Last November, while on vacation in Hawaii, I headed out for what I expected to be an easy run. On my very first stride, I felt a sharp pain deep in the back of my left buttock. Within minutes, I knew I had injured my hamstring.
Fortunately, I didn’t believe it was a complete rupture. A full hamstring tear is often accompanied by an audible pop, significant bruising, and sometimes a noticeable defect or “knot” in the muscle. Even so, the injury was concerning. With triathlon season just around the corner, I knew I needed to recover the right way.
Hamstring injuries are among the most frustrating injuries for runners and triathletes. They have a high recurrence rate, and when they aren’t rehabilitated properly, they can linger for months—or even years. My own recovery reinforced something I tell patients every day: successful rehabilitation requires patience, progressive loading, and an individualized plan.
Understanding the Hamstrings
The hamstrings are a group of three muscles located along the back of the thigh:
- Biceps femoris – long and short heads
- Semitendinosus – superficial
- Semimembranosus – deep
Three of the four hamstring muscles originate from the ischial tuberosity, commonly known as the “sit bone,” and extend down the thigh to attach around the knee. The fourth, the biceps femoris short head, originates on the femur.
The hamstrings serve two primary functions:
- Bend (flex) the knee
- Extend the hip
For endurance athletes, they play an even larger role.
Running
During running, the hamstrings work eccentrically to slow the lower leg as it swings forward. As your foot contacts the ground, they transition into a powerful hip extensor, helping propel your body forward.
Cycling
While cycling, the hamstrings contribute during the latter portion of the pedal stroke by helping pull the pedal backward and upward, particularly during higher-power efforts.
Swimming
In freestyle swimming, the hamstrings assist with kick recovery, stabilize the pelvis, and generate force when pushing off the wall.
Why Do Hamstrings Tear So Often?
The biceps femoris is the most commonly injured hamstring muscle, particularly near its attachment at the sit bone—the exact location of my injury.
Although hamstring strains frequently occur during sprinting, researchers have not identified a single cause. Instead, injuries appear to result from a combination of factors.
Some recognized risk factors include:
- Sudden increases in training load
- Inadequate warm-up
- Poor lumbopelvic stability
- Muscle weakness or asymmetry
- Fatigue
- Limited mobility
- Previous low back pain
- Poor recovery strategies
- Nutritional factors
- Psychosocial stressors
For endurance athletes, these factors often accumulate gradually rather than appearing all at once.
The Biology of Healing: Why Recovery Takes Time
One of the biggest misconceptions about muscle injuries is that healing can be accelerated through aggressive stretching or strengthening. While rehabilitation can optimize recovery, biology still dictates the timeline.
Phase 1: Acute / Inflammatory (Days 1–5)
What’s happening?
The body’s inflammatory response begins. Pain, swelling, and muscle guarding help protect the injured tissue.
Rehabilitation goals
- Protect the injured muscle
- Control pain
- Maintain gentle mobility without excessive stretching
- Avoid prolonged immobilization
Progression criteria
- Normal walking without pain
- Pain-free slow jogging
- Pain-free medium-intensity isometric hamstring contraction with the knee flexed to 90°
Phase 2: Proliferation (Days 6–21)
What’s happening?
The body begins producing new collagen fibers to bridge the injured tissue. Initially, these fibers are disorganized and relatively weak.
Rehabilitation goals
- Introduce progressive loading
- Encourage proper collagen alignment
- Continue avoiding painful end-range stretching when weakness is present
Progression criteria
- 5/5 manual hamstring strength with the knee flexed to 90°
Phase 3: Remodeling and Maturation (Weeks 3–6 and Beyond)
What’s happening?
The new tissue becomes stronger, more organized, and better able to tolerate higher loads.
Rehabilitation goals
- Progress strength training
- Restore endurance
- Introduce running-specific drills
- Gradually add speed, power, and sport-specific activities
Before returning to higher-speed running, athletes should demonstrate:
- Full, symmetrical range of motion
- Approximately 90% strength compared to the uninjured side
- Strong performance with the hamstring tested in a lengthened position
- Confidence running without compensation
What I Learned From My Own Recovery
As physical therapists, we often rely on research-supported rehabilitation protocols. When I injured my hamstring, I decided to follow one of these published programs myself.
Unfortunately, it proved too aggressive for my injury.
Within a short period, my pain increased, and my recovery stalled. I quickly adjusted my rehabilitation based on my clinical experience and how my body responded.
That experience reinforced an important lesson: even evidence-based protocols are only starting points.
No two hamstring injuries are identical. Differences in injury location, severity, tissue quality, training history, age, and sport all influence recovery. The best rehabilitation program isn’t simply one pulled from a research paper—it’s one that’s continually adjusted based on how the athlete responds.
After several more weeks of individualized rehabilitation, I returned to full triathlon training and competition completely pain-free.
The Bottom Line
Hamstring strains can be frustrating, but they don’t have to become chronic.
Successful recovery depends on respecting the biology of healing while progressively rebuilding strength, mobility, and running capacity. Trying to rush the process—or following a one-size-fits-all program—often leads to setbacks.
With the right plan, most athletes can return to running stronger and with a lower risk of reinjury.
Ready to Get Back to Running?
If a lingering hamstring injury is keeping you from running, cycling, or training for your next race, don’t rely on guesswork.
At Evolve Physical Therapy, we provide one-on-one evaluations and individualized rehabilitation programs designed specifically for runners and triathletes. Our clinics have state-of-the-art equipment that will help in your recovery by safely and effectively reintroducing running. Whether you’re recovering from a recent strain, dealing with a recurring injury, or recovering from surgery, we’ll help you build a clear roadmap back to training and competition.
Schedule an evaluation at our Sherwood or Bethany clinic and take the first step toward a confident return to sport.
