Gabriel Fernando Esteves Cardia
gfecardia2@uem.br

Doutor em Ciências da Saúde

Professor do Departamento de Educação Física

Universidade Estadual de Maringá
(Brasil)

Reception: 11/14/2023 - Acceptance: 07/25/2026

1st Review: 07/04/2026 - 2nd Review: 07/22/2026

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Suggested reference: Cardia, G.F.E. (2026). Monitoring Internal and External Training Load in Team Sports. A Comprehensive Review of Methods and Technologies. Lecturas: Educación Física y Deportes, 31(339), 166-182. https://doi.org/10.46642/efd.v31i339.7330

 

Abstract
    Monitoring training load is a key strategy for optimizing performance and reducing injury risk in team sports. Internal and external load measures provide complementary information that supports evidence-based decision-making in training prescription and athlete management. The objective of this review was to synthesize and critically analyze the main methods and technologies currently used to monitor internal and external training load in team sports, emphasizing their practical applications, advantages, and limitations. A narrative literature review with a structured search strategy was conducted, using PRISMA recommendations as a reporting guide. Studies were retrieved from the Web of Science, PubMed, and Scopus databases. Peer-reviewed articles addressing subjective and objective monitoring approaches were included, encompassing perceptual measures, heart rate–based indices, global positioning systems, accelerometry, and wearable microtechnology. The evidence indicates that external load is predominantly monitored through variables such as distance covered, speed, acceleration, power output, and time-motion characteristics, whereas internal load is commonly assessed using session rating of perceived exertion, heart rate–derived indices, and subjective well-being questionnaires. The combined use of internal and external load measures supports training individualization, improves load management, and contributes to injury risk reduction. In conclusion, training load monitoring should be understood as a dynamic and context-dependent process that requires an integrated and individualized approach to support applied decision-making and long-term athlete development in team sports.

    Keywords: Athlete management. Wearable sensors. Rating of perceived exertion. Recovery status. Injury prevention.

 

Resumo
    O monitoramento da carga de treinamento constitui uma estratégia fundamental para a otimização do desempenho e a redução do risco de lesões em esportes coletivos. As medidas de carga interna e externa fornecem informações complementares que subsidiam a tomada de decisão baseada em evidências na prescrição do treinamento e no gerenciamento dos atletas. O objetivo desta revisão foi sintetizar e analisar criticamente os principais métodos e tecnologias atualmente utilizados para o monitoramento da carga interna e externa em esportes coletivos, destacando suas aplicações práticas, vantagens e limitações. Foi realizada uma revisão narrativa da literatura com estratégia de busca estruturada, utilizando as recomendações do PRISMA como guia de relato. Os estudos foram identificados nas bases de dados Web of Science, PubMed e Scopus. Foram incluídos artigos revisados por pares que abordaram ferramentas subjetivas e objetivas de monitoramento, contemplando medidas perceptivas, índices baseados na frequência cardíaca, sistemas de posicionamento global, acelerometria e dispositivos vestíveis de microtecnologia. As evidências indicam que a carga externa é predominantemente monitorada por meio de variáveis como distância percorrida, velocidade, aceleração, potência e características de tempo-movimento, enquanto a carga interna é comumente avaliada por meio da avaliação da percepção de esforço durante a sessão, índices derivados da frequência cardíaca e questionários subjetivos de bem-estar. O uso combinado dessas medidas contribui para individualização do treinamento, gerenciamento adequado da carga e redução do risco de lesões. Conclui-se que o monitoramento da carga de treinamento deve ser compreendido como um processo dinâmico e dependente do contexto nos esportes coletivos.

    Unitermos: Gestão de atletas. Sensores vestíveis. Percepção subjetiva de esforço. Estado de recuperação. Prevenção de lesões.

