Research

Achilles Tendon Force by Activity

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Updated: May 2026 · 7 min read

General information only. Forces shown are population averages from published research, expressed as multiples of body weight (BW). Actual load varies with speed, technique, body mass, footwear, and individual biomechanics. This table is a reference tool — not a prescription for what activities are safe at your stage of recovery. Always follow your surgeon or physiotherapist's guidance.

In this article

One of the most practically useful things to understand during Achilles rupture recovery is how different activities compare in terms of the actual force they place through the tendon. The difference between walking slowly in a boot and landing from a box jump is not just intuitive — it is measurable, and the research has measured it.

This article compiles the best available force data across a wide range of activities, expressed as multiples of body weight (BW). A person weighing 80 kg has a body weight of approximately 785 N. An activity generating 3× BW therefore places roughly 2,355 N through the tendon at peak load. These are peak forces during the activity — not sustained loads.

Forces are derived from in vivo tendon transducer studies, inverse dynamics calculations from motion capture and force plate data, and ultrasound-based musculoskeletal models. Where ranges are reported, the table shows the published range and midpoint.

How to Read This Table

BW = body weight. A value of 3× BW for an 80 kg person = approximately 2,350 N peak tendon force. Forces are peak values during the activity, not sustained. Load tier classifications (Very Low → Very High) are based on clinical rehabilitation literature and reflect the activity's position in standard Achilles rehab progression frameworks. Filter by category or sort any column by clicking the header.

The Force Table
How to Use This Table in Recovery
References
Related Reading

The Force Table

Load tier: Very Low (<1× BW) Low (1–2× BW) Moderate (2–4× BW) High (4–7× BW) Very High (>7× BW)

