Calf Injuries: An Anatomy-Based Approach to Diagnosis, Management and Return to Sport

Abstract

Purpose of Review

Calf muscle injuries are common in athletes but represent a heterogeneous group of lesions involving different muscles and myoconnective structures. This review provides a practical overview of gastrocnemius–soleus injuries, with particular emphasis on how anatomical characterization can contribute to diagnosis, management and return-to-sport decision-making. It also examines the limitations of current evidence and the extent to which increasingly detailed imaging findings translate into clinically meaningful information.

Recent Findings

Advances in ultrasound and magnetic resonance imaging have improved the identification of specific injury patterns involving the gastrocnemius and soleus. Recent studies support moving beyond a muscle-based diagnosis towards more precise characterisation of the myoconnective structures involved. However, evidence linking individual anatomical patterns to prognosis and return-to-sport outcomes remains limited and largely observational. Current rehabilitation approaches favour progressive, criteria-based loading rather than fixed timelines, while return-to-sport decisions increasingly integrate clinical recovery, functional capacity, sport-specific demands and acceptable risk. No validated calf-specific rehabilitation or return-to-sport criteria are currently available.

Summary

Anatomical characterization provides a useful framework for understanding the heterogeneity of calf muscle injuries but should inform rather than determine clinical management. Rehabilitation should remain function-led and progressively restore the mechanical capacities required for sport, while return to sport should be considered a multifactorial decision rather than the result of isolated imaging findings, tests or predefined timelines. Future prospective studies should determine which anatomical features provide clinically relevant prognostic information and develop validated calf-specific functional and return-to-sport outcomes.

Introduction

Calf muscle injuries are among the most common muscle injuries in athletes and represent an important cause of time loss from sport. Although many athletes recover uneventfully, these injuries may result in prolonged absence, persistent symptoms and recurrence [1]. Their management remains challenging because clinical recovery and return-to-sport are not always predictable from the initial presentation or imaging findings.

The term calf muscle injury encompasses a heterogeneous spectrum of lesions involving different muscles, anatomical regions and myoconnective structures [2]. Injuries of the medial gastrocnemius and soleus differ in their functional anatomy, injury mechanisms and clinical presentation, while lesions involving different connective tissue structures within the same muscle may also exhibit distinct clinical behavior. Consequently, identifying the affected muscle alone may provide insufficient information for diagnosis, management and prognostic interpretation.

Advances in musculoskeletal ultrasound and magnetic resonance imaging have improved the anatomical characterization of injuries involving the gastrocnemius–soleus complex [3–5]. Beyond confirming the presence of muscle injury, imaging can identify the specific muscle and myoconnective structures involved and define the extent and distribution of structural damage. This anatomy-based approach may provide clinically relevant information for injury characterisation and management [6]. However, the relationship between increasingly detailed anatomical descriptions and clinically meaningful outcomes remains incompletely established, and robust evidence supporting their independent prognostic value is still limited. Accordingly, contemporary management should integrate anatomical information with the mechanism of injury, clinical findings, functional recovery and sport-specific demands rather than rely on imaging findings in isolation. In this review, we provide a practical anatomy-based overview of gastrocnemius–soleus muscle injuries in athletes, integrating current evidence on functional anatomy, clinical assessment, imaging, rehabilitation and return-to-sport decision-making. Particular attention is given to the clinical relevance of different injury patterns, while highlighting areas of uncertainty, ongoing controversies and priorities for future research.

Functional Anatomy and Injury Mechanisms

The gastrocnemius and soleus muscles form the triceps surae and act synergistically to generate the plantarflexion force required for walking, running and jumping. Despite functioning as part of the same muscle–tendon unit, they differ substantially in their anatomy, mechanical role and loading characteristics during sporting activities. These differences contribute to distinct injury mechanisms and clinical presentations and should be considered when assessing calf muscle injuries [2, 7].

The gastrocnemius is a biarticular muscle crossing both the knee and ankle joints and is exposed to high mechanical demands during sprinting, jumping, acceleration and rapid changes of direction. Medial gastrocnemius injuries therefore typically occur during a well-defined event, with athletes frequently reporting sudden, sharp pain that immediately limits performance [8]. In contrast, the soleus is monoarticular and plays an important role in plantarflexion force production during walking, running and repetitive locomotor activities. Soleus injuries may present less acutely, with athletes commonly reporting progressive calf pain or tightness during running or sustained loading and, in some cases, no clearly identifiable traumatic event [7, 9].

