Can Stretching or Training Remodel the Hamstring Aponeurosis?

Q: Why is this interesting?

The most surprising finding was that static stretching remodeled the aponeurosis to a similar extent as eccentric training, despite producing little or no muscle growth. This suggests that connective tissue responds differently to mechanical loading than muscle tissue and may adapt even without high-force contractions.

Q: What does this mean for Physiotherapists?*

- Eccentric training remains the standard for increasing hamstring strength and muscle mass. - However, static stretching may also stimulate beneficial adaptations of the hamstring aponeurosis, making it a potential option when high-load strengthening is not yet appropriate (e.g., during early rehabilitation). - Since the aponeurosis adaptations persisted after detraining, connective tissue may retain training-induced changes longer than muscle. - Whether these structural changes actually reduce hamstring injury risk still needs to be confirmed in future research.

3 days ago
2 min read

Hamstring strain injuries most commonly affect the biceps femoris long head, particularly near the myotendinous junction. While strengthening exercises are a cornerstone of injury prevention, the role of the aponeurosis (the connective tissue within and around the muscle) has received much less attention.

A recent MRI study compared 10 weeks of eccentric hamstring training (on a isokinetic dynamometer) with time-matched static stretching (maximal knee extension, for 3x ~68 seconds), in healthy, untrained men. Researchers measured changes in hamstring muscle volume and both the outer and inner aponeurosis before training, after training, and after four weeks of detraining.

Key Findings

Both eccentric training and static stretching significantly increased hamstring aponeurosis size.
Only eccentric training produced substantial muscle hypertrophy.
After 4 weeks without training, the increased aponeurosis dimensions were largely maintained, whereas muscle size declined following eccentric training (although it remained above baseline).
Changes in muscle size and aponeurosis size were largely unrelated, suggesting that muscle and connective tissue remodel independently.

Why is this interesting?

The most surprising finding was that static stretching remodeled the aponeurosis to a similar extent as eccentric training, despite producing little or no muscle growth. This suggests that connective tissue responds differently to mechanical loading than muscle tissue and may adapt even without high-force contractions.

What does this mean for Physiotherapists?*

Eccentric training remains the standard for increasing hamstring strength and muscle mass.
However, static stretching may also stimulate beneficial adaptations of the hamstring aponeurosis, making it a potential option when high-load strengthening is not yet appropriate (e.g., during early rehabilitation).
Since the aponeurosis adaptations persisted after detraining, connective tissue may retain training-induced changes longer than muscle.
Whether these structural changes actually reduce hamstring injury risk still needs to be confirmed in future research.

Source: C. Sahinis, R. Kawama, Y. Okuda, K. Takahashi, T. Wakahara, and E. Kellis, “ Training and Detraining Effects of Eccentric Exercise and Static Stretching on Hamstring Aponeurosis Dimensions,” Scandinavian Journal of Medicine & Science in Sports 36, no. 7 (2026): e70351, https://doi.org/10.1111/sms.70351

*Disclaimer: This document contains a summary and interpretation of scientific material and does not constitute an official representation of the original publication. No guarantee is made regarding the accuracy, completeness, or interpretation of the information presented. All responsibility for verifying the content and drawing conclusions from the original source rests with the reader. I expressly disclaim any liability for errors, inaccuracies, omissions, or any direct or indirect consequences arising from the use or reliance on this document.