camp was relatively high (998 +/- 171 mOsmol . kg-1), suggesting that a significant number of the athletes were already hypohydrated. However, no significant differences were detected in urine osmolality at the three time points during the study. There were no significant differences in any of the four methods of urine analysis during the study (P > 0.05). The average values for all samples were 989 +/- 205 mOsmol . kg-1 for osmolality, 25.5 +/- 6.7 mS . cm-1 for conductivity, 1.017 +/- 0.010 g . cm-3 for specific gravity and 4 +/- 1 arbitrary units for colour. Correlation analysis between the different methods suggested moderately good agreement (correlation coefficient = 0.5-0.7) between all four measurement techniques (P < 0.01). The coefficients of variation for these techniques were relatively low (CV = 11.8 - 35.0%). The results of this study suggest that some of the taekwon-do athletes were slightly hypohydrated in the morning on each of the test days, but there was no evidence to suggest that most of the athletes further restricted their fluid intake to make weight. In addition, it appears that each of the four methods used gave essentially the same estimate of hydration status of these athletes.