The mechanism and onset of symptoms therefore provide useful information during the initial assessment. Sudden pain during an explosive push-off or acceleration is more suggestive of gastrocnemius involvement, whereas symptoms developing progressively during running or repeated loading may raise suspicion of a soleus injury [7, 9]. However, considerable overlap exists between these presentations, and injury mechanism should be integrated with clinical examination and imaging rather than used as an isolated diagnostic criterion.

Beyond these functional differences, the internal connective tissue architecture of the gastrocnemius–soleus complex is particularly relevant to injury characterisation. The distal medial gastrocnemius has a relatively consistent anatomical organisation. Muscle fibres insert onto the gastrocnemius aponeurosis, which continues distally as a free aponeurosis before contributing, together with the soleus aponeurosis, to the Achilles tendon [10–12]. This relatively consistent arrangement allows reproducible injury patterns involving different myoconnective structures to be recognised on ultrasound and magnetic resonance imaging [9, 13, 14].

The soleus has a more complex connective tissue architecture, including the central tendon, medial and lateral aponeuroses and proximal tendinous structures, with substantial interindividual anatomical variability [2]. Consequently, soleus injuries may involve different combinations of intramuscular and peripheral connective tissue structures, contributing to considerable heterogeneity in their imaging appearance and clinical presentation. Whether these anatomical differences independently determine prognosis or recovery time, however, remains uncertain.

From a clinical perspective, understanding these anatomical and functional differences provides a framework for interpreting calf injuries beyond identification of the affected muscle. Characterisation of the specific myoconnective structures involved may improve diagnostic precision, communication between clinicians and interpretation of imaging findings [2, 4, 14]. Nevertheless, prospective evidence directly linking individual anatomical injury patterns to clinically relevant outcomes remain limited. Anatomy should therefore inform, rather than independently determine, subsequent management and return-to-sport decision-making.

Clinical Diagnosis and the Role of Imaging

Clinical assessment remains the cornerstone of the diagnostic process. The mechanism of injury, symptom onset and physical examination provide important information regarding the likely injured muscle. Sudden pain during an explosive movement is more suggestive of gastrocnemius involvement, whereas progressively increasing pain during running or sustained loading may raise suspicion of a soleus injury [5, 7, 15]. However, clinical examination alone is often insufficient to determine the precise anatomical location and the specific myoconnective structure involved.

Physical examination should therefore aim to establish the clinical diagnosis and functional consequences of the injury while guiding subsequent imaging when required. Palpation may help localise superficial lesions, particularly within the medial gastrocnemius, but is less informative for deeper soleus injuries. Pain reproduced during resisted plantaflexion, passive stretch or functional loading may further support the diagnosis, although none of these findings reliably characterises the underlying anatomical injury pattern in isolation [5, 7].

Imaging complements the clinical assessment by defining the anatomical characteristics of the injury. From a practical perspective, it should address clinically relevant questions: which muscle and myoconnective structure are involved, what is the extent of structural damage, and are there anatomical features that may influence management or return-to-sport planning [4, 5]?. A structured anatomical description may also facilitate communication among clinicians, physiotherapists, radiologists and performance staff.

Ultrasound (US) is frequently used as the first-line imaging modality in athletes with suspected calf muscle injury. It is readily available, allows dynamic assessment and provides high spatial resolution for superficial structures, particularly injuries involving the distal medial gastrocnemius. US also enables comparison with the contralateral limb and can be used for serial assessment when clinically indicated. However, its diagnostic performance is operator-dependent, and evaluation of deep soleus injuries and complex myoconnective anatomy may be more challenging [13, 16, 17]. It is also important to note that in US scan oedema can be delayed as long as 48–72 h, and in the professional athlete’s care situation where imaging is obtained on day of injury, serial US studies may be required to truly understand the extent of the injury if acute.

Magnetic resonance imaging (MRI) provides a more comprehensive assessment of the gastrocnemius–soleus complex and is particularly valuable when soleus injury is suspected, US findings are inconclusive or detailed anatomical characterisation is required. MRI enables visualisation of deep connective tissue structures, including the central tendon and the medial and lateral aponeuroses of the soleus [5, 14, 17]. This additional anatomical information may improve injury characterisation and assist management planning; however, evidence that increasingly detailed MRI findings independently improve prognostic accuracy or prediction of return-to-sport remains limited [4, 18].

