Quick Answer
Most important insight: the soleus (bent-knee exercises) produces more force during running than the gastrocnemius and predicts Achilles injury when weak. Key distinction: straight knee = gastrocnemius; bent knee = soleus. Priority exercise: single-leg bent-knee calf raise. For Achilles: eccentric heel drop + isometric holds. Frequency: 2 sessions/week, 20–25 minutes.
The Two Calf Muscles — and Why Runners Need to Know the Difference
The calf consists of two muscles that work together but have meaningfully different anatomy and function:
The gastrocnemius is the muscle you see — the one that gives the calf its shape. It has two heads that attach above the knee, then merge with the soleus to form the Achilles tendon at the heel. Because it crosses the knee, it works most effectively when the knee is straight. It contributes to explosive, powerful movements — sprinting, jumping, rapid acceleration.
The soleus lies beneath the gastrocnemius. It doesn’t cross the knee — it attaches below the knee and runs to the heel via the Achilles. This is the critical point for runners: because the knee is never fully extended during running (maintaining approximately 15 degrees of flexion throughout midstance), the soleus — not the gastrocnemius — is the dominant force producer throughout the running gait cycle.
The numbers are striking. Research by Dorn et al. (2012) found that at typical running speeds below 7 m/s (25 km/h), the soleus produces approximately 8.71 times bodyweight of force, while the gastrocnemius produces approximately 3.23 times bodyweight. The soleus also has 50% more muscle mass than the gastrocnemius. Research published in Physical Therapy in Sport (O’Neill et al. 2019) identified soleus weakness as the single best predictor of non-insertional Achilles tendinopathy in runners.
The practical implication: standard standing calf raises (straight knee) primarily train the gastrocnemius. Bent-knee calf raises — seated or standing with a bent knee — target the soleus. Most runners do only straight-knee raises and under-train the muscle that matters most for their sport. A complete programme includes both.
How the Calf Actually Works During Running
The common mental model of calf function in running — that the calf pushes off at toe-off like a calf raise — is misleading. Runners Connect’s analysis of the research puts it clearly: the calf is most active as the foot contacts the ground and begins to generate hip extension to propel the body forward, not primarily when you push off.
More accurately: as the foot contacts the ground, the calf complex (gastrocnemius and soleus) and Achilles tendon act eccentrically — absorbing and storing energy as the ankle dorsiflexes (foot tilts upward relative to the leg). This stored elastic energy is then returned during the propulsive phase. The tendon functions like a spring. The calf’s strength determines how much energy the spring can store and how efficiently it returns — which is why calf strength directly affects running economy and why weak calves increase the load on the tendon itself.
Because this storage-and-return cycle depends on the interaction between calf muscle fibres and tendon fibres, research from Handsfield et al. specifically identified interfascicular sliding — the movement of tendon fibres against each other — as the key mechanism in both tendon health and rehabilitation. The bent-knee heel drop produced the greatest interfascicular sliding with the least tendon stress of all exercises studied, making it particularly valuable for both prevention and early rehabilitation of Achilles issues.
This calf spring mechanism connects directly to running cadence and form. A well-functioning calf complex with adequate elastic recoil contributes to the quick, light foot contact that characterises efficient running. Our running technique guide covers how cadence and foot contact time relate to running economy — the calf’s elastic storage capacity is one of the mechanisms underlying the efficiency advantage of higher cadence.
The 8 Exercises: Four Loading Types
Calf training for runners is most effective when it covers four types of loading, each serving a different purpose. Isometric (static hold) reduces pain and builds initial tendon strength. Eccentric (controlled lowering) builds tendon structure and is the primary rehabilitation exercise. Concentric (raising) builds muscle strength. Plyometric (bouncing/hopping) builds the elastic power that translates to faster running.
