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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated

Titles & IDs
Public title
Effects of regular yoga practice
Scientific title
Effects of a 12-week hatha yoga program on individuals with and without metabolic syndrome
Secondary ID [1] 282861 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Metabolic syndrome 289673 0
Condition category
Condition code
Metabolic and Endocrine 289991 289991 0 0
Metabolic disorders

Study type
Description of intervention(s) / exposure
The 12-week hatha yoga program:
This program will consist of 12 weekly classes of one hour duration. All classes will be taught by the same instructor, who has three years of hatha yoga instructing experience. Sixty yogic poses and breathing commonly taught in fitness centres and private yoga studios will be instructed and practiced throughout the program. Modification of some poses will be suggested if subjects have limitations in their flexibilities. Props such as mats and blocks will be used.
Intervention code [1] 287556 0
Other interventions
Intervention code [2] 287557 0
Comparator / control treatment
No treatment
Control group

Primary outcome [1] 290039 0
In this study, the instruments with established validity and reliability will be used to determine each outcome. Each outcome and related instrument are as follows:

A. Metabolic risk factors:
Outcome 1. Blood pressure:
Blood pressure measurements will be measured in seated position according to the American Heart Association Scientific Statement (Pickering et al., 2005). The average of the second and third systolic and diastolic pressure reading will be used in the analyses.

Outcome 2. Waist circumference (WC):
WC will be measured at the nearest 0.5 cm at the shortest point below the lower rib margin and the iliac crest.

Outcomes 3-5 Blood profile (fasting glucose, triglycerides, and HDL-C):
The profile will obtained by taking blood samples from subjects and sent the samples to the laboratory for analysis.

B. Physiological stress:
Outcome 6. Cortisol level:
The measurement of salivary cortisol provides a non-invasive and reliable tool for investigation of HPA axis activity. Subjects will be instructed to obtain salivary samples at the same time to control the circadian rhythm (Kirschbaum & Hellhammer, 1989). Samples will be sent to the laboratory for electrochemiluminescence immunoassay. Raw cortisol values will be log transformed to reduce skewness of their distribution.

C. Health-related physical fitness:
C1. Cardiovascular endurance
Outcome 7. Resting heart rate:
Resting heart rate will be measured following a seated ten-minute rest period. The heart rate will be detected by electronic device (Polar Electro, Finland).
Outcome 8. VO2max (Maximum Oxygen Consumption):
The concept of cardiovascular endurance is an individual’s aerobic capacity, and the most reliable and valid measure of aerobic capacity is VO2max (Morrow, Jackson, Disch, & Mood, 2005). Bruce Protocol will be applied in the study. This test consists of several 3-minute stages, where the speed and grade are changed each stage, using the treadmill as a mode (ACSM, 2010).

C2. Muscular endurance:
Outcomes 9-10. Upper body muscular endurance and abdominal muscle endurance:
The Canadian Standardized Test of Fitness - Push-up and Curl-up Tests will be conducted to measure the muscle endurance of upper-body muscles and the abdominal muscle groups, respectively. The test procedures for the measurements will be according to the descriptions from Canadian Society for Exercise Physiology (Canadian Society for Exercise Physiology, 2003, as cited in ACSM, 2010).

C3. Flexibility
Outcomes 11-12. Left leg and right leg flexibilities:
The modified back-saver sit-and-reach test (MBS test) will be used to test of trunk flexion. The MBS test is a comparative better test to measure the low back and hamstring flexibility than other protocols as its similarity of criterion-related validity in women but it has better criterion-related validity in men, more practical as it requires minimal preparation time and equipment. It also eliminates excessive posterior compression of the vertebral disk when performing a single leg reach (Hui & Yuen, 2000).