Importantly, imaging findings should not be interpreted as direct surrogates of clinical severity or functional recovery. Structural abnormalities may persist despite satisfactory clinical progression, while symptom severity and functional impairment may not parallel the extent of abnormalities observed on imaging [4, 18, 19]. Imaging should therefore be interpreted in conjunction with the athlete’s symptoms, clinical examination, functional status and sporting demands.

Main Injury Patterns and Their Clinical Relevance

Calf muscle injuries represent a heterogeneous group of lesions involving different muscles and myoconnective structures. Although identifying the affected muscle remains clinically relevant, a more detailed anatomy-based approach provides a more precise description of the structural injury pattern and may help contextualise its potential implications for management [1, 5, 15].

The following sections summarise the main injury patterns encountered in athletes, with particular emphasis on the anatomical features that may influence clinical interpretation and management (Fig. 1). Given the limited prospective evidence linking individual anatomical patterns to prognosis, these classifications should primarily be regarded as tools for injury characterisation rather than deterministic predictors of recovery.

Fig. 1.

Main anatomical patterns of calf muscle injury. Calf injuries may involve different myoconnective structures within the gastrocnemius and soleus or present as combined injuries affecting multiple structures. Accurate anatomical identification with ultrasound and MRI may improve injury characterisation and help guide clinical management and rehabilitation

Medial Gastrocnemius Injuries

The medial gastrocnemius is the most frequently injured muscle within the gastrocnemius–soleus complex and typically presents with acute pain during explosive movements involving rapid loading of the muscle–tendon unit. Owing to its relatively consistent distal connective tissue anatomy, reproducible injury patterns can be identified using ultrasound and magnetic resonance imaging [1, 15].

Most injuries involve the distal myoconnective region, although the specific connective tissue structure affected may vary. Lesions may involve the musculotendinous junction, gastrocnemius aponeurosis, free distal aponeurosis or, less frequently, the tendon itself [13] (Fig. 2). Recognition of the structure involved provides a more precise anatomical description than the generic diagnosis of “medial gastrocnemius injury” and may assist clinical interpretation and management planning.

Fig. 2.

Ultrasound classification of medial gastrocnemius injuries. Schematic representation and corresponding ultrasound examples of the different injury patterns according to the myoconnective structure involved, based on the previously described ultrasound classification of medial gastrocnemius injuries. Type 1 is a myotendinous junction injury. Type 2 A is a MG aponeurotic rupture (< 50% of its width). Type 2B is a MG aponeurotic rupture (> 50% of its width). Type 3 is a rupture to the free gastrocnemius aponeurosis. Type 4 is a MG aponeurotic rupture (> 50% of its width) + a rupture to the free gastrocnemius aponeurosis

Recent imaging-based classifications have attempted to categorise medial gastrocnemius injuries according to the connective tissue structures involved.

These classifications provide a reproducible framework for describing injury morphology and may facilitate communication between clinicians and radiologists. However, their prognostic value remains incompletely established, and prospective evidence demonstrating that individual imaging patterns independently predict recovery or return-to-sport outcomes is limited [13, 19]. They should therefore not be interpreted as stand-alone prognostic models or used to determine fixed rehabilitation or return-to-sport timelines.

Soleus Injuries

Compared with the medial gastrocnemius, the soleus has a substantially more complex and variable connective tissue architecture. Relevant structures include the central tendon, medial and lateral aponeuroses, anterior aponeurosis and proximal tendinous arch, which may be injured either in isolation or in combination [7, 20] (Fig. 3). This anatomical variability contributes to the heterogeneous imaging appearance of soleus injuries and may make precise anatomical characterisation more challenging.

Fig. 3.

MRI examples of soleus injuries involving different aponeurotic structures. A Axial T2 TSE image showing a proximal aponeurotic arch tear. B Axial STIR image showing an anterior aponeurosis tear involving the lateral aspect of the soleus. C Axial proton density fat-suppressed (PD-FS) image showing a posterior aponeurosis tear involving the medial aspect of the soleus. D Axial PD-FS image showing a lateral aponeurosis tear. E Axial PD-FS image showing a central tendon tear. F Axial PD-FS image showing a medial aponeurosis tear

Soleus injuries may involve peripheral aponeurotic tissues or deeper intramuscular connective tissue structures with different anatomical and biomechanical characteristics [7, 21].