| Exercise | Type | Knee position | Primary target | Sets × Reps | Priority |
|---|---|---|---|---|---|
| 1. Single-leg bent-knee calf raise | Concentric + eccentric | Bent (~30°) | Soleus | 3 × 10–15 | ✓ Highest |
| 2. Eccentric heel drop (single-leg) | Eccentric | Straight | Gastrocnemius + Achilles tendon | 3 × 10–15 slow | ✓ Highest |
| 3. Eccentric heel drop (bent knee) | Eccentric | Bent (~30°) | Soleus + Achilles tendon | 3 × 10–15 slow | ✓ High |
| 4. Standing single-leg calf raise | Concentric + eccentric | Straight | Gastrocnemius | 3 × 15–20 | ✓ High |
| 5. Isometric calf hold (wall) | Isometric | Straight or bent | Gastroc / soleus | 3 × 30–45 sec | ✓ High (Achilles pain) |
| 6. Seated calf raise (heavy) | Concentric + eccentric | Bent (~90°) | Soleus (isolated) | 3 × 12–15 heavy | ✓ High |
| 7. Tiptoe walk | Dynamic concentric | Variable | Full calf complex + proprioception | 3 × 20–30m | Medium |
| 8. Single-leg hop/jump rope | Plyometric | Slight bend | Elastic calf power | 3 × 20–30 contacts | High — for speed |
The Exercises in Detail
1. Single-Leg Bent-Knee Calf Raise
This is the highest-priority calf exercise for runners based on current research. The bent knee removes the gastrocnemius’s contribution (because it can’t work effectively with a bent knee) and isolates the soleus — the muscle that produces the most force during running and whose weakness best predicts Achilles injury. The single-leg loading is sufficient challenge for most runners without additional weight, though a dumbbell or loaded backpack can be used for progression.
How to do it: stand on one foot with the knee bent to approximately 25–35 degrees — think of a very slight squat position, not a deep bend. Hold a wall for balance if needed. Raise the heel as high as comfortable, hold 1 second at the top, lower slowly over 3 seconds. Lowering slowly is important — the eccentric component of this exercise provides much of the training stimulus. 10–15 reps each leg, 3 sets.
Key cue: the knee bend must be maintained throughout the movement — don’t straighten the knee as you rise. If you straighten, the gastrocnemius takes over and the soleus loses its targeted stimulus. A 25–30 degree bend maintained from start to finish is the goal.
Progression: hold a dumbbell in the opposite hand to the working leg, or use a weighted backpack. Progress weekly by adding load rather than reps once 15 controlled reps become manageable.
2. Eccentric Heel Drop — Straight Leg
The eccentric heel drop is the most researched calf exercise in the literature, forming the basis of the Alfredson protocol for Achilles tendinopathy. The eccentric phase — the controlled lowering — is the primary therapeutic and strengthening stimulus for the tendon. Research by Beyer et al. (2015) found heavy slow resistance training equally effective to eccentric training for Achilles tendinopathy, which validates the eccentric heel drop as one of the most evidence-backed exercises available for calf health.
How to do it: stand on a step with the ball of the foot on the edge and the heel hanging off. Use both legs to raise up onto the toes, then transfer weight to the single working leg and lower the heel slowly (3–5 seconds) until it is below the level of the step. Raise back up using both legs to reset. The lowering phase is the important part — it should be slow and controlled, not dropped. 10–15 reps each leg, 3 sets.
3. Eccentric Heel Drop — Bent Knee
The bent-knee version of the eccentric heel drop specifically targets the soleus through the eccentric loading that research has shown produces the greatest interfascicular tendon sliding (Handsfield et al.). It’s the exercise that Fairfield Podiatry specifically recommends as the most important calf exercise for runners, complementing the straight-leg version which prioritises the gastrocnemius.
How to do it: identical set-up to the straight-leg version — ball of foot on a step edge — but with the working knee bent to approximately 30 degrees throughout the movement. Rise using both legs, then lower slowly on one leg while maintaining the knee bend. 3–5 second lowering phase. 10–15 reps each leg, 3 sets.
Why the slow lower matters: the collagen remodelling that makes tendons stronger and more resilient happens in response to the mechanical stress of eccentric loading. Fast, uncontrolled lowering provides far less stimulus than a slow, deliberate 4-second descent. The research specifically on heavy slow resistance for tendinopathy (Beyer et al. 2015) demonstrates that load and control are what matter — not speed.
