Single-joint eccentric knee extension training preferentially trains the rectus femoris within the quadriceps muscles

Abstract

Eccentric contraction‐induced quadriceps strains, particularly in the rectus femoris (RF), frequently occur in sports. By using MRI‐based transverse relaxation time (T2) as an index of exercise‐induced muscle edema, previous studies found pronounced damage in RF after an acute single‐joint eccentric knee extension exercise. This study examined whether single‐joint eccentric knee extension training would preferentially train RF, resulting in greater hypertrophy of RF than the other quadriceps muscles. Twelve males conducted work‐matched single‐joint isokinetic (180°/s) maximal eccentric contractions of the knee extensors in one leg (ECC‐leg) and concentric in the other (CON‐leg), six sets/session (3‐5 sets in the initial 1‐3 sessions), two sessions/wk for 10 weeks. Muscle volume of each quadriceps was measured pre‐ and post‐training. T2 of each muscle was assessed weekly throughout the training period and pre‐ and post‐training. Muscle volume significantly increased in all muscles in ECC‐leg only, with a greater degree for RF (+7.3%) than the vasti (2.9%‐3.7%). T2 did not change in all muscles throughout. These results suggest that RF can be preferentially trained by single‐joint eccentric knee extension training. Cooperatively with the potential repeated bout effect (ie, protective effect) in eccentric exercise, this training modality would have positive implications for strain injury prevention of RF.

Triceps brachii hypertrophy is substantially greater after elbow extension training performed in the overhead versus neutral arm position

“…only the overhead condition is fine). On the other hand, there is some evidence that single‐joint (Maeo, Shan, Otsuka, Kanehisa, & Kawakami, 2018) and multi‐joint (Kubo, Ikebukuro, & Yata, 2019) exercises preferentially train biarticular and monoarticular muscles, respectively, the former of which is supported by this study. Thus, a combination of overhead elbow extension (single‐joint exercise) and lying dumbbell press (multi‐joint exercise) may further promote hypertrophy of the Whole‐TB.…”

Does Back Squat Exercise Lead to Regional Hypertrophy among Quadriceps Femoris Muscles?

“…They observed an increase in the volume of the gluteal and three vasti muscles; however, the hypertrophy of RF was not significant for either squat regimen. Similar findings were noted by Earp et al [ 12 ] and Zabaleta-Korta et al [ 13 ], where parallel squat RT resulted only in an increase in CSA of the vasti muscles, suggesting that for targeting the RF muscle, single-joint exercises may be a better option [ 14 ]. However, some of the recent studies have reported opposite results [ 15 , 16 , 17 ].…”

Physical preparation and return to performance of an elite female football player following ACL reconstruction: a journey to the FIFA Women’s World Cup

“…Throughout reconditioning (4-9.5 months; figure 2), we progressively integrated dynamic strength training (figure 9; online supplemental video 1) using predominately closed kinetic chain exercises except for the leg extensionspecifically to isolate eccentric knee extension. 38 Strength training biased the involved limb, progressively using a higher volume in unilateral strength exercises (ie, 5:2 sets ratio). 15 As neuromuscular performance deficits at joints other than the knee are associated with ACL injury risk, 39 40 we programmed accessory strength exercises (figure 9), and monitored isometric hip strength ( figure 7A).…”

“…Throughout reconditioning (4–9.5 months; figure 2 ), we progressively integrated dynamic strength training ( figure 9 ; online supplemental video 1 ) using predominately closed kinetic chain exercises except for the leg extension — specifically to isolate eccentric knee extension. 38 Strength training biased the involved limb, progressively using a higher volume in unilateral strength exercises (ie, 5:2 sets ratio). 15 …”