The Calf Muscle Nobody Talks About: Why Your “Calf Strain” Keeps Coming Back

Josh Hazlewood is one of the most accurate fast bowlers Australia has produced. He is also one of the most frustrated. Over the four years to the start of the 2025/26 summer, Hazlewood missed parts of four of his last six Australian summers, with calf and side strains cited again and again as the cause. The December 2024 Border-Gavaskar Test against India at the Gabba was the most public version of the story: he hurt his right calf in warm-ups, bowled one over on day four, walked off, and was ruled out for the rest of the series. He told reporters the injuries were probably the two things that had kept him out most often over the last four years. Australia faced a Sri Lanka tour shortly after, and he was ruled out again with a recurring calf injury.

Hazlewood is not alone, and the pattern is not a cricket pattern. Patrick Dangerfield, Geelong’s captain and one of the most decorated midfielders of his generation, lost five weeks of the Cats’ 2022 premiership year to a calf strain and then lost large chunks of 2026 to the same calf, including pre-season and early-season recurrences. Jason Taumalolo, North Queensland’s enforcer and the most physically dominant forward of the modern NRL, tore his calf in Round 15 of a recent season, returned, and re-tore it in the warm-up of his comeback game — the textbook recurrence that the calf rehab literature keeps documenting. Michael Hooper, the long-serving Wallabies captain with more than 120 Tests, missed the July 2023 Argentina Test with a calf strain, did not get back, and was left out of the 2023 Rugby World Cup squad by Eddie Jones with the calf cited as the reason. Four codes — cricket, AFL, NRL, Rugby Union — same story, same muscle.

None of these medical teams have publicly broken down which calf muscle was involved in each of these injuries. What we can say with confidence — based on the largest dataset ever assembled of MRI-confirmed calf strains in elite Australian sport — is that when a fast bowler, a footballer or a runner has a “calf strain” that keeps coming back, the muscle involved is overwhelmingly likely to be the soleus, not the more famous gastrocnemius. The Green et al. 2020 AFL Soft Tissue Injury Registry study found that 84.6% of MRI-confirmed calf strains in elite Australian football were soleus injuries. The calf is two muscles, the deep one heals slower, and recurrent calf problems are a soleus story far more often than they are a gastrocnemius story.

If your calf injury has not fully resolved, or has come back, the chances are you have not had a soleus problem managed as a soleus problem. This piece explains what the soleus actually is, why it gets missed, why standard calf rehab undertrains it, and what to do instead.

Your calf is two muscles, not one

When you grab the back of your lower leg and feel the visible muscle bulge, you are mostly holding the gastrocnemius. It is the showy one — the surface muscle that gives the calf its shape, the one that fires hard when you sprint and jump.

Underneath it, deeper, broader, and much less visible, is the soleus. It does not have an obvious shape on the surface. You cannot point to it in the mirror. It is not the muscle people think of when they think of “the calf”. And it is the muscle that does the majority of the work during walking, jogging, easy running, and any time you are upright and weight-bearing for long stretches.

Two facts about the soleus matter for any athlete who has had a calf injury.

The first is that it does most of the load-bearing work in the calf for the activities you do every day. When you walk, the soleus generates most of the force across the Achilles tendon. When you run at easy or moderate pace, the soleus is still the dominant force-producer. The gastrocnemius takes over more of the load only at higher running speeds. This is why a calf injury that feels fine when you walk can blow up when you try to run — the load profile shifts as you speed up, and the muscle that bears most of the load in your training pace is the soleus.

The second is that the soleus is built for endurance, not for short bursts. Its fibre composition is roughly 70–80% slow-twitch — the highest of any major muscle in the leg. It is, biologically, a postural muscle. It is on, quietly, all the time. This matters for rehab, because muscles like the soleus do not respond well to short, heavy sets of exercise. They respond to volume — high repetitions, sustained loading, time under tension. Most calf rehab does not give them that.

