16/06/2025
Hot off the Press 🔥
Practical recommendations on stretching exercise: A Delphi consensus statement of international research experts
📘 A brand-new study by Warneke et al. (2025, https://www.sciencedirect.com/science/article/pii/S2095254625000468), published in the Journal of Sport and Health Science, provides evidence-based guidelines on stretching applications for healthy populations. Utilizing a Delphi consensus method, a panel of 20 international experts synthesized systematic reviews to address inconsistencies in stretching definitions and applications. This study responds to challenges highlighted by prior reviews, such as methodological heterogeneity in stretching research (Medeiros & Lima, 2017) and inconsistent definitions across studies (Afonso et al., 2024).
🔑 Key references guiding the consensus include
➡️Behm et al. (2016) for acute stretching effects on performance and range of motion (ROM),
➡️Konrad et al. (2024) for chronic ROM effects,
➡️Thomas et al. (2021) for cardiovascular impacts, and
➡️Warneke & Lohmann (2024) for stretch-induced force deficits.
The consensus aims to provide clear definitions, practical recommendations, and identify research gaps for stretching applications in athletic and clinical settings.
Background and Objectives 📘
Stretching is a widely adopted practice to enhance flexibility, prevent injuries, promote recovery, and improve strength, muscle hypertrophy, and cardiovascular health. However, conflicting evidence and non-standardized definitions have created confusion in its application. This study used a Delphi consensus process to establish uniform definitions for static, dynamic, and proprioceptive neuromuscular facilitation (PNF) stretching and to develop evidence-based recommendations across eight key areas: acute and chronic effects on ROM, strength performance, muscle hypertrophy, muscle stiffness, injury prevention, post-exercise recovery, posture correction, and cardiovascular health.
Methods 🔬
A panel of 20 experts from 12 countries, selected based on a minimum of five peer-reviewed articles on stretching, conducted a three-step Delphi process:
1. Evidence Review: Systematic reviews were sourced from Web of Science, PubMed, and Scopus to form an evidence base for the eight topics.
2. Stretching Definitions: Consensus on definitions for static, dynamic, and PNF stretching was achieved through iterative rounds, requiring at least 80% agreement.
3. Clinical Recommendations: Evidence-based guidelines were developed for each topic, also requiring 80% consensus, with additional remarks to contextualize findings.
Results📊
Stretching Definitions ✅
After three Delphi rounds, the panel agreed on the following definitions:
▶️ Static Stretching (SS, 90% agreement): Elongates soft tissues (muscles, tendons, etc.) beyond slack length by holding a joint position, inducing passive resistance, stretch sensation, or discomfort. It can be assisted (external force) or unassisted.
▶️ Dynamic Stretching (80% agreement): Cyclic, unloaded motion elongating soft tissues without a static phase, reaching stretch sensation or tissue resistance. Ballistic stretching is a faster, less controlled variant.
▶️ PNF Stretching (85% agreement): Combines static stretching with submaximal-to-maximal muscle contractions, including contract-relax (CR), antagonist-contract (AC), and contract-relax-antagonist-contract (CRAC) methods.
Clinical Recommendations 💡
The panel reached consensus on the following recommendations after three rounds, unless otherwise noted:
1️⃣. ROM (Acute) (95% agreement) 🏃♂️
👉Recommendation: Perform at least 2 bouts of 5–30 s of stretching to acutely improve ROM, with no specific technique preferred due to similar effects across modalities.
👉Remarks: Alternatives like foam rolling, cycling, or eccentric resistance training are equally effective. Joint-specific responses vary (e.g., limited ankle dorsiflexion improvements due to bone configuration).
2️⃣. ROM (Chronic)(95% agreement) 🌱
👉 Recommendation: Use static or PNF stretching (2–3 sets, 30–120 s per muscle daily) for chronic flexibility gains, as they show larger effect sizes than dynamic stretching.
👉 Remarks: Full-ROM resistance training or foam rolling can achieve comparable ROM increases. No significant difference exists between high- and low-intensity stretches.
3️⃣. Strength Performance (Acute) (95% agreement) ⚠️
👉 Recommendation: Avoid prolonged static stretching (>60 s per muscle) before maximal or explosive contractions to prevent force deficits. Short-duration static or dynamic stretching within a dynamic warm-up is recommended instead.
👉 Remarks: Alternatives like foam rolling or jogging avoid force deficits. Careful planning is needed to balance ROM gains with performance.
4️⃣. Strength Performance (Chronic) (85% agreement) 💪
👉 Recommendation: Stretching is not a primary strategy for strength gains, but high-dosage static stretching (≥15 min per muscle, 5×/week for ≥6 weeks) may yield small benefits for those unable to perform resistance training.
👉 Remarks: Resistance training is more efficient. Stretching may aid rehabilitation or elderly populations, but intensity effects require further research. (s. https://link.springer.com/article/10.1007/s40279-025-02237-y)
5️⃣. Muscle Hypertrophy (90% agreement) 🏋️♀️
👉Recommendation: Stretching is not a primary strategy for hypertrophy, but daily static stretching (>15 min per muscle for ≥6 weeks) may induce small effects when resistance training is not feasible.
