How to Progress Calf Raises for Achilles Tendinopathy

"Do some calf raises" is probably the most common piece of advice people with Achilles tendinopathy receive. And it's not wrong — calf loading is the cornerstone of Achilles rehabilitation. But the advice usually stops there, and that's where the problem starts.

Which calf raises? How many? With how much weight? On a flat surface or off a step? Two legs or one? And how do you know when to make it harder?

Without answers to those questions, most people either do too little (gentle bilateral raises that don't provide enough stimulus) or too much (jumping to aggressive single-leg loading before the tendon is ready). Neither works well. Here's the complete progression — four phases, with the reasoning behind each one.

Why the progression matters

Tendon adaptation is dose-dependent and time-dependent. The tendon responds to mechanical load by gradually remodelling its collagen structure — but this process is slow, and it requires the right load at the right time. Too little load produces too little adaptation stimulus. Too much load exceeds the tendon's current capacity and drives inflammation and pain.

The four-phase progression is designed to start within the tendon's current tolerance and build load systematically over weeks, so that adaptation keeps pace with demand. Each phase builds the foundation for the next.

Phase 1: Isometrics (Weeks 1–2)

Isometric calf loading means contracting the calf muscle against a fixed resistance without movement — essentially holding a calf raise at a mid-range position. You push, but nothing moves.

Why start here: Isometrics provide two things that matter at the start of rehab. First, they produce analgesic effects — sustained isometric contractions appear to reduce tendon pain, likely through a cortical inhibition mechanism. This means you can often do isometrics with minimal pain even when other loading aggravates things. Second, they begin creating the mechanical signal the tendon needs to start adapting, without the reactive risk that comes from full-range movement loading.

How to do it: Stand with both feet flat on the floor. Rise up onto your toes, and hold. Start with both legs for 30–45 seconds per hold, 4–5 repetitions, with 2 minutes rest between holds. Aim for 4–6 sessions per week. Pain during isometrics should be manageable — 3–4/10 is acceptable. Pain that persists or worsens after the holds suggests you're working too hard.

When to progress: When your baseline pain is consistently low (0–2/10) and isometric holds produce minimal discomfort, you're ready for Phase 2. This typically takes 1–2 weeks.

Phase 2: Bilateral heel raises (Weeks 2–4)

Bilateral heel raises — two feet, full range, slow and controlled — are the bridge between isometrics and the more demanding single-leg work ahead.

Why this phase: Full-range loading introduces the concentric and eccentric components that isometrics lack, while keeping the total load manageable by distributing it between both limbs. The Achilles is still doing significant work, but at roughly half the load of a single-leg raise.

How to do it: Stand on a flat surface with feet hip-width apart. Rise slowly onto the balls of your feet (3 seconds up), hold briefly at the top, and lower slowly (3 seconds down). Start with 3 sets of 15 reps. If this is easy, move to the edge of a step and allow the heels to drop below step height on the way down for a greater range of motion. Progress to 3 sets of 20–25 reps before moving on.

Pain monitoring: Keep pain at or below 3–4/10 during the exercise. Check morning stiffness the next day — it should be the same or better than your baseline.

When to progress: When 3 × 20–25 bilateral raises are pain-free or nearly pain-free, and morning stiffness is well-controlled. Typically 2–3 weeks into the program.

Phase 3: Single-leg loading (Weeks 4–8)

Single-leg calf raises are the central phase of Achilles rehabilitation. This is where the most significant tendon adaptation happens — and where most people rush or skip steps.

"The jump from bilateral to single-leg loading roughly doubles the load through the Achilles. For a reactive tendon, this transition needs to be gradual and monitored carefully."

Why this phase matters so much: Single-leg loading replicates the demands placed on the Achilles during normal walking, running, and sport. You can't get to full return-to-activity without being able to load the tendon under single-limb conditions. But the load is substantial — a single-leg heel raise places approximately 2–3× bodyweight through the Achilles at the end of range.

How to do it: Progress through these levels, spending 1–2 weeks at each:

• Level 1: Single-leg raises on a flat surface, using fingertips on a wall for balance (not support). 3 × 10–15 reps.
• Level 2: Single-leg raises off the edge of a step (heel-drop range). 3 × 10–15 reps. The eccentric (downward) phase is particularly important here — lower slowly.
• Level 3: Single-leg raises off a step, increasing to 3 × 20–25 reps. When 3 × 25 is achievable with good control and minimal symptoms, you've built the foundation for Phase 4.

A common mistake: Using the arms and the other leg to assist. If you're pushing off the wall or hovering the other foot as a safety net, you're reducing the load through the working leg and slowing adaptation. Challenge the tendon fully — with appropriate pain monitoring as your guide.

Phase 4: Heavy slow resistance (Weeks 6–12)

Phase 4 adds external load to make single-leg calf raises genuinely challenging in the 8–12 repetition range. This is what heavy slow resistance (HSR) means in practice.

Why external load: As the tendon adapts to bodyweight single-leg loading, bodyweight alone stops providing sufficient stimulus for further adaptation. To keep driving collagen remodelling, you need to increase the load. External load — a weighted backpack, a gym machine, a barbell — allows you to do that progressively.

How to do it: Start with a load that makes 8–10 single-leg raises difficult but achievable with good form. Perform 3–4 sets with 90–120 seconds rest between sets. Sessions every 48 hours — the tendon needs recovery time between heavy loading sessions. Increase load by 2–5% when 3 × 12 becomes comfortable.

The tempo still matters: Even with added load, keep the controlled 3-second up / 3-second down pace. Fast or bouncy reps shift the load pattern toward elastic energy storage, which is a different stimulus. The value of HSR comes specifically from slow, sustained mechanical loading.

When to introduce it: Phase 4 overlaps with Phase 3 — you don't need to complete all of Phase 3 before starting to add load. Once single-leg raises off a step are well tolerated, begin introducing external resistance.

How to know when you're progressing correctly

Three checks at each phase:

• Pain during exercise: Acceptable up to 3–4/10. Above that, reduce volume or load before the next session.
• Pain after exercise: Should settle within 30 minutes of finishing. If it lingers for hours, the session was too demanding.
• Morning stiffness the next day: Should be the same or better than your baseline. A significant increase means yesterday's load was too high.

If all three are in the acceptable range, you're progressing well. If any one of them is consistently outside range, something about the load needs to adjust before moving forward.

Getting the full picture

The calf raise progression is the core of Achilles rehab — but it works best when it's embedded in a proper program with pain monitoring, load management, and clear return-to-activity criteria built in. The 12-week Achilles program covers all four phases in detail, with downloadable exercise cards for each phase and a load tracking log for Phase 4. It's built around the same progression described here, with the pain monitoring framework integrated throughout.

If you're not sure where to start in the progression, or your tendon keeps reacting despite a good-faith effort, a session with me can help identify what's driving the symptoms and get the load calibrated correctly.