Why soleus injuries get missed

The soleus injury is a quiet injury compared to the dramatic gastrocnemius tear. Gastrocnemius strains usually announce themselves with a sudden sharp pain, sometimes a snap, often during a sprint or a jump. The athlete pulls up. The injury is obvious.

A soleus strain is often a deep ache that builds. The athlete feels it during running but can walk fine. The pain is in the middle of the calf, deeper, harder to point to. There is sometimes no clear single-moment-it-happened. Imaging is harder — ultrasound struggles with the deep, complex layered structure of the soleus, and you need MRI to see it properly. And because the gastrocnemius is the famous calf muscle, the default story most clinicians reach for is gastrocnemius strain — particularly if they did not test bent-knee plantarflexion strength or palpate deep in the mid-calf.

The result is a familiar pattern. The athlete is told they have a low-grade calf strain. They are given exercises — usually some version of straight-knee heel raises off a step. They feel fine within a few weeks. They return to running. The pain comes back. Lather, rinse, repeat. The Australian La Trobe Sport and Exercise Medicine Research Centre group — Dr Tania Pizzari and Brady Green — have spent years studying this exact pattern in elite AFL players and have published widely on the recurrence problem. One of their public-facing statements on the Physical Performance Show podcast: “don’t neglect your calfs”, and the practical advice that calf rehab needs to deliberately target both the gastrocnemius and the soleus, with the right exercise for each.

Why standard calf rehab undertrains the soleus

The straight-knee heel raise is the exercise most calf injuries get rehabbed with. Off a step, slow eccentric lower, two or three sets of fifteen, both sides. It is in every protocol. It is what your physio probably gave you.

The straight-knee heel raise loads the gastrocnemius preferentially. That is what the straight-knee position does — it lengthens the gastrocnemius (which crosses both the knee and the ankle) and recruits it as the dominant muscle. The soleus does some of the work, but it is not the muscle being trained.

To target the soleus, the knee needs to be bent. Bent-knee calf raises — done seated with weight on the thigh, or standing with the knee flexed to around 60–90 degrees — slacken the gastrocnemius and force the soleus to take the load. This is well-established in the rehabilitation literature and increasingly in the running and physiotherapy community.

Two implications.

First, if you have done weeks of straight-knee heel raises after a calf injury and you are still breaking down when you run, the soleus is probably still weak — because you have not actually trained it.

Second, the soleus needs high-repetition loading to respond. Three sets of fifteen will not get there. Most rehabilitation protocols built around the soleus now aim for 25 or more bent-knee calf raises per set, often progressed to weighted versions, and built up over weeks. The benchmark Tania Pizzari and Brady Green flagged on the Physical Performance Show — 25 single-leg calf raises per side — is in the right ballpark.

What not to do

The most common mistake is returning to running when your calf “feels fine” walking. The soleus only fully reveals itself in propulsive loading. You can walk pain-free for a week, jog for ten minutes, and re-injure on minute eleven. Pain-free walking is not a return-to-run criterion. Pain-free bent-knee calf raises at full volume on both sides, plus a graded build through jogging, are.

The other mistake is treating recurrence as bad luck. If you have had two or more “calf strains” in two years, the most likely explanation is that the original injury was not fully resolved — almost certainly a soleus problem that was managed as a generic calf strain.

When to see a doctor urgently: a sudden snap with severe pain, an inability to push off through the foot, a visible bruise or deformity, or any suspicion of an Achilles tendon rupture. These need imaging and assessment quickly.

A realistic timeline

Honest numbers. A low-grade gastrocnemius strain in a recreational runner is typically 2–6 weeks back to running. A soleus strain is slower. Most low-grade soleus strains take 6–10 weeks to return to running and 8–14 weeks to return to full training load without symptoms. Higher-grade or central-tendon injuries take longer. The Pedret cohort of athletes showed central aponeurotic soleus injuries averaging 44 days return to play, more than twice the lateral aponeurotic injuries at 19 days. These are elite athletes with full-time rehab teams. For most people, longer.

