Knee flexion range of motion does not influence muscle hypertrophy of the quadriceps femoris during leg press training in resistance-trained individuals.
Stian Larsen, Milo Wolf, Brad J Schoenfeld, Nordis �� Sandberg, Andrea B Fredriksen, Benjamin S Kristiansen, Roland van den Tillaar, Paul A Swinton, Hallvard N Falch
Author Information
Stian Larsen: Department of Sports Science and Physical Education, Nord University, Levanger, Norway. ORCID
Milo Wolf: Department of Exercise Science and Recreation, Applied Muscle Development Lab, CUNY Lehman College, Bronx, NY, USA.
Brad J Schoenfeld: Department of Exercise Science and Recreation, Applied Muscle Development Lab, CUNY Lehman College, Bronx, NY, USA.
Nordis �� Sandberg: Department of Sports Science and Physical Education, Nord University, Levanger, Norway.
Andrea B Fredriksen: Department of Sports Science and Physical Education, Nord University, Levanger, Norway.
Benjamin S Kristiansen: Department of Sports Science and Physical Education, Nord University, Levanger, Norway.
Roland van den Tillaar: Department of Sports Science and Physical Education, Nord University, Levanger, Norway.
Paul A Swinton: Department of Sport and Exercise, School of Health Sciences, Robert Gordon University, Aberdeen, UK.
Hallvard N Falch: Department of Sports Science and Physical Education, Nord University, Levanger, Norway.
This study investigated the effect of knee flexion range of motion (ROM) during the leg press exercise on quadriceps femoris muscle hypertrophy in resistance-trained individuals. Twenty-three participants (training age: 7.2��������3.5���years) completed a within-participant design, performing four sets of unilateral leg presses to momentary failure twice weekly for 8 weeks. In one leg, the knee flexion range of motion (ROM) was fixed at approximately 5-100��, while for the other leg, participants used their maximum individualized ROM (5-154��������7.8��). Quadriceps muscle thickness was assessed via B-mode ultrasonography in the proximal, central, and distal regions of the mid- and lateral thighs. Bayesian analyses were conducted to quantify treatment effects and provide inferential estimates using credible intervals and Bayes Factors (BF). Univariate and multivariate analyses indicated 'moderate' (BF���=���0.14 to 0.22) and 'extreme' (BF���<���0.01) evidence in support of the null hypothesis, respectively. Within-condition analyses revealed small-to-medium hypertrophic adaptation in both conditions, with absolute increases ranging from 1.08���mm to 1.91���mm. These findings suggest that both knee flexion ROMs are similarly effective for promoting quadriceps femoris muscle hypertrophy over a relatively short training-period in resistance-trained individuals.
