A hamstring strain is a common leg injury involving a tear in one or more of the hamstring muscles. A hamstring strain can range from mild to very severe involving a complete tear of the hamstring muscle.

You have four hamstring muscles: semimembranosus and semitendinosus (medially) and biceps femoris - short and long heads (laterally).

What Causes a Hamstring Strain?

Common reasons for hamstring strain or injury can be categorized as primary or secondary.


Poor timing/intermuscular coordination and eccentric strength in the hamstring muscles during the switch between late leg recovery and initial leg approach in the swing phase of sprinting (Woods et al. 2004).

Lack of “stiffness” and eccentric strength in the hamstring muscles during the ground contact phase of running (Bosch and Klomp 2005). “Stiffness” refers to the ability of the hamstring muscle to absorb shock and rebound. Dropping a golf ball onto concrete is an example of stiffness, it immediately rebounds off the surface.

Previous hamstring strain is a very good indicator of potential for future injury (Crosier 2004).


  • Poor running mechanics. This consists primarily of over-striding or poor pelvic control, which puts the hamstrings in a vulnerable position at ground contact.
  • Improper warm-up. Your warm-up must be active and dynamic to prepare the hamstring muscles for the forces involved. Passive stretching is only one segment of warm-up.
  • Inappropriate training loads. Your hamstrings are primarily fast twitch Type II fibres that fatigue quickly. High-speed work should be done early in the workout, as close to warm-up as possible to avoid fatigue.
  • Fatigue (neural and local muscle).
  • Lower back pathology. Abnormalities of the lumbar spine or poor pelvic control that can cause nerve dysfunction and subsequent muscle weakness can predispose you to injury.
  • Playing surfaces. A wet slippery surface will put more strain on the hamstring due to slipping.

Are you having hamstring pain or hamstring tension that you want assessed? Are you stretching and foam rolling and finding that the benefit is short-lived? Have you wondered about IMS, dry-needling, manual therapy or evidence-based exercise to address your symptoms?

For a thorough assessment to determine the specific causes of your hamstring symptoms, call Physiohaus at 519-204-4445 or visit physiohaus.ca to book an appointment.