Running injuries are commonly seen by physiotherapists, with most running injuries a result of poor lower limb biomechanics and / or prolonged heavy training loads (in particular during pre-season training). Biomechanics involves the observation, description and evaluation of a sporting technique to assess its ‘efficiency of movement'. While correct biomechanics plays a key role in optimising sporting performance, faulty biomechanics, whether these are static (anatomical i.e. leg length discrepancy), or functional (secondary i.e. ligament sprain causing joint instability) abnormalities, significantly increases the risk of injury to the athlete.

Biomechanics of Running

Characteristics

• Is divided into 3 phases: (1) contact (stance), (2) swing and a (3) flight (floating) phase.
• Contact phase is divided into: (1) foot strike, (2) midsupport (midstance) and (3) take off (propulsion).
• Swing phase is divided into: (1) follow through, (2) forward swing and (3) foot descent.
• Flight phase (floating) occurs when both feet are in the air, in between stance phases.
• Stride length and frequency tend to increase with increased running speed.
• With increasing running speed, duration of contact period decreases but that of swing phase increases.
• At foot strike, the body's muscles must absorb the initial impact from the foot striking the ground.
• As speed of running increases, the base of gait decreases.

Abnormal Lower Limb Biomechanics

• Excessive Foot Pronation: excessive ‘flattening' of the foot results in the lower limb to excessively internally rotate. This ‘overloads' numerous structures of the lower limb including the plantar fascia (sole of foot), achilles tendon, medial shins and patella tendon.
• Excessive Foot Supination: excessive ‘arching' of the foot results in a stiffer foot, and thus poorer shock absorption of forces. This may predispose to the development of stress fractures in bones of the leg and foot.
• Abnormal Pelvic Mechanics: Poor control of the pelvic stabilizing muscles results in increased anterior and / or lateral pelvic movement, causing ineffective transmission of forces, and thus less efficient movement. Increased anterior tilt may overload the lumbar spine and patella tendon, while increased lateral tilt may overload the outside of the upper thigh.

The Most Common Running Injuries are:

1. Groin Pain:

• Frequent running, particularly with sudden change of direction or hill climbing / descending, stress abductor (hip) muscles and pelvic / pubic structures. 

2. Heel and Foot Pain

• Chronic degeneration of the achilles tendon and inflammation of the plantar fascia (a thick band on the sole of the foot) is usually associated with regular running and poor foot mechanics or arch formation.

3. Stress Fractures

• These are seen as a result of overtraining and are located mainly in the foot and lower leg (shin). Pain in these areas requires immediate attention.

4. Knee Pain

• Normally involves the patella (knee cap)
• The ache, which occurs at the front of the knee, is known as patello-femoral pain and is due to abnormal ‘tracking' of the patella.
• Inflammation arises and creates further biomechanical changes, which worsens the condition.
• Pain at the outside of the knee can be a condition called Iliotibial Band Friction Syndrome, and is due to inflammation of the thick band structure which runs from the hip to the outside of the knee. Tightness of this, the hip / hamstrings and over-pronation of the foot (flattening of the foot arch) are contributing factors."

These and many other limb injuries are best diagnosed by a sports physiotherapist performing a thorough musculoskeletal assessment and biomechanical analysis (which may include video analysis) of the individual's specific sporting technique.

Published by Balmain Sports Physiotherapy