 

Resumen

    La monitorización de la carga de entrenamiento es una estrategia clave para optimizar el rendimiento y reducir el riesgo de lesiones en deportes de equipo. Las mediciones de carga interna y externa proporcionan información complementaria que respalda la toma de decisiones basada en evidencias en prescripción del entrenamiento y gestión del atleta. El objetivo fue sintetizar y analizar críticamente los principales métodos y tecnologías utilizados actualmente para monitorizar la carga de entrenamiento interna y externa en deportes de equipo, haciendo hincapié en sus aplicaciones prácticas, ventajas y limitaciones. Se realizó una revisión narrativa de literatura con una estrategia de búsqueda estructurada, utilizando las recomendaciones PRISMA como guía de presentación de informes. Los estudios se recuperaron de las bases de datos Web of Science, PubMed y Scopus. Se incluyeron artículos revisados por pares sobre monitorización subjetiva y objetiva: medidas perceptuales, frecuencia cardíaca, GPS, acelerometría y microtecnología portátil. La evidencia indica que la carga externa se evalúa mediante distancia, velocidad, aceleración y potencia, mientras que la interna mediante percepción del esfuerzo, frecuencia cardíaca y cuestionarios de bienestar. El uso combinado de mediciones de cargas internas y externas favorece la individualización del entrenamiento, mejora la gestión de la carga y contribuye a la reducción del riesgo de lesiones. En conclusión, la monitorización de la carga de entrenamiento debe entenderse como un proceso dinámico y dependiente del contexto que requiere un enfoque integrado e individualizado para apoyar la toma de decisiones aplicadas y el desarrollo a largo plazo del atleta en deportes de equipo.

    Palabras clave: Gestión del atleta. Sensores portátiles. Escala de esfuerzo percibido. Estado de recuperación. Prevención de lesiones.

 

Lecturas: Educación Física y Deportes, Vol. 31, Núm. 339, Ago. (2026)

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Introduction 

 

    The performance of athletes in team sports and the prevention of sport-related injuries are strongly influenced by the appropriate management and monitoring of training load. Recent advances in sports science and training monitoring have reinforced the central role of workload quantification in supporting evidence-based training prescription and athlete management in team sports (Clemente et al., 2025; Branquinho et al., 2025). As a result, training load monitoring has become an essential component of contemporary training processes in team sports.

 

    Training load can be strategically manipulated throughout the competitive season to promote specific physiological and neuromuscular adaptations and to elicit supercompensation effects in response to training stimuli. However, inadequate management of training load may lead to undesirable outcomes, such as excessive fatigue, increased susceptibility to illness, and a higher risk of injury, all of which can negatively affect athletic performance and long-term athlete availability (Mohr et al., 2023; Morgans et al., 2026). Consequently, balancing training stimulus and recovery has emerged as a central challenge for coaches and sports scientists working in team sport contexts.

 

    To achieve this balance, it is necessary to continuously monitor athletes’ responses to imposed training loads, particularly their global fatigue levels. Recent investigations have demonstrated that cumulative internal training load is associated with the occurrence of non-contact muscle injuries in professional team sport athletes, reinforcing the relevance of systematic workload control strategies (Mohr et al., 2023; Rico-González et al., 2024). Within this framework, training load monitoring serves not only as a performance optimization strategy but also as a key element in injury prevention programs.

 

    Training load monitoring encompasses both subjective and objective measures that allow for the assessment of load and fatigue. External load is commonly quantified through variables such as training volume, duration, exposure, number of technical actions, distance covered, speed, acceleration, and power output, often measured using global positioning systems, inertial measurement units, and accelerometry. In contrast, internal load reflects the individual physiological and perceptual responses to training stimuli and is typically assessed using rating of perceived exertion (RPE), session-RPE (sRPE), heart rate–based indices, and subjective well-being questionnaires. Recent meta-analytic evidence supports the criterion-related validity of sRPE as a practical indicator of internal training load across team sport contexts (Liu et al., 2023). Fatigue assessment may also include neuromuscular, sleep-related, and perceptual markers.

 

    These monitoring tools are widely used in elite sport settings and are considered useful indicators of athletes’ recovery status, providing valuable information to support decision-making regarding training prescription and recovery strategies. Nevertheless, recent literature highlights that discrepancies between internal and external load measures may occur, indicating that single-domain monitoring approaches may be insufficient to fully capture athletes’ responses to training (Kårström et al., 2024; López-Sierra et al., 2025). Despite their widespread application, limitations related to the interpretation, sensitivity, and integration of monitoring metrics remain evident, reinforcing the need for critical appraisal of current methods.

