Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison between Knee Extension and Leg Press.
Level 2 - randomized trial
Within-subject controlled trial (contralateral limb design)
PubMed 41630124 · doi:10.1249/MSS.0000000000003957
What was done
Seventeen untrained adults completed a 12-week resistance training intervention (70% 1RM, 10 reps/set, 5 sets/session, 2 sessions/week). Each participant performed single-joint knee extension (KE) with one leg and multi-joint leg press (LP) with the contralateral leg. Pre- and post-training muscle volumes for 17 individual lower-limb muscles—including all four quadriceps femoris (QF) heads, gluteals, hamstrings, and adductors—were measured using magnetic resonance imaging (MRI). Surface electromyography was evaluated in a follow-up experiment to assess muscle excitation patterns.
What was found
Both KE and LP significantly increased whole QF and vasti muscle volumes (P <= 0.026). Total QF growth (+7.1% KE vs +4.9% LP) and vasti growth (+5.0% to +7.2% KE vs +4.4% to +6.2% LP) did not differ significantly between conditions (P >= 0.319). Rectus femoris volume increased significantly more with KE than LP (+13.2% vs +1.1%, P <= 0.001; LP rectus femoris growth was not statistically significant, P = 0.379). LP produced significant increases in the gluteus maximus (+15.4%) and adductor magnus (+6.2%) (P <= 0.001), which did not occur with KE. Surface electromyography mirrored these regional hypertrophic adaptations.
Why it matters
While the multi-joint leg press is time-efficient for building the vasti, gluteus maximus, and adductor magnus, it fails to meaningfully stimulate the rectus femoris. Single-joint knee extension is necessary to target rectus femoris hypertrophy, which may have clinical implications for strain injury prevention.
Limits
The study had a small sample size (n = 17) and was conducted exclusively in untrained adults, limiting generalizability to resistance-trained populations. Functional outcomes, such as sport-specific performance or injury rates, were not assessed.
Cited by
- context A study found that leg extensions preferentially hypertrophied the rectus femoris, whereas the leg press preferentially hypertrophied the vastus lateralis.