Imaging, particularly MRI, can therefore be useful in identifying the structures involved and defining the extent and distribution of the injury. This information may help clinicians interpret the clinical presentation and individualise management, particularly when symptoms or recovery do not follow the expected course [4, 5, 7]. Some observational evidence suggests that injury location and the connective tissue structures involved may be associated with differences in recovery time [7, 21]. In particular, injuries involving the central tendon and more proximal soleus injuries have been associated with longer recovery periods, although substantial variability exists between individual cases. However, the available evidence remains insufficient to establish anatomy-specific prognostic rules or management algorithms. Anatomical findings should therefore be integrated with symptoms, functional recovery and sport-specific demands rather than interpreted in isolation.

Less Common Injury Patterns

Less frequently, calf injuries may involve the lateral gastrocnemius, plantaris muscle or multiple components of the gastrocnemius–soleus complex [9, 15]. These presentations may be diagnostically challenging and can mimic more common calf injuries during the initial clinical assessment.

Combined injuries may involve more than one muscle or myoconnective structure and therefore present greater anatomical complexity than isolated lesions [22]. Although current evidence is insufficient to support specific management or prognostic recommendations for these patterns, recognizing their combined nature is important for accurate injury characterization and interpretation of imaging findings.

Among less common injury patterns, anatomic variants that may alter clinical presentation and imaging interpretation should be considered. The accessory, or supernumerary, soleus is an independent muscle belly, typically located anterior to the Achilles tendon within Kager’s fat pad. Although usually asymptomatic, it may cause exertional pain, posteromedial swelling, or, rarely, rupture [23, 24]. The so-called low-lying soleus is not an accessory muscle, but rather a distal extension of the normal soleus belly, characterized by a very distal myotendinous junction and a short free Achilles tendon [25]. The gastrocnemius tertius is a congenital third head, generally an incidental finding, but clinically relevant because of its potential relationship to the popliteal neurovascular bundle [26].

Management and Rehabilitation

General Principles

Rehabilitation after calf muscle injury should be anatomy-informed but function-led. Anatomical diagnosis can identify the injured muscle and myoconnective structures and highlight loading conditions that may require particular consideration; however, anatomical findings should not be translated into fixed rehabilitation timelines. Instead, progression should be individualised according to the athlete’s clinical presentation, functional capacity, injury mechanism, previous injury history, sporting demands and response to progressively increasing loads [5, 27, 28] with exercise selection regarded as a means of delivering the appropriate mechanical stimulus rather than as an end in itself.

Although the overall principles of rehabilitation are broadly similar across calf injuries, the anatomical injury pattern may influence loading priorities. The principal objectives are to restore normal gait and ankle mobility, recover plantarflexion strength across relevant joint positions, rebuild rapid force production and stretch-shortening-cycle capacity, and progressively restore tolerance to running and sport-specific mechanical demands. Symptoms, clinical findings, movement quality, completed workload and the response during and after loading should be interpreted together rather than as isolated progression criteria. Most calf muscle injuries can be managed non-operatively. However, an atypical presentation, disproportionate symptoms or unexpected clinical progression should prompt reconsideration of the diagnosis and exclusion of relevant differential diagnoses, including Achilles tendon rupture, deep-vein thrombosis and acute compartment syndrome [5, 29].

Initial Management

Initial management should aim to control pain and swelling while avoiding unnecessary unloading. Relative protection, compression and temporary gait assistance may be appropriate when required to restore a near-normal walking pattern, whereas prolonged immobilisation and complete rest should generally be avoided. As symptoms permit, active ankle movement and low-level isometric or isotonic plantarflexion loading can be introduced and progressed according to symptoms, movement quality and the subsequent response to loading [5, 29, 30].

Early loading should not be interpreted as aggressive loading. Forced stretching, forceful manual treatment and high-strain positions are generally inappropriate while walking or plantarflexion contraction remains clearly painful, particularly in injuries with substantial aponeurotic or tendinous involvement. The objective during this phase is to restore tolerance to mechanical loading without provoking a sustained exacerbation of symptoms.

In a randomised study of 50 amateur athletes with severe thigh or calf muscle injuries, initiation of a standardised rehabilitation programme 2 rather than 9 days after injury reduced return-to-sport time by approximately three weeks [30]. However, the small sample size and inclusion of a mixed muscle-injury cohort limit direct extrapolation to individual calf injury patterns. These findings support avoiding unnecessary delay in rehabilitation rather than prescribing a universal time point for initiating loading.

