FAQs

Factors impacting pain and healing times

• Blood supply - type of tissue and its function.

• Tissue health - sleep, age, nutrition, medications, metabolic health and lifestyle factors such as smoking, alcohol consumption and stress.

• Loading - opportunity for rest, followed by adequate, progressive loading to fast-track the tissue remodelling phase.

Types of tissues

• Epithelial tissue forms the linings and controls movements of materials across surfaces e.g. skin, blood vessels, glands 

• Connective tissue provides support, protection and binds tissues together e.g. bone, cartilage, blood, tendons, fascia, ligaments and adipose tissue (fat)

• Muscle tissue enables function. This can be voluntary (skeletal) and involuntary e.g. heart and organ muscle.

• Nervous tissue transmits electrical signals throughout the body, providing feedback about stimuli from our environment via our tissues and responses to these from our brain to influence voluntary and involuntary control of our body.

Stages of tissue healing

There are four tissue repair steps, which overlap but occur in the following order:

1. 1. 1. Haemostasis stage (stop the bleed)

If there is injury to a blood vessel the body will restrict its blood flow by initiating a spasm, followed by formation of a plug of platelets to seal the wall of the blood vessel within seconds. A cascade of reactions then occur utilising prothrombin, an inactive protein produced in the liver, to reinforce the platelet plug with threads of fibrin to stabilise the clot, and prevent further blood loss. 

1. 1. 2. Inflammatory stage (prevent infection)

Once clotted, the damaged blood vessels leak water, salt and a protein called transudate to the surrounding injury site. This enables healing and repair cells, growth factors, nutrients and enzymes to move to the site through the bloodstream. These are responsible for the swelling, heat, pain and redness that is commonly seen. White blood cells then remove damaged cells, bacteria and any pathogens that can cause infection. 

Inflammation is an essential part of the wound healing process and is only problematic if it is prolonged or excessive, which can occur with repetitive low load tissue trauma, infection or health conditions (diabetes, venous insufficiency etc) that may affect blood supply and this process. 

1. 1. 3. Proliferation stage (repair tissues)

Proliferation is the rapid reproduction of a cell, part, or organism, which means the injury site is then rebuilt with new tissues including connective tissue, collagen and a new network of blood vessels so the new tissues can receive oxygen and nutrients.

1. 1. 4. Maturation stage (remodelling)

Repair cells during the proliferation phase lay down collagen, however this is disorganised, thickening the injury site or wound. These repair cells are then removed by a process called programmed cell death and any remaining water is reabsorbed so the collagen fibers can lie closer together and cross-link along lines of tension. This reduces scar thickness and strengthens the injury site. 

Generic healing times of tissues and injuries

The tissue healing process occurs with all injuries in every tissue, regardless of whether it is a strain, tear, break or micro-trauma due to overloading. Healing times vary depending on the tissue’s blood supply and the stress or load placed on it at each stage of the healing process.

Muscles:

• Muscles have a rich blood supply which is why they heal fast. Contracting and stretching muscles, as well as resolving trigger points, stimulates blood flow through the muscle tissue which encourages a healthy tissue environment and healing. 

• When muscles are overloaded or stressed this leads to micro-trauma and initiation of the healing process. Without correcting underlying muscle imbalances this can lead to chronic inflammation, pain and further trauma or tearing of the tissue. 

Tendons

• Tendons attach muscles to bones, and generally have a more limited blood supply than muscles as they require less energy for their function. This makes them somewhat slower to heal.

• Bloody supply to tendons is stimulated through tension, when they are stretched or when a muscle contracts. 

• Tendon remodelling typically responds better when they are lengthened under tension, which is known as eccentric loading. However, excessive tension whilst they are in the inflammatory phase can prolong healing and cause pain.

Ligaments

• Ligaments attach bones to other bones, prevent excessive movement around joints and provide valuable sensory information. They have a more limited blood supply than muscles and tendons, which increases their healing time.

• Ligaments are prone to reinjury as they never truly regain their full strength once they heal. 

• Protecting the ligament from strain associated with excessive movement, whilst allowing the joint to move and blood to circulate, is critical to promote healing. For example, bracing is often used for ankle and knee ligament injuries to support this function of the ligament while it heals. 

Bones

• Once bones are stabilised to prevent movement at the fracture site they heal best with gentle loading. 

• However, too much or too little load can prolong the healing process. For example, immobilisation boots are often used in ankle and foot fractures rather than plaster casts, which allows for gentle and stable loading while walking. 

Cartilage

• Cartilage, such as your knee’s meniscus, or the labrum in your hip and shoulder, has no blood supply. This means it is very slow to heal and times can vary greatly depending on the severity of the injury or type of surgical repair. 

• Recovery can take anywhere from 6 weeks for a simple cartilage repair known as chondroplasty, which shapes and smooths the cartilage, and up to 6 to 12 months for major cartilage restoration or grafts. 

• Cartilage also has no nerve supply, so pain is not felt when the cartilage is damaged until it has been worn down significantly, and movement at the injury site starts to impact surrounding tissues.

• Nutrients are flushed through the cartilage via joint fluid as load is applied and removed. This is why inactivity can cause thinning of the cartilage, making it more susceptible to injury. 

• Activities that promote smooth joint movement without excessive loading, like cycling and walking, can promote this process. Increased stress through joint loading needs to be applied gradually to protect it as it heals. 

Nerves

• Nerves need to stay mobile so they can glide smoothly among muscles and tissues; this mobility helps them send and receive signals properly.

• Nerves can be injured by pinching or overstretching, which may cause pain, tingling, numbness, or muscle weakness, sometimes along the whole length of the nerve.

• Nerves heal very slowly (about 1 mm per day), so recovery takes patience. Gentle, carefully planned exercises in short intervals can support healing without overstressing the nerve.

How does exercise and rehabilitation promote healing?

Exercise is essential, but it must respect the healing process. Pain is the best indicator for this. If it stays mild and temporary, the tissue is likely healing well. However if it spikes or persists, you may need to reduce intensity, duration, or modify the exercise.

Exercise is best at stimulating blood flow and promotes tissues to remodel and strengthen through lines of tension, making it stronger to endure more loading. It also helps to reduce swelling which increases stiffness and restricts normal movement, fast-tracking each stage of the healing process if used effectively. 

Rehabilitation that promotes correct biomechanics and movement patterns is important. This will ensure the injured tissue does not continue to be overloaded and other tissues are protected from potential injuries due to compensatory strategies.