The strongest predictor of reinjury, across the evidence, is returning too soon. If your sport is going to be there in twelve weeks anyway, it is going to be there in fourteen.

The Sleeve — the tool for the soleus problem

Most of what this article has described is rehab. Bent knees. Volume. Patience for the timeline the soleus actually heals on. That is the work, and there is no shortcut for it. But there is a piece the standard rehab plan tends to ignore, and it is the reason so many soleus injuries never fully clear.

The piece is your daily walking load.

The soleus is the dominant force-producer at the Achilles during walking, and its peak output comes during the late stance phase — the moment your weight rolls forward over the front of your foot and you push off. Every step you take loads the soleus. A typical day involves several thousand of them. You can do your bent-knee calf raises perfectly in clinic three times a week and still spend the other six and a half days putting low-grade, high-volume load through a muscle that has not finished healing. That is the gap that explains why so many calf injuries plateau at “almost better” and never quite resolve.

The Orthopaedic Sleeve is designed to close that gap. It sits below the knee and offloads the calf during walking and standing. The University of Queensland’s June 2025 biomechanical evaluation tested the device on real walking gait and measured the calf muscle activity directly with EMG. The headline number: an individual peak reduction of 20.4% in soleus EMG during the late stance phase of walking (UQ Final Report §3.2.5). That is the exact phase of gait, and the exact muscle, that a soleus injury cannot tolerate being re-loaded in. The same report also documented a group-significant 32% reduction in medial gastrocnemius activity during standing balance, and individual peak reductions of 47.8% in lateral gastrocnemius and 21.9% in medial gastrocnemius during late-stance walking.

The honest framing: the Sleeve is not a treatment for the underlying injury and it is not a substitute for bent-knee calf raises, the longer rehab timeline, or the gradual return to running. What it is is the tool that takes the daily ambulatory load off the deep calf so the healing tissue can actually finish healing. If your calf injury has not fully resolved, the soleus is probably part of the story — and the Sleeve is the offload that gives the rehab a chance to land.

The soleus is the calf muscle nobody talks about. It is also the calf muscle that fails most often, takes longest to heal, and reinjures most readily. If your calf has been giving you trouble for months, the most likely answer is that you have a soleus problem that has been treated as a gastrocnemius problem. The fix is not new technology. It is the right exercise — bent knees — for long enough, with patience for the timeline the soleus actually heals on.

Sources and further reading

• Hazlewood injury reporting: ESPNcricinfo and cricket.com.au coverage of the 2024 Border-Gavaskar Trophy and 2025 Sri Lanka tour.
• Dangerfield calf injury reporting: ESPN AFL, AFL.com.au and Geelong Cats club statements (2022 mid-season calf, 2026 pre-season and early-season recurrences).
• Taumalolo calf injury reporting: Zero Tackle, NRL.com casualty ward, Stuff (NZ) coverage of recurrent calf strain and re-injury in return-game warm-up, North Queensland Cowboys.
• Hooper calf injury reporting: ESPN Rugby (July 2023 Pumas Test), Rugby Pass and Planet Rugby coverage of the 2023 Rugby World Cup squad omission with calf injury cited.
• Green B, Lin M, et al. Return to play and recurrence after calf muscle strain injuries in elite Australian Football Players. Am J Sports Med. 2020.
• Pedret C, Rodas G, et al. Return to play after soleus muscle injuries. Orthop J Sports Med. 2015.
• Green B, Pizzari T. Calf muscle strain injuries in sport: a systematic review of risk factors for injury. Br J Sports Med. 2017.
• Pizzari T, Green B. Calf strain rehabilitation. The Physical Performance Show, Episode 276 (Pogo Physio, La Trobe Sport and Exercise Medicine Research Centre).
• University of Queensland. Biomechanical Evaluation of the Orthopaedic Sleeve, Final Report. June 2025, §3.2.5.