4. Standing Single-Leg Calf Raise (Straight Leg)
The standard single-leg calf raise with a straight knee targets the gastrocnemius and provides the concentric strength complement to the eccentric heel drop. Both the concentric (raising) and eccentric (lowering) phases are valuable, though the lowering should be deliberately slow. This is the most accessible calf exercise — requires only a wall for balance and produces significant gastrocnemius strength with bodyweight alone for most runners.
How to do it: stand on one leg, hand touching a wall for light balance support. Rise on the toes as high as possible, hold 1 second, lower slowly over 3 seconds. Keep the knee straight throughout — the moment the knee bends, the exercise shifts to a bent-knee variation. 15–20 reps, 3 sets. Progress by holding a dumbbell or wearing a loaded backpack.
5. Isometric Calf Hold
Isometric exercises — sustained contractions without joint movement — are the most appropriate first step for runners with active Achilles pain. The Run Rx’s clinical framework for Achilles tendinopathy rehabilitation specifically begins with isometrics before progressing to concentric/eccentric work, because isometric loading builds tendon strength and reduces pain without the movement that aggravates acutely inflamed tissue.
How to do it: stand facing a wall, ball of foot on the floor, lean forward so the wall supports you. Transfer all weight to one foot and rise onto the toes. Hold for 30–45 seconds — the burn is the point. Return, rest 2 minutes, repeat. For the soleus-specific version, add a 30-degree knee bend and hold the same position. 3 holds each leg.
Frequency note: isometric holds can be performed daily as part of pain management for Achilles issues — unlike dynamic exercises, daily isometric work does not overstress healing tissue and provides consistent tendon loading stimulus.
6. Seated Calf Raise (Heavy)
The seated calf raise with the knee at approximately 90 degrees is the most isolated soleus exercise available. At this knee angle, the gastrocnemius is almost entirely unloaded, and the soleus must do all the work. Fairfield Podiatry specifically recommends heavy seated calf raises as the best way to target soleus strength for runners who have gym access. The “heavy” is important — the soleus responds best to significant load, not light high-rep work.
How to do it: sit on a bench or chair with knees bent at approximately 90 degrees. Place a dumbbell or weight across the thighs near the knees. Rise onto the toes, hold 1 second at the top, lower over 3 seconds. Use a weight that makes 12–15 reps genuinely challenging by the final set. For home use without a dedicated machine, a dumbbell held across the thigh while seated on a chair achieves the same stimulus.
7. Tiptoe Walk
Tiptoe walking — sustained walking on the balls of the feet — provides dynamic calf loading through a running-specific stance pattern while also developing proprioception and ankle stability. The Run Rx includes it in their Achilles rehabilitation progression as a dynamic exercise that challenges the calf in a single-leg loading pattern similar to running without the impact forces.
How to do it: rise onto the toes and walk forward in small, controlled steps without allowing the heels to touch the ground. Keep an upright posture — don’t lean forward or let the torso drop. 20–30 metres, 3 sets. Progress by carrying light weights (dumbbells at sides) or wearing a weighted vest. Can be done anywhere — outside before a run as part of a warm-up, or in a corridor at home.
8. Single-Leg Hops / Jump Rope
Plyometric exercises — single-leg hops, jump rope, small bouncing jumps — train the elastic power of the calf spring. This is the loading type closest to actual running mechanics, where the calf and Achilles store and return elastic energy rapidly with each stride. It’s the final progression in calf training and the one most directly connected to running speed and economy. The Run Rx includes plyometrics as an essential piece of performance training once the tendon tolerates load.
How to do it: begin with two-leg small bounces, progressing to single-leg hops in place (quick, light contact with the ground — the heel should barely touch down), progressing to forward hops and eventually jump rope. The key quality: the contact time should be short and the rebound quick, training the reactive stiffness of the calf-Achilles spring. Start with 20 contacts per set, rest 60–90 seconds between sets, 3 sets. Only progress to this stage once eccentric and concentric work is pain-free. Our speed work guide covers how this elastic calf power transfers into strides and interval training — the calf’s plyometric capacity is one of the mechanisms underlying running economy at faster paces.
