Achilles tendinopathy is the most common chronic running injury after iliotibial band syndrome and plantar fasciitis, depending on the cohort studied. The research consensus, drawn from clinical guidelines by JOSPT and the British Journal of Sports Medicine across the last decade, is that prevention rests on three pillars: progressive loading, ankle and calf strength, and training-load management. This article reviews the evidence-based exercises that reduce Achilles tendon risk in runners, with a focus on what the research actually demonstrates rather than what running culture assumes.
I'll cover the pathophysiology briefly, the exercises with strongest evidence, the loading parameters that matter, and the common training errors that increase risk. Where evidence is unclear, I'll say so.
What Achilles tendinopathy is, and isn't
Achilles tendinopathy is a degenerative tendon condition characterised by pain, swelling, and impaired performance. It is not the same as Achilles tendinitis, a term largely abandoned in current literature.
The research distinction
Histopathological studies, summarised in reviews by Cook and Purdam (2009) and updated through the 2020s, show that chronic Achilles tendon pain rarely involves classical inflammation. Instead, the pathology is degenerative — disorganised collagen, increased ground substance, neovascularisation. This distinction matters because anti-inflammatory protocols are not the first-line intervention they were once assumed to be.
Two main subtypes
Insertional tendinopathy occurs at the calcaneal insertion. Mid-portion tendinopathy occurs 2-7 cm proximal to the insertion. The exercise prescriptions for the two subtypes differ slightly — insertional cases respond worse to deep-stretch eccentric loading and better to neutral-range loading.
The evidence base for prevention exercises
The strongest research support for Achilles tendon health centres on progressive resistance training, particularly heavy slow resistance and eccentric loading.
Heavy slow resistance (HSR) training
A landmark study by Beyer et al. (2015) in the American Journal of Sports Medicine compared heavy slow resistance to eccentric loading for Achilles tendinopathy and found both effective, with HSR showing better patient satisfaction. The principles transfer to prevention. Loading the tendon with heavy weights at slow tempo (3 seconds up, 3 seconds down) builds collagen capacity. Recommended frequency: 3 sessions per week, 3-4 sets per exercise, 8-12 repetitions, at loads heavy enough that the final two reps are difficult.
Eccentric calf raises
The Alfredson protocol, first published by Alfredson et al. in 1998, demonstrated that eccentric calf loading improves outcomes in mid-portion Achilles tendinopathy. Subsequent systematic reviews, including a Cochrane review in 2013, support the protocol for both treatment and prevention. The exercise: heel raise on a step with both legs, slow lower (4-6 seconds) on the affected leg. 3 sets of 15, twice daily.
Isometric holds
Rio et al. (2015) demonstrated that isometric loading reduces patellar tendon pain in athletes. Subsequent work suggests similar effects for Achilles. The protocol: heavy isometric calf raises held for 30-45 seconds, 5 sets, with 2 minutes rest. Useful particularly in-season for runners who cannot tolerate heavier loading.
Loading parameters that matter
The exercise alone does not prevent tendinopathy. The dosage does.
Load progression
Tendon adaptation follows a slower timeline than muscle adaptation. Magnusson et al. (2010) and subsequent reviews suggest that meaningful tendon collagen turnover takes 12-16 weeks of consistent loading. Progressing load by 5-10% every two weeks is supported by current literature; rapid progressions outpace tendon adaptation.
Time under tension
Slow eccentric and concentric phases (3-6 seconds each) produce higher tendon strain stimulus than ballistic loading. This is reflected in the heavy slow resistance protocols of Kongsgaard, Beyer, and colleagues across multiple Danish studies.
Frequency
Most controlled studies use 2-3 loading sessions per week. Higher frequency does not reliably produce better outcomes and may increase injury risk in runners with concurrent training load.
Training-load management
The most important factor in Achilles tendinopathy prevention is not the strength exercise. It is the training load.
Acute:chronic workload ratio
Gabbett's work on acute:chronic workload ratios, published across several papers from 2014 onwards, suggests that abrupt increases in weekly running load (acute load) relative to four-week rolling average (chronic load) increase soft-tissue injury risk. A ratio above 1.5 is associated with elevated risk in several cohort studies. The 10% rule for weekly mileage progression, while empirical rather than perfectly evidence-based, aligns with this principle.
Hill running
Hill running, particularly downhill, increases eccentric load on the Achilles tendon. Sudden increases in hill volume are a recognised risk factor in retrospective injury studies. Progressive introduction over 4-6 weeks is the practical guideline.
Speed work
Track intervals and tempo runs increase peak tendon strain. Their sudden introduction, particularly in runners who have only done easy running, is a recognised trigger event in clinical case series. Browse STRIDD exercise resources for structured strength routines.
Common errors that increase Achilles risk
Across clinical reports and cohort studies, several training errors recur.
Skipping the warm-up
Cold tendons are less compliant and absorb load less efficiently. A 5-10 minute easy jog before harder running is supported by clinical consensus, though specific RCT evidence is mixed. The principle holds: prepare the tissue before loading it.
Sudden footwear changes
Switching from high-drop trainers (10-12mm) to zero-drop or minimalist shoes increases Achilles loading. Ryan et al. (2014) and subsequent biomechanical studies confirm this. Progressive transition over 8-12 weeks is the practical recommendation.
Ignoring early symptoms
Morning stiffness in the heel cord that resolves within 5-10 minutes of walking is an early warning sign. Persistent symptoms past 7-10 days warrant a load reduction and clinical assessment. Read the STRIDD injuries hub for symptom triage and the STRIDD recovery guide for rest-and-return frameworks.
A practical weekly framework for runners
Synthesising the evidence into a runnable weekly plan.
The strength routine
Three sessions per week, 25-40 minutes each. Include: heel raises (3 sets of 12-15), single-leg calf raises (3 sets of 10-12 per leg), Romanian deadlifts (3 sets of 8-10), single-leg squats (3 sets of 8-10 per leg). Progress load every 2 weeks.
Running load
Increase weekly volume by no more than 10% from the previous four-week rolling average. Introduce hills and speed work progressively over 4-6 weeks. Take a deload week every 4 weeks.
Monitoring
Track morning stiffness, pain on the first run of the week, and pain response to hill running. Any persistent change should trigger a load reduction. The body warns before it breaks. Listen.
For structured strength routines, browse the STRIDD exercise library. For training-load management, build a balanced plan at the plan generator. For more clinical guides, visit Running Lab and the injuries hub.