Load Progression and Restoration of Function

Progressive loading represents the cornerstone of rehabilitation after calf muscle injury. Rather than being defined by a specific exercise sequence, progression should manipulate relevant mechanical variables, including load magnitude, volume, muscle–tendon length, contraction mode, rate of force development and fatigue [28, 30]. In clinical practice, loading commonly progresses from bilateral to unilateral tasks, supported to unsupported positions, partial to greater ranges of motion, and slower to faster force production, before incorporating increasingly dynamic and sport-specific movements. External resistance should be progressively increased once body-weight exercises no longer provide an adequate stimulus [28, 30]. Importantly, progression should be guided by the athlete’s response to loading rather than successful task completion alone.

The anatomical and functional characteristics of the injured muscle should inform loading emphasis. Following gastrocnemius injury, progressive exposure to knee-extended plantarflexion loading, longer muscle–tendon lengths and subsequently higher-rate activities is particularly relevant. In soleus injuries, knee-flexed plantarflexion loading, repeated force production and tolerance to cumulative loading and fatigue may warrant greater emphasis. Injuries involving substantial aponeurotic or tendinous components may regain clinical comfort before the capacity to tolerate high-rate mechanical loading is fully restored. In these cases, anatomical findings may justify greater caution during progression to long-length, elastic and high-speed loading, but should not determine arbitrary delays or fixed timelines [5, 13, 14, 21, 27, 28].

As capacity improves, rehabilitation should incorporate stretch-shortening-cycle activities with progressively increasing intensity, speed, directionality and reactivity. The objective is to restore the mechanical capacities required by the athlete’s sport rather than simply increase exercise difficulty. Although plyometric exercises are commonly incorporated into muscle-injury rehabilitation, current evidence does not support their use as an isolated strategy to reduce reinjury risk [27, 31].

Running Progression and Sport-Specific Rehabilitation

Running should be considered a progressive mechanical exposure rather than simply cardiovascular exercise. Its introduction should be based on the integration of clinical and functional findings rather than elapsed time. Relevant considerations include a near-normal gait, functional ankle range of motion, adequate plantarflexion capacity with both the knee extended and flexed, and tolerance to low-level stretch-shortening-cycle activities without a clinically meaningful increase in symptoms during or after loading [28]. None of these findings represents a validated stand-alone threshold for initiating running.

Early running exposure should be controlled and progressively increased according to the athlete’s response. In general, increasing volume and intensity simultaneously should be avoided, particularly during the initial stages. Progression should account for speed, acceleration and deceleration demands, changes of direction, work-to-rest ratio, surface, footwear and the specific requirements of the athlete’s sport and playing position [31].

The injury mechanism and muscle involved may further inform the type of running exposure required. Following gastrocnemius injury, later rehabilitation should progressively reproduce high-speed running, acceleration, braking and change-of-direction demands. Following soleus injury, repeated running exposures, cumulative load and performance under fatigue may be particularly relevant [32]. These distinctions should be regarded as principles for individualising exposure rather than anatomy-specific rehabilitation protocols. Sport-specific rehabilitation should ultimately expose the athlete to representative mechanical demands in a controlled environment. This may include high-speed running, repeated accelerations and decelerations, multidirectional tasks, jumping or other sport- and position-specific activities [33]. Successful completion of these exposures provides information regarding functional recovery; however, clearance for unrestricted training and competition remains a separate, multifactorial return-to-sport decision [3, 34, 35] (Fig. 4).

Fig. 4.

Criteria-based rehabilitation continuum after calf muscle injury. MTU, muscle–tendon unit; RFD, rate of force development; SSC, stretch–shortening cycle

Criteria for Progression

Progression throughout rehabilitation should be based on the integration of clinical findings, functional capacity and response to loading rather than time since injury alone [31]. No single assessment can determine readiness to progress, and calf-specific evidence supporting universal progression thresholds remains limited. Transition from the initial phase towards more demanding strengthening should be supported by restoration of a near-normal gait, improving local symptoms, functional ankle range of motion and the ability to perform plantar-flexor contractions with acceptable symptom levels [28]. Progression towards dynamic loading should additionally consider movement quality during unilateral tasks, tolerance to increasing loads with both the knee flexed and extended, and the subsequent response to loading.

As rehabilitation advances, the athlete should demonstrate increasing tolerance to stretch-shortening-cycle activities, running and progressively more demanding sport-specific tasks without relevant pain, apprehension, compensatory movement or sustained symptom exacerbation [5, 28]. These findings should be interpreted as a multidimensional profile rather than as a checklist of mandatory cut-offs.