C4. Body composition:
Outcome 13. Body weight (BW):
BW will be measured in light clothing and without shoes to the nearest 0.5 kg at the start and the end of the program.
Outcome 14. Body mass index
BMI will be calculated as weight in kilograms divided by height in meters squared. (Height will be measured to the nearest 0.5 cm)

D. Mental health:
Outcome 14. Health related quality of life (HRQOL)
The MOS 36-Item Short-Form Health Survey (SF-36) (Ware, Kosinski, & Gandek, 2000) includes one multi-item assessing each of eight health concepts: 1) physical functioning; 2) role limitations due to physical problems, 3) social functioning, 4) bodily pain, 5) general mental health, 6) role limitations due to emotional problems, 7) vitality, 8) general health perceptions. The internal consistency of the SF-36 ranged from .63 to .96 and the test–retest reliability ranged from .60 to .81 (Ware, Kosinski, & Gandek, 2000).
Outcome 15. Perceived stress:
Perceived Stress Scale (PSS) assesses the degree to which an individual appraises situations in his or her life as stressful (Cohen, & Williamson, 1988). It consists of 10 Likert-type items designed to assess how unpredictable, uncontrollable, and overloaded respondents perceived their lives to be. A lower score is indicative of lower perceived stress and score can range from 0 to 56. The PSS has been shown to be valid, with internal reliability as determined by Cronbach’s a of 0.902 (Smith et al., 2008).
Outcome 16. Depression:
The Centre for Epidemiologic Studies Depression Scale (CES-D) is a 20-item self-report scale to measure depressive symtomatology in the general population. The scale has high internal consistency with Cronbach’s a of 0.85 (Radloff, 1977). It yielded Cronbach’s a of 0.92 in the study of Mitchell et al. (2007).
Outcome 17. Anxiety:
State-Trait Anxiety Inventory (STAI) is a 40-item self-report scale to evaluate state and trait anxiety (Spielberger, 1983). Cronbach’s a for the state and trait subscales were 0.92 and 0.96, respectively, in the study of Mitchell, Mazzeo, Rausch, and Cooke (2007).
Outcome 18. Self-esteem
Rosenberg Self-Esteem Scale (RSES) (Rosenberg, 1965) consists of 10-items, which examines the global self-esteem of individuals. The original scale is typically replaced with a Likert-type response format using a four-point scale anchored by 1 (Always Disagree) and 4 (Always Agree) (Sheasby, Barlow, Cullen, & Wright, 2000). The reproducibility of the scale is 93%, scalability of items is 73%, and scalability of individuals is 72 % (Rosenberg, 1965). Internal consistencies in the study of Elavsky and McAuley (2007) were good (a ranged from .89 to .92 for baseline and post-intervention assessments, respectively).

E. Physical activity level
The short (7 day) form of the International Physical Activity Questionnaire (IPAQ) (Craig et al., 2003) will be applied to investigate the subjects’ physical activity level. A study was carried out to examine the reliability and validity of IPAQ in 12 countries (Craig et al., 2003). The result showed that IPAQ had reasonable measurement properties for monitoring population levels of physical activity among 18 to 65 years old adults in the diverse sample settings. Spearman’s Rho clustered around 0.8 indicating reliable responses between repeat administrations for all versions of the IPAQ. The short IPAQ has been translated to Chinese and has demonstrated adequate reliability and validity for the measurement of total physical activity in a Chinese population (Macfarlane, Lee, Ho, Chan, & Chan, 2007).

The “Yoga and Health Questionnaire” was developed which consisted of the short form of IPAQ, RSEE, PSS, CEDS, SF-36, and STAI in order to measurement the aforementioned outcomes. Demographic data of each subject will be collected by the “Demographic Data Sheet”. Subjects’ gender, age, education level, employment status, martial status, smoking and alcoholic intake will be asked.
Timepoint [1] 290039 0
At Baseline and post-intervention
Secondary outcome [1] 303824 0
Attrition rate of the study
Timepoint [1] 303824 0
The number of participants recruited at baseline and the number of participants dropouts at post-intervention
Secondary outcome [2] 303825 0
Attendance of the yoga program (for intervention group only)
Timepoint [2] 303825 0
The time of the yoga program

