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【English】Title: A Research Paper by Ms. Momoka Kinoshita (Alumna of SHS) Has Been Published in “Medicine & Science in Sports & Exercise”

Ms. Momoka Kinoshita, who graduated from the Faculty of Sport and Health Science in March 2025 and is currently a first-year master’s student at the University of Jyväskylä (Finland), has published a research paper entitled “Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press,” with Dr. Sumiaki Maeo, Assistant Professor, Dr. Tadao Isaka, Professor, and colleagues, both in the Faculty of Sport and Health Science, in the journal “Medicine & Science in Sports & Exercise.”

[Research Overview]

Maintaining and increasing muscle mass is essential for health and physical function. Among human muscles, the quadriceps femoris, located at the front of the thigh, is the largest muscle group and plays a critical role in daily movements such as walking, standing, and jumping, as well as in athletic performance. However, it has remained unclear whether single-joint exercises, which involve movement at one joint, or multi-joint exercises, which involve multiple joints, are more effective for increasing muscle mass.

In this study, two representative exercises targeting the quadriceps were directly compared: knee extension, a single-joint exercise, and leg press, a multi-joint exercise. Untrained young adults performed knee extension with one leg and leg press with the opposite leg for 12 weeks (2 sessions per week) under matched relative intensity and repetiton conditions. Muscle volume changes in 17 individual muscles, including those of the thigh and hip, were assessed before and after training using magnetic resonance imaging (MRI). In a separate experiment, electromyography (EMG) was used to evaluate muscle activation during each exercise.

The results showed that overall quadriceps muscle volume increased similarly with both exercises. However, the rectus femoris, a biarticular muscle spanning both the hip and knee joints, exhibited substantial hypertrophy following knee extension, whereas little hypertrophy was observed after leg press. In contrast, leg press induced significant hypertrophy not only in the quadriceps but also in the gluteus maximus and adductor muscles, particularly the adductor magnus, resulting in greater increases in total lower-limb muscle volume. EMG findings generally mirrored these differences, indicating that exercise-specific muscle activation patterns contribute to distinct hypertrophic responses.

This study provides practical evidence that leg press is a highly time-efficient exercise for increasing overall lower-limb muscle mass, while knee extension is essential for effectively targeting the rectus femoris, which is clinically relevant given its high susceptibility to strain injuries.

Journal website (open access):

https://journals.lww.com/acsm-msse/abstract/9900/hypertrophic_effects_of_single__versus_multi_joint.1002.aspx