👉Remarks: Effects are small relative to time investment. Potential applications include sedentary populations or type 2 diabetes patients for blood glucose management.
6️⃣. Stiffness (Acute) (90% agreement) 🔧
👉 Recommendation: Use static stretching (>4 min per muscle) to acutely reduce muscle-tendon stiffness, as shorter durations or other techniques are less effective.
👉 Remarks: Stiffness reduction may impair stretch-shortening cycle performance. Limited evidence exists on deep fascia adaptations.
7️⃣. Stiffness (Chronic) (90% agreement) 🛠️
👉 Recommendation: Perform supervised, intensive static stretching (≥4 min per muscle, 5 days/week for ≥3 weeks) to chronically reduce muscle stiffness.
👉 Remarks: Stiffness reductions may have both positive and negative effects. Muscle stiffness decreases, but tendon stiffness remains unaffected, and fascia adaptations are understudied.
8️⃣. Injury Risk (85% agreement) 🚑
👉 Recommendation: Stretching is not recommended for general injury prevention. Static stretching may reduce muscle injury risk but may increase bone and joint injury risk.
👉 Remarks: Strength, stability, and postural control interventions are more effective. Limited studies suggest trade-offs in injury types, and acute effects are not well-studied.
9️⃣. Post-Exercise Recovery (100% agreement) 😴
👉 Recommendation: Stretching is not recommended for post-exercise recovery, as it does not reduce delayed onset muscle soreness (DOMS) or improve ROM or strength recovery.
👉 Remarks: DOMS may originate from fascia, not muscle, and is more common in untrained individuals. Stretching may have psychological benefits but lacks evidence for recovery.
🔟. Muscle Imbalance and Posture (100% agreement, 1 round) 🧍
👉 Recommendation: Stretching alone is not recommended for postural changes.
👉 Remarks: Combined stretching and strengthening is effective, but isolated stretching lacks evidence. Higher-volume stretching needs further exploration.
1️⃣1️⃣. Vascular System (Acute) (90% agreement) ❤️
👉Recommendation: Use 1 bout of ≥7 min of static stretching per muscle for acute circulatory benefits as a supplementary strategy.
👉 Remarks: Limited studies show benefits, but mechanisms (e.g., strain vs. autonomic balance) are unclear. Alternatives like foam rolling or light resistance training may be equally effective.
1️⃣2️⃣.Vascular System (Chronic) (95% agreement) 🩺
👉 Recommendation: Perform 15 min of static stretching per muscle, 5 days/week for ≥4 weeks, to reduce arterial stiffness, increase heart rate variability, and improve endothelial function, especially for those unable to perform active exercise.
👉 Remarks: Effects vary by body region, and clinical indications are premature. More research is needed on mechanisms and clinical populations.
Discussion 📊
The consensus provides standardized definitions and practical guidelines, addressing heterogeneity in stretching research. Stretching is effective for ROM and stiffness reduction but less so for strength, hypertrophy, injury prevention, recovery, or posture correction compared to alternatives like resistance training. Potential cardiovascular benefits are promising but require further study. The panel emphasizes the need for better dissemination of findings, as awareness of exercise guidelines is low (Hyde et al., 2019; Chen et al., 2023).
📸 Picture: Graphical summary of the final panel recommendations in the 8 topics. ↑ indicates stretching promotes measures; ↓indicates stretching declines measures; = means no effect; ? means that no clear evidence exist, * whether an improvement of stiffness can be equalized with a stiffness decrease depends on the specific setting. d/wk = days/week; HI = high intensity; PNF = proprioceptive neuromuscular facilitation; SS = static stretching.
📒 Key References
1. Afonso, J., Andrade, R., Rocha-Rodrigues, S., et al. (2024). Sports Medicine, 54, 1517–1551. [DOI: 10.1007/s40279-024-02007-3]
2. Behm, D. G., Blazevich, A. J., Kay, A. D., & McHugh, M. (2016). pplied Physiology, Nutrition, and Metabolism*, 41, 1–11. [DOI: 10.1139/apnm-2015-0235]
3. Konrad, A., Alizadeh, S., Daneshjoo, A., et al. (2024). Journal of Sport and Health Science, 13, 186–194. [DOI: 10.1016/j.jshs.2023.06.002]
4. Medeiros, D. M., & Lima, C. S. (2017). Human Movement Science, 54, 220–229. [DOI: 10.1016/j.humov.2017.05.006]
5. Thomas, E., Bellafiore, M., Gentile, A., Paoli, A., Palma, A., & Bianco, A. (2021). International Journal of Sports Medicine, 42, 481–493. [DOI: 10.1055/a-1312-7131]
6. Warneke, K., & Lohmann, L. H. (2024). Journal of Sport and Health Science, 13, 805–819. [DOI: 10.1016/j.jshs.2024.02.001]
7. Hyde, E. T., Omura, J. D., Watson, K. B., Fulton, J. E., & Carlson, S. A. (2019). Journal of Physical Activity and Health, 16, 616–622. [DOI: 10.1123/jpah.2018-0521]
8. Chen, T. J., Whitfield, G. P., Watson, K. B., et al. (2023). Journal of Physical Activity and Health, 20, 742–751. [DOI: 10.1123/jpah.2022-0067]
