If you want to grow the inner part of your calf muscle, doing straight-leg calf raises might work better than seated ones.
Scientific Claim
In resistance-trained individuals, straight-leg plantar flexion exercises (e.g., straight-leg toe press) are more likely to increase medial gastrocnemius muscle thickness than seated calf raises, based on 8 weeks of training with a posterior probability of 0.991.
Original Statement
“Regarding the triceps surae, the point estimate favored straight-leg plantar flexion for muscle thickness of the medial gastrocnemius (P = 0.991), with equivocal results observed for the lateral gastrocnemius and soleus.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
probability
Can suggest probability/likelihood
Assessment Explanation
The RCT design supports causal inference, and the use of 'more likely' correctly reflects the probabilistic Bayesian evidence. The claim avoids overstatement by not claiming universal applicability.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aWhether straight-leg plantar flexion consistently produces greater medial gastrocnemius hypertrophy than seated calf raises across populations.
Whether straight-leg plantar flexion consistently produces greater medial gastrocnemius hypertrophy than seated calf raises across populations.
What This Would Prove
Whether straight-leg plantar flexion consistently produces greater medial gastrocnemius hypertrophy than seated calf raises across populations.
Ideal Study Design
A meta-analysis of 12+ RCTs (n≥40 per trial) comparing straight-leg vs. seated calf raises in resistance-trained adults (age 18–40), using MRI-measured medial gastrocnemius thickness as primary outcome, with standardized volume, intensity, and duration (6–12 weeks).
Limitation: Cannot determine if differences are due to muscle activation or fascicle length changes.
Randomized Controlled TrialLevel 1bIn EvidenceCausal effect of straight-leg vs. seated calf raises on medial gastrocnemius growth.
Causal effect of straight-leg vs. seated calf raises on medial gastrocnemius growth.
What This Would Prove
Causal effect of straight-leg vs. seated calf raises on medial gastrocnemius growth.
Ideal Study Design
A double-blind, crossover RCT with 30 resistance-trained adults (age 20–35), randomized to 8 weeks of straight-leg toe press or seated calf raise (3x/week, 4 sets, 10–15 reps, RPE 8–9), with MRI-measured medial gastrocnemius thickness as primary outcome and contralateral leg as within-subject control.
Limitation: Cannot eliminate performance bias if participants know exercise type.
Prospective Cohort StudyLevel 2bLong-term association between habitual straight-leg calf training and medial gastrocnemius size.
Long-term association between habitual straight-leg calf training and medial gastrocnemius size.
What This Would Prove
Long-term association between habitual straight-leg calf training and medial gastrocnemius size.
Ideal Study Design
A 2-year prospective cohort tracking 150 resistance-trained individuals who self-select straight-leg or seated calf raises as primary calf exercise, measuring medial gastrocnemius thickness via ultrasound every 6 months while controlling for total volume and diet.
Limitation: Cannot control for confounding variables like footwear or ankle mobility.
Evidence from Studies
Supporting (1)
Exercise Selection Differentially Influences Lower Body Regional Muscle Development
The study found that doing toe presses with straight legs made the inner part of the calf muscle grow more than doing seated calf raises, just like the claim said.