Activity ↕	Category ↕	Peak Force (× BW) ↕	Load	Notes
Cycling — stationary, seated, easy	Cycling	~0.1–0.2×	Very Low	Non-weight-bearing. Small ankle arc. Boot further limits motion. E-bike assist reduces calf demand further. Estimated from cycling biomechanics literature; direct Achilles transducer data not available for this condition.
Cycling — stationary, in boot	Cycling	~0.1–0.2×	Very Low	Boot constrains ankle arc further. No ground reaction force. Lowest Achilles load of any dynamic activity. Standard recommendation in boot-phase rehabilitation protocols.
Cycling — road, moderate pace	Cycling	0.41–0.7×	Very Low	Non-weight-bearing; seated. Demangeot et al. systematic review lower bound for strengthening exercises. Calf activation present but force well below walking. Saddle height and resistance influence load.
Cycling — high resistance / standing climb	Cycling	~1.0–1.5×	Low	Standing out of saddle significantly increases calf demand. Still lower than walking in normal shoes. Not appropriate during boot phase.
Seated bilateral heel raise	Rehab	~1.1×	Low	Lowest loaded heel raise variant. Soleus dominant. Starting point for calf loading in early post-boot rehab. Fourchet et al.; Baxter et al.
Walking — normal shoes, preferred speed	Gait	2.7–3.95×	Moderate	Demangeot et al. systematic review range. Jozwiak et al. in vivo measurement ~2.63 kN (~2.5–3.4× BW depending on body mass). Peak at push-off phase. Increases with walking speed.
Walking — in recovery boot (plantarflexed)	Gait	~0.7–1.5×	Low	Boot reduces load 60–77% vs normal shoes (Baxter et al. 2022). Angle, boot type, and speed are key variables. Still present with every step — not zero.
Bilateral standing heel raise	Rehab	~2.0–2.5×	Moderate	Standard entry-level weight-bearing rehab exercise. Both legs share load. Fourchet et al.; consistent with Baxter et al. exercise progression data.
Bodyweight squat	Strength	~2.0–3.0×	Moderate	Load varies with depth and forward shin angle (dorsiflexion). Greater dorsiflexion = higher Achilles load. Heel raise or wedge under heel reduces tendon demand. Demangeot et al. range for strengthening exercises; squat biomechanics literature.
Deadlift (conventional)	Strength	~1.5–3.0×	Moderate	Ankle remains relatively neutral; Achilles load lower than squat variants. Calf contribution modest compared to hip and knee extensors. Heel lift or shoes with heel drop recommended during early return. Load varies with bar path and hip position.
Bilateral heel raise, fast tempo	Rehab	~2.5–3.5×	Moderate	Faster tempo increases peak load and rate of force development. Baxter et al. progression data; Fourchet et al.
Split squat / Bulgarian split squat	Strength	~2.5–4.0×	Moderate	Front leg dorsiflexion increases Achilles demand significantly compared to bilateral squat. Load asymmetric between front and rear leg. Heel elevation on front foot reduces tendon stress. Demangeot et al. range.
Unilateral (single-leg) heel raise	Rehab	~2.5–4.5×	Moderate	Full single-leg load. Key functional test and rehabilitation exercise. Fourchet et al.; Baxter et al. Deficits in height and repetitions are primary markers of Achilles recovery. Decline variant increases load further.
Loaded back squat (moderate load)	Strength	~3.5–5.0×	High	External load adds substantially to Achilles demand, especially with forward lean and deep knee bend. Front squat variant generates similar or greater ankle dorsiflexion. Heel elevation significantly reduces load. Demangeot et al. upper range for strengthening exercises.
Running — slow to moderate pace (3–4 m/s)	Gait	4.15–7.71×	High	Demangeot et al. systematic review (2022). Jozwiak et al. 3.06–4.64 kN in vivo. BMC Musculoskeletal Disorders: "approximately 6–8 times body weight" at running pace. Force increases with speed. Tensiometry estimates range 8.2–10.1× BW at race pace.
Vertical jump — squat jump (no counter-movement)	Plyometric	~3.0–4.5×	High	In vivo buckle transducer study: peak Achilles force 2,233 N (~3× BW for 75 kg subject). Fukashiro et al. No stretch-shortening cycle — lower peak than counter-movement jump or hopping. Higher total mechanical work than landing-only tasks.
Vertical jump — counter-movement jump	Plyometric	~3.5–5.0×	High	In vivo measurement: peak Achilles force 1,895 N for 75 kg subject (~2.5×); higher estimates in larger athletes. Stretch-shortening cycle involved. Force rate of development high. Fukashiro et al.; Finni et al.
Box jump — landing phase	Plyometric	~4.0–6.0×	High	Landing phase generates high eccentric load. Force depends on drop height, landing technique (stiff vs soft), and foot strike pattern. Forefoot landing increases Achilles load. Not appropriate until late-stage rehabilitation. Crossfit literature; CrossFit Rife; Fukashiro et al. landing equivalents.
Single-leg hopping on spot	Plyometric	~4.5–6.5×	High	In vivo buckle transducer: peak force 3,787 N in 75 kg subject (~5.0×). Lichtwark & Wilson: 3,500–4,000 N. Highest peak in jumping literature. High rate of force development. Tendon strain 8.3% average; range 6.2–10.3%. Fukashiro et al.; PMC5343533.
Running — fast pace / race pace	Gait	6.0–10.1×	High	Tensiometry estimates 8.2–10.1× BW at higher running speeds (Demangeot et al. review note). Tendon force and strain increase with speed. BMC Musculoskeletal Disorders: "close to maximum load tolerable by the tendon" at 6–8× BW. Normal healthy tendon can withstand up to ~7× BW (PMC11379499).
Sprinting — maximal effort	Gait	6–12×	Very High	Estimated 6–8× BW during maximal sprinting (Wheeler Sports Tech; Outperform Sports). Up to 12× BW cited in Physiotutors / Baxter et al. progression commentary. Forefoot contact only; rapid stretch-shortening cycle; very high rate of force development. Last activity cleared in return-to-sport protocols.

How to Use This Table in Recovery

The numbers above are not a green-light list. An activity appearing low on this table does not mean it is appropriate at your stage of recovery — it means the tendon force is low when that activity is performed by a healthy person with a normal tendon. A healing or recently repaired tendon has a much lower load tolerance than an uninjured one, and that tolerance increases gradually over months as the repair matures.

What the table does usefully show is the relative order of activities — which is broadly consistent with how rehabilitation protocols sequence exercise progression. Clinicians do not typically prescribe sprinting before single-leg hopping, or box jumps before running, and the force data explains why. Each step up in the table represents a meaningful jump in peak tendon demand.

A few specific observations worth highlighting:

Cycling sits well below walking

The gap between cycling in a boot (~0.1–0.2× BW) and walking in normal shoes (2.7–3.95× BW) is striking. Even walking in a boot (0.7–1.5× BW) generates several times more Achilles tendon force than stationary cycling. This is the biomechanical basis for cycling being introduced as a fitness maintenance tool during the boot phase in many published protocols.

Squats and deadlifts are more variable than they appear

The range of force in squat variants is wide because ankle dorsiflexion during the movement is the primary driver. A shallow squat with heels raised generates far less Achilles load than a deep squat barefoot. A conventional deadlift with the ankle close to neutral generates less Achilles force than a front squat with a forward shin. Heel elevation — whether through shoes with a drop, a wedge, or a heel raise — is a practical tool for reducing Achilles demand in strength training during recovery.

