The last thing that happens in every step you take is a push from the calf. The heel lifts, the ankle levers the body forward, and two muscles you rarely think about do most of the work. So the calf raise benefits that matter most are not about looks: this is the exercise that trains the engine of walking, stairs, and running, which is why it appears in so many rehab programs.
Which muscles do calf raises work?
A calf raise trains the two muscles that share the Achilles tendon. The gastrocnemius is the visible one; it crosses both the knee and the ankle and supplies much of the power for push-off and jumping. Beneath it sits the soleus, a flat, deep muscle that crosses only the ankle and does a large share of the quiet work of standing and slow walking. Because both pull on the heel through the same tendon, calf strengthening and Achilles rehab are closely intertwined.
That strength shows up in how people move. In a 2026 study in Frontiers in Aging, researchers tested 51 active adults with an average age of 78 and found that maximal plantar flexion strength, the calf's action, was significantly correlated with both normal and maximal walking speed. Weak calves are not the only reason walking slows with age, but the link is strong enough that clinicians treat calf strength as a mobility issue.
Knee straight or knee bent: why it changes the target
The gastrocnemius crosses the knee, so bending the knee puts it on slack and takes it partly out of the movement. A straight-knee calf raise therefore biases the gastrocnemius, while a bent-knee calf raise, done seated or standing with the knees softly bent, shifts more of the load to the soleus. Programs often include both on purpose: the two muscles share one tendon but adapt to training somewhat separately.
Eccentric heel drops and the Achilles: a short history
In 1998, the Swedish physician Håkan Alfredson described a program for stubborn midportion Achilles tendon pain built around lowering rather than lifting: rise onto the toes using mostly the healthy leg, then lower slowly on the sore side over the edge of a step. A 2017 paper in BMC Musculoskeletal Disorders summarizes the classic dose, three sets of 15 heel drops with the knee straight and again with the knee bent, twice a day for 12 weeks, 180 repetitions daily, and notes there is strong evidence for eccentric exercise therapy in this condition. It is equally frank about the catch: that volume is a burden, and the burden can undermine adherence. In practice the dose is something a physical therapist adapts to the person, not a number to copy from a 1998 protocol.
How many single-leg calf raises is normal?
The standard clinical measure is the single-leg heel-rise test: rise and lower on one leg, through full range at a steady pace, until you cannot continue. In a 2017 study in the journal Physiotherapy, 566 healthy adults aged 20 to 81 performed the test to fatigue while standing on a 10-degree incline. Men completed a median of 24 repetitions and women 21, and in an interesting wrinkle, women over 60 outperformed men of the same age. Treat numbers like these as reference points rather than pass-fail scores; pace, range, and how strictly the test is scored all change the count.
A sensible progression, and the mistakes that stall it
Progress calf work the way you would any strength work: earn the next step by controlling the current one through full range. A common ladder looks like this.
- Double-leg calf raises with fingertips resting on a wall or counter, using the support for balance only, never as a place to lean.
- Free-standing double-leg raises, rising as high as possible and taking two to three seconds to lower.
- Single-leg calf raises, which shift the whole body's weight onto one calf; many clinicians use around three sets of 10 to 15 as a starting convention.
- Eccentric-emphasis work, such as slow lowering or heel drops off a step edge, if your clinician builds them into your plan.
The common mistakes are mirror images of good form. Bouncing out of the bottom uses the tendon's spring instead of the muscle. Partial range, skipping the deep stretch at the bottom or the full rise at the top, quietly shrinks the exercise. And leaning into the countertop makes a single-leg raise far easier than it looks. A slower, fully controlled repetition is worth more than several rushed ones.
Calf raises are generally low-risk, but stop and check in with your physical therapist or clinician if you feel sharp pain in the tendon or heel, notice a sudden snap or giving way, or find that pain and morning stiffness build over days instead of settling. Pain where the tendon meets the heel bone sometimes behaves differently, and lowering below a step edge can aggravate it. If these exercises are part of rehab, let your therapist set the dose; the numbers in the research are context, not a personal prescription.