 

    Therefore, the objective of this review was to synthesize and critically analyze the main methods and technologies currently used to monitor internal and external training load in team sports, emphasizing their practical applications, advantages, and limitations. By consolidating existing evidence, this review aims to contribute to a clearer understanding of training load monitoring and to support coaches and practitioners in the implementation of more effective, individualized, and evidence-based monitoring strategies in team sports.

 

Methods 

 

    This study was conducted as a narrative literature review with a structured, transparent, and reproducible search strategy, aiming to synthesize and critically discuss current evidence on internal and external training load monitoring in team sports. To improve reporting clarity and methodological transparency, the review process was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations (Page et al., 2021), which were used as a reporting guide rather than as a formal systematic review protocol, in accordance with the scope and objectives of the present investigation.

 

    A comprehensive electronic search was performed in the Web of Science, PubMed, and Scopus databases. Records published from database inception through June 2026 were eligible; no lower publication-date limit was imposed because earlier seminal studies were considered necessary to establish the conceptual and methodological foundations of training-load monitoring. The search strategy targeted peer-reviewed articles published in English that addressed training load monitoring in team sports contexts. The following keywords and their combinations were applied independently and in combination to maximize the retrieval of relevant studies: “training load”, “team sports”, “collective sports”, “monitoring tools”, “internal load”, and “external load”.

 

    Studies were considered eligible if they investigated methods or technologies related to the monitoring of training load and fatigue in team sports. Both subjective and objective approaches were included, encompassing perceptual measures, heart rate–based indices, global positioning systems (GPS), accelerometry, and microtechnology-based monitoring devices. Only articles published in peer-reviewed scientific journals were included, ensuring a minimum standard of methodological rigor and relevance to applied sport settings.

 

    The study selection process involved an initial screening of titles and abstracts to identify potentially relevant publications. Subsequently, full-text articles were assessed to confirm alignment with the objectives of the review. Data extraction followed a standardized and non-combined protocol, allowing for the systematic organization of information related to sport modality, competitive context, monitoring methods, variables assessed, and the technical characteristics of the monitoring tools.

 

    The analysis was based on a descriptive and critical synthesis of the literature, focusing on identifying the main applications, advantages, and limitations of the different monitoring approaches. No quantitative synthesis or meta-analysis was performed. This methodological approach was adopted to provide a comprehensive overview of current practices, highlight methodological challenges, and support the practical interpretation of training load monitoring strategies in team sports environments.

 

Results and discussion 

 

External load monitoring methods 

 

    The analysis of the selected literature indicates that external load monitoring in team sports has been predominantly conducted through technological tools capable of quantifying the mechanical demands imposed on athletes during training and competition. Recent advances in wearable technology and positioning systems have expanded the precision and applicability of external load metrics, allowing a more detailed characterization of the volume, intensity, and distribution of physical demands in team sports (Clemente et al., 2025; López-Sierra et al., 2025). Measures such as total distance covered, speed, acceleration, deceleration, and power output are widely used to characterize the volume and intensity of physical activity performed by players.

 

    Among these variables, total distance covered represents one of the most frequently reported indicators of external load, particularly in sports such as soccer. This measure provides a general estimate of physical workload and can be expressed in absolute or relative terms. However, recent literature has emphasized that distance-based metrics alone may not adequately represent the intermittent and high-intensity characteristics of team sports, highlighting the need for complementary indicators that capture rapid changes in movement and mechanical stress. (Kårström et al., 2024; Clemente et al., 2025)

 

    Speed monitoring has become increasingly relevant due to its association with decisive actions during competition. Contemporary studies employing global and local positioning systems have demonstrated that the classification of movement into speed zones facilitates the identification of high-intensity efforts and their distribution across training sessions and matches (Rico-González et al., 2024). Similarly, acceleration and deceleration metrics provide valuable insights into the neuromuscular demands of team sports, as these actions are closely related to changes in direction, rapid transitions, and elevated mechanical load. Recent evidence suggests that high volumes of accelerative and decelerative actions may impose substantial neuromuscular stress, reinforcing their relevance for external load monitoring and load management strategies. (López-Sierra et al., 2025)

 

    Recent evidence indicates that external load distribution across the weekly microcycle may be influenced by contextual variables such as match location, opponent level, and training schedule, reinforcing the need to interpret workload data within the competitive context (Hernández et al., 2021). More recent investigations using wearable inertial measurement units have further demonstrated position-specific and microcycle-dependent variations in external load, particularly in women’s football, supporting the ecological validity and applied usefulness of these technologies in daily training monitoring. (Motato et al., 2024)

 

    Power output has also been highlighted as an important indicator of external load, particularly in sports requiring frequent explosive actions. Recent studies have increasingly relied on accelerometer-derived metrics and inertial sensors to estimate power-related variables in field-based settings, enabling the assessment of explosive demands without the need for laboratory equipment (López-Sierra et al., 2025; Branquinho et al., 2025). Collectively, these findings support the relevance of a multidimensional approach to external load monitoring to better represent the complex and dynamic demands of team sports.

 

Time-motion analysis and accelerometry 

 

    Time-motion analysis (TMA) has traditionally been used to assess external load by quantifying movement patterns and activity profiles during training and competition. This approach includes both video-based analysis and sensor-based systems such as GPS (Gómez-Carmona et al., 2020). More recently, athlete-tracking technologies based on global navigation satellite systems (GNSS) and local positioning systems have been widely adopted to describe locomotor demands, temporal distribution of efforts, and peak-demand periods in team sports. (Torres-Ronda et al., 2022)

 

    Although TMA has contributed substantially to understanding physical demands in team sports, limitations related to reliability, observer dependency, and the inability to capture sport-specific actions have been reported (Boyd et al., 2013). Contemporary evidence further highlights that TMA outcomes are highly dependent on methodological decisions, such as data filtering, variable selection, and analytical models, which may limit comparability across studies and applied settings if not adequately standardized. (Torres-Ronda et al., 2022; Dhahbi et al., 2024)

 

    Task design and specificity have been shown to significantly influence external load responses, particularly in futsal, where variations in technical and tactical demands result in distinct workload profiles across training tasks (Muñoz-Gracia, & Caparrós, 2023). Recent applied research reinforces that external-load outputs derived from TMA should be interpreted within the ecological constraints of the task, rather than as isolated indicators of physical demand. (Ferraz et al., 2023)

 

    Accelerometry has emerged as a valuable alternative to traditional TMA, offering improved sensitivity for quantifying workload demands associated with changes in velocity and direction (Coutts et al., 2010; Gabbett et al., 2012). Current evidence indicates that accelerometer-based metrics provide complementary information to tracking-derived variables, particularly in intermittent team sports characterized by frequent accelerations, decelerations, and multidirectional movements (Staunton et al., 2026). Accelerometers allow the continuous measurement of movement-related forces and have been widely adopted in both research and applied settings.

 

    However, these devices are not without limitations, as they require appropriate calibration and may be influenced by non-sport-specific movements (Čović et al., 2016). Recent methodological investigations emphasize that the validity and reliability of accelerometer-derived metrics depend on device model, sensor placement, signal processing, and the movement profile analyzed, reinforcing the need for cautious interpretation of proprietary “black-box” load indicators. (Dawson et al., 2024; Dawson et al., 2026)

 

    Recent advances in wearable microtechnology have facilitated the integration of accelerometry with individualized speed thresholds, replacing arbitrary speed zones previously used in TMA (Duthie et al., 2003). Recent synthesis studies indicate that individualized speed and load thresholds may enhance the ecological validity of external load assessment; however, substantial methodological heterogeneity remains, limiting direct comparisons across studies and monitoring systems (Clemente et al., 2023). This individualized approach has gained increasing acceptance among sports scientists and practitioners.

 

GPS and integrated monitoring systems 

 

    The use of GNSS/GPS-based wearable tracking technology has become one of the most common approaches for monitoring external load in team sports. Modern tracking systems quantify locomotor demands (e.g., distance and speed-related variables) and, depending on the system, may also support the identification of peak-demand periods, thereby assisting practitioners in interpreting competition and training requirements. (Torres-Ronda et al., 2022)

 

    GPS devices provide information on movement intensity, distance covered, average speed, and time spent at different intensity thresholds. However, the accuracy and practical usefulness of high-intensity metrics depend not only on sampling frequency but also on the validity of instantaneous speed/acceleration estimates and on signal-processing choices (e.g., filtering/smoothing), which can meaningfully alter acceleration outputs. (Crang et al., 2024; Ellens et al., 2024)