Whenever available, pre-injury performance data provide the most relevant reference for interpreting functional recovery. In their absence, comparison with the contralateral limb, previous testing, normative values and the specific physical demands of the athlete’s sport may assist clinical reasoning [36]. However, no validated calf-specific test battery or universal limb-symmetry threshold currently exists. Functional assessments, including the single-leg heel-rise test, should therefore be interpreted within the broader clinical context rather than used as isolated progression criteria [12, 37, 38].

Common Errors and Unresolved Controversies

Several common errors may compromise the management of calf muscle injuries. One is allowing elapsed time or imaging findings to dictate rehabilitation progression rather than integrating anatomical information with clinical and functional recovery. Conversely, symptom resolution alone should not be considered evidence that mechanical capacity has been fully restored. Structural, mechanical and neuromuscular alterations may persist beyond clinical recovery, although this does not justify delaying progression until imaging abnormalities have completely resolved [21, 27, 28, 39].

Other potential pitfalls include delaying loading until complete symptom resolution, relying exclusively on standing heel raises to assess recovery, progressing running volume and intensity simultaneously, and failing to reproduce the mechanical demands associated with the athlete’s sport or original injury mechanism. These approaches may underestimate the multidimensional nature of calf muscle function and the demands encountered during sport.

Routine follow-up imaging is generally unnecessary when clinical and functional progression is satisfactory. Repeat imaging may be considered when symptoms persist or recur, recovery is unexpectedly delayed, or the clinical course raises concern regarding the initial diagnosis or injury evolution [27, 28, 39, 40]. Similarly, reported associations between anatomical injury patterns and recovery duration should not be interpreted as deterministic prognostic rules for individual athletes [35, 41].

Ultimately, successful rehabilitation should be defined by restoration of the capacities required to tolerate sport-specific mechanical demands rather than completion of a predefined programme. Whether this restoration is sufficient to permit unrestricted training and competition requires a broader return-to-sport decision-making process.

Return-to-Sport

Return-to-sport (RTS) after calf muscle injury should be considered a continuum rather than a single clearance event. This process can be conceptualised as progression from return to participation, in which the athlete resumes selected sport activities with restrictions, to return-to-sport, characterised by unrestricted participation, and ultimately return to performance, when the athlete regains the level of performance required before injury [42]. This distinction is particularly relevant after calf injury, as tolerance of training does not necessarily indicate restoration of competition-level performance.

Return-to-Sport Decision-Making

The decision to RTS should integrate clinical recovery, functional capacity, sport-specific demands and the acceptable level of risk rather than rely on elapsed time or any single criterion [28, 31, 42]. Evidence supporting calf-specific RTS criteria remains limited, and no validated test battery or universal threshold has been established [28, 31]. RTS should therefore be approached as a multidimensional clinical decision-making process throughout rehabilitation rather than a single decision at the end of recovery or the completion of a predefined checklist.

Anatomical injury characteristics may contribute to this process by identifying structures or loading conditions requiring particular consideration. However, current evidence does not support anatomy-specific RTS algorithms or predetermined timelines based solely on the injured muscle or imaging classification [21, 27, 40].

Clinical, Functional and Sport-Specific Assessment

Clinical assessment should establish that residual symptoms no longer meaningfully limit the activities required by the athlete’s sport. However, absence of pain should not be considered synonymous with complete recovery. Functional assessment should determine whether plantar-flexor capacity has been restored across relevant mechanical conditions, including force production at different knee positions, repeated efforts and rapid force generation [28, 31].

Readiness for unrestricted sport should ultimately be demonstrated under conditions that reproduce relevant sport- and position-specific demands. Depending on the sport, these may include high-speed running, acceleration, deceleration, changes of direction, jumping, repeated efforts and performance under fatigue. The objective is not simply to complete an isolated test, but to demonstrate the capacity to repeatedly tolerate representative sporting demands without clinically meaningful symptoms, compensatory strategies or deterioration in performance.

Role of Imaging

Imaging should complement, rather than dictate, RTS decisions [3]. Residual structural abnormalities may persist despite satisfactory clinical and functional recovery, and complete radiological resolution should not be considered a prerequisite for RTS [19, 39]. Conversely, favorable imaging findings cannot compensate for persistent symptoms or insufficient functional recovery.

