Why "Resting It" Often Makes Injuries Worse: An Exercise Physiologist's Guide to Active Recovery

What disuse actually does

The physiology of unloading is well described. Wall and colleagues (Acta Physiologica, 2014) showed that five days of single-leg immobilisation in healthy young men reduced quadriceps cross-sectional area by around 3.5% and isometric strength by roughly 9%. Fourteen days produced losses closer to 8% in muscle size and 23% in strength. Older adults lose more, faster.

Aerobic capacity drops faster than strength. A two-week layoff can knock several percent off VO2max in trained individuals. Tendon stiffness declines as well: collagen turnover slows, the tendon becomes less able to tolerate the same load it handled before, and re-introducing activity at the previous volume produces a flare. The "rest until it feels better" loop then repeats.

This is the mechanism behind the familiar pattern: pain settles with two weeks off, the person returns to the activity that hurt, and within a fortnight the symptoms are back. The tissue was not being healed by the rest. It was being deconditioned.

Relative rest, not absolute rest

The concept worth borrowing from sports medicine is relative rest: remove the specific loading vector that is currently aggravating the tissue, and keep the rest of the system working. A runner with reactive patellar tendinopathy does not need to stop training. They need to stop the spikes — hill repeats, deep squats, plyometrics — while continuing cycling, upper-body strength work and isometric quadriceps loading.

A client with lateral elbow pain from pickleball can train legs, hinge, press overhead within tolerance, and load the wrist extensors isometrically. Sitting on the couch for two weeks gives the elbow nothing useful and removes everything else.

The genuine 48 to 72 hour exception

There is a narrow category where short-term protection is appropriate: acute soft-tissue injuries with a clear mechanism and significant tissue disruption — a Grade II hamstring strain after a sprint, a moderate ankle sprain, a sudden calf tear. For these, the current consensus framework is PEACE and LOVE (Dubois and Esculier, British Journal of Sports Medicine, 2020).

• Protection — unload for the first one to three days, only as long as needed
• Elevation — to assist venous return
• Avoid anti-inflammatories in the early phase — they may impair tissue repair
• Compression — to limit swelling
• Education — set realistic expectations and avoid unnecessary imaging
• Load — reintroduce mechanical stress as symptoms permit
• Optimism — psychological factors meaningfully predict outcome
• Vascularisation — pain-free aerobic activity from early on
• Exercise — restore mobility, strength and proprioception progressively

Subacute and chronic complaints — where most people live

The majority of musculoskeletal problems that walk through a coaching door are not in the acute window. They are tendinopathies that have grumbled for months, low backs that flare every few weeks, knees that ache on stairs, shoulders that catch overhead. For these, load is the medicine.

In tendinopathy, the Cook and Purdam continuum (BJSM, 2009) and subsequent loading work has reframed the problem: tendons respond to progressive mechanical stress through isometric holds, then heavy slow resistance, then energy-storage loading. Rest reduces both pain and capacity in the short term, and capacity does not return on its own.

In low back pain, graded exposure and progressive loading outperform avoidance in every modern guideline. In knee osteoarthritis, the GLA:D programme (Skou and Roos, BMC Musculoskeletal Disorders, 2017) — eight weeks of supervised neuromuscular exercise and education — produces clinically meaningful improvements in pain and function across thousands of participants, often comparable to surgical alternatives for appropriate candidates. In shoulder impingement, progressive rotator cuff and scapular loading consistently beats passive treatment.

A practical decision tree

Most adults do not need a flowchart, but the following four questions cover the great majority of presentations.

• Is the pain above 7/10, sharp, electric, or accompanied by significant swelling, locking or neurological symptoms? See a clinician before training.
• Did this happen in the last 72 hours with a clear mechanism? Protect briefly, then follow PEACE and LOVE.
• Has it been grumbling, niggling or recurring for weeks or months? The answer is progressive load, not rest.
• Does it hurt during the activity but feel fine after, and not flare the next morning? That is a green light to continue training within that envelope.

The pain monitoring rule

The most useful clinical tool for guiding load through symptomatic tissue is the traffic-light system originally described in Silbernagel's Achilles tendinopathy work (American Journal of Sports Medicine, 2007). Pain on a 0 to 10 scale during loading is acceptable up to roughly 3 to 5 out of 10, provided two conditions are met: pain returns to baseline within 24 hours, and symptoms do not progressively worsen week to week.

This rule lets people train through symptomatic tendons and joints without the guesswork. It also disarms the most common psychological trap — the assumption that any pain during exercise means damage.

What active recovery actually looks like

Active recovery is not foam rolling and a smoothie. In a structured programme it means specific work that loads the affected tissue at an intensity it can currently tolerate, alongside everything else the person can still do safely.

• Low-load aerobic work — walking, cycling, swimming — to maintain cardiovascular conditioning and assist tissue perfusion
• Isometric loading of the symptomatic tissue at sub-symptomatic intensities for pain modulation
• Heavy slow resistance work for the surrounding musculature that is not aggravated
• Mobility work where it actually changes symptoms, not as a reflex
• Sleep, protein intake and total weekly load monitored as carefully as the exercises themselves

A few myths worth retiring

Inflammation is not the enemy. It is the early phase of the repair process. Routinely suppressing it with NSAIDs in the first 48 hours is associated with impaired tendon and muscle healing in animal models and in some human work — hence its placement in the "avoid" column of PEACE and LOVE.

Stretching does not prevent injury in any meaningful way for most populations. Multiple systematic reviews have failed to find a protective effect for static stretching prior to activity. It can feel good, and it can help in specific stiffness presentations, but it should not be sold as injury prevention.

The plan to "start training again when it stops hurting" frequently produces years of inactivity. For chronic tendinopathy and recurrent back pain, the symptom often does not fully resolve until load capacity has been rebuilt. The order of operations is the reverse of what most people assume.

Coach or clinician

See a physiotherapist or doctor first when there are red flags — severe pain, neurological signs, significant trauma, suspected fracture, or symptoms that are getting worse rather than better. See a coach with rehabilitation experience when you have a diagnosis or a stable chronic complaint and need someone to build progressive load around it. The two roles complement each other; they are not interchangeable.

Putting it to work

If you are in Salou or Cambrils and you have been sitting on a niggling shoulder, knee or Achilles for months, the most likely missing ingredient is structured, progressive loading — not more rest. Personal training in Salou with a rehabilitation-informed approach means we build the plan around what the tissue can currently tolerate, monitor symptoms with the traffic-light rule, and progress load on a timeline that matches biology rather than impatience. Injury prevention and return-to-activity work share the same principles: load, recover, repeat, measure. If you would like to talk through a specific complaint, the contact page is the place to start.