 

    Recent validation studies have shown that widely used microtechnology devices (e.g., Catapult Vector S7) can provide valid and reliable estimates of distance in controlled team-sport simulation settings, supporting their applied use for workload monitoring (Ocak et al., 2025). Nevertheless, inter-unit reliability should be considered when monitoring athletes longitudinally, particularly when protocols involve frequent changes of direction, as reliability may vary across metrics and conditions. (Dawson et al., 2026)

 

    Modern monitoring systems often integrate GPS/GNSS with inertial sensors (accelerometers, gyroscopes, and magnetometers), allowing a more comprehensive quantification of external load. In applied contexts, this integration can improve the description of multidirectional and intermittent demands that are not fully captured by displacement-based variables alone. (Torres-Ronda et al., 2022)

 

    However, device-specific limitations must be acknowledged. For example, Polar Team Pro has demonstrated underestimation of distance and velocity in indoor conditions, especially at higher speeds, indicating that practitioners should be cautious when interpreting outputs outside the system’s optimal operational context. (van den Tillaar et al., 2023)

 

    Studies using positioning and inertial technologies in futsal indicate that external load varies according to contextual and player-specific factors, including positional demands and differences observed in elite futsal (Illa et al., 2021). Recent evidence in elite futsal demonstrates positional and microcycle-related variability in external load across training weeks, reinforcing the need for position-sensitive monitoring and context-aware interpretation (Gadea-Uribarri et al., 2025). In addition, inertial-unit approaches have been employed in futsal to monitor external load under competition constraints and to support the normalization/interpretation of performance indicators. (Spyrou et al., 2023)

 

    Evidence also supports integrating external and internal load measures. For instance, in youth soccer, GPS-derived variables (e.g., total distance) have shown meaningful associations with internal load indicators such as TRIMP and heart-rate exertion, while RPE/sRPE has been associated with external-load measures including distance and accelerometer-derived indices, supporting the applied value of combined monitoring (Havanecz et al., 2025). Accordingly, integrated internal–external load monitoring is best framed as a decision-support strategy for training prescription and load management, rather than as a standalone determinant of performance outcomes. (Torres-Ronda et al., 2022)

 

Internal load monitoring methods 

 

    The assessment of internal load provides critical information regarding athletes’ physiological and perceptual responses to training stimuli. Among the most widely adopted subjective tools, the rating of perceived exertion (RPE) scale remains central due to its demonstrated associations with cardiovascular and metabolic responses in team sport athletes. (López-Sierra et al., 2025)

 

    The session-RPE (sRPE) method has been extensively applied in team sports as a practical tool for quantifying internal load. By multiplying the perceived exertion score by session duration, sRPE offers a global estimate of training load that has demonstrated good validity and reliability across different training contexts (Inoue et al., 2022). Recent studies have also confirmed acceptable concurrent validity and reliability of the sRPE scale across multiple training modalities, suggesting that it can serve as a feasible and informative internal load indicator when used systematically. (Dai et al., 2025)

 

    Despite its utility, both perceptual measures and heart rate measures capture different aspects of physiological stress, which is why combined approaches are recommended (Macedo et al., 2024). Variations of the RPE approach, including separate assessments of cardiorespiratory and muscular exertion, have also been proposed to enhance sensitivity; however, the incremental benefit of these subdivisions varies according to sport and context and should be interpreted cautiously. (Macedo et al., 2024)

 

    Heart rate–based indices, particularly the training impulse (TRIMP) method and its modifications, remain a cornerstone of internal load quantification due to their direct reflection of cardiovascular strain during exercise (Clemente et al., 2025). Meta-analytic evidence indicates that TRIMP measures correlate with endurance adaptations such as VO₂max and lactate thresholds, while session-RPE exhibits comparatively smaller associations with these physiological adaptations, underscoring the value of HR-based methods for certain internal load insights. (Clemente et al., 2025)

 

    Although heart rate methods provide valuable insights into cardiovascular stress, their applicability may be limited in activities characterized by high neuromuscular demands or intermittent effort patterns. Consequently, integrating subjective measures (e.g., sRPE) and cardiovascular indicators (e.g., TRIMP, HR exertion) has been recommended to achieve a more comprehensive assessment of internal load responses in team sports. (Havanecz et al., 2025)