Hopping generates more force than jumping

Single-leg hopping on the spot generates higher peak Achilles forces than a maximal vertical jump. This is because hopping involves a rapid stretch-shortening cycle with a very short ground contact time, loading the tendon quickly and repeatedly. It is why hop tests appear late in return-to-sport criteria — they are genuinely high-demand tasks, not just coordination challenges.

Sprinting is the ceiling

Maximal sprinting places the greatest demands on the Achilles tendon of any common human movement. Forces approach or exceed the normal tendon's reported tolerance in some estimates. It is not a coincidence that Achilles ruptures occur most commonly during explosive push-off movements — the tendon is operating near its structural limit at those moments.

Important Context

The Achilles tendon in a healthy athlete has been adapted to tolerate these forces over years of progressive loading. A repaired or recently healed tendon has not. The forces in this table tell you what a normal tendon experiences — not what your healing tendon is ready for. Rehabilitation protocols manage the gap between current tolerance and the demands of the activity you want to return to. That process takes months to years, not weeks.

References

Force values are drawn from peer-reviewed studies. Methods vary — some use direct in vivo tendon transducers, others use inverse dynamics from force plate and motion capture data, and others use musculoskeletal models or tensiometry. Where ranges are reported in the literature, the table reflects those ranges. Values for cycling in a boot are estimated from cycling biomechanics literature, as direct transducer measurements in this condition are not available.

Demangeot Y, Whiteley R, Gremeaux V, Degache F. The load borne by the Achilles tendon during exercise: A systematic review of normative values. Scandinavian Journal of Medicine & Science in Sports. 2022;33(2):110–126. PubMed 36278501 — Key systematic review reporting AT load 2.7–3.95× BW walking, 4.15–7.71× BW running, 0.41–7.3× BW for strengthening exercises.
Jozwiak M et al. Quantifying mechanical loading and elastic strain energy of the human Achilles tendon during walking and running. Scientific Reports. 2021;11:5971. PMC7955091 — In vivo AT force ~2.63 kN walking, 3.06–4.64 kN running at 2.5–3.5 m/s; tendon strain 4.0–4.9%.
Fukashiro S, Komi PV, Järvinen M, Miyashita M. In vivo Achilles tendon loading during jumping in humans. European Journal of Applied Physiology. 1995;71:453–458. PubMed 8565978 — Buckle transducer: peak AT force 2,233 N squat jump, 1,895 N CMJ, 3,787 N hopping (75 kg subject).
Lichtwark GA, Wilson AM. In vivo mechanical properties of the human Achilles tendon during one-legged hopping. Journal of Experimental Biology. 2005;208:4715–4725. — Peak AT forces during single-limb hopping 3,500–4,000 N; tendon strain 8.3% mean during hop. Referenced via PMC5343533.
Fourchet F et al. Achilles tendon forces and pain during common rehabilitation exercises in male runners with Achilles tendinopathy. Physical Therapy in Sport. 2023. ScienceDirect — AT load exercise progression 1.1–6.4× BW across common rehabilitation exercises including heel raise variants and SSC activities.
Baxter JR, Corrigan P, Hullfish TJ et al. Exercise Progression to Incrementally Load the Achilles Tendon. Medicine & Science in Sports & Exercise. 2021;53(5):968–974. — Established progressive exercise framework for AT loading; noted running can place up to 12× BW on the AT; documented that walking and running exceed many therapeutic exercises in peak load.
Baxter JR, Hullfish TJ, Farber DC, Humbyrd CJ. Achilles Tendon Loading During Walking Differs Between Commonly Used Immobilizing Boots. Foot & Ankle Orthopaedics. 2022;7(2). PMC9661566 — Boot reduces AT load 60–77% vs normal shoes; boot type and ankle angle are primary determinants.
Ericson MO, Nisell R, Arborelius UP, Ekholm J. On the biomechanics of cycling. Scandinavian Journal of Rehabilitation Medicine. 1985;17(4):187–94. PubMed 3468609 — AT tensile force and talocrural joint compressive force during cycling substantially lower than during level walking.
Bitterman A et al. Rehabilitation and Return to Sports after Achilles Tendon Repair. International Journal of Sports Physical Therapy. 2024. PMC11379499 — Normal AT can withstand up to 7× BW; running 6–8× BW cited as approaching tendon load tolerance; exercise progression framework referenced.
Shalabi A et al. (BMC Musculoskeletal Disorders, 2019). Achilles tendon force approximately 6–8× BW during running; cited in context of Achilles tendinopathy and orthotic effect on tendon load. BMC MSD