Acute changes in gastrocnemius muscle stiffness following different work-rest calf-raise protocols and percussive therapy: A randomized crossover experimental study.
Eken &, Çiftçi R, Aldhahi M • Medicine • 2026
Work density altered acute gastrocnemius shear-wave elastography responses, with the highest-density 45-15 protocol producing the largest stiffness increase, and stiffness returned toward baseline during the postexercise percussive therapy recovery period, though PT-specific effects cannot be isolated from spontaneous recovery.
Key Findings
Results
A significant Time effect on medial gastrocnemius stiffness was observed across all calf-raise protocols.
F(2,58) = 51.51, P < .001, ηp2 = 0.64
SWE was measured at three timepoints: baseline (Pre), immediately postexercise (Acute), and after a 5-minute percussive therapy period (Post)
Thirty trained volleyball athletes (15 women, 15 men) participated in the crossover study
The large effect size (ηp2 = 0.64) indicates time accounted for a substantial portion of variance in stiffness changes
Results
A significant Time × Protocol interaction effect on gastrocnemius stiffness was observed, indicating that different work-rest configurations produced different stiffness response patterns over time.
F(4,116) = 7.16, P < .001, ηp2 = 0.20
Three protocols were compared: 30s work/30s rest (30-30), 15s work/45s rest (15-45), and 45s work/15s rest (45-15)
Sessions were randomized in a 3-period crossover design reported in accordance with CONSORT 2010 Statement and its extension for crossover trials
The interaction effect size was moderate (ηp2 = 0.20)
Results
The highest work-density protocol (45-15) produced the largest acute increase in gastrocnemius stiffness immediately after exercise.
45-15 protocol: acute increase of +0.22 m/s (95% CI: 0.20–0.24)
30-30 protocol: acute increase of +0.15 m/s (95% CI: 0.10–0.20)
15-45 protocol: acute increase of +0.08 m/s (95% CI: 0.05–0.12)
Stiffness was measured using shear-wave elastography (SWE), with values expressed in meters per second
The ordering of acute stiffness increases followed the ordering of work density across all three protocols
Results
Gastrocnemius stiffness decreased from the acute postexercise measurement to the post-percussive therapy measurement in all three protocols, with the largest reduction observed in the 45-15 protocol.
45-15 protocol: reduction of -0.32 m/s (95% CI: -0.40 to -0.24) from Acute to Post
Stiffness decreased toward baseline levels during the 5-minute percussive therapy recovery period in all protocols
No sham or passive recovery condition was included, so PT-specific effects cannot be isolated from spontaneous recovery
The largest reduction corresponded to the protocol that produced the largest acute increase
Methods
The study design included limb side and sex as exploratory factors examined cautiously.
The sample included 15 women and 15 men (total N = 30 trained volleyball athletes)
Limb side and sex were described as 'exploratory factors' and examined 'cautiously'
The randomized 3-period crossover design meant each participant completed all three protocol sessions
Estimated marginal means and 95% confidence intervals were reported for within-protocol contrasts
Discussion
The absence of a passive recovery or sham condition is identified as a key limitation preventing attribution of post-exercise stiffness reductions specifically to percussive therapy.
No sham or passive recovery condition was included in the study design
Authors explicitly state 'PT-specific effects cannot be isolated from spontaneous recovery'
This limitation was noted in both the abstract and presumably the Discussion section
The 5-minute PT recovery period followed immediately after the acute postexercise measurement
What This Means
This research suggests that how you structure the work and rest periods during calf-raise exercises significantly affects how stiff the calf muscle (specifically the medial gastrocnemius) becomes immediately afterward. Researchers had 30 trained volleyball players perform calf raises under three different timing conditions — equal work and rest (30 seconds each), more rest than work (15 seconds work, 45 seconds rest), and more work than rest (45 seconds work, 15 seconds rest) — and measured muscle stiffness using a specialized ultrasound technique called shear-wave elastography before exercise, immediately after, and following a 5-minute percussive therapy (massage gun) session.
The key finding was that the protocol with the most work relative to rest (45 seconds work, 15 seconds rest) caused the greatest spike in muscle stiffness right after exercise, while the protocol with the least work relative to rest (15 seconds work, 45 seconds rest) caused the smallest stiffness increase. In all three conditions, muscle stiffness appeared to decrease back toward pre-exercise levels after the percussive therapy session, with the biggest reduction again seen in the highest-intensity protocol.
This research suggests that athletes and coaches can expect greater acute muscle stiffness when performing high work-density exercise intervals, which could be relevant for planning recovery between training bouts or competitions. However, a notable limitation is that the study did not include a control condition where athletes simply rested without percussive therapy, so it is not possible to conclude that the massage gun itself was responsible for reducing stiffness — the muscle may have recovered on its own during that same 5-minute window. Future studies including a passive rest comparison would help clarify the specific contribution of percussive therapy devices to muscle recovery.
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Eken &, Çiftçi R, Aldhahi M. (2026). Acute changes in gastrocnemius muscle stiffness following different work-rest calf-raise protocols and percussive therapy: A randomized crossover experimental study.. Medicine. https://doi.org/10.1097/MD.0000000000050494