 

Subjective monitoring and well-being assessment 

 

    Subjective monitoring tools, such as questionnaires and self-report measures, play an important role in capturing athletes’ perceptions of fatigue, stress, recovery, and readiness to train. Instruments such as the Hooper Index and its adaptations have been widely used to assess daily well-being and to support the early identification of maladaptive responses to training in applied team-sport environments. (Hooper et al., 1995; Sioud et al., 2023; Andersen et al., 2023)

 

    More recent applied evidence in elite and youth football contexts supports the practical utility of brief daily wellness screening, especially when interpreted alongside workload exposure and schedule-related constraints (e.g., match congestion, travel, and training distribution). (Sioud et al., 2023; Andersen et al., 2023)

 

    Additional tools, including broader recovery–stress instruments such as the Recovery–Stress Questionnaire for Athletes (RESTQ-Sport), allow a more comprehensive assessment of recovery and stress states and have been used across different sports and cultural contexts (Nicolas et al., 2019). Recent psychometric work has also strengthened the evidence base for newer recovery–stress scales and their convergent relationships with established measures (e.g., RESTQ-Sport), supporting their application for routine monitoring when resources or time constraints limit extensive testing batteries. (Brauers et al., 2024)

 

    Despite their subjective nature, these measures have demonstrated sensitivity to training load fluctuations and are considered valuable complements to objective monitoring methods (Saw et al., 2015). In addition, recent applied work has explored predictive/analytic approaches combining internal–external workloads with wellness/self-report outcomes, reinforcing the practical relevance of integrating subjective monitoring into multi-source decision frameworks. (Rossi et al., 2022)

 

Integrating monitoring data and practical implications 

 

    The literature consistently emphasizes the importance of integrating internal and external load measures to support evidence-based decision-making in team sports. Monitoring data can be used to identify performance limitations, guide training adjustments, and evaluate the effectiveness of training interventions (Bourdon et al., 2017). Recent evidence highlights the feasibility of integrating multiple low-cost monitoring tools to assess training load in team sports, supporting practical and context-specific load management strategies. (Molina et al., 2025)

 

    Approaches such as magnitude-based inferences have been proposed to assess the practical relevance of observed changes in training variables, although their application requires careful interpretation and consideration of measurement reliability (Hopkins et al., 2009). Load management models based on the relationship between acute and chronic workload have been explored as practical tools to support training prescription and injury risk management in team sports contexts (Pajuelo, & Caparrós, 2021). Ultimately, the effectiveness of monitoring systems depends not only on data collection but also on the ability of coaches and practitioners to interpret and apply information within the training context. (Soligard et al., 2016)

 

Conclusion 

 

    Monitoring internal and external training load represents a central strategy for optimizing performance and reducing injury risk in team sports. The evidence synthesized in this review highlights that no single monitoring method is sufficient to capture the complex and multidimensional demands imposed on athletes during training and competition. Instead, the combined use of internal and external load measures provides a more comprehensive understanding of training stress and athlete responses.

 

    External load monitoring, primarily assessed through variables such as distance covered, speed, acceleration, power output, and time-motion characteristics, offers valuable information regarding the mechanical demands of team sports. Conversely, internal load measures, including session-RPE, heart rate–based indices, and subjective well-being assessments, reflect the individual physiological and perceptual responses to these demands. The integration of these approaches enables more informed decision-making in training prescription, load management, and recovery strategies.

 

    Despite the widespread application of monitoring tools in applied settings, the literature indicates that limitations related to validity, sensitivity, and contextual interpretation persist. These challenges reinforce the need for careful selection of monitoring methods and for the consideration of sport-specific, individual, and contextual factors when interpreting training load data. Moreover, effective monitoring systems depend not only on data collection but also on the expertise of coaches and practitioners to translate information into meaningful adjustments within the training process.

 

    In conclusion, training load monitoring should be understood as a dynamic and context-dependent process, requiring an integrated and individualized approach. Future research should focus on refining monitoring technologies, improving the integration of mechanical, physiological, and perceptual indicators, and developing practical frameworks that support long-term athlete development and injury prevention in team sports.

 

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Lecturas: Educación Física y Deportes, Vol. 31, Núm. 339, Ago. (2026)