Key inclusion criteria
1) A Chinese national and is able to communicate in Cantonese
2) Aged 18 or above
3) Is physically and mentally capable of practicing yoga safely
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1) Regular participation of (> 1/week) yoga for last 3 months or concurrent use of yoga, Qigong or meditation
2) Pregnancy or breast feeding
3) Anticipate any planned life stressors (moving, divorce, changing job, etc.), shift work, or transcontinental travel during the intervention
4) Undergo any other concurrent nonpharmacological treatment of MetSyn
5) Chronic illnesses: cancer, kidney disease, cirrhosis, rheumatologic diseases, or chronic inflections
6) Current major psychiatric illnesses, cognitive impairment, or substance abuse
7) Concurrent enrollment in any other studies, experimental therapies, or blinded treatments

Study design
Purpose of the study
Allocation to intervention
Nonrandomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The statistical analysis will be conducted using SPSS 16.0 software (SPSS Inc, Chicago, Illinois). Sample description will be described; baseline characteristics, retention and program adherence, and all other outcome measures will be analyzed and reported. Paired t test and independent t test will be used to analyze continuous variables. Mann-Whitney test will be used to analyze continuous variables which did not have normal distribution. Chi square test will be employed to compare categorical variables. Statistical significance will be inferred by a two-tailed p value of .05 or less.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 5231 0
Hong Kong
State/province [1] 5231 0

Funding & Sponsors
Funding source category [1] 287637 0
Name [1] 287637 0
Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong
Address [1] 287637 0
Department of Medicine and Therapeutics, 9/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
Country [1] 287637 0
Hong Kong
Primary sponsor type
Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong
Department of Medicine and Therapeutics, 9/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
Hong Kong
Secondary sponsor category [1] 286379 0
Name [1] 286379 0
Address [1] 286379 0
Country [1] 286379 0

Ethics approval
Ethics application status
Ethics committee name [1] 289608 0
Joint Chinese University of Hong Kong-New Territories East Cluster Clinical Reseaerch Ethics Committee
Ethics committee address [1] 289608 0
Flat 3C, Block B, Staff Quarters, Prince of Wales Hospital, Shatin, Hong Kong
Ethics committee country [1] 289608 0
Hong Kong
Date submitted for ethics approval [1] 289608 0
Approval date [1] 289608 0
Ethics approval number [1] 289608 0

Brief summary
Physical inactivity is one of the main causes of major noncommunicable diseases and contributes substantially to the global burden of disease, death and disability. To reverse the trend towards inactivity, it is important to promote physical activities with low participation barrier and numerous benefits to encourage sedentary individuals to become physically active. Yoga has been increasingly popular and practiced as a low-to-moderate intensity physical activity in recent years. Yoga originated in India more than 5000 years ago and its principle is to achieve the integration of body, mind, and spirit. Growing evidence suggests the beneficial effects of Hatha yoga on various ailments, yet potential long-term effects of yoga on health are under-researched. Interpretation of and comparisons across many existing studies are limited by methodological problems. The current study aims to investigate the effects of yoga on physical and mental health in individuals with and without metabolic syndrome.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 41546 0
Prof Jean Woo
Address 41546 0
Department of Medicine & Therapeutics, 9/F., Clinical Sciences Building, Prince of Wales Hospital, Shatin, N.T. Hong Kong SAR
Country 41546 0
Hong Kong
Phone 41546 0
Fax 41546 0
Email 41546 0
Contact person for public queries
Name 41547 0
Miss Lau Hoi Lam
Address 41547 0
Room 124021, 10/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong SAR
Country 41547 0
Hong Kong
Phone 41547 0
Fax 41547 0
Email 41547 0
Contact person for scientific queries
Name 41548 0
Miss Lau Hoi Lam
Address 41548 0
Room 124021, 10/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong SAR
Country 41548 0
Hong Kong
Phone 41548 0
Fax 41548 0
Email 41548 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary