Hamstrings: What they are and why they’re important

The strength of your hamstrings can literally make or break your athletic performance. Physio Trishul Vegad explains more…

why are hamstrings important for athletes

The hamstrings are a group of three key muscles that run behind the thigh muscle and are responsible for extending the hip and and flexing the knee. 


What and where are the hamstrings?

Unlike the bulky quadriceps you see in the mirror, hamstrings are a group of muscles hidden at the back side of the upper leg, underneath the buttocks and above the knees. The biceps femoris, semitendinosus and semimembranosus make up this power group of muscles. They are connected to the pelvis and the back of the knee via strong, stable and solid tendons.

Credit: Getty Images

What do the hamstrings do?

Simply put, their role is to extend the hip and flex the knee. So, whether it’s pedalling on your bike or driving through your heels during the final step of your run gait, rest assured that this group of muscles will be put through its paces.

The hamstrings can be thought of like the biceps of the leg. In fact, the biceps femoris muscle is similar to the biceps brachii muscle in the arm in that it has two heads – a long head and a short head. As they work in unison, they afford movements such as hip thrusts, leg curls and Romanian deadlifts.

Why are hamstrings important?

From the get-go, hamstrings control your kicking motion when swimming. But the real test is when you hit the bike. Here, the hamstrings are engaged in the downward stroke as the hip and knee extends, and in the upwards stroke as the knee and hip flexes. Honing well-conditioned hamstrings will help to replace an ineffective figure-of-eight shape to a more rounded efficient shape when pedalling.

As you move into the final running stage of your triathlon, like swimming the hamstrings help to eccentrically decelerate hip flexion and knee extension during terminal swing. (1) They also help to maintain an ‘upward attitude’ of the trunk; in other words, to keep your posture more upright for efficiency.

How to diagnose a hamstring problem?

In triathlon, hamstring and calf injuries are mainly attributed to running over cycling or swimming. (2) Pain in the hamstrings may be down to weakness in the glutes. The hamstrings and gluteus maximus work as agonists to decelerate the thigh during the terminal swing phase and to control hip flexion during loading response of running, so strengthening the gluteus maximus might decrease effort required by the hamstrings. (1) In cycling, the main risk is a strain that might occur when the muscle is loaded too heavily or too much over time. Swimming is considered low impact but, if injury has been sustained elsewhere, the movement will become painful and performance will suffer.

Common reasons for hamstring injury include:

  • Muscle tightness
  • Imbalances
  • Muscle weakness
  • Poor form

Hamstring injuries are relatively common. The diagnosis will begin with a verbal interview to describe symptoms, followed by a physical examination by a qualified physiotherapist that might include palpating areas around the injury or demonstrating specific stretches or exercises to assess strength and range of motion. If something more severe than a standard strain is suspected, you might be referred on for medical imaging.

Strains are graded 1-3 as follows:

1: Mild strain, sudden pain and tenderness

2: Mild tear, more painful and may be bruised or have weakness

3: Severe tear, high pain, swelling and bruising, inability to use leg

Looking after your hamstrings

We’d recommend hamstring- and glute-specific stretching and strengthening exercises for triathletes of every level to avoid injuries associated with weakness or overuse…

  • Warm your hamstrings up
    Preparing your hamstrings for exercise should begin before the workout. Tight, sore or cold muscles are already at a higher risk of injury, so it’s vital you don’t go straight into something like an intense run without any preparation. We’d recommend upping the intensity of exercise gradually to raise body temperate, heart rate and blood flow before moving into the actual training session. Light cycling – this could be on a spin bike – has been shown to be effective to improve hamstring stiffness and range of motion before competition. (3)
  • Strengthening
    A single lower-body strengthening session a week should suffice, including exercises such as box squats, single-legged glute bridges, hyperextension and hamstring curl variations. One to not miss is the Nordic hamstring curl, which recreates the eccentric loading fashion that the muscle group commonly find themselves in. Remember that strong muscles don’t fatigue as quickly so this’ll only translate into better performance for the multisport athlete.
  • Form
    Hamstring stress can be reduced by shortening your run stride and undertaking a professional bike fit, as too high saddle height can cause issues.
  • Stretch
    We’d advise stretching post-exercise and either before bed or in the morning as part of your daily routine. Simple stretches for the hamstrings include: reaching down towards your toes and holding; or sitting with one leg bent in towards your body as though you were going to sit crossed legged, and the other leg outstretched, then leaning the torso down and forward into the outstretched leg. You could also foam roll during these times to aid in blood flow and breaking down scar tissue.

Due to the high reoccurrence risk of hamstring injury, prevention is clearly the best route. But If you do happen to have an injury, a plan to return to sport safely can be put in place by a physiotherapist who’ll guide you and ensure your hamstrings are rehabilitated to safely handle high eccentric loading upon your return to running. (4)

Like with any health issue, if you have any concerns at all, seek medical advice from a qualified medical practitioner, whether that’s a doctor or physiotherapist. 

Trishul Vegad is a Senior Physiotherapist at Sano Physiotherapy Nottingham


  1. Wagner, T., Behnia, N., Ancheta, W., Shen, R., Farrokhi, S. and Powers, C., 2010. Strengthening and Neuromuscular Reeducation of the Gluteus Maximus in a Triathlete with Exercise-Associated Cramping of the Hamstrings. Journal of Orthopaedic & Sports Physical Therapy, 40(2), pp.112-119.
  2. Vleck, V., Bentley, D., Millet, G. and Cochrane, T., 2010. Triathlon Event Distance Specialization: Training and Injury Effects. Journal of Strength and Conditioning Research, 24(1), pp.30-36.
  3. Morales-Artacho, A., Lacourpaille, L. and Guilhem, G., 2017. Effects of warm-up on hamstring muscles stiffness: Cycling vs foam rolling. Scandinavian Journal of Medicine & Science in Sports, 27(12), pp.1959-1969.
  4. Heiderscheit, B., Sherry, M., Silder, A., Chumanov, E. and Thelen, D., 2010. Hamstring Strain Injuries: Recommendations for Diagnosis, Rehabilitation, and Injury Prevention. Journal of Orthopaedic & Sports Physical Therapy, 40(2), pp.67-81.