REF-318 · Wilke J, Schwiete C & Behringer M, 2022 · Journal of Sports Science and Medicine, · Paper · PubMed

Effects of Maximal Eccentric Exercise on Deep Fascia Stiffness of the Knee Flexors: A Pilot Study using Shear-Wave Elastography

After 6 × 10 maximal eccentric knee flexions in 19 active men, biceps femoris MUSCLE stiffness did not change but the overlying deep FASCIA stiffened (median 18 → 21.12 kPa at 24 h, 21.3 kPa at 72 h); the 24-h fascia change explained 22% of the pressure pain at 72 h

Blimited evidenceMeasured on recreational to trained athletesWritten before October 2026, being re-checked

Participants

n=19 healthy active male adults (27 ± 4 years)

Protocol

6 × 10 maximal eccentric knee flexions on an isokinetic dynamometer
Shear-wave elastography of the biceps femoris muscle AND its overlying deep fascia at baseline, immediately (T0), 1 h (T1) and daily up to 72 h (T24-T72)
Pain on palpation (100 mm VAS) as the DOMS surrogate

Key Results

Muscle stiffness remained unchanged at all time points (p > 0.05)
Deep fascia stiffness increased from baseline to T24 (median 18 → 21.12 kPa, p = 0.017) and to T72 (median 18 → 21.3 kPa, p = 0.001)
Linear regression: the fascia stiffness change at T24 was associated with pressure pain at T72 (r² = 0.22, p < 0.05)
Authors' conclusion: maximal eccentric exercise stiffens the fascia, and that stiffening is related to the magnitude of later DOMS

Mechanism

The tissue that stiffened after maximal eccentric work was the connective tissue layer over the muscle, not the muscle itself, and the size of that early stiffening tracked (weakly, r² = 0.22) how sore the site was two days later. Inference, not tested here: fascia is densely innervated, so a stiffened fascial layer is a plausible source of the pressure pain; the study measured stiffness and pain, not innervation or nociceptor activity.

Practical Application

In 19 active men, 60 maximal eccentric knee flexions left biceps femoris MUSCLE stiffness unchanged for 72 h while the deep fascia over it stiffened by roughly 3 kPa (median 18 → 21.12 kPa at 24 h, 21.3 kPa at 72 h); the 24-h fascia change explained 22% of the variance in pressure pain at 72 h
The "tight hamstring" after heavy eccentric work may be a fascial, not a muscular, event — which is why muscle-level measures (and muscle-targeted "release") can miss it
Fascia stiffness at 24 h carried some information about soreness at 72 h (r² = 0.22 — most of the variance is unexplained), so it is at best a weak early-warning signal, not a predictor to act on alone
Not from this paper; the base's own practice: foam rolling, dynamic mobility or manual therapy aimed at the connective tissue after eccentric-heavy sessions is a practice, not a finding — this study tested no intervention; the one manual-therapy trial in the base is Brandl 2024 REF-324

Limitations

Pilot study (n=19), uncontrolled, men only
Only knee flexors; only the biceps femoris and its fascia measured
Maximal eccentric — not submaximal endurance
r² = 0.22 for pain prediction — weak explanatory power
How this entry was checked and changed
Why this level

regraded 2026-09-27 from B+: uncontrolled pre-post pilot, n=19

Content correction 2026-09-27
Mechanism claims about "fascial nociceptors (free nerve endings in thoracolumbar fascia and epimysium)" -> not in the abstract; relabelled as untested inference.
"Reframes Bakken's muscle tone" and the recovery-modality recommendations -> relabelled as house practice (no intervention tested).
Level B+ -> B (uncontrolled pre-post pilot, n=19).