The goal of this clinical trial is to test in the effects of pain pressure threshold (PPT) looking out to 30 minutes in the lumbar spine. The main question[s] it aims to answer are:

• Is there a difference between PPT from baseline, immediately after, or 30 minutes after compared to sham ultrasound control group? Participants will be exposed to sham ultrasound or sidelying lumbar manipulation with between groups and within group comparisons of PPT at the posterior superior iliac spine up to 30 minutes following the intervention.

Inclusion Criteria:

• Asymptomatic individuals between the ages of 18-50

Exclusion Criteria:

• Current low back pain (LBP)
• A history of low back pain LBP within the last three months
• Previous spinal surgery
• Rheumatological condition or neurological symptoms or conditions
• Recent ingestion of pain-relieving medications within the last 24 hours
• A lumbar manipulation within three days prior to the exam
• Exhibited any contraindications to manipulation
• Positive findings during screening precautions