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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
The effects of a single chiropractic session on lower limb muscle blood flow
Scientific title
The effects of a single chiropractic session on lower limb muscle blood flow in subclinical pain subjects, measured with near-infrared spectroscopy (NIRS)
Secondary ID [1] 288432 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
lower limb muscle function
297451 0
Condition category
Condition code
Alternative and Complementary Medicine 297642 297642 0 0
Other alternative and complementary medicine
Physical Medicine / Rehabilitation 297698 297698 0 0
Other physical medicine / rehabilitation
Musculoskeletal 297803 297803 0 0
Other muscular and skeletal disorders

Study type
Description of intervention(s) / exposure
The intervention is a single session of chiropractic care for the intervention group. The session will take approximately ten minutes. The entire spine and both sacroiliac joints will be assessed for segmental dysfunction, and treated where deemed necessary by a registered chiropractor with fifteen years clinical experience. The clinical indicators that will be used to assess the function of the spine prior to and after each spinal manipulation intervention include assessing for tenderness to palpation of the relevant joints, manually palpating for restricted intersegmental range of motion, assessing for palpable asymmetric intervertebral muscle tension, and any abnormal or blocked joint play and end-­-feel of the joints. All of these biomechanical characteristics are used by the chiropractors as clinical indicators of spinal dysfunction. All of the spinal manipulations carried out in this study will be high-­-velocity, low-­-amplitude thrusts to the spine or pelvic joints. This is a standard manipulation technique used by chiropractors, and is also referred to as spinal adjustments. The mechanical properties of this intervention have been investigated; and although the actual force applied to the subject's spine depends on the therapist, the patient, and the spinal location of the manipulation, the general shape of the force-­-time history of spinal manipulations is very consistent and the duration of the thrust is always less than 200 milliseconds. The high-­-velocity type of manipulation is chosen specifically because previous research has shown that reflex electromyographic activation observed after manipulations only occurred after high-­- velocity, low-­-amplitude manipulations (as compared with lower-­-velocity mobilizations). This manipulation technique has also been previously used in studies that have investigated the neurophysiological effects of spinal manipulation. The washout period for this project is 1 week.
Intervention code [1] 293752 0
Treatment: Other
Comparator / control treatment
The control is a single session. The subject’s head and/or spine will be moved in ways that include passive and active movements, similar to what is done by the chiropractor that provide actual chiropractic treatment during the spinal manipulation intervention. Thus this control intervention involves the subjects being moved into the manipulation setup positions similar to how the chiropractor would normally setup a subject prior to applying the thrust to the spine to achieve the manipulations. Loading a joint, as is done prior to spinal manipulation has been shown to alter paraspinal proprioceptive firing in anesthetized cats, and therefore will be carefully avoided by ending the movement prior to end-­-range-­-of-­-motion when passively moving the subjects. No spinal manipulation will be performed during any control intervention. This control intervention is intended to act as a sham treatment session as well as to act as a physiological control for possible changes occurring due to the cutaneous, muscular or vestibular input that would occur with the type of passive and active movements involved in preparing a subject/patient for a manipulation.
Control group

Primary outcome [1] 297180 0
The outcome measure will be assessed pre and post spinal manipulation session and pre and post control intervention session. The primary outcome measure that will be included is haemodynamic kinetics of the Tibialis Anterior (TA) muscle, which will be measured with NIRS while the subject performs five maximum voluntary contractions of their TA muscle.
Near-infrared spectroscopy (NIRS) is a method using the infrared region of the electromagnetic spectrum to measure the relative changes in the hemoglobin concentration through the use of light attenuation at multiple wavelengths. This is a non-invasive technique using near-infrared light in a range of several transmitters and receivers placed in a matrix over the muscle. NIRS provides local information about hemoglobin, changes in and independent measurements of deoxyhemoglobin, oxyhemoglobin and total hemoglobin concentrations.
Timepoint [1] 297180 0
Immediately pre and post spinal manipulation session and immediately pre and post control intervention.
Secondary outcome [1] 320254 0
Timepoint [1] 320254 0

