A hamstring injury is a strain or tear affecting one of the three muscles running along the back of the thigh, ranging from a mild pull (Grade 1) to a complete rupture (Grade 3). These injuries frequently occur during activities involving high-speed running, sudden stops, or extensive muscle lengthening, making them common in sports. Consulting a medical professional is necessary to accurately grade the injury and establish a safe, individualized rehabilitation plan. Starting an exercise program without professional guidance significantly increases the risk of re-injury and can lengthen the recovery time.
Movements and Activities to Avoid
During the acute phase following a hamstring strain, certain movements must be avoided as they place excessive strain on the healing muscle tissue. High-speed, ballistic, or uncontrolled movements are damaging because they require the hamstrings to generate or absorb force quickly. Activities like sprinting, jumping, or sudden changes in direction should be suspended until much later in recovery.
Deep, passive stretching and aggressive yoga poses that pull forcefully on the hamstring should also be avoided, especially in the early stages. This type of stretching can aggravate the injury by placing tension on the healing fibers. Heavy resistance exercises that involve deep hip flexion, such as deadlifts, good mornings, or squats past 90 degrees, are prohibited. These movements create high mechanical load and tension on the hamstrings, which can worsen the tear or delay healing.
Early Stage Gentle Rehabilitation
Once the initial pain and swelling subside, typically after the first few days, the focus shifts to gentle, pain-free movements to maintain range of motion and prevent muscle atrophy. The goal of this phase is to load the muscle minimally without causing pain, which helps promote blood flow and healing. Exercises must be performed in a controlled manner, and any sharp pain should signal the need to stop or reduce intensity.
Gentle isometric holds are the safest way to introduce tension to the muscle. This involves contracting the hamstring sub-maximally for short durations, typically 5 to 10 seconds, without moving the joint. Simple exercises like gentle heel slides, where the heel is slid toward the buttocks while lying on the back, or short-arc quadriceps exercises can promote movement in the area. These movements are low-load and focus on the knee joint without aggressively stretching the injured tissue.
Building Strength with Progressive Loading
The mid-to-late stage of recovery concentrates on rebuilding the muscle’s strength and resilience through progressive loading, which is necessary to prevent future injury. This phase introduces exercises involving the muscle lengthening while under load, known as eccentric contractions. These contractions mimic the action that often causes the injury during sprinting. Slow, controlled resistance is applied, and the load or speed should only progress when the exercise can be performed without pain.
Several exercises are used to incorporate eccentric loading:
- Glute bridges, which can be progressed from two legs to single-leg variations, and eventually with added weight resting on the hips.
- Resistance band exercises, such as seated or prone hamstring curls against a light band, emphasizing a slow return phase to load the muscle eccentrically.
- Stability ball hamstring curls offer another way to incorporate eccentric loading by rolling the ball away slowly while maintaining a lifted hip bridge position.
- The Nordic hamstring curl, a highly effective eccentric exercise, which is introduced later and requires significant control and strength, often starting with a focus on the controlled lowering phase.
Criteria for Returning to Full Activity
The decision to return to full activity, like competitive sport or heavy lifting, should not be based solely on the absence of pain, as re-injury rates are high if the muscle is not fully rehabilitated. A pain-free state during strength and flexibility testing is a foundational requirement, but objective measures are also necessary to confirm readiness.
Achieving near-equal strength between the injured and uninjured legs is required, often targeting a deficit of less than 5% to 10%. This comparison must specifically assess the eccentric strength of the hamstring, often using specialized equipment or functional tests like the single-leg bridge hold time. Full range of motion, comparable to the uninjured side, must be restored without pain during active and passive flexibility tests. Finally, the individual must successfully complete sport-specific functional tests, such as pain-free running at high speeds and performing acceleration and deceleration drills, to confirm the muscle can handle the required dynamic loads.