Most people need to wait at least 2 to 3 weeks before returning to any structured exercise after a PRP injection, and 6 to 8 weeks before high-impact activities like running, jumping, or heavy lifting. The exact timeline depends on which body part was treated, but the general principle is the same: the first few weeks after PRP are when your body is actively using the injected platelets to repair tissue, and exercising too soon can disrupt that process.
Why the Waiting Period Matters
PRP works by concentrating your own platelets and injecting them into damaged tissue. Those platelets release growth factors that trigger a controlled inflammatory response, which is the first step in tissue repair. In the first week, this inflammation is doing exactly what it’s supposed to do: signaling your body to send repair cells to the area. By weeks 2 to 4, new tissue starts forming and collagen production ramps up. Exercising too aggressively during these early phases can overwhelm the healing response or mechanically stress tissue that isn’t ready for load.
A case report in the Turkish Journal of Physiotherapy and Rehabilitation documented what can go wrong. A patient exercised just 16 hours after a knee PRP injection. Within 24 hours of the injection, she was hospitalized with fever, severe pain, and inflammatory arthritis in the knee. The researchers attributed the reaction to exercise occurring during the initial burst of growth factor release, essentially pouring fuel on an already active inflammatory fire. There’s also at least one documented case of a patellar tendon rupture following a PRP injection series in a soccer player. These are rare events, but they illustrate why the rest period isn’t optional.
The First 72 Hours: Rest and Protect
The day of your injection, the recommendation is simple: rest. Expect soreness at the injection site, which is a normal part of the inflammatory response PRP is designed to trigger. For lower body injections, particularly to the patellar or quadriceps tendons, you may need crutches and partial weight bearing for the first three days. For shoulder injections, most protocols call for a sling for 2 to 3 days, though you don’t need to sleep in it.
Light walking is generally fine during this window. Short, gentle walks of 5 to 10 minutes once or twice a day help maintain circulation without stressing the treated area. Avoid anything beyond that.
One important note about pain management: avoid anti-inflammatory medications like ibuprofen and naproxen. These drugs directly interfere with the inflammatory process PRP relies on. Ohio State University’s clinical guidelines recommend avoiding them for two weeks before and at least one week after the procedure. Acetaminophen (Tylenol) and ice are typically the recommended alternatives.
Weeks 1 to 4: Gradual Movement Only
From about day 4 through week 2, you can begin light functional movement. For shoulder injections, this means discontinuing the sling around day 4 and starting gentle range-of-motion exercises, lifting no more than 1 to 5 pounds. You can use your arm for basic daily tasks like dressing, eating, and short drives. For lower body injections, you can gradually wean off crutches and increase walking to about 20 minutes by week 2.
During weeks 2 to 4, the focus stays on mobility rather than strength. Shoulder patients typically begin very light isometric strengthening of the rotator cuff during this window. For knee and tendon injections, UW Health Sports Medicine guidelines are clear: no overstressing the tendon through exercise, lifting, or impact activity during the first 10 to 14 days. Resistance training, gripping, and lifting should be avoided until at least week 4 for most injection sites.
Weeks 4 to 8: Building Back Strength
This is when most people can start reintroducing real exercise, but the emphasis is on controlled, progressive loading. Around week 4, low-impact cardio like stationary cycling and swimming typically gets the green light. Resistance can increase slowly from here.
For shoulder PRP, weeks 4 to 6 mark the transition to actual strengthening exercises, including concentric and eccentric movements under the supervision of a physical therapist. By weeks 6 to 8, the intensity increases further with band exercises, rows, and sport-specific movements. All strength work should be performed every other day, and a key rule of thumb from Ohio State’s protocol: if an exercise causes reactive pain lasting more than 24 hours, you’ve done too much.
For lower body injections, high-velocity activities like running, jumping, and plyometrics remain off-limits until at least 6 to 8 weeks post-injection, per UW Health guidelines. When you do return to running, expect a gradual progression from single-plane landing drills to multi-directional agility work before full sport participation.
Timelines by Injection Site
The treated area significantly affects how quickly you can return to exercise:
- Knee (osteoarthritis or patellar tendon): Partial weight bearing for up to 3 days, no impact activity for 6 to 8 weeks, return-to-sport programs begin after meeting strength and movement criteria in the 6 to 8 week range.
- Shoulder (rotator cuff): Sling for 2 to 3 days, gentle range of motion starting day 2 to 3, light isometric strengthening at weeks 2 to 4, progressive resistance from week 4 onward, plyometrics and sport-specific training at weeks 8 to 10.
- Elbow (tennis elbow): 3 to 6 weeks before exercise, with gripping and lifting avoided until at least week 4.
- Foot or ankle: A walking boot may be recommended in the early days, with a similar 6 to 8 week timeline before impact activities.
What “Full Recovery” Actually Looks Like
Returning to exercise is not the same as full recovery from PRP. The tissue remodeling process continues for 3 to 6 months after injection. During months 1 to 3, the new tissue your body has been building gets progressively stronger. Most people notice meaningful improvements in pain and function during this window. By months 3 to 6, the full benefits of the injection become apparent.
This means that even after you’ve returned to your normal exercise routine, you’re still healing. It’s worth being attentive to how the treated area responds to increasing loads during this period. Gradual progression remains important even after you’ve cleared the initial restrictions. For shoulder injections specifically, Ohio State’s guidelines note that it can take up to 3 months to experience the full improvement in symptoms, so patience with the process tends to pay off.
No Universal Standard Exists Yet
One thing worth knowing: there are currently no universally established post-injection exercise guidelines for PRP. A systematic review of randomized controlled trials on PRP for knee osteoarthritis found that only about 34% of studies even provided information about weight-bearing restrictions after injection. Protocols vary between clinics and between providers. The timelines in this article reflect the most commonly referenced rehabilitation frameworks from major academic medical centers, but your provider may adjust the schedule based on the severity of your injury, the specific tissue treated, and how your body responds in the early weeks.