Key inclusion criteria
15 subclinical pain subjects will be recruited via advertising within the New Zealand College of Chiropractic community. Participants may include students, staff, faculty, and previous patients of the College’s chiropractic centre and also family, friends and acquaintances of the New Zealand College of Chiropractic community. Subjects will be eligible for inclusion if they are English speaking, aged 18-50, and have previously sought chiropractic care, and have some history of recurring spinal dysfunction such as mild pain, ache, and/or stiffness with or without a history of known trauma.
Minimum age
18 Years
Maximum age
50 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Subjects will be ineligible to participate if they exhibit no evidence of vertebral subluxations, have absolute contraindications to spinal adjustment, have experienced previous significant adverse reactions to chiropractic care, or they are suffering from a current lower limb disorder/dysfunction that would make them unable to carry out data recording sessions (e.g. sprain/strain/fracture), and if they have sought treatment for the subclinical pain symptoms.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
A within-­-subject crossover design with a one-­-week washout period between interventions will be used.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
A multifactorial repeated measures ANOVA will be used to assess for within and between group differences. TIME (pre and post intervention measures) and INTERVENTION (Chiro vs. Control) will be used as factors. A priori pairwise comparisons of the pre and post intervention data will be carried out when an interactive effect is significant. Significance will be set at P = .05.

Allocation of participants will be carried out using an online randomisation programme. The randomisation sequence will created using Minimizer (Microsoft Corp., Redmond, WA) with a 1:1 allocation to control and experimental groups. Allocation will remain concealed until after the baseline assessment has taken place. Participants and the chiropractors providing care during the study will not be blinded to group allocation. Outcomes assessors and data analysts will remain blinded to group allocation throughout the study period.

Sample size calculations are based on detecting a difference in a continuous response variable from independent control and experimental participants with one control per experimental participant. Calculations are made based on the changes observed in our previous study that investigated changes in force of lower limb muscles pre and post a chiropractic adjustment session. If the true difference in haemodynamic kinetics between the experimental session and the control session has an effect size of 0.5 we will need 11 participants to be able to reject the null hypothesis that the population means of the experimental and control groups are equal with probability (power) 0.8. The Type I error probability associated with the test of this null hypothesis is 0.05. To allow for attrition during the trial and relative uncertainty relating to power outcomes we will enroll 15 participants in this trial.

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] 7558 0
New Zealand
State/province [1] 7558 0

Funding & Sponsors
Funding source category [1] 292775 0
Name [1] 292775 0
New Zealand College of Chiropractic
Address [1] 292775 0
6 Harrison Road Mount Wellington Auckland 1060
Country [1] 292775 0
New Zealand
Primary sponsor type
New Zealand College of Chiropractic
6 Harrison Road Mount Wellington Auckland 1060
New Zealand
Secondary sponsor category [1] 291511 0
Name [1] 291511 0
Address [1] 291511 0
Not applicable
Country [1] 291511 0

Ethics approval
Ethics application status
Ethics committee name [1] 294270 0
Health and Disability Ethics Committees
Ethics committee address [1] 294270 0
Ministry of Health Freyberg Building 20 Aitken Street PO Box 5013 Wellington 6011
Ethics committee country [1] 294270 0
New Zealand
Date submitted for ethics approval [1] 294270 0
Approval date [1] 294270 0
Ethics approval number [1] 294270 0

Brief summary
Over the past ten years several research groups have demonstrated that spinal manipulation can change various aspects of nervous system function, including altered motor control, cognitive processing, reaction time, and the speed at which the brain processes information. Although motor control is altered after spinal manipulation, it is not yet clear if these alterations result in clinically significant changes to outcomes that are important for functional performance.
A basic understanding of the mechanisms behind such changes needs further research. Various neurophysiological techniques can be utilized to study specific types of underlying mechanisms. In recent years, near-infrared spectroscopy (NIRS) has been utilized to gain a better understanding of muscle function. This proposed study will build on our previous work by investigating whether spinal manipulation influences muscles hemodynamic kinetics using NIRS. This randomised controlled trial will be conducted at the Centre for Chiropractic Research at the New Zealand College of Chiropractic. A within-­-subject crossover design with a one-­-week washout period between interventions will be used to assess 15 subjects.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 63070 0
Dr Imran Niazi
Address 63070 0
Dr. Imran Niazi
New Zealand College of Chiropractic
6 Harrison Road Mount Wellington Auckland 1060
Country 63070 0
New Zealand
Phone 63070 0
Fax 63070 0
Email 63070 0
Contact person for public queries
Name 63071 0
Dr Kelly Holt
Address 63071 0
Dr. Kelly Holt
New Zealand College of Chiropractic
6 Harrison Road Mount Wellington Auckland 1060
Country 63071 0
New Zealand
Phone 63071 0
Fax 63071 0
Email 63071 0
Contact person for scientific queries
Name 63072 0
Dr Kelly Holt
Address 63072 0
Dr. Kelly Holt
New Zealand College of Chiropractic
6 Harrison Road Mount Wellington Auckland 1060
Country 63072 0
New Zealand
Phone 63072 0
Fax 63072 0
Email 63072 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