TY - JOUR

T1 - Rugby Players Exhibit Stiffer Biceps Femoris, Lower Biceps Femoris Fascicle Length to Knee Extensors, and Knee Flexors to Extensors Muscle Volume Ratios Than Active Controls

AU - Yagiz, Gokhan

AU - Shida, Nami

AU - Kuruma, Hironobu

AU - Furuta, Masahiro

AU - Morimoto, Koji

AU - Yamada, Mutsuo

AU - Uchiyama, Tatsuji

AU - Kubis, Hans-Peter

AU - Owen, Julian

PY - 2023/9

Y1 - 2023/9

N2 - Purpose: This study aimed to determine if hamstring-strain-injury risk factors related to muscle structure and morphologydiffered between rugby union players and controls. Methods: The biceps femoris long head (BFlh) fascicle length and passive muscle stiffness and relative and absolute muscle volume of knee flexors (KF) and extensors (KE) were measured in 21 male subelite rugby players and 21 male physically active nonathletes. Results: BFlh fascicle length was significantly longer (mean difference [MD] = 1.6 [1.7] cm) and BFlh passive muscle stiffness was significantly higher in rugby players (MD = 7.8 [14.8] kPa). The absolute BFlh (MD = 71.9 [73.3] cm3 ), KF (MD = 332.3 [337.2] cm3 ), and KE (MD = 956.3 [557.4] cm3 ) muscle volumes were also significantly higher in rugby players. There were no significant differences in the relative BFlh and KF muscle volumes. The relative KE muscle volumes were significantly higher in rugby players (MD = 2.3 [3.7] cm3/kg). However, the percentage BFlh fascicle length:KE (MD = −0.1% [0.1%]), BFlh/KE (MD = −0.9% [1.9%]), and KF:KE (MD = −4.9% [5.9%]) muscle volume ratios were significantly lower in the rugby players. BFlh muscle volume significantly correlated with BFlh fascicle length (r = .59, r 2 = .35) and passive muscle stiffness (r = .46, r 2 = .21). Conclusion: Future prospective studies should examine whether there are threshold values in BFlh passive muscle stiffness and BFlh fascicle length:KE, BFlh:KE, and KF:KE muscle volume ratios for predicting hamstring strain injuries.

AB - Purpose: This study aimed to determine if hamstring-strain-injury risk factors related to muscle structure and morphologydiffered between rugby union players and controls. Methods: The biceps femoris long head (BFlh) fascicle length and passive muscle stiffness and relative and absolute muscle volume of knee flexors (KF) and extensors (KE) were measured in 21 male subelite rugby players and 21 male physically active nonathletes. Results: BFlh fascicle length was significantly longer (mean difference [MD] = 1.6 [1.7] cm) and BFlh passive muscle stiffness was significantly higher in rugby players (MD = 7.8 [14.8] kPa). The absolute BFlh (MD = 71.9 [73.3] cm3 ), KF (MD = 332.3 [337.2] cm3 ), and KE (MD = 956.3 [557.4] cm3 ) muscle volumes were also significantly higher in rugby players. There were no significant differences in the relative BFlh and KF muscle volumes. The relative KE muscle volumes were significantly higher in rugby players (MD = 2.3 [3.7] cm3/kg). However, the percentage BFlh fascicle length:KE (MD = −0.1% [0.1%]), BFlh/KE (MD = −0.9% [1.9%]), and KF:KE (MD = −4.9% [5.9%]) muscle volume ratios were significantly lower in the rugby players. BFlh muscle volume significantly correlated with BFlh fascicle length (r = .59, r 2 = .35) and passive muscle stiffness (r = .46, r 2 = .21). Conclusion: Future prospective studies should examine whether there are threshold values in BFlh passive muscle stiffness and BFlh fascicle length:KE, BFlh:KE, and KF:KE muscle volume ratios for predicting hamstring strain injuries.

U2 - 10.1123/ijspp.2023-0077

DO - 10.1123/ijspp.2023-0077

M3 - Article

VL - 18

SP - 1030

EP - 1037

JO - International Journal of Sports Physiology and Performance

JF - International Journal of Sports Physiology and Performance

SN - 1555-0265

IS - 9

ER -