Routine follow-up imaging solely to determine RTS readiness is therefore not supported by current evidence. Repeating ultrasound or magnetic resonance imaging may nevertheless be useful when symptoms persist or recur, recovery is unexpectedly delayed, or clarification of structural evolution is likely to influence management [18, 27].

Shared Decision-Making and Elite Sport

RTS ultimately represents a risk-management decision made under a degree of uncertainty. The estimated risk of recurrence should be balanced against functional readiness, performance demands and the consequences of returning or delaying return [40, 42]. This process should involve shared decision-making between the athlete and the medical and performance team.

In elite sport, risk tolerance may also be influenced by the competitive calendar, importance of upcoming competitions, player availability, playing position, expected exposure and previous injury history [43]. These contextual factors may legitimately influence the decision but should not be confused with biological or functional readiness. A distinction should therefore be maintained between whether an athlete can return, whether the associated risk is acceptable and whether the athlete is capable of performing at the required competitive level [42].

Return to competition should not be considered the endpoint of recovery. Restoration of pre-injury performance and the capacity to tolerate repeated training and competition loads remain the ultimate objectives of the RTS process [40, 42].

Current Controversies and Future Directions

Despite advances in anatomical characterisation and imaging, several uncertainties remain in the management of calf muscle injuries. A major challenge is determining whether increasingly detailed anatomical classifications translate into clinically meaningful improvements in prognosis and treatment. Although specific injury patterns and connective tissue involvement may be associated with recovery time, current evidence remains largely observational, and imaging findings alone provide limited certainty regarding individual outcomes [18, 21, 40]. Prospective studies should therefore determine which anatomical features provide prognostic information beyond clinical and functional assessment.

A second priority is the development of standardised outcome measures and prospective calf-specific cohorts. Current studies use heterogeneous definitions of injury severity, return-to-sport and recurrence, limiting comparisons between studies and the development of validated rehabilitation or RTS criteria [28, 31]. Future research should combine detailed anatomical characterisation with serial measures of symptoms, plantarflexor function, sport-specific workload and return to performance, rather than considering time to RTS as the only relevant outcome.

The role of follow-up imaging also remains controversial. Structural abnormalities may persist after clinical recovery, while their relationship with reinjury risk and subsequent performance remains incompletely understood [18, 39]. Further studies are needed to establish whether selected imaging findings provide incremental value over clinical and functional assessment and, importantly, whether this information modifies management or improves outcomes.

A further clinically relevant question is whether calf muscle injury may influence the subsequent risk of Achilles tendon injury. The gastrocnemius–soleus complex and Achilles tendon function as a continuous mechanical unit, making such an association biologically plausible. In our clinical experience, persistent deficits in plantarflexor capacity or altered loading strategies following calf injury may be relevant when considering subsequent Achilles tendon symptoms or injury. However, direct evidence establishing calf muscle injury as an independent risk factor for subsequent Achilles tendon injury is currently lacking. This potential relationship therefore remains an important area for future prospective investigation.

The role of invasive interventions in acute calf muscle injuries also remains poorly defined. Ultrasound-guided aspiration or evacuation of a large haematoma may occasionally be considered when there is substantial symptomatic mass effect or when the collection interferes with clinical progression, while surgical intervention is generally reserved for exceptional circumstances such as compartment syndrome or other clearly defined clinical indications. Evidence supporting routine injection therapies, including orthobiological treatments, remains insufficient. These interventions should therefore be considered selectively and should not replace progressive, criteria-based rehabilitation.

Artificial intelligence (AI) and machine-learning approaches represent an emerging opportunity in this context [43, 44]. Rather than relying on isolated imaging features, future models could integrate clinical characteristics, anatomical and quantitative imaging data, functional testing and workload variables to identify recovery patterns and estimate individualised RTS or reinjury risk [45]. AI-assisted analysis of musculoskeletal imaging, including automated segmentation and quantitative feature extraction, may also improve the reproducibility of anatomical assessment [46]. However, these applications remain exploratory, and there is currently insufficient evidence to support AI-based decision-making specifically for calf muscle injuries. Large, multicentre datasets, external validation and clinically interpretable models will be required before such approaches can meaningfully support practice.

