This study would be the first study to assess the immediate effects of dry needling of latent trigger points of the gastrocnemius muscle on muscle stiffness, gait, range of motion, and strength. The study has the potential to demonstrate that dry needling may have immediate effects on mechanical properties of muscle and may thus guide future treatment for individuals with changes in muscle tissue secondary to pain and/or injury.

Participants will complete the following tests: muscle stiffness testing in both a relaxed and contracted position, GAITRite for spatial and temporal gait characteristics, the Ankle Lunge Test (ALT) to assess range of motion, and calf strength using a dynamometer. Subjects will then receive treatment according to which group they are randomized. Muscle stiffness, gait, motion and strength will be reassessed immediately following treatment at the first session. Four to10 days later, participants will complete the same tests and measures prior to treatment being administered a second time. Another 4-10 days after the second session, participants will complete the tests and measures one final time.

Inclusion Criteria:

1. Age 18-50 years
2. Able to read and speak sufficient English to complete consent form
3. Symmetrical gait pattern demonstrated through observation
4. Presence of latent trigger point in gastrocnemius muscle

Exclusion Criteria:

1. Any prior foot/ankle surgery, deformity, or injury on the which would affect strength of the gastrocnemius
2. Any prior acupuncture or dry needling within the past month
3. History of systemic disorder in which dry needling would be contraindicated (i.e. bleeding disorders or anticoagulant medication use)
4. Have fractures of the spine, hip, or knee that would likely affect their weight bearing or gait
5. Restrictions in plantar flexion range of motion which would inhibit performing a heel raise
6. No specific calf injury in the past 6 months
7. Participants known or thought to be pregnant

Participants will be blinded to group allocation. Participants in the control group will receive sham needling.