The Mechanics of Exercise Rehabilitation

It is widely accepted that exercise is immensely important to rehabilitation and the successful return to work or pre-injury life. But what is actually happening in the body that reduces the symptoms of injury? Furthermore, how is exercise utilised in the different stages of recovery? Quite simply, it is all about adaptations! Let’s get into it.

Our body has a powerful ability to adapt to stress. In terms of musculoskeletal rehab, stress is external forces applied to soft tissue, or in other words, exercise. The Physical Stress Theory by Mueller and Maluf essentially states that biological tissue adapts to changes in the level of applied stress. This figure represents a simplified depiction of how soft tissue, for example muscles, responds to forceful stimuli. Low levels of physical activity result in decreased tolerance, however as stress levels increase, so too does our tolerance in the form increased muscle size (hypertrophy) and aerobic efficiency (to name a few).

The goal of any rehabilitation programme is to restore movement, reduce symptoms of injury and restore function back to a pre-injury state. Injury recovery can be divided into three stages, that is, 1- Acute Inflammatory, 2 – Regeneration and 3- Repair and Remodelling. The initial state, Acute Inflammatory, can last between 48-72 hours and is a period where immobilisation of the joint or limb is common. Whilst this is important, there can be negative effects from restricting activity and limiting loading. According to Hammond, Chun and Mishra (2012), “muscle atrophy can occur, bone density can be affected, and scar tissue can accumulate.” Early mobilisation after injury or surgery is vital to increasing tissue strength, improve the orientation of healing muscle fibres, encourage resorption of scar tissue, and decrease muscle atrophy.  As an Exercise Physiologist, this is one of the most important points we try to communicate – early intervention is paramount and gentle mobility exercise can reduce the length of time one is incapacitated for.

Regeneration is the second phase of the recovery process and can last from 2 days to 6 weeks. During this period, exercise is critical to increasing muscular strength and restoring range of motion. Progressive loading provides controlled stress to the repairing soft tissue, forcing adaptation of the muscle fibres and encouraging remodelling of the tissue. Generally speaking, this is still in the acute phase of injury and many find the intervention of a physiotherapist to be beneficial.

The final stage of recovery, Remodelling, can last up to 12 months post injury or surgery and is a period where soft tissue is still regaining strength. It is not uncommon for imbalances and poor biomechanics to occur and as a result of pain avoidance and muscular guarding. When creating an exercise programme, it is important to consider sound muscular recruitment patterns to address asymmetries and restore synergy between muscle groups.

As an Exercise Physiologist working with many patients in the Workers Compensation system, there is one more fancy word I want to talk about and that is ‘mechanotransduction’. This basically refers to the conversion of stress on the cellular level resulting in structural change. A simple example of this is the increase in bone density as a result of consistent exercise. The reason this is important is because tissue adapts to the specific force applied. So, if soft tissue is exposed to compressive forces, the tissue will adapt tolerate compressive forces only. During the rehab process, an exercise physiologist will determine the types of forces one will experience as a requirement of their employment duties and replicate these in a controlled gym setting. If you’re being treated by any EP at Absolute Balance, you can be sure that by the time you return to your preinjury duties, the adaptations your body has made after an injury is tailor-made to your job role and the risk of reinjury is greatly reduced.

Ed Daccache

B.Ex.SpSc, Grad.Dip.Ex.Sc (AEP, AES) (ESSAM)
Accredited Exercise Physiologist


Crews.R., Schneider.K., Yalla.V., Reeves.N., Vileikyte.L. (2016). Physiological and Psychological Challenges of Increasing Physical Activity and Exercise in Patients at Risk of Diabetic Foot Ulcers: A Critical Review. Diabetic/ Metabolism Research and Reviews. 32; 792-804. DOI 10.1002/dmrr.2817

Hammond. J., Chun.J., Mishra.Dev. (2012). The Science of Science of Unloading and Progressive Loading. Retrieved from

Physiopedia. Principles of Exercise Rehabilitation. Retrieved from