Cryotherapy In Sports Medicine

Chelsea’s Erin Cuthbert in action with Manchester United’s Geyse Action Images via Reuters/Peter Cziborra

Cryotherapy, or the application of ice, is a prominent practice in sports medicine, primarily used to manage acute soft tissue injuries by reducing pain, limiting secondary damage, and controlling inflammation. Despite its widespread use, its efficacy and mechanisms remain subjects of debate. The traditional recommendations focus on animal studies’ findings, and clinicians must consider the practical implications for athletes when managing them. Cryotherapy has become a cornerstone of injury treatment in sports medicine, often incorporated into protocols like RICE (Rest, Ice, Compression, Elevation), PRICE (Protect, Rest, Ice, Compression, Elevation), and POLICE (Protect, Optimal Loading, Ice, Compression, Elevation)⁽¹⁾. These protocols have popularized the use of ice to manage injuries, with about 88% of athletes reportedly using cryotherapy after an acute sport-related injury⁽¹⁾. Clinicians need to use clinical reasoning and understand the mechanisms of action for cryotherapy before advocating its implementation. A global team of researchers conducted a comprehensive literature review that thoroughly screened over 450 studies, providing a detailed exploration of cryotherapy’s impact across multiple tissues and contexts. This article unpacks what they found to guide clinical decision-making.

“Cryotherapy might impair and delay tissue regeneration, particularly in muscle injuries."

Proposed Intervention Targets

Pain relief
One of the primary benefits of cryotherapy is its ability to provide short-term pain relief, a significant reason for its recommendation in the initial hours following an injury⁽¹⁾. This analgesic effect can allow for earlier and more aggressive rehabilitation exercises, although this theory lacks substantial supporting evidence⁽¹⁾. However, cryotherapy can significantly reduce pain and swelling immediately following a soft tissue injury⁽²⁾.

Reduction in inflammation and swelling
Cryotherapy decreases tissue metabolism, limiting secondary injury, inflammation, and swelling. Researchers at the Nicholas Institute of Sports Medicine and Athletic Trauma in the USA have shown that cryotherapy can reduce the blood flow rate, venule diameter, and erythrocyte velocity, limiting early swelling and hematoma formation⁽¹⁾. These effects are crucial in the first few hours post-injury when controlling inflammation is vital. However, it is important to note that these results are predominantly from animal models and may not directly translate to human physiology⁽¹⁾.

Negative Consequences

Delayed healing and tissue regeneration
Cryotherapy might impair and delay tissue regeneration, particularly in muscle injuries. The Nicholas Institute of Sports Medicine and Athletic Trauma researchers showed that animal studies indicate that prolonged cryotherapy can decrease blood vessel volume and the expression of angiogenic markers, essential for tissue healing⁽¹⁾. Furthermore, the application of ice delays muscle fiber cross-sectional area recovery and increases collagen deposition, which can negatively impact muscle regeneration⁽¹⁾. Researchers at the Hafer Al Batin Central Hospital in the Kingdom of Saudi Arabia demonstrated that chronic cryotherapy can hinder muscle adaptations and impair muscle protein synthesis, raising concerns about its application during routine training⁽³⁾.

Potential negative impact on tendon and ligament healing
The evidence supporting cryotherapy’s benefits for tendon and ligament injuries is limited and conflicting. Some studies report that cryotherapy can reduce postoperative pain, while others found no significant benefits in pain relief, limb swelling reduction, or increased range of motion⁽¹⁾. Animal studies have shown that cryotherapy might inhibit the early inflammatory phase, which is crucial for tissue repair, potentially compromising long-term tendon healing and mechanical integrity⁽¹⁾. Additionally, some studies suggest that cryotherapy might disrupt inflammation, leading to impaired tissue repair and redundant collagen synthesis⁽³⁾.

“One of the primary benefits of cryotherapy is its ability to provide short-term pain relief..."

Evidence Gaps

Lack of human studies
Despite its popularity, there is a significant lack of human studies investigating the effects of cryotherapy on soft tissue injuries. Most current understanding derives from animal models, which may not accurately reflect human musculoskeletal injuries⁽¹⁾. The only human study did not demonstrate a significant difference in pain perception, functional recovery, or convalescence time between the cryotherapy and control groups⁽¹⁾.

Variability in animal study protocols
Animal studies on cryotherapy show large variability in protocols, including differences in cooling methods, duration, frequency, and injury models, making it challenging to draw definitive conclusions and apply the findings to human sports medicine⁽¹⁾. Furthermore, the cooling effect on deep muscle tissues and areas covered by adipose tissue in humans remains largely unknown⁽¹⁾.

Clinical Implications

Use Cryotherapy Cautiously
•    Apply cryotherapy within the first 6 hours post-injury to manage pain and potentially limit hematoma formation.
•    Avoid prolonged or excessive use, particularly beyond 12 hours post-injury, to minimize risks of delayed tissue regeneration.

Adopt Individualized Approaches
Customize protocols based on injury severity, location, and tissue type.
•    Minor injuries: Controlled cooling may accelerate healing.
•    Major injuries: Consider alternative treatment methods.

Combine with Other Therapies
Integrate cryotherapy with:
•    Compression,
•    Controlled loading,
•    Patient education.

Educate Athletes and Coaches
Share evidence-based guidelines to discourage reliance on outdated practices, such as chronic icing for multiple days.

Questioning cryotherapy
Cryotherapy can be effective for pain management and reducing swelling in acute sports injuries. Cryotherapy decreases edema, reduces pain, and controls inflammation, critical in managing acute injuries and postoperative conditions⁽²⁾. However, clinicians must consider if the inflammatory response disruption negatively affects the natural psychological recovery and may not significantly contribute to long-term functional recovery or tissue regeneration. For example, researchers at the Department of Kinesiology at Pennsylvania State University found that cryotherapy did not significantly improve swelling or range of motion compared to other rehabilitation techniques⁽⁴⁾.

Additionally, chronic use of cryotherapy might hinder muscle adaptations and impair muscle protein synthesis, raising concerns about its application during routine training⁽³⁾. Furthermore, cryotherapy might disrupt the natural inflammatory response, essential for tissue healing, potentially leading to impaired tissue repair and redundant collagen synthesis⁽³⁾. Therefore, pain management may be the only beneficial reason for applying ice to acute injuries. While this is vital, as clinicians can use it to initiate appropriate rehabilitation early, they must consider the long-term physiological consequences. 

Practical Implications

Sports medicine professionals should approach the use of cryotherapy with caution. While cryotherapy can benefit short-term pain relief in the initial hours following an injury, its prolonged use may interfere with the healing processes⁽¹⁾. Therefore, cryotherapy should be recommended immediately post-injury to manage pain and possibly reduce hematoma, but its use beyond the initial 12 hours should be carefully considered (see table 1).

Table 1: Practical Recommendations for Cryotherapy

Conclusion

Sports medicine practitioners use cryotherapy widely, primarily for its analgesic effects. However, the lack of human studies and the conflicting results from animal studies highlight the need for caution in its application. They should balance the immediate benefits of pain relief with the potential long-term impacts on tissue healing. More research is needed to establish evidence-based protocols for effectively using cryotherapy to treat athletes’ soft tissue injuries. Changing public perceptions to ensure adequate use of cryotherapy will take time, and clinicians will play a vital role in ensuring accurate and up-to-date information for athletes to optimize their recovery. 

References

1. Eur J Appl Physiol. 2021;121:2125-42.
2. Br J Sports Med. 2024;58:1215-1223.
3. Saudi J Sports Med. 2020;20:1-5.
4. J Athl Train. 2004;39(3):273-278.