How to Fit Calf Work Into Your Training Week
Two sessions per week — 20–25 minutes each — placed on easy run or rest days. Avoid calf strength sessions the day before long runs or intervals, where pre-fatigued calves produce worse running mechanics and higher injury risk. Combine with our hip strengthening programme for a complete lower-body durability routine that addresses both the primary drivers of running performance (hips) and the primary site of running tendon injury (calves and Achilles).
A practical two-session week for a runner training 4–5 days:
Session A: isometric calf hold (warm-up, 2 holds each leg) → single-leg bent-knee raise (3 sets each leg) → eccentric heel drop straight (3 sets each leg) → tiptoe walk (3 sets). Total: ~20 minutes.
Session B: seated calf raise heavy (3 sets) → eccentric heel drop bent (3 sets each leg) → standing single-leg raise (3 sets each leg) → single-leg hops (3 sets — only when ready). Total: ~22 minutes.
For runners currently experiencing Achilles tenderness, start with Session A only, prioritise the isometric holds, and omit the plyometric work entirely until pain-free. True strengthening adaptations in muscle tissue take 6–8 weeks; tendon remodelling takes 3 or more months. Patience and consistency matter more than intensity in the first weeks. Our guide on building marathon mileage safely covers the broader principle of connective tissue adaptation lag — the same patience required for mileage increases applies to calf and tendon rehabilitation.
Barefoot running and minimalist shoe training dramatically increase calf and Achilles loading — the reduced cushioning shifts more impact absorption to the calf-Achilles spring. Our barefoot running guide covers the specific transition protocol that prevents the calf and Achilles overload that sidelines most runners who switch too quickly. Building calf strength before transitioning — not after problems develop — is the right order.
For older runners, the Achilles tendon changes its structure with age, becoming less mobile and losing some elastic properties. The Run Rx notes that eccentric exercises can prevent and partially reverse this decline. Our guide for older athletes covers how maintaining plyometric and eccentric calf work becomes increasingly important with age — the elastic spring of the calf-Achilles complex is one of the first systems to decline without specific training. Our warm-up and cool-down guide covers the calf stretches that pair with this strength programme — static calf stretches post-run are the appropriate complement to calf strength work, not a replacement for it.
Build Calves That Last the Distance
SportCoaching's running plans include calf strength, hip work, and progressive mileage in one coordinated programme — so your lower legs develop the strength and tendon resilience to handle your running volume without the injuries that accumulate when strength work is an afterthought.
FAQ: Calf Exercises for Runners
Why is the soleus more important than the gastrocnemius for runners?
During running, the knee maintains ~15° of flexion at midstance, which limits gastrocnemius function. The soleus — which doesn’t cross the knee — produces 8.71× bodyweight force during running vs 3.23× for the gastrocnemius (Dorn et al. 2012). It also has 50% more muscle mass. O’Neill et al. 2019 identified soleus weakness as the single best predictor of non-insertional Achilles injury. Train it with bent-knee exercises.
What is the best calf exercise for runners?
Single-leg bent-knee calf raise for soleus-dominant strength. Eccentric heel drop (straight leg) for gastrocnemius and tendon structure. Together these cover the most critical calf functions for running performance and Achilles health.
How do calf exercises prevent Achilles tendinopathy?
The Achilles experiences 8–12.5× bodyweight per step. Strong calves absorb this load; weak calves let the tendon take it. Eccentric and bent-knee exercises stimulate collagen remodelling in the tendon. Beyer et al. 2015 found heavy slow resistance equally effective to eccentric training for Achilles tendinopathy.
How often should runners do calf exercises?
Two sessions per week on easy/rest days, 20–25 minutes. For active Achilles pain, add daily isometric holds (30–45 seconds each leg). Strength adaptations take 6–8 weeks; tendon remodelling takes 3+ months.
Should runners do calf raises with bent or straight knees?
Both. Straight knee = gastrocnemius dominant. Bent knee = soleus dominant (more important for running). Most runners only do straight-knee raises and under-train the soleus. A complete programme includes both.
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