An interventional study of Pain expectation conditioning and Comparator (Control Group) in Nocebo Effect and Pain Anticipation, sponsored by Universite de Picardie Jules Verne. Recruiting at 1 site in France. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-11.
Sponsored by Universite de Picardie Jules Verne · Not applicable, Interventional, and Basic science
The purpose of this study is to determine whether the anticipation of pain influences gait control and psychophysiological responses in healthy individuals. Participants will receive a neutral cream described either as potentially painful (experimental group) or inert (control group), and their behavioral and physiological adaptations will be measured during walking tasks.
Pain anticipation can significantly alter motor behavior and physiological responses, even in the absence of actual pain. While previous research has established that conditioned expectations can modify gait patterns, muscle activation, and autonomic responses, the specific locomotor adaptations triggered by pain anticipation in healthy individuals remain insufficiently understood. This study examines how manipulating expectations about a neutral cream influences gait control and psychophysiological markers during walking tasks.
Participants will be recruited through university announcements including posters and emails, with eligibility determined via an online screening questionnaire and verbal confirmation the day of the experience. Healthy adults aged 18-35 who meet the inclusion criteria will participate in a single 90-minute experimental session. Random assignment will place participants into either an experimental group, where they receive the neutral cream with verbal suggestions that it may cause localized pain, or a control group that receives identical application with neutral instructions.
The experimental protocol consists of two primary walking assessments conducted both before and after cream application. First, participants perform free walking trials on a GAITRite mat to measure baseline spatiotemporal parameters including walking speed, cadence, and step length at a comfortable speed until completion of 30 gait cycles. Second, treadmill walking and running trials using a Zebris system evaluate gait transitions through incremental speed changes from 0.8 m/s to 1.3 m/s in increments of 0.1 m/s with 10 second familiarisation time in-between measurements. Both walking tasks are recorded using GoPro cameras to subsequent analysis of changes in joint amplitudes. Throughout these tasks, physiological monitoring captures muscle activity via surface EMG, cardiac responses through ECG and heart rate variability measurements, and electrodermal activity as an indicator of autonomic arousal.
Following the first movement assessments and before the application of the cream, participants complete standardized questionnaires evaluating pain perception using the Brief Pain Inventory and visual analog scales (VAS), fear of movement through the Tampa Scale of Kinesiophobia and Fear-Avoidance Components Scale, and pain catastrophizing via the Pain Catastrophizing Scale.
The cream is applied at the level of the knee, between the two lateral epicondyles of the femur with a 4 cm width, and another VAS is filled in after application. The walking tasks are repeated, measuring the same physiological signs and a final VAS is administered one at the end of the protocol.
The primary outcome measure focuses on changes in the walk ratio, calculated as step length divided by cadence, while secondary outcomes examine alterations in kinematic patterns, muscle activation strategies, and autonomic nervous system responses.
Universite de Picardie Jules Verne is the lead sponsor of 5 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Participants in this arm will receive the neutral cream with instructions suggesting it may cause pain.
Other: Pain expectation conditioning · Other: Intervention: Gait
Participants receive application of identical neutral cream with verbal and behavioral suggestions that it may cause localized pain, creating a nocebo effect through expectation manipulation.
Other: Comparator (Control Group) · Other: Intervention: Gait
Participants receive application of a neutral cream (MEDICAFARM) with verbal and behavioral suggestions that it may cause localized pain. Researchers wear gloves during application and emphasize potential discomfort, stating effects may intensify with movement.
Participants receive identical application of the neutral cream but are informed it is inert and harmless. Researchers apply the cream without gloves and provide neutral instructions.
Participants undergo assessment procedures including: * Pre- and post-application gait analysis (GAITRite mat, Zebris treadmill) * Physiological monitoring (EMG, HRV, EDA) * Identical questionnaires (BPI, TSK, FACS, PCS, VAS)
Walk ratio
Index that quantifies gait adaptations. Measured via GAITRite mat and Zebris treadmill.
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds.
ECG/Heart Rate Variability (HRV)
R-R interval variability during walking tasks.
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds.
Electrodermal Activity (EDA)
Skin conductance during tasks.
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds.
Pain Catastrophizing (PCS)
Pain Catastrophizing Scale total score (0-52). Users rate 13 statements on a scale from 0 (not at all) to 4 (all the time).
Time frame: Before intervention.
Fear-Avoidance Beliefs (FACS)
Fear-Avoidance Components Scale total score (0-100). Users rate 20 statements from 5 (Strongly agree) to 0 (Strongly disagree).
Time frame: Before intervention.
Kinesiophobia (TSK)
Tampa Scale of Kinesiophobia total score (17-68). Users rate 17 statements in a scale from 1 (Strongly disagree) to 4 (Strongly agree).
Time frame: Before intervention.
Pain Severity (BPI)
The Brief Pain Inventory (Short Form) (BPI-SF) measures pain using three key scales: the Pain Severity Scale (ranging from 0 = "No pain" to 10 = "Pain as bad as you can imagine"), which assesses worst, least, average, and current pain over 24 hours; the Pain Interference Scale (0 = "Does not interfere" to 10 = "Completely interferes"), evaluating how pain affects daily activities like mood, work, and sleep; and the Pain Relief Scale (0% = "No relief" to 100% = "Complete relief"), indicating the effectiveness of pain treatments.
Time frame: Before intervention.
Self-Reported Pain (VAS)
Visual Analog Scale (0-100 mm) for immediate pain intensity, where 0 = "No pain" and 100 = "Worst pain imaginable."
Time frame: 1 and 2. before and after application of the cream (intervention); 3. During the treadmill task: upon finishing the 1.3 m/s speed recording; 4. During the free-walking task: at half of the gait cycles; 5. Upon finishing all tasks.
Gait Variability Index
Step-to-step variability in stride time/length (coefficient of variation, %) derived from GAITRite/Zebris data.
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds.
Gait Symmetry Index
Inter-limb asymmetry ratio (affected/unaffected side) for step length, stance time, and ground reaction forces (Zebris treadmill).
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds.
Muscle synergies
Electromyographic analysis of lower-limb muscle coordination during walking using non-negative matrix factorisation.
Time frame: During intervention (pre/post cream application): for the mat, during a 2-minute free walk and for the treadmill, during a 5-minute treadmill walk with increases in speed every 30 seconds
Plan to share: No — Participants consented to data use only for this specific study under CERSTAPS-approved protocols. French and EU GDPR regulations prohibit broad sharing of pseudonymized sensor/video data that could potentially be re-identified (e.g., physical features in GoPro videos, unique gait patterns).
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Universite de Picardie Jules Verne