What is physically happening to the muscle?

Several things may be happening to your muscle(s) when you experience muscle pain:

Contusions / Bruises are caused by impact to a muscle. Muscle fibres compressed in this manner can become irritated and even torn. Capillaries and sometimes venules are damaged by the trauma, allowing blood to seep and haemorrhage into the surrounding tissues. Contusions can involve capillaries at the level of skin, subcutaneous tissue, muscle, or bone. Bruises often induce pain, but small bruises are not normally dangerous alone.

Elongation of the muscle occurs when a muscle is stretched beyond its capacity. Certain muscle fibres can become torn in this manner, causing pain.

Strain is caused when intense and rapid contraction is demanded of a muscle. Such contractions can be too strong, and muscle fibres may tear due to extensive mechanical stress. This type of muscle injury is more typical in sports with dynamic character such as sprinting or jumping. Strains range in severity and can be categorized into 3 grades:

• Grade I (Mild): Strains affect only a limited number of fibres in the muscle. There is no decrease in strength and there is full active and passive range of motion. Pain and tenderness are often delayed to the next day, often referred to as DOMS (Delayed Onset Muscle Soreness).
• Grade II (Moderate): Strains have nearly half of muscle fibres torn. Acute and significant pain is accompanied by swelling and a minor decrease in muscle strength. Pain is reproduced on muscle contraction.
• Grade III (Severe): Strains represent complete rupture of the muscle. This means either the tendon is separated from the muscle belly or the muscle belly is torn into two parts. Severe swelling and pain and a complete loss of function are characteristic for this type of strain.

Knots occur as a result of muscle fibres adhering to each other, or when the bands of tissue underneath them (called fascia) tense or tighten, resulting in a small hard lump. The medical term for muscle knots is myofascial trigger points. Trigger points can be classified as active or latent. Active trigger points cause pain and discomfort without touch or pressure. Latent trigger points are only painful if pressure is applied to them. Common causes of knots include stress and tension, poor posture, staying in the same position for prolonged periods, and dehydration, for example. Although muscle knots are very common, they should not be considered normal or harmless. Myofascial trigger points can cause pain and affect mobility and flexibility. If left untreated, muscle tissue can continue to lose elasticity and cause postural stress that is hard to reverse.

Cramps can be described as a sudden, involuntary muscle contraction or over-shortening of the muscle. While generally temporary and non-damaging, they can cause mild through to excruciating pain, and a paralysis-like immobility of the affected muscle. Cramps usually resolve on their own ranging from a period of several seconds, and up to a week. Muscle cramps may be caused by muscle fatigue or a lack of electrolytes (e.g., low sodium, low potassium, or low magnesium). Hence, muscle cramps during exercise and strenuous physical activity are very common, even in elite athletes. However, cramps can even occur while inactive/relaxed.

Spasms / Muscle Guarding refers to the body’s natural protective response to prevent further injury by seizing up and going into spasm. As a result of some form of injury or internal derangement, the muscles’ reaction acts as a splint to protect the joint from further damage. This muscle spasm can last for days, weeks, months and even years and is extremely uncomfortable/ painful. Although initially a line of defence, if left untreated it may stop being part of the solution and become part of the problem.