Exploration of Gait Biomechanics and Pain

Undersøgelse af sammenhængen Mellem Biomekanik og Smerter Ved Gang

This interventional study aims to test gait biomechanics in healthy individuals with and without experimental knee pain. The main questions it aims to answer are:

• How do gait patterns change during painful walking?
• Can pain sensitivity testing and gait biomechanics predict experimental knee pain intensity?

Participants will receive two knee injections: a) Hypertonic saline (painful condition) and b) Isotonic saline (control condition).

This study will be a randomized, crossover design where experimental knee pain will be provoked in healthy subjects using hypertonic saline injections to the infrapatellar fat pad (IFP). This will be controlled with a second injection of isotonic saline, which is non-painful. The participants will not be informed of the type of injection.

Hypertonic saline injections to the IFP usually provoke pain lasting about 15 minutes. Within this timeframe, motion capture will be conducted to estimate the biomechanics of gait. During the motion capture the participants will perform five 10-meter walking trials and three jumps. This process will be replicated for the control condition.

Additionally, the participants will have their pain sensitivity tested using cuff-pressure algometry before both IFP injections.

Inclusion Criteria:

• Healthy men and women aged 18-45 years

Exclusion Criteria:

• Pregnancy
• Drug addiction, defined as the use of cannabis, opioids, or other drugs
• Previous or current neurologic or musculoskeletal illnesses
• Current pain
• Lack of ability to cooperate