From our clinical experience, the calf injuries that tend to require greater caution are not necessarily those with the largest initial imaging abnormalities. Injuries involving substantial aponeurotic or tendinous components, proximal soleus injuries, recurrent injuries and cases in which symptoms resolve before plantarflexor capacity has been fully restored may follow a more prolonged or less predictable course. Considerable individual variability nevertheless exists, and these observations should be regarded as clinical experience rather than established prognostic criteria.

Ultimately, future research should move beyond predicting when an athlete will return and focus on understanding how safely and at what performance level return occurs. Combining anatomical information with longitudinal clinical, functional and performance data may provide a more individualised framework for managing calf muscle injuries while avoiding the false precision of deterministic prognostic models.

Conclusions

Calf muscle injuries represent a heterogeneous group of lesions whose clinical behaviour cannot be fully understood by identifying the injured muscle alone. An anatomy-based approach can improve injury characterisation and support clinical decision-making, but anatomical and imaging findings should be integrated with symptoms, functional recovery and sport-specific demands rather than interpreted in isolation. Rehabilitation should remain function-led and progressively restore the mechanical capacities required for sport, while return to sport should be considered a multifactorial risk-management decision rather than the achievement of predefined timelines or isolated criteria. Further prospective research is needed to clarify the prognostic relevance of specific injury patterns and develop more individualised approaches to management and return to performance.

Key References

• Pagan-Rosado R, Troyer W, Rosario-Concepcion R, et al. Calf Strains in Athletes: A Narrative Review of Management, Injury Grading, and Return to Sport. Sports Med Open.2025. https://doi.org/10.1186/s40798-025-00960-4.

  • ○ A recent comprehensive review of calf muscle injuries covering diagnosis, injury classification, rehabilitation and return to sport. It provides a useful overview of the current evidence and highlights the limited availability of validated calf-specific management and return-to-sport criteria.
• Balius R, Pedret C, Pujol-Marzo M, Valle X, de la Fuente J. Triceps surae muscle injuries—a clinical challenge more complex than you think. Br Med Bull. 2026;159.

  • ○ A recent clinically oriented review emphasising the anatomical and functional complexity of triceps surae injuries and the need to move beyond considering calf injuries as a single clinical entity.
• Green B, McClelland JA, Semciw AI, Schache AG, McCall A, Pizzari T. The Assessment, Management and Prevention of Calf Muscle Strain Injuries: A Qualitative Study of the Practices and Perspectives of 20 Expert Sports Clinicians. Sports Med Open. 2022;8:10.

  • ○ An important study describing contemporary clinical practice in calf injury assessment and rehabilitation. It supports a criteria-based, individualised approach to loading and highlights areas in which current practice remains largely informed by expert experience rather than high-quality prospective evidence.
• Pecci J, van Dyk N, Myer GD, Sañudo B. Return-to-Play Criteria Following Lower Limb Muscle Injuries in Soccer: A Systematic Review with Evidence Synthesis. Sports Med. 2026;56:1433–1465.

  • ○ A recent systematic review demonstrating the heterogeneity of return-to-play criteria following lower-limb muscle injuries and the limited evidence supporting validated muscle-specific thresholds, reinforcing the need for multidimensional return-to-sport decision-making.
• Nielsen LB, Svensson RB, Fredskild NU, et al. Chronic changes in muscle architecture and aponeurosis structure following calf muscle strain injuries. Scand J Med Sci Sports.2023;33:2585–2597.

  • ○ This study demonstrates that structural and architectural changes may persist after clinical recovery from calf muscle injury, illustrating why symptom resolution or imaging findings alone should not be considered direct surrogates of complete functional recovery.

Author Contributions

CP: Conceptualization, Methodology, Writing – Original Draft, Writing – Review & Editing, Supervision, Project Administration.SP: Investigation, Writing – Original Draft, Writing – Review & Editing.SM: Investigation, Writing – Review & Editing, Visualization.EJF: Investigation, Writing – Original Draft, Writing – Review & Editing.JR: Investigation, Writing – Review & Editing.OV: Investigation, Writing – Original Draft, Writing – Review & Editing.RB: Conceptualization, Methodology, Writing – Review & Editing, Supervision.All authors read and approved the final manuscript.

Data Availability

No datasets were generated or analysed during the current study.

Declarations

AI Disclosure

ChatGPT (OpenAI) was used solely to assist with the visual enhancement of Figure 1 and Figure 4. No AI-generated content was used for data generation, analysis, or scientific interpretation.

Disclosure

The authors declare that they have no conflicts of interest relevant to the content of this article.

Competing Interests

The authors declare no competing interests.