Relative Energy Deficiency in Sport (RED-S) is a complex syndrome resulting from insufficient energy availability relative to the energy expended during exercise. This imbalance affects various physiological systems, including metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health. Initially recognised as the Female Athlete Triad, RED-S has been redefined by the International Olympic Committee (IOC) to encompass a broader range of symptoms and include both male and female athletes.

Physiotherapists play an essential role in the early detection, treatment, and long-term management of RED-S. This blog explores their role in detail and highlights key research findings in this area.

Diagnostic Criteria for RED-S

Unlike single-diagnosis conditions, RED-S is identified through a constellation of clinical signs and symptoms, primarily centered around Low Energy Availability (LEA)—a state where insufficient dietary energy remains after exercise to support normal body functions.

Common diagnostic indicators include:

  • Low Energy Availability with or without disordered eating or an eating disorder

  • Menstrual dysfunction (e.g., amenorrhea, oligomenorrhea) in females

  • Reduced libido or testosterone in males

  • Decreased bone mineral density and stress fractures

  • Gastrointestinal dysfunction (bloating, constipation)

  • Persistent fatigue

  • Increased frequency of illness or injury

  • Mood changes such as irritability, anxiety, or depression

  • Poor or plateauing athletic performance

Screening tools such as the Low Energy Availability in Females Questionnaire (LEAF-Q) and RED-S Clinical Assessment Tool (RED-S CAT) can support the clinical evaluation process.

The Role of Physiotherapy in RED-S

1. Early Detection and Risk Identification

Physiotherapists are often among the first healthcare professionals to interact with athletes, making them uniquely positioned to spot early warning signs of RED-S. Common presentations may include recurring stress injuries, unexplained performance decline, delayed healing, or signs of overtraining.

Routine assessments, combined with a thorough history and musculoskeletal evaluation, can raise suspicion of RED-S—particularly in lean sports such as running, gymnastics, rowing, or dance.

2. Injury Management and Load Adaptation

Musculoskeletal complications such as stress fractures, tendinopathies, and bone stress injuries are hallmark features of RED-S. Due to impaired tissue repair and compromised bone health in low energy states, injuries may take longer to heal.

Physiotherapists can:

  • Develop modified, low-impact training programs (e.g., pool work, Pilates)

  • Manage training load to minimise stress on vulnerable areas

  • Monitor fatigue and recovery markers

  • Promote optimal biomechanics to reduce injury risk

These interventions help maintain functional capacity without exacerbating injury or energy deficits.

3. Education and Athlete Empowerment

One of the most powerful tools a physiotherapist offers is education. Athletes often equate more training with better results, overlooking the importance of recovery and adequate nutrition. Physiotherapists can guide conversations around:

  • The risks of chronic under-fueling

  • The importance of rest and energy availability

  • Debunking myths around body image and performance

  • How RED-S can impact long-term health and sport longevity

Athletes are more likely to trust clinicians with whom they have an ongoing relationship, which places physiotherapists in an excellent position to influence positive behavior change.

4. Team-Based Collaboration

RED-S management requires a multidisciplinary approach. Physiotherapists often work closely with:

  • Sports physicians, who can evaluate hormonal and metabolic parameters

  • Dietitians, who guide the athlete toward nutritional recovery

  • Psychologists, who address disordered eating, anxiety, and compulsive training behaviors

  • Coaches, who need to align training plans with recovery protocols

Physiotherapists help bridge communication between these roles and support consistent messaging.

The article by Rudin et al (2025) “Managing Relative Energy Deficiency in Sport (REDs): A systematic review of the evidence and best practice recommendations” offers a comprehensive review of the current evidence surrounding RED-S. It emphasises the importance of multidisciplinary care involving nutrition, medical, psychological, and physiotherapy support. The review highlights the need for early identification, individualised treatment plans, and education to ensure long-term health and performance. It also stresses the value of physiotherapists in managing injury risk and rehabilitation as part of an integrated care model.

Conclusion

Physiotherapy is a critical component in the detection and recovery of athletes affected by RED-S. With the ability to recognise early warning signs, manage injuries within a holistic framework, and educate athletes on the risks of under-fueling, physiotherapists serve as both clinicians and advocates for athlete health.

However, studies show that knowledge gaps still exist. Continued professional education and greater integration of RED-S awareness into clinical training are essential to improving outcomes.

By collaborating within a multidisciplinary team and emphasising long-term health over short-term performance, physiotherapists can help athletes thrive both in sport and life.

References

Rudin et al (2025) https://doi.org/